Patent Application
20250205146
The present invention relates to the field of drug-delivery systems.
In particular, it relates to a device for mucosal and transmucosal drug delivery providing a controlled release of active pharmaceutical ingredients.
Drug delivery devices with either one-time release, for example for an acute treatment, or long-term operation, for example for chronic treatments, over 2-12 months, are known.
For example US20190091061A1 discloses a drug-delivery system for the treatment of sleep disorders comprising a removable mandibular device with a pharmaceutical compound reservoir for drug release to the oral mucosa upon electrical stimulation.
U.S. Pat. No. 7,070,590B1 discloses a drug-delivery microchip system, based on reservoirs for subcutaneous drug release via an implantable device. This drug-release system is based on passive principles, i.e. drugs diffusion, upon opening the reservoir cap, and active principles, i.e. ion-exchange properties.
Also the use of electrical stimuli was previously proposed to actuate the drug reservoirs, in passive release or ion-responsive drug release systems.
For example, CN102641547 discloses an intraluminal device for transmucosal drug delivery comprising a drug-dispensing portion and an electrically drivable portion which can be operated to dispense the drug from the housing to the area of the mucosal barrier layer that is partially destroyed by the electrically drivable portion.
Similarly, EP2311522 discloses a transmucosal delivery device comprising a drug reservoir and an electrically-actuatable portion.
However, the systems of the prior art do not allow to finely regulate and control the rate, timing and speed of drug release.
Also known in the prior art are reservoirs usually suitable for either one single or several drugs storage. However, in such devices the release actuation cannot be specified independently for each drug, see for example the transmucosal device described in US2014207111.
Most of commercial transmucosal pharmaceutical formulations contain polymer composites that play an important role as a vehicle in the drug-delivery formulations, by providing controlled release of pharmacologic agents. For example in US2021030693 the drug is dispersed on a polymeric film which controls the release of the drug. However, due to its high density the availability of the drug for immediate release to the mucosal membranes progresses slowly.
In view of the above, it is still needed a drug delivery system which is finely tunable and useful for both short- and long-term release profiles, suitable for either one single or several drugs administration, with various dosages.
It has now been found a programmable device for transmucosal drug delivery, optionally coupled with a nanoelectrochemical system, for controlled release of active pharmaceutical ingredients which is particularly useful for on-demand drug administration. The present invention takes advantage of the electrical conductivity properties of graphene, and of its potential to operate as a drug- and electron-carrier, to create a programmable drug delivery.
These properties provide a miniaturized tunable drug-delivery device, capable of finely regulating rate, timing, and speed of drug release.
The role of graphene as drug carrier for drug delivery system has been explored (see for example WO 2017/066583 A1; CN109464397). It has been also described that graphene-based materials are able to cross physiological barriers (Fadeel et al., 2018 doi: 10.1021/acsnano.8b04758).
However, it is known that graphene can elicit organ toxicity effects in the biological system by accumulating in the lung, liver and spleen (Ou et al., 2016, doi: 10.1186/s12989-016-0168-y).
Therefore, the administration of drugs composition comprising graphene can be dangerous and cause toxic effects in the user.
It has now been found a drug delivery system wherein only drugs are released to mucosa/submucosa region, while graphene nanoparticles are either kept inside the reservoir or be prevented to reach the mucosa through current-controlled nanomagnetic field that prevents the absorption of the graphene-based magnetic sheets to the biological system, avoiding toxicity.
In particular embodiments, the device of the invention enables extraction of mucosa and submucosa body fluids throughout microneedles controlled by an electromagnetic element for biometric signals measurement based on sensor system.
Biometric signals can be processed by an electronic device, for example by machine learning techniques, to integrate the subjective and interactive evaluation of the user's need of drug delivery device intervention with an objective estimate of the biometric signal processing.
The drug delivery device of the invention allows a controlled retainment and release of drugs for extended periods of time, as well as of an immediate release for quick action of drugs at different doses, on an as-needed basis. Therefore, the present innovation allows both immediate-release system and zero-order release system improving pharmacokinetics of mucosa drug release.
It has been found a drug delivery system which uses graphene or derivatives thereof as a platform for loading agents via non-covalent interaction and enabling the release of active pharmaceutical ingredients in response to an applied electric potential, at the same time preventing the potential organ toxicity caused by the accumulation of graphene in vital organ when injected systemically. With the device of the invention it is possible to control the speed and dose of the released agent by electrochemical system, indeed application of a low voltage break the pi-interaction resulting in adsorption of the active pharmaceutical ingredient.
The capability of the device of the invention to deliver a drug loaded on graphene or a derivative thereof with a modulatory electro-responsive release was demonstrated with caffeine and ibuprofen, however it can be applied to organic and inorganic molecules, polar, apolar, aromatic or non-aromatic pharmaceutical ingredients as well.
It is an object of the present invention, a drug delivery device for mucosal and/or transmucosal drug delivery comprising at least one drug reservoir, said drug reservoir comprising:
In an embodiment, the presence of the filter advantageously prevents the graphene and/or derivative thereof to leave the drug reservoir and reach the mucosa.
In another embodiment, graphene and/or its derivatives are functionalised with magnetic nanoparticles and a current-controlled nanomagnetic field is used, after release of the pharmaceutical ingredient from the complex with graphene, to maintain graphene-based magnetic nanoparticles inside the drug reservoir so that they, advantageously, do not reach the mucosa.
In a preferred embodiment, the pharmaceutical ingredient is loaded on graphene oxide.
In an embodiment, the release of said active pharmaceutical ingredient from graphene and/or its derivatives occurs upon electrochemical reaction.
In a preferred embodiment, said drug reservoir further comprises an electromagnetic element and said microcontroller further delivers a current-controlled magnetic field through said electromagnetic element.
In a preferred embodiment, said drug reservoir further comprises at least one electrode and said microcontroller delivers electric current through said at least one electrode.
The device of the invention provides the following main advantages:
The device of the invention is as defined in the claims.
Embodiments illustrating the invention will be discussed with reference to the following figures.
Within the meaning of the present invention, for drug delivery device is herein intended a device suitable for the delivery of one or more drugs.
Within the present invention, “active pharmaceutical ingredient” “drug” and “active ingredient” are used as synonyms.
The present invention provides a device for mucosal drug delivery and transmucosal drug delivery. The term “mucosal drug delivery” refers to the release of one or more drugs to any kind of mucosa of a subject for subsequent mucosa absorption. The term “transmucosal drug delivery” refers to the delivery of one or more drugs to any kind of mucosa of a subject that enables the introduction of the active pharmaceutical ingredient at the submucosal level. Said mucosa can be for example oral, nasal or urogenital mucosa.
The device of the invention comprises one or more drug reservoirs. The drug reservoirs can be commercially obtained or manufactured according to methods commonly known in the art, see for example US20080047926A1. Typically, drug reservoirs are embedded in a matrix able to separate the drug reservoirs one from the other and to provide electrical insulation. The matrix can be commercially obtained or manufactured according to methods commonly known in the art, see for example US20080047926A1. Preferably, the matrix can be of non-conductive polymers and ceramics, such as epoxy or epoxy resins, silicon dioxide and silicon carbide providing support for the drug reservoirs. The drug reservoirs are positioned in the matrix in such a way to face the mucosa when the device is used in a subject, typically to be in touch with the mucosa. So typically each drug reservoir has at least one side configured to face the mucosa of a subject. The drug reservoir has typically the shape of a cube or of a parallelepiped but other shapes are also suitable. Each side of the drug reservoir may have a length comprised between 10 mm and 50 mm.
The drug reservoir typically comprises a solvent in which the graphene and/or its derivatives and optionally further compounds are dispersed. For “solvent” it is intended a liquid or gel medium wherein graphene or its derivatives can remain individually dispersed among the solvent molecules. The solvent can be liquid, such as water, physiological saline, ethanol, 1-propanol, ethylene glycol, dimethyl sulfoxide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, tetrahydrofuran and/or gel such as tragacanth, pectin, starch, carbomer, sodium alginate, gelatin, cellulose derivatives, polyvinyl alcohol within a liquid vehicle such as aqueous, hydroalcoholic, alcohol based or non-aqueous.
Each drug reservoir comprises one or more active ingredients loaded on graphene and/or its derivatives. Graphene derivatives are compounds derived from graphene, which have chemical composition and physical properties similar to graphene, but have been modified or functionalized. Derivatives of graphene include graphene oxide and graphene modified by covalent and non-covalent functionalization.
Exemplary derivatives of graphene are graphene oxide, reduced graphene oxide, hydrogenated graphene, graphane, graphone, graphyne, graphdiyne, fluorographene.
Graphene and derivatives of graphene can be modified by covalent and non-covalent functionalization with organic and inorganic molecules, for example with proteins, peptides, fenilamina, polymers or magnetic nanoparticles, as described hereinafter. For example graphene can be covalently functionalized with ferric sulfate.
In a preferred embodiment, the active ingredient is loaded on graphene oxide.
For graphene oxide it is intended a compound of carbon, oxygen, and hydrogen in variable ratios, typically obtained by oxidation and exfoliation of graphite sheets.
Graphene and its derivatives, such as graphene oxide, can be commercially obtained or manufactured according to methods commonly known in the art (see for example Andrade et al., 2021; Paulchamy et al., 2015).
Preferably, graphene or its derivatives are in the form of one or more layers sheets, preferably having a thickness of about 1-9 nm with lateral size distribution of about 0.1 μm-5 mm, for example 0.5 μm-1 mm.
As mentioned above, graphene and/or its derivatives can be dispersed in a solvent. Reference can be made for example to Jasim et al., 2016; Liu et al., 2013; Paredes et al., 2008.
The pharmaceutical active ingredient is loaded on graphene and/or its derivatives according to common methods known in the art, see for example Abdelhamid and Hussein, 2021; Masoudipour et al., 2017. For “loaded on” it is intended that the pharmaceutical ingredient is attached to graphene and/or its derivatives via non-covalent interactions. Typically, the pharmaceutical active ingredient is attached to graphene and/or its derivatives via non-covalent functionalization, see for example Georgakilas et al., 2016.
More than one active pharmaceutical ingredient can be loaded on graphene and/or its derivatives in the same drug reservoir. For example, two or three active ingredients can be loaded on the same graphene sheet.
In an embodiment, graphene, in particular graphene oxide, after the loading with the desired pharmaceutical ingredient(s) can be coated by one or more polymers such as, but not limited to, polyethylene glycol, poly(pyrrole), poly(ethylene oxide), poly(propylene oxide), poly(vinyl alcohol), polylactic acid, polyacrylic acid, poly lactic-co-glycolic acid and chitosan, thus forming a polymer nanocomposite. Polymer nanocomposite comprising graphene coated by a polymer can be obtained according to common methods known in the art, see for example Singh et al., 2012. For polymer nanocomposite it is intended a polymer or copolymer as a composite material comprising a polymer matrix having graphene and/or its derivatives as a dispersed nanofiller appropriately distributed in the polymer matrix wherein at least one dimension of the matrix is in the range of 1-100 nm (see for example Lawal et al., 2020). The presence of the polymer advantageously provides additional stability for the drug to be released and can also function as a vehicle for the drug, as described in Yi et al., 2020. The polymer nanocomposites can or can not be released from the reservoir together with the active ingredient.
Coating of the graphene with the polymer occurs as known in the art see for example Ahmad et al., 2019; Pei et al., 2020, for example by way of dispersion methods producing noncovalent functionalized composites.
In some embodiments, graphene sheets are functionalised with one or more magnetic nanoparticles comprising for example Fe3O4 (magnetite), γ-Fe2O3 (maghemite), magnetic chitosan composites and Fe3O4/SiO2 (magnetite-silica coated surface). Coating of graphene with magnetic nanoparticles occurs before graphene is loaded with the desired pharmaceutical ingredient(s).
Coating of graphene with magnetic nanoparticles occurs as known in the art, typically it is produced by way of covalent synthesis methods, see for example Huang et al., 2020; Yang et al., 2015. Graphene-based magnetic nanoparticles may provide large surface area for functionalization, magnetism and high carrier mobility for delivering macromolecules active pharmaceutical ingredients, which are generally not well absorbed through the mucosa, across the mucosa membrane.
The drug reservoir can further comprise one or more compounds useful for improving drug formulation preparation and mucosal permeability as described in the art (Sharma et al., 2006; Davis and Illum, 2003). Such compounds can be one or more of excipients, surfactants, preservatives, stabilizers, chelating agents, enzyme inhibitors, antibacterial agents such as, sodium taurodihydrofusidate, sugar, sodium glycocholate, lecithins, polycarbophil, didecanoyl-1-alpha-phosphatidylcholine, dioctylsulphosuccinate, methylcellulose, chitosan and chitosan derivative, cyclodextrins, polysorbate-80, polyethyleneglycol-8-laurate, glyceryl monolaurate, laurenth-9, lysophosphatidyl choline and palmitoylcarnitine chloride, benzalkonium chloride. Such further compound can be included in the solvent. If two or more further compounds are present, they can be included in the solvent as a homogeneous mixture.
In an embodiment, such compounds useful for improving drug formulation preparation and mucosal permeability can be included in a compartment inside the drug reservoir.
The drug reservoir further comprises a microcontroller which is usually at one end of the drug reservoir, preferably at the end opposite to the portion of the drug reservoir which is configured to face the mucosa. The microcontroller is able to deliver an electrical current and/or a current-controlled magnetic field to the inner portion of the drug reservoir, containing the graphene loaded with the active ingredient.
In a preferred embodiment, the microcontroller delivers electrical current to the inner portion of the drug reservoir through at least one electrode, preferably two electrodes, preferably located on opposite walls of the drug reservoir.
In another preferred embodiment, the microcontroller delivers a current-controlled magnetic field to the inner portion of the drug reservoir through an electromagnetic element. Such electromagnetic element can be a solenoid, toroid, electromagnet or electromagnetic coil, preferably it is a solenoid.
The microcontroller is also able to connect via radio signals, e.g. near field communication, radio-frequency identification and wireless network interconnecting via wireless personal area network or local area network, with an electronic device such as a smart-phone, a tablet or a personal computer as described by Farra et al., 2012. The user can modulate from the electronic device the kind and timing of deliver of electrical stimulus released from the microcontroller and consequently control the drug release. Advantageously, the user can thus easily configure the timing and rate of drug release from the electronic device and the drug can be released in a programmable on-demand fashion. The electronic device typically has an interface allowing the user to control and schedule the desired drug administration.
In an embodiment, the microcontroller is connected to two electrodes (an anode and a cathode), enabling the delivery of an electrical current upon wireless signal by a connected electronic device. The electrodes can be commercially obtained or manufactured according to methods commonly known in the art (Guo et al., 2016). Preferably, the electrodes are placed on opposite walls of the reservoir. The potential applied by the microcontroller is used to induce electrolysis, which determines the release of the pharmaceutical ingredient(s) from the graphene and its derivatives by desorption. Such electrolysis may occur in presence of electrolytes.
In an embodiment, the device further comprises one or more electrolyte compartment embedded in the same matrix in which the drug reservoirs are embedded. Electrolyte compartment may be filled with electrolyte solution, which preferably comprises one or more of physiological sodium chloride, dimethyl sulfoxide, ringer's solution, lactated ringer's solution, phosphate-buffered saline, Hank's balanced salt solution, glycerol, ethanol or poly (ethylene glycol)-grafted chitosan.
Electrolyte compartment may be placed adjacent to the drug reservoir and preferably separated from it by a stimuli-responsive polymeric wall. Said stimuli-responsive polymer wall can comprise a polymer such as polypyrrole, poly(3,4-ethylenedioxythiophene), poly(N-isopropylacrylamide), poly(lactic-co-glycolic acid), polyethylene glycol, chitosan/Fe3O4, polypyrrole-chitosan or xanthan/Fe3O4.
In an embodiment, the electrolyte compartment further comprises a cathode which, when receiving a signal from the microcontroller, delivers electrical stimulus to said stimuli-responsive polymer wall. In this embodiment, said wall functions as an anode and under electrical stimulus can disintegrate or modify its structure in the form of porous, allowing the electrolytes pass through the polymer wall reaching inside the reservoir. Advantageously, once inside the reservoir, such electrolyte may facilitate the flow of charge between the two reservoir electrodes, allowing the electrochemical reaction to proceed. Electrochemical reaction is defined as electrolysis process, at which an external source of electrical current is used to drive a non-spontaneous redox reaction. The electrochemical reaction is able to break the bonds between the drug-conjugated graphene compound present in the drug reservoir, promptly releasing the active pharmaceutical ingredients from graphene and its derivatives. In one embodiment the electrolyte may facilitate the production of hydrogen gas inside the reservoir, which may affect the electrostatic, hydrophobic and π-π interactions between active pharmaceutical ingredients and graphene and its derivatives allowing the releasing process. Moreover, the hydrogen gas formation may lead to an increasing of the pressure inside the reservoir, advantageously allowing a quick extravasation of the pharmaceutical ingredients out of the reservoir.
In an embodiment, the drug reservoir further comprises an excipient compartment placed adjacent to the compartment comprising the active pharmaceutical ingredient loaded on graphene, on the side opposite to the microcontroller, and separated by the compartment comprising the active pharmaceutical ingredient loaded on graphene by a nanofilter. Said further compartment comprises one or more excipients that may enhance the bioavailability of the active pharmaceutical ingredients. The excipient can be chosen among the excipients known in the pharmaceutical field.
For microcontroller is intended a small computer on a single VLSI integrated circuit (IC) chip. In an embodiment, the microcontroller is or comprises a microprocessor.
In a preferred embodiment, the microcontroller is a battery-operated miniaturized digital embedded electronic system. Battery is preferably rechargeable by wireless power transfer, but it may be disposable. The microcontroller can comprise battery-charge regulation and control, low-power wireless Bluetooth data transfer, and analog real-time operation as one- or two-channel voltage-controlled or current-controlled stimulus isolator. Such microcontroller is commercially available as standard off-the-shelf microcontroller or can be manufactured according to common general knowledge in the field, see for example Abadal et al., 2013; Furniturewalla et al., 2018; Kang et al., 2021; Lukas et al., 2019. The microcontroller can generate repeated biphasic voltage or current pulses, for example with amplitudes in the range of 0-5V, which are able to reach the graphene sheets. Repetition rates are preferably programmable, typically in the range 0-50 Hz, allowing advantageously to determine the desired drug-delivery concentration profile.
The drug reservoir can further comprise one or more electromagnetic device, such as a solenoid, able to deliver a magnetic field upon electrical control. In an embodiment said electromagnetic device is located inside the drug reservoir, preferably on the opposite side with respect to the microcontroller. In another embodiment said electromagnetic device surrounds the drug reservoir. Such electromagnetic device can be connected to the microcontroller from which it may receive signals. For example one or more electromagnetic solenoid can be present on the opposite side of the microcontroller. In an embodiment, the microcontroller is connected to an electromagnetic solenoid through a relay module, which is an electromechanical switch used to turn the solenoid on or off. It typically consists of a coil and a set of contacts. The electromagnetic solenoid can be commercially obtained or manufactured according to methods commonly known in the art (Khalifa et al., 2021).
The invention will be now further described with reference to the enclosed figures.
With reference to
In an example of functioning of the device of the invention, the microcontroller 7 receives a signal from an electronic device, e.g. a smartphone 8, to deliver electrical current.
The electrical current determines the release of the pharmaceutical ingredient(s) conjugated to the graphene oxide from the drug reservoir. Intensity and timing of the electrical stimuli determine different modalities of release of the drug and they can be operated by a user through an electronical device connected to the microcontroller. With regard to the modulation of the drug release through electrical stimulation reference can be made to the work of Weaver et al., 2014. For example electrically controlled release of active pharmaceutical ingredients can be achieved under an applied voltage of −0.5 V for 5 s followed by 0.5 V for 5 s delivered by the microcontroller (see Wu et al., 2015; Reddy et al., 2018; Weaver et al. 2014, Hou et al., 2020). Such electrical stimulus may affect the electrostatic, hydrophobic and π-π interactions between active pharmaceutical ingredients and graphene oxide and its derivatives allowing the releasing process, see for example Weaver 2014.
The electronical device may be orchestrated by an application software upon a command signal to generate a voltage impulse delivered by the microcontroller.
Application software can be based on responsive web design as known in the art (Weichbroth, 2020), e.g. follow IEEE guidelines for mobile app design. The application software can display information about the operating system such as controller of dose or programming the time period of the drug to be delivery. Application software may also be used for monitoring the drug delivery device status such as amount of drug in the reservoir, a log of previous drug deliveries including the amount and time of drug delivered.
The microcontroller may also generate a signal to be transmitted to the electronic device after the drug delivery operation to confirm the appropriated delivery of the drug. Information can be transmitted by the electronic device to other electronic devices upon an appropriate command.
With reference to
With reference to
The reservoir also comprises a filter cover 12 placed on top of the nanofilter 11 which separates the reservoir content from the filter. Such filter cover may be preferably made of a stimuli-responsive polymer such as polypyrrole, poly(3,4-ethylenedioxythiophene), poly(N-isopropylacrylamide), poly(lactic-co-glycolic acid), polyethylene glycol, chitosan/Fe3O4, polypyrrole-chitosan or xanthan/Fe3O4 optionally combined with one or more metals such as copper, gold, silver, and zinc.
On both sides of the filter cover electrodes 13 are present. When an electrical current is applied from the microcontroller the electrode 13 functions as cathode and the filter cover 12 functions as anode where the oxidation reaction occurs, thus advantageously allowing to control the time of filtering of the reservoir content. The electrode preferably comprises a metal or non-metal material, such as copper, gold, silver, platinum, carbon or graphite.
The drug reservoir also comprises an excipient compartment 14 placed adjacent to the filter and comprising one or more excipients that may enhance the bioavailability of the active pharmaceutical ingredients.
The device of the invention 1 also comprises an electrolyte compartment 15 embedded in the matrix 3. Electrolyte compartment may be filled with electrolyte solution, which preferably comprises one or more of physiological sodium chloride, dimethyl sulfoxide, ringer's solution, lactated ringer's solution, phosphate-buffered saline, Hank's balanced salt solution. Electrolyte compartment may be separated from the drug reservoir by a stimuli-responsive polymer wall 29, made of for example of polypyrrole, poly(3,4-ethylenedioxythiophene), poly(N-isopropylacrylamide), poly(lactic-co-glycolic acid), polyethylene glycol, chitosan/Fe3O4, polypyrrole-chitosan or xanthan/Fe3O4. Electrolyte compartment may also comprise of cathode 17 to delivery electrical stimulus to the stimuli-responsive polymer wall, which under electrical stimulus leads to a disintegration or porous formation, allowing the electrolytes pass through the polymer wall reaching inside the reservoir. Such electrolytes may facilitate the flow of charge between the two reservoir electrodes, allowing the electrochemical reaction to proceed. Electrochemical reaction is defined as electrolysis process, at which an external source of electrical current is used to drive a non-spontaneous redox reaction. This process can be used to extract pharmaceutical ingredients from graphene and its derivatives or produce hydrogen gas, which may affect the electrostatic, hydrophobic and π-π interactions between active pharmaceutical ingredients and graphene and its derivatives allowing the releasing process.
In
The device of the invention 1 comprises several drug reservoirs 2 embedded in a matrix 3.
In the drug reservoir on the left (A) the microcontroller 7, controlled by an electronic device, delivers an electrical stimulus to the stimuli-responsive polymer wall of the electrolyte compartment 15, which under electrical stimulus leads to its disintegration or porous formation, allowing the electrolytes pass through the polymer wall and reaching inside the reservoir 16. Such electrolytes may facilitate the flow of charge between the two reservoir electrodes 9, allowing the electrolysis process. The microcontroller also delivers an electrical stimulus inside the drug reservoir 16 through two electrodes 9, an anode and a cathode, placed on opposite walls of reservoir 2. When the electrical stimulus is applied to the electrode the electrolysis starts. Electrodes are preferably made of metals such as copper, gold, silver, zinc, platinum, carbon or graphite.
Such electrolysis is an electrochemical reaction defined as an electric current that is sent through the electrolytes and into the dispersion of graphene 5 conjugated with pharmaceutical ingredients 4 in order to stimulate the flow of ions necessary to separate pharmaceutical ingredients and graphene and its derivatives sheets. During electrolysis, an oxidation-reduction reaction takes place at the electrodes as a result of the flow of electric current through the electrolyte solution. In some embodiments, electrolysis may also be used to produce hydrogen gas at the anode, which may affect the electrostatic, hydrophobic and π-π interactions between active pharmaceutical ingredients and graphene and its derivatives allowing the releasing process by desorption. Following such electrochemical reaction, the active ingredient 4 is released from graphene oxide 5. The polymer coating 6 can be released together with the active ingredient. A nano filter 11 is present at the end of the drug reservoir opposite to the microcontroller 7 allowing the exclusive release of the active ingredient. The reservoir also comprise a filter cover 12 placed on top of the filter, separating the reservoir content from the filter to control the time of filtering of the reservoir content. On both sides of the filter cover electrodes 13 are present. When an electrical current is applied from the microcontroller the electrode 13 functions as cathode and the filter cover 12 functions as anode where the oxidation reaction occurs, thus advantageously allowing to control the time of filtering of the reservoir content.
The reservoir also comprises an excipient compartment 14 placed adjacent to the filter to store excipients that may enhance the bioavailability of the active pharmaceutical ingredients.
Reservoir comprises a reservoir cap 10 located at the end of the drug reservoir which is configured to face the mucosa. Two electrodes 13, an anode and a cathode, are placed on opposite walls of the reservoir in contact with the reservoir cap. Electrical current can be delivered from these electrodes to the reservoir cup determining its disintegration, therefore allowing to control the release of the reservoir content and of the excipients to the mucosa.
In the drug reservoir on the right (B), graphene oxide sheets and its derivatives 5 loaded with the pharmaceutical ingredient 4 are conjugated with magnetic nanoparticles 17. The microcontroller 7, controlled by an electronic device, delivers an electrical stimulus inside the drug reservoir through the electrodes 9, an anode and a cathode, placed in the opposite walls of reservoir. When the electrical stimulus is applied to the electrode the electrochemical reaction starts. An electromagnet solenoid 18 is present on the side of the reservoir opposite to the microcontroller and connected to said microcontroller. The reservoir also comprises a gate 19 placed adjacent to the solenoid 18 and controlled by it allowing the opening and closing of the reservoir. Gate can be preferably of non-conductive polymers and ceramics, polyethylene, polypropylene, polystyrene, polyvinyl chloride, poly(methyl methacrylate), polyethylene terephthalate, polycarbonate, silicon dioxide and silicon carbide.
Reservoir also comprises a reservoir cap 10 located at the end of the drug reservoir which is configured to face the mucosa, controlling the time that reservoir content, and excipients are delivered to the mucosa thanks to the electrical stimulus received by the two electrodes 13, an anode and a cathode, placed on opposite walls of the reservoirs in contact with the reservoir cap.
In an example of functioning of the device, a first electric stimulus is operated by the microcontroller in order to deliver an electrical current to the stimuli-responsive polymer wall of the electrolyte compartment 15 through the cathode 9, which under electrical stimulus leads to a disintegration or porous formation of the wall, allowing the electrolytes pass through the polymer wall reaching inside the reservoir. A second electric stimulus is operated by the microcontroller inside the drug reservoir through the cathode 9 in order to induce the electrolysis process, which allows the release of the pharmaceutical ingredients from magnetic graphene nanoparticles. Subsequently, the electromagnet solenoid 18 is operated to attract the magnetic graphene nanoparticles, consequently preventing the release of the graphene-based magnetic sheets from the reservoir. When an electrical current passes through the electromagnetic solenoid, it generates a magnetic field, which exerts a force of attraction, pulling the magnetic graphene nanoparticles towards the solenoid. The solenoid frame is then operated by the microcontroller to activate the gate 19 by electrical stimulus, opening the reservoir and allowing only the pharmaceutical ingredients to reach the excipient compartment 14. After the pharmaceutical active ingredients have reached the excipient compartment, the reservoir gate is operated by the solenoid frame to close the reservoir, preventing the releasing of graphene sheets. Then, the electromagnet solenoid can be switched off. Finally, the reservoir cap can be disintegrated by electrical stimulus delivered by the microcontroller through the cathode pole 13, allowing the release of the pharmaceutical ingredients and excipients from the reservoir. Such embodiment of the reservoir is suitable for magnetic nanoparticles conjugated with graphene or its derivatives and loaded with pharmaceutical ingredient.
In an embodiment, the device of the invention comprises one or more sensor reservoirs. Each sensor reservoir comprises a first compartment comprising at least one microneedle configured to puncture the mucosa, and a second compartment separated from said first compartment by a matrix and comprising a microcontroller, an electromagnetic element connected to said microcontroller, at least one microplunger connected to said microneedle and operated by said electromagnetic element and an electrochemical biosensor. The electromagnetic element, which is preferably a solenoid frame, pulls the microneedles toward the mucosa through operation of the microplunger thus allowing the microneedles to reach the biological tissue and collect the body fluid. The solenoid then push the microplunger up so that the body fluid can reach the second compartment and the electrochemical biosensor. Preferably, more than one microneedle is present and they are typically arranged in an array. The body fluid can be or comprise mucosa body fluid, submucosa body fluid, epithelial mucosa, fluid mucosal, blood, saliva, seminal fluid, vaginal fluids, mucus and/or phlegm.
An electrochemical biosensor typically comprises a receptor for the biological element to be recognized, an electrochemical transducer that converts the biochemical reaction induced by the binding of the biological element in a measurable signal and a signal processing unit which provides the interpretation of the signal. Electrochemical biosensors, herein named also “biochemical sensors”, are of common use in the field and commercially available. The biological element recognized can be epithelial mucosa, fluid mucosal, blood, saliva, seminal fluid, vaginal fluids, mucus and phlegm. Electrochemical biosensors can provide information regarding the presence and quantity of an analyte in the biological element, such as gases, organic compounds, local cells, hormones, drug or its metabolites, enzymes, bacterial and viral pathogens, temperature, pH. Reference can be made for example to Kim et al., 2015; Slaughter and Kulkarni, 2017; Stevenson et al., 2019. Depending on the body fluid to be extracted, one or more suitable electrochemical biosensors may be used according to the general knowledge in the field.
The signals obtained by the biochemical sensors can be transmitted to an electronic device, such as a personal computer, a tablet or a smartphone. Said electronic device can be also connected with the microcontrollers embedded in the drug reservoirs.
The microcontroller has the same features described above in relation to the drug reservoir, in particular it is able to emit electrical stimulus.
The sensor reservoir is configured to be in contact with the mucosa when the device is used in a subject.
A particular embodiment of a sensor reservoir is herein described with reference to
In an example of functioning of the sensor reservoir of the invention, the microcontroller delivers an electrical current to the solenoid frame to operate the solenoid plunger. The solenoid frame moves the solenoid plunger down, pulling the microneedle toward the mucosa thus allowing the microneedle to reach the biological tissue to collect the body fluid. The plunger is then moved up by the solenoid to suck the body fluid which can then reach the electrochemical biosensor. The microcontroller 7 is able to connect with an electronic device through which the emission of electrical stimulus and consequently the movement of the microneedles are controlled.
Another object of the invention is an integrated system comprising:
The biosensor system can be a device suitable to be applied to the mucosa of a subject comprising one or more sensor reservoirs as above described.
In an embodiment, the biosensor system is located on said drug delivery device.
In other embodiments, the biosensor system can comprise one or more sensors suitable to be applied to a subject and to collect biometric information.
For example biometric information from the subject can be collected by remote sensors placed on the body of the user, such as wearable sensor patches or devices, which detect biometric information and send them to an electronic device. Remote sensors collecting biometric information are commercially available. Wearable devices can be for example commercially available smart-watches or fitness bracelets.
Biometric information can comprise skin conductivity, heart rate, blood oxygenation.
The electronic device, e.g. a personal computer, a smart-phone or a tablet, processes the information received from the biosensor system, located inside the drug delivery device or as a separate system, and optionally further information inserted by a user to provide an estimate of the condition of the subject, for example by an application software. Information processing can advantageously be carried out by machine learning techniques, which are well known in the field. The estimation of the condition of the subject allows to monitor in real time the physiological response of the subject to the drug-delivery. The electronic device can thus combine the feedback obtained by the biosensor system with the operation of the drug delivery device in a closed-loop process advantageously monitoring in real time the effects of the drug delivery and decreasing the chance for accidental overdosage of the compounds.
The drug delivery device of the invention can be advantageously used for the treatment of any condition which would take advantage from a transmucosal administration of a pharmaceutical ingredient. For example, it can be used for the treatment of gastroenterology, hematology, infectious, neurology, psychiatry, endocrinology, nutrition, genitourinary and respiratory tract diseases, in particular for the treatment of at least one disorder or condition selected from the following group: gastrointestinal disorders, genitourinary disorders, psychiatric disorder, neurological disorder and nutritional deficiency, including but not limited to adrenal insufficiency, allergy, anxiety disorder, asthma, attention-deficit hyperactivity disorder, bipolar disorder, chronic and acute pain, chronic bronchitis, chronic obstructive pulmonary disease, chronic obstructive pulmonary disease, congestion, cramp, cyclic vomiting syndrome, dementias, dependence syndrome, diabetes mellitus, epilepsy, fever, genitourinary disorder, hypercholesterolemia, hormonal imbalance, hyperglycemia, hypersalivation, hypertension, hypotension, hypothyroidism, infectious disease, inflammatory diseases, menopause, menstrual regulation, migraine, mood disorders, musculoskeletal pain, nausea, neoplasms, obesity, Parkinson's disease, pulmonary disease, respiratory disease, sexual dysfunction, sleep disorder, smoking cessation, vaginal diseases, vomiting.
The pharmaceutical ingredient to be delivered can be selected from the skilled person depending on the pathology to be treated and the conditions of the patients. In an embodiment, the pharmaceutical ingredient is for the treatment of at least one disorder or condition selected from the following group: gastrointestinal disorders, genitourinary disorders, psychiatric disorder, neurological disorder and nutritional deficiency, including but not limited to adrenal insufficiency, allergy, anxiety disorder, asthma, attention-deficit hyperactivity disorder, bipolar disorder, chronic and acute pain, chronic bronchitis, chronic obstructive pulmonary disease, chronic obstructive pulmonary disease, congestion, cramp, cyclic vomiting syndrome, dementias, dependence syndrome, diabetes mellitus, epilepsy, fever, genitourinary disorder, hypercholesterolemia, hormonal imbalance, hyperglycemia, hypersalivation, hypertension, hypotension, hypothyroidism, infectious disease, inflammatory diseases, menopause, menstrual regulation, migraine, mood disorders, musculoskeletal pain, nausea, neoplasms, obesity, Parkinson's disease, pulmonary disease, respiratory disease, sexual dysfunction, sleep disorder, smoking cessation, vaginal diseases, vomiting.
In an embodiment, the pharmaceutical ingredient is one of the followings: analgesics, anesthetics, angiotensin-converting enzyme agent, anorectic, anti-addiction agents, antiallergy agent, antibacterials, anticonvulsants, anxiolytics, antidementia agents, antidepressants, antidiabetic agent, anti-diuretic, antiemetics, antiepileptic, antifungals, antihelminthic, antihistamine, anti-hyperglycemic, antihypertensive agent, anti-hypotensive agent, anti-inflammatories, antimigraine agents, antimuscarinic, antineoplastics, anti-obesity agents, antiparasitics, anti-Parkinson agent, antipyretics, antipsychotic, antispasmodic, antiviral, anxiolytic, benzodiazepines, beta adrenergic blocking agents, bronchodilator, cardiovascular agent, central nervous system agents, cholesterol lowering drug, contraceptives, cough suppressant, dopaminergic agonist, expectorant, gastrointestinal agent, genitourinary agents, glycogenolytic agents, hormonal agents, immunosuppressant agent, minerals, mucolytic, muscle relaxant, nasal decongestant, neurosteroids, opioid agonist, parasympathomimetic, pherine, prostaglandin, respiratory tract agents, sedative, sexual disorder agents, smoking cessation agents, sleep disorder agents, stimulant, vitamins.
In particular, the pharmaceutical ingredient can be selected from the group consisting of: acyclovir, albuterol, alclometasone, alfentanil, allergen extracts, allopregnanolone, almotriptan, aloradine, alprazolam, alprostadil, amoxicillin, amphetamines, androstanediol, apomorphine, arctigenin, articaine, ascorbic acid, asenapine, atomoxetine, atorvastatin, atropine, azathioprine, azelastine, barbiturate, beclometasone, bisphosphonates, budesonide, bupivacaine, buprenorphine, bupropion, caffeine, cannabidiol, captopril, carfentanil, chlordiazepoxide, chloropheniramine, chlorpromazine, cholecalciferol, clonidine, clorazepate, clorazepic acid, cobalamin, cortisone, cromolyn, cyclobenzaprine, desmopressin, dexamethasone, dextroamphetamine, diazepam, diethylcarbamazine, dihydroergotamine, dinoprostone, donepezil, econazole, eletriptan, endorphins, enkephalins, ephedrine, epinephrine, ergoloid, ergonovine, ergotamine, estazolam, estradiol, estropipate, etonogestrel, fentanyl, fluconazole, fludrocortisone, fluoxetine, flurazepam, fluticasone, fluticasone, framycetin, frovatriptan, furosemide, gabapentin, ganaxolone, gentamicin, glimepiride, glucagon, gramicidin, guaifenesin, halazepam, heparin, hydrocortisone, hyoscyamine, ibuprofen, insulin, ipratropium, isoproterenol, ivermectin, ketamine, ketoprofen, labetalol, levothyroxine, lidocaine, lofentanil, loratadine, lorazepam, magnesium, melatonin, mepivacaine, metformin, methadone, methylphenidate, methylsergide, methyltestosterone, metoclopramide, metoprolol, metronidazole, midazolam, midazolam, misoprostol, mometasone, morphine, nadolol, nalbuphine, naloxone, naltrexone, naproxen, naratriptan, nicotine, nifedipine, nimesulide, nitroglycerin, norethindrone, novocaine, olanzapine, ondansetron, opiates, oxycodone, oxycodone, oxymetazoline, oxymetazoline, oxytocic, paracetamol, pentobarbital, phenylephrine, phytonadione, pilocarpine, prazosin, prednisone, pregabalin, pregnanolone, prilocaine, prilocaine, promethazine, propofol, propranolol, prostaglandin, pyridoxine, retinol, rizaptril, salicylic acid, salmeterol, scopolamine, segesterone, selegiline, sildenafil, sufentanil, sumatriptan, temazepam, terbutaline, tetracaine, thiamine, thymosin, timolol, tinidazole, tocopherol, tramadol, triamcinolone, triazolam, tryptophan, vardenafil, varenicline, verapamil, zoledronic acid, zolmitriptan, zolpidem. Preferred active pharmaceutical ingredients are caffeine and ibuprofen.
In particular, the pharmaceutical ingredient and respective disorder or condition to be treated, can be as follows: acetylsalicylic acid for anticoagulant effect, acyclovir for the treatment of herpes virus infections, albuterol to prevent bronchospasm, alclometasone to treat itching, redness, crusting, scaling and inflammation, alfentanil for analgesia, allergen extracts for allergic diseases, allopregnanolone for depression, almotriptan for migraine headaches, aloradine and alprazolam for anxiety disorder, alprostadil for erectile dysfunction, amoxicillin to treat bacterial infections, amphetamines for attention-deficit hyperactivity disorder, androstanediol to increase the production of the hormone testosterone, apomorphine for Parkinson's disease, arctigenin for inflammation or control of blood glucose levels, articaine for anesthesia, ascorbic acid as a nutraceutical, asenapine for bipolar disorder, atomoxetine for the treatment of attention deficit hyperactivity disorder, atorvastatin for the treatment of high cholesterol, atropine for management of secretions in the respiratory tract or gastrointestinal tract, azathioprine for autoimmune diseases, azelastine for respiratory allergies, barbiturate treating seizure disorder, beclomethasone for asthma and chronic obstructive pulmonary disease, bisphosphonates for osteopenia or osteoporosis, budesonide for asthma and inflammation in the respiratory tract, bupivacaine as local anesthetic, buprenorphine as a painkiller agent, bupropion for depression, caffeine for mental alertness, headache, migraine, athletic performance, memory, and obesity, cannabidiol for the treatment of seizures, captopril for hypertension, chlordiazepoxide for anxiety and alcohol withdrawal, chloropheniramine for allergy, chlorpromazine to treat anxiety, mania, psychosis and schizophrenia, cholecalciferol as dietary supplement, clonidine for hypertension, clorazepate for skeletal muscle relaxant, clorazepic acid to treat anxiety, partial seizures, and alcohol withdrawal, cobalamin as dietary supplement, cortisone for asthma and allergies, cromolyn for allergic rhinitis, cyclobenzaprine for painful musculoskeletal conditions, desmopressin for treatment of diabetes insipidus, dexamethasone for severe allergies and asthma, dextroamphetamine to treat attention-deficit hyperactivity disorder and sleep disorder, diazepam anxiety disorder, dihydroergotamine for migraine headaches, dinoprostone for the evacuation of uterine contents and labor induction, donepezil for treatment of dementia, econazole as antifungal agent, eletriptan for migraine headaches, endorphins analgesic and for management of opioid withdrawal, enkephalins as pain killer agent, ephedrine for hypotension, epinephrine for anaphylaxis, ergoloid for cognitive disorders, ergonovine for haemorrhage, ergotamine for migraine, estazolam for sleep disorder, estradiol for menopausal symptoms, estropipate for menopause related issues, etonogestrel for birth control, fentanyl for pain condition, fluconazole as an antifungal agents for urinogenital tract infections, fludrocortisone for adrenocortical insufficiency, fluoxetine for depression, flurazepam for sleep disorder, fluticasone for asthma, frovatriptan for migraine, furosemide to treat conditions with volume overload and edema, gabapentin for neuropathic pain, ganaxolone to treat status epilepticus, gentamicin for bacterial infection treatment, glimepiride for treatment of type 2 diabetes mellitus, glucagon for hypoglycemia, guaifenesin for respiratory congestion, halazepam for anxiety disorders, heparin for anticoagulant therapy, hydrocortisone for inflammation, hyoscyamine for decreasing the motion of the stomach and intestines, ibuprofen anti-inflammatory, antipyretic and pain killer agent, insulin for diabetes type 1 and 2 treatment, ipratropium for chronic obstructive pulmonary disease, isoproterenol to treat bradycardia conditions, ivermectin as antiparasitic agent, ketamine as anesthetic agent, ketoprofen as analgesic agent, labetalol for hypertension, levothyroxine for hypothyroidism, lidocaine for local anesthesia, lofentanil for chronic pain, loratadine for allergies, lorazepam for anxiety disorders, magnesium for the management of preterm labor, melatonin for sleep disorder, mepivacaine for local anesthesia, metformin treatment of type 2 diabetes and gestational diabetes, methadone for pain management, methylphenidate for attention deficit hyperactivity disorder, methysergide for migraines, methyltestosterone for testosterone deficiency, metoclopramide to treat nausea and vomiting, metoprolol to treat angina, metronidazole to treat bacterial and parasitic infections, midazolam for the treatment of status epilepticus, misoprostol for gastric ulcers, mometasone for the treatment of nasal polyps, morphine for pain management, nadolol for angina pectoris, nalbuphine for respiratory depression, naltrexone to treat alcohol use disorder and opioid dependence, naproxen for pain in joints and muscles, naratriptan for migraine, neuropeptide Y for the treatment of post-traumatic stress disorder, nicotine for nicotine replacement therapies, nifedipine for the management of vasospastic angina, nimesulide for pain and fever management, nitroglycerin for angina pectoris, norethindrone for amenorrhea management, novocaine for local anesthesia, nystatin as an antifungal agent, olanzapine for schizophrenia and bipolar disorder treatment, ondansetron to prevent nausea and vomiting, opiates for the treatment of opioid dependence, oxycodone for the management of severe pain, oxymetazoline to treat nasal congestion and rosacea, oxytocic for strengthening uterine contractions, paracetamol for pain and fever management, pentobarbital for convulsive episodes, phenylephrine for nasal congestion, phytonadione for prophylaxis and treatment of vitamin K-deficiency bleeding, prazosin to treat hypertension, prednisone for anti-inflammatory effects, pregabalin to treat neuropathic pain, pregnenolone for hormone replacement, prilocaine for local anesthesia, promethazine allergic rhinitis, propofol for sedation, propranolol for the treatment of essential tremors and migraine, prostaglandin for the evacuation of uterine contents and labor induction, pyridoxine to treat nausea and vomiting of pregnancy, salmeterol for management and treatment of asthma and chronic obstructive pulmonary disease, scopolamine for postoperative nausea and vomiting, segesterone as hormonal contraceptive, selegiline for Parkinson disease and major depressive disorder treatment, sildenafil erectile dysfunction, sufentanil as analgesic adjunct, sumatriptan for acute treatment of migraine, temazepam for the short-term treatment of insomnia, terbutaline for bronchospasm, tetracaine as local anesthetic agent, thiamine for the treatment of thiamine deficiency, timolol to treat hypertension and glaucoma, tinidazole for the treatment of bacterial vaginosis, tocopherol for the treatment of tocopherol deficiency, tramadol for the management of pain, triazolam for sleep disorder, tryptophan for sleeping difficulties, premenstrual syndrome, stress, depression and alcohol and drug abuse, vardenafil to treat erectile dysfunction, varenicline for smoking cessation treatment, verapamil for angina, zolmitriptan for migraine headaches, zolpidem for sleep disorder.
All such pharmaceutical ingredients are known in the field and the skilled person is able to choose the suitable ingredient in view of the desired application of the device of the invention. The skilled person is also able to choose the suitable dosage of the active ingredient in view of the conditions of the subject and of the therapeutical application.
Depending on the desired medical application the device of the invention can be applied in contact with a specific kind of mucosa. In a preferred embodiment, the device is suitable for the delivery of drug to oral, nasal or urogenital mucosa. In this embodiment, the device is placed in contact with said oral, nasal or urogenital mucosa.
The activity of the device can be local, for example if applied on urogenital mucosae, or systemic, for example if applied to the oral or nasal mucosa, from where the drug can diffuse to reach the blood circulation.
The device is removable and can be applied in contact with the mucosa of a subject through a support adapted for each body region of interest. For example, a device according to the invention for application to the oral mucosa can be clopped to a removable orthodontic appliance. Such removable orthodontic appliance can be commercially obtained or can be manufactured according to methods commonly known in the art (Del Rossi and Leyte-Vidal, 2007). For example, it can be manufactured specifically for mucosa drug delivery from thermoplastic polymers, which can be soften when immersed in hot water and then molded to a new shape to adapt to the user dental arch thus obtaining a customized removable orthodontic appliance allowing an appropriately positioning of the device to either buccal or sub-lingual mucosa.
In an embodiment, a device according to the invention for application to the nasal mucosa can be clopped to a respiratory wearable device which can be commercially obtained or manufactured according to methods commonly known in the art (Massaroni et al., 2019). Respiratory wearable device may comprise a catheter tip wherein the drug delivery device of the invention can be placed. The respiratory wearable device can be placed in the right or left nostril and the catheter tip reaches the nasal mucosa.
A device according to the invention for application to the urogenital mucosa can be clopped to removable urogenital apparatus, which can be commercially obtained or manufactured according to methods commonly known in the art. For example, a device according to the invention for application to the male urethral mucosa can be clopped to the tip of an intra-urethral applicator (Padma-Nathan et al., 1997), which can be placed into the urethra allowing the device to be in contact to the urethral mucosa. A device according to the invention for vaginal application can be clopped to a elastomeric polymers vaginal ring (Morrow et a., 2011) and placed in the vaginal canal for vaginal mucosa drug delivery.
The invention will be now described by the following examples.
Caffeine (CAF), graphene oxide (GO), GO conjugated with CAF coated with chitosan (CH), ibuprofen (IBU) and ferric sulfate (Fe3SO4) reduced graphene oxide (rGO) conjugated with CAF provided by Federal University of Sao Paulo—Unifesp—Brazil, along with sodium chloride and dimethyl sulfoxide were used in the present study. The concentration of drugs, CAF and IBU were at 2 mg/mL and GO or rGO at 0.5 mg/mL. Arduino Uno microcontroller, membrane filter with a pore size of 0.45 μm and polypropylene reservoir were also used to fabricate the device.
Sodium chloride (NaCl) was prepared at 0.9% in distilled water. Dimethyl sulfoxide (DMSO) at 0.25M was prepared in sodium chloride 0.9% solution.
To fabricate the drug delivery device according to the invention a commercialized reservoir was used as a solution container and the place where the electrolysis were performed. An Arduino microcontroller board was used to perform the electrochemical process as described by Crespo et al., 2021. For that, a portable Arduino Uno microcontroller, connected through Wi-Fi to a notebook computer, with boards operating with digital outputs, which go up to 5V, capable of producing a programmable output voltage with the help of a voltage shifter circuit, was configurated using a custom software, written in Visual C++. Graphite counter electrode and working electrode were placed in the opposite walls of device reservoir. All electrodes were in contact with the GO dispersion, that was placed inside the reservoir, along with either NaCl or DMSO electrolyte solution. Finally, a membrane filter with a pore size of 0.45 μm was placed in the bottom of reservoir.
Experiments were performed inside the reservoir containing graphite as counter and work electrodes connected to a portable Arduino Uno microcontroller. All electrodes were immersed in dispersed graphene conjugated with active ingredients and electrolyte. Therefore, NaCl and/or DMSO solutions were used as electrolyte. Based on previously experiments, electrochemical performances were evaluated by applying chronoamperometry under a low given potential of 1.2 V during different periods.
The electrochemical reactions under the given potential was performed, to measure the redox potential. The current variation was measured along the time until 5 minutes in presence of water dispersed graphene oxide loaded with either IBU (GO-IBU), or CAF (GO-CAF), in the last case coated with CH (GO-CH-CAF); and reduced graphene oxide, functionalized with Fe3SO4, conjugated with caffeine (rGO-F-CAF).
To induce an electrolytic water splitting, known to produce hydrogen at the cathode electrode and oxygen in the anode one, a potential was applied during 5 minutes (Wang et al., 2021). Then, the capability of graphene oxide to release active ingredients under water electrolysis were evaluated. After that, solution containing caffeine and electrolyte was filtered and analysed by Fourier Transform Infrared Spectroscopy (FTIR) to identify the presence of caffeine in the sample. The analyses were performed in a FTIR Spectrum One (Perkin Elmer), using the liquid film method, in the range of 4,000-550 cm−1, with resolution of 4 cm−1 and 32 scans.
All experimental procedure were performed at room temperature.
We designed, fabricated, and tested a drug delivery device with graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets as nanocarrier for drug delivery applications upon electrochemical reaction. Indeed, graphene-based nanomaterials are being investigated for therapeutic applications to support the delivery of active pharmaceutical ingredients more efficiently (Cellot et al., 2022). Graphene derivatives such as GO and rGO consist of carbon, oxygen, and hydrogen atoms suitable for non-covalent binding of drugs. Thus, drugs can be linked to their surface by physical adsorption through electrostatic interactions, van der Waals forces or π-π stacking interactions (Georgakilas et al., 2016).
In the present study, GO were conjugated with different active ingredients, such as CAF and IBU, additionally GO-CAF was coated with CH by non-covalent bonds. Moreover, rGO were covalently functionalized with ferric sulfate and conjugated with CAF by non-covalent bonds.
Electrically controlled release of drugs was investigated by applying an electrical potential into the reservoir for different periods of time (5 minutes) in presence of either NaCl physiological solution or NaCl/DMSO vehicle used as a supporting electrolyte solution. Electrolytes play a key role in electrolysis because they increase the conductivity of the water, which allows a greater flow of ions through the solution. Thus, the presence of saline solution leads to a more efficient and effective electrolysis process. Regarding to DMSO, a polar aprotic solvent that can dissolve both water-soluble and water-insoluble substances (Kazi and Dehghan, 2020), it was used as a surfactant excipient, which can increase hydrophilicity of caffeine. In some electrolysis experiments, DMSO is used also to control the reaction kinetics by either donating or accepting electrons (Butler, 1967).
An electric current (+1.2 V) was applied into the reservoir containing GO-CAF, GO-CH-CAF, rGO-F-CAF or GO-IBU water dispersion and the electrolyte solution, inducing water electrolysis. In such condition, water molecules can split into hydrogen and oxygen, with hydrogen formed at the cathode and oxygen at the anode (Wang et al., 2021). The hydrogen gas formed may break the pi bonds through the hydrogenation reactions (Weber et al., 2019), enabling the hydrogen atoms to be adsorbed to GO surface and after breaking the pi interaction with drugs. Besides, hydrogen-rich water has the capability of reducing the amount of oxygen molecule from GO, resulting in an enhancement of its electrical conductivity property (Akhavan et al., 2015). Whereas drugs are released into the solution by desorption process. In a matter of fact, electrochemical reaction can determine the release of adsorbed drug molecules from the graphene-based nanomaterial through desorption (Weaver et al., 2014; He et al., 2017; Teodorescu et al., 2015).
In the present work, chronoamperometry was employed for the evaluation of drug release from GO nanosheets over time. By measuring the current over time, it is possible to obtain information about the redox reaction and the stability of the reaction products (Nishiumi et al., 2005).
Results showed that the current density increases over the time upon electrochemical reaction characterizing the effective diffusion of drugs, compared to the first measure (time 0; according to the paired T test; t(263)=2.54; p<0.05;
Our results are in agreement with the electrochemically controlled delivery approach, where graphene platform pre-coated with aniline groups by covalent bonds was shown to control the cargo release upon a low voltage (Hou et al., 2020) that is an advantage for clinical application (Fish and Geddes, 2009).
To evaluate the impact of a long-term electrolysis condition, solutions containing CAF released in response to the applied potential, during 5 minutes, were filtered and posteriorly analyzed by IFRT (
Membrane filtration is a process of separating particles in liquid solutions used in a wide range of applications. By applying external pressure, smaller molecules can pass through the membrane filter, retaining larger particles (Cevallos-Mendoza et al., 2022). In the present study, the pressure was applied by the gas formed inside the reservoir. The electrolysis of water is a transformation process of liquid to gas (Xu et al., 2019), useful to convert electrical energy to pressure-volume changes (Cameron and Freund, 2002). Such process may generates sufficient pressure within the drug reservoir, accelerating the transport of caffeine through the membrane filter. In that regard, filtering process was aimed to permit the passage of caffeine and the electrolyte solution, but not graphene oxide nanosheets, that are retained due to their big lateral size work (Tang et al., 2016). By blocking the passage of graphene oxide it's possible to prevent potential toxicity. Despite the fact that graphene oxide shows good biocompatibility and no cytotoxicity (Rauti et al., 2016; Biagioni et al., 2021), the systemic distribution can cause organ toxicity by accumulation mechanism (Zhang et al., 2011). Therefore, filtration process prevents the toxicity effect caused by graphene-based material.
Regarding the analysis, FTIR-spectra showed characteristic peaks of caffeine in the spectral range of 612-1701 cm−1 after 5 minutes of applied voltage in presence of either saline of DMSO (
Thus, we demonstrated that the capability of graphene oxide to delivery its cargo (caffeine) can be determined by electrical stimulus upon a low voltage and short period of time. The present strategy is not limited to caffeine. Instead, it may be applied for organic and inorganic molecules, polar, apolar aromatic or non-aromatic pharmaceutical ingredients as well. Because graphene can be functionalized by binding different chemical groups to its surface, as demonstrated in previous works (Mancilla et al., 2020; Wang et a., 2013; Kavitha et al., 2013; Liu et al., 2013; Park et a., 2014; Servant et al., 2014).
Summarizing, we have fabricated a remote-controlled drug delivery device that enable the releasing of active pharmaceutical ingredients in response to an applied electric potential. By using graphene oxide as a platform for loading agents via non-covalent interaction, it is possible to control the speed and dose of the released agent by electrochemical system. Application of a low voltage breaks the pi-interaction resulting in adsorption of the active pharmaceutical ingredient, enabling the control of the releasing profile by applying different electric potential in different time before filtering the solution. This system offers an effective application of graphene as drug delivery system, preventing the potential organ toxicity caused by the accumulation of graphene in vital organ when injected systemically.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102022000004892 | Mar 2022 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/056424 | 3/14/2023 | WO |
