The present disclosure relates generally to autonomic neural ablation, and more specifically to a sustained-release formulation and method for autonomic neural ablation for the treatment of cardiovascular disease.
The autonomic nervous system (ANS), which includes the sympathetic nervous system, is interconnected with the cardiovascular system. Certain cardiovascular disease states originate from the neurohormonal response to renal sympathetic nerve activation, including hypertension, heart failure, type II diabetes and atrial and/or ventricular tachycardia. Other sympathetic neural systems such as those associated with the hepatic and pulmonary system may be targeted for fatty liver disease or pulmonary arterial hypertension. The sympathetic nervous system is also interconnected with the digestive system and may impact digestive functions including but not limited to resting metabolic rate and dissipation of consumed calories, so sympathetic nerve activation may lead to weight gain. One sympathetic nerve treatment includes oral medications, but some patients are unresponsive and about half of patients fail to take such oral medications at all or properly. Another sympathetic nerve treatment includes energy-based ablation procedures, but anatomical features may limit the depth and uniformity of such procedures. Yet another sympathetic nerve treatment includes acute drug delivery, but the amount of drug delivered may be limited by nonspecific tissue toxicity.
A denervation formulation is disclosed including a denervation drug incorporated into a sustained-release matrix. The sustained-release matrix may include a polycarbonate or a fluoropolymer. The sustained-release matrix may form a plurality of microparticles and/or nanoparticles to encapsulate the denervation drug. The denervation formulation may be delivered to a patient's autonomic neural tissue, including but not limited to a renal sympathetic nerve, a carotid nerve, a pulmonary nerve, a hepatic nerve and/or a cardiac sympathetic nerve. Upon release, the denervation drug may ablate the patient's autonomic neural tissue for treatment of cardiac disease, including but not limited to hypertension, heart failure, and/or atrial and ventricular tachycardia, treatment of bariatric conditions, or treatment of other disease states.
According to one example (“Example 1”), a formulation is provided including a sustained-release matrix comprising at least one of a polycarbonate and a fluoropolymer; and a denervation drug incorporated into the sustained-release matrix.
According to another example (“Example 2”), a denervation method is provided including delivering a denervation formulation to an autonomic neural tissue of a patient with a cardiovascular disease, the denervation formulation comprising a denervation drug incorporated into a sustained-release matrix, gradually releasing the denervation drug into the autonomic neural tissue of the patient, and ablating the patient's autonomic neural tissue.
The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments, and together with the description serve to explain the principles of the disclosure.
This disclosure is not meant to be read in a restrictive manner. For example, the terminology used in the application should be read broadly in the context of the meaning those in the field would attribute such terminology.
With respect terminology of inexactitude, even when the terms “about” and “approximately” are not used any stated value referring to a measurement includes the stated measurement and that also includes any measurements that are reasonably close to the stated measurement. Measurements that are reasonably close to the stated measurement deviate from the stated measurement by a reasonably small amount as understood and readily ascertained by individuals having ordinary skill in the relevant arts. Such deviations may be attributable to measurement error or minor adjustments made to optimize performance, for example.
The foregoing Examples are just that and should not be read to limit or otherwise narrow the scope of any of the inventive concepts otherwise provided by the instant disclosure. While multiple examples are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature rather than restrictive in nature.
Persons skilled in the art will readily appreciate that various aspects of the present disclosure can be realized by any number of methods and apparatuses configured to perform the intended functions. It should also be noted that the accompanying drawing figures referred to herein are not necessarily drawn to scale but may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the drawing figures should not be construed as limiting.
With reference to
The denervation formulation 100 includes a plurality of particles 101, which may be microparticles (e.g., microspheres) and/or nanoparticles, with each particle 101 including a denervation drug 102 incorporated into a sustained-release matrix 104 (which may also be referred to as a controlled-release matrix). The denervation formulation 100 may also include one or more optional excipients 106 and a delivery fluid 108. Each ingredient of the denervation formulation 100 is described further below.
The denervation drug 102 is a neurotoxin configured to ablate (i.e., inhibit or destruct) the patient's autonomic neural tissue and interrupt or otherwise hinder the transmission of neural signals from the autonomic neural tissue. Suitable denervation drugs 102 include but are not limited to paclitaxel (PTX), suramin, digoxin, altretamine, oxaliplatin, vincristine, vinblastine, cisplatin, carboplatin, bortezomib, and etoposide, as well as analogs and salts thereof.
The sustained-release matrix 104 may encapsulate the denervation drug 102 to form the particle 101, as shown in
The particles 101 of the instant invention are durable. As is known to the art, durable microparticles and nanoparticles do not immediately dissolve into their molecular entities after administration or immediately degrade through normal biodegradation mechanisms within the body (J L Weaver et al., Evaluating the potential of gold, silver, and silica nanoparticles to saturate mononuclear phagocytic system tissues under repeat dosing conditions, Particle and Fibre Toxicology, Vol 14, No. 1, Article 25). Rather, durable microparticles and nanoparticles remain in the particulate state during administration, distribution, accumulation, or elimination. In certain embodiments, the microparticles and nanoparticles when implanted remain durable for a time period of 7 days to 180 days, such as 7 days, 20 days, 40 days, 60 days, 80 days, 100 days, 120 days, 140 days, 160 days, or 180 days.
Examples of suitable sustained-release matrices 104 include polycarbonates and fluoropolymers, as described further below. Furthermore, the sustained-release matrix may be a solid, a gel, or combinations thereof.
The sustained-release matrix 104 is a material configured to release the denervation drug 102 gradually over an extended time period of several hours, several days, weeks, or months following delivery to the patient. The extended time period may be 1 day to 180 days, such as 1 day, 10 days, 20 days, 40 days, 60 days, 80 days, 100 days, 120 days, 140 days, 160 days, or 180 days. In certain embodiments, the extended time period is 5 days, 7 days, 9 days, 11 days, 13 days, or 15 days, for example.
The sustained-release matrix 104 may be designed to control the gradual release rate of the denervation drug 102 between a minimum rate sufficient to achieve neural ablation and a maximum rate that ensures patient safety by avoiding nonspecific tissue toxicity. For example, the gradual release rate may be 0.1 μg/day to 6 mg/day, such as 0.1 μg/day, 0.5 μg/day, 1 μg/day, 1.5 μg/day, or 2 μg/day. In some embodiments, the gradual release rate may be 1 μg/day to 800 μg/day, 1 μg/day to 700 μg/day, 1 μg/day to 600 μg/day, 1 μg/day to 500 μg/day, 1 μg/day to 400 μg/day, 1 μg/day to 300 μg/day, 100 μg/day to 700 μg/day, 200 μg/day to 700 μg/day, 300 μg/day to 700 μg/day, 400 μg/day to 700 μg/day, 500 μg/day to 700 μg/day, 100 μg/day to 500 μg/day, 100 μg/day to 400 μg/day, or 100 μg/day to 300 μg/day. For example, the gradual release rate may be 300 μg/day, 350 μg/day, 400 μg/day, 450 μg/day, 500 μg/day, 550 μg/day, 600 μg/day, 650 μg/day, 700 μg/day, or 750 μg/day. The gradual release rate may vary based on the selected denervation drug 102, the exact or approximate anatomical site, the patient's weight, the patient's age, the patient's overall health, and other factors. The gradual release rate may be steady over time or may vary over time (e.g., a faster initial rate (i.e., burst) followed by a slower final rate).
Because the denervation drug 102 is released gradually, each dose of the denervation formulation 100 that is delivered to the patient may contain a large amount of the denervation drug 102. For example, each dose of the denervation formulation 100 depending on the drug may contain 30 to 400 μg of the denervation drug 102 in one case and 7 mg to 30 mg in another, such as 50, 100 μg, 400 ug in the case of one drug and 7 mg, 10 mg and 30 mg in another case of the denervation drug 102. In some embodiments, the denervation drug 102 may account for 1 wt. %, 5 wt. %, 10 wt. %, 15 wt. %, 20 wt. %, or more of each particle 101.
The optional excipient(s) 106 may be configured to alter the release rate of the denervation drug 102 from the denervation formulation 100, to increase tissue permeability of the denervation drug 102, and/or to interact with surface receptors that are neural cell specific to increase the potency of the denervation drug 102. Suitable excipients 106 include cyclodextrin, polyethylene glycol (PEG), poloxamers, polyvinyl alcohol (PVA), dodecylsulfoxide, decylmethylsulfoxide, calcium salicylate or any other organo-calcium sources, and sodium glutamate, for example. The excipient(s) 106 may be present within the particles 101, around the particles 101, and/or in the delivery fluid 108. In some embodiments, the excipients 106 may account for 1 wt. %, 5 wt. %, 10 wt. %, 15 wt. %, 20 wt. %, 25 wt. %, or more of the denervation formulation 100.
The delivery fluid 108 may be mixed with the particles 101 to produce an injectable denervation formulation 100. The particles 101 may be suspended, dissolved, or otherwise mixed with the delivery fluid 108. The delivery fluid 108 may maintain a non-inflammatory surrounding state. The delivery fluid 108 may include, for example, water, phosphate buffered saline (PBS), parenteral oils, triacetin (1,2,3-triacetoxypropane), acetyltributyl citrate, triethyl citrate, tributyl citrate, acetyl triethyl citrate, 1-butanol, 2-butanol, butyl acetate, dimethylsulfoxide (DMSO), tert-butylmethyl ether, formic acid, 3-methyl-1-butanol, propylene glycol, polyethylene oxide, and combinations thereof.
An example of a suitable polycarbonate sustained-release matrix 104 for the denervation formulation 100 is a bioabsorbable trimethylene carbonate (TMC) based polymer, which may include a TMC moiety polymerized with a polylactic acid (PLA) moiety and/or a polyglycolic acid (PGA) moiety.
In one embodiment, the TMC-based polymer may be a poly(lactic acid-TMC) copolymer, hereinafter “PLA:TMC”. The PLA:TMC copolymer may be synthesized using methods well known to the art, such as by combining TMC monomers with suitable comonomers of lactic acid, such as L-Lactic acid comonomers creating poly(L,Lactic acid-TMC) hereinafter “L-PLA:TMC”; D-Lactic acid comonomers creating poly(D,Lactic acid-TMC) hereinafter “D-PLA:TMC”; and comonomers of L-lactic acid and D-lactic acid and TMC creating Poly(DL,Lactic acid-TMC) hereinafter “D,L-PLA:TMC”. The PLA:TMC copolymers may have a weight ratio of D-PLA to TMC of 55% to 45% (55:45) or 75% to 25% (75:25), L-PLA to TMC of 55% to 45% (55:45) or 75% to 25% (75:25), and D,L-PLA to TMC of 50% to 50% (50:50) or 75% to 25% (75:25) (all based on weight). In some aspects, the PLA:TMC copolymer may comprise from 45 to 60 wt. % PLA and from 40 to 55 wt. % TMC. The PLA:TMC copolymer may have a number average molecular weight greater than 20,000 g/mol and a solubility in the delivery fluid 108 greater than 2 wt. %.
In another embodiment, the TMC-based polymer may be a poly(lactic and glycolic acid-TMC) terpolymer, hereinafter “PLA:PGA:TMC”. The PLA:PGA:TMC terpolymer may be synthesized using methods well known to the art, such as by combining TMC monomers, comonomers of lactic acid (as discussed above), and comonomers of glycolic acid. The PLA:PGA:TMC terpolymer may comprise from 3-19 wt. % PGA and may comprise PLA:TMC in a weight ratio from 3.25:1 to 0.75:1. The PLA:PGA:TMC terpolymer may have a weight ratio of D-PLA to TMC of 3.25:1 to 0.75:1, L-PLA to TMC of 3.25:1 to 0.75:1, or D,L-PLA to TMC of 3.25:1 to 0.75:1. The PLA:PGA:TMC terpolymer may have a number average molecular weight of 25,000 to 40,000 g/mol.
In another embodiment, the sustained-release matrix 104 may comprise an amphiphilic block copolymer, and/or may comprise additional additives, surfactants, or compounds to provide amphiphilic characteristics to the sustained-release matrix 104. Examples of amphiphilic block copolymers may comprise hydrophobic and hydrophilic domains or blocks. The hydrophobic domain/block may comprise lactide, glycolide, trimethylene carbonate and combinations thereof. The hydrophilic domain/block may consist of polyethylene glycol or hydrophilic naturally derived polymers such as saccharides including heparin, or block polymers thereof with polyethyleneglycol.
The PLA:PGA:TMC terpolymer may be synthesized using methods well known to the art, such as by combining TMC monomers, comonomers of lactic acid (as discussed above), and comonomers of glycolic acid, while using a terminal hydroxyl of the hydrophilic polymer as the initiator for the ring opening polymerization The PLA:PGA:TMC terpolymer may comprise from 3-19 wt. % PGA and may comprise PLA:TMC in a weight ratio from 3.25:1 to 0.75:1. The PLA:PGA:TMC terpolymer may have a weight ratio of D-PLA to TMC of 3.25:1 to 0.75:1, L-PLA to TMC of 3.25:1 to 0.75:1, or D,L-PLA to TMC of 3.25:1 to 0.75:1. The PLA:PGA:TMC terpolymer may have a number average molecular weight of 25,000 to 40,000 g/mol. The hydrophilic domain may have a molecular weight between 600 g/mol to 20,000 g/mol. If a hydrophobic-hydrophilic block copolymer with polyethylene glycol-saccharide blocks are used the hydrophobic-polyethylene glycol can be used as a substrate for saccharide coupling as known in the art.
In one example, the denervation formulation 100 may be formed by: dissolving the denervation drug 102 and the TMC-based polymer optionally comprising an absorbable amphiphilic polymer in an organic solvent (e.g., dichloromethane (DCM)/methanol); emulsifying the organic solution in an aqueous solution (e.g., PVA/water) to form particles 101 containing the denervation drug 102 and the TMC-based polymer as the sustained-release matrix 104; isolating the particles 101; and drying the particles 101. The particles 101 may then be mixed into the delivery fluid 108 for injection into the patient. The denervation formulation 100 may be stored and/or produced directly within vials, syringes, or any other suitable container.
A denervation formulation 100 with a TMC-based sustained-release matrix 104 is further exemplified in Example A below.
Another example of a suitable sustained-release matrix 104 for the denervation formulation 100 is a fluoropolymer including a tetrafluoroethylene (TFE) moiety and a vinyl moiety, wherein the vinyl moiety comprises at least one functional group selected from acetate, alcohol, amine, and amide. Suitable fluoropolymers include poly(tetrafluoroethylene-co-vinyl acetate) (TFE-VAc), poly(tetrafluoroethylene-co-vinyl alcohol) (TFE-VOH), and/or poly(tetrafluoroethylene-co-vinyl alcohol-co-vinyl[aminobutyraldehyde acetal]) (TFE-VOH-AcAm), for example. The fluoropolymer may have a TFE moiety mole content of at least 15%, such as 15.5% to 23.5%, and a vinyl moiety mole content of at least 76%, such as 76.5% to 84.5%. However, other TFE moiety and vinyl moiety mole contents are also contemplated.
In this example, the denervation formulation 100 may be formed by: dissolving the denervation drug 102 in water; dissolving the fluoropolymer in an organic solvent; emulsifying the water solution with the organic solution (where such emulsification is described in U.S. Pat. No. 9,731,017); and then hardening the emulsion to form a solid or gel containing the denervation drug 102 and the TFE-based fluoropolymer as the sustained-release matrix 104. In certain embodiments, the TFE-based sustained-release matrix 104 may be formed into particles 101 as described above. The particles 101 may then be mixed into the delivery fluid 108 for injection into the patient.
Suitable fluoropolymer compositions such as TFE-VOH may spontaneously form dispersed nanoparticles upon addition into an aqueous solvent. The hydrophobicity of TFE coupled with vinyl moiety hydrophilicity may enable simple nanoparticle formation due to thermodynamics. Specifically, it may be entropically favorable for TFE-VOH to precipitate into nanoparticles, which would lower the interfacial energy between the hydrophobic TFE and the aqueous environment leading to VOH likely residing on the nanoparticle perimeter. TFE-VOH that did not form nanoparticles may be of high molecular weight, which may be separated from solution such as by centrifugation or filtration. Additionally, the vinyl moiety may act as an electrostatic barrier enabling charge repulsion of the nanoparticles ultimately preventing agglomeration.
A TFE-VOH nanoparticle formulation is further exemplified in Example E below.
With reference to
In step 202, the denervation formulation 100 may be injected, delivered to the periadventitial region using a catheter or otherwise delivered in vivo to the patient's autonomic neural tissue. The autonomic neural tissue may be located in the adventitial or periadventitial region of a vascular structure, a cardiovascular structure, or another organ. The autonomic neural tissue may include, for example, a renal sympathetic nerve, a carotid nerve, a pulmonary nerve, and/or a cardiac sympathetic nerve. The delivery step 202 may be performed using a syringe 203 (
Following the delivery step 202, the sustained-release matrix 104 may gradually degrade and release the denervation drug 102 into the patient in step 204. This gradual release step 204 may occur over an extended time period of several days, weeks, or months, as described further above.
The denervation drug 102 that is released during the gradual release step 204 may ablate the patient's autonomic neural tissue in step 206. This neural ablation step 206 may interrupt or otherwise hinder the transmission of neural signals from the patient's autonomic neural tissue. This neural ablation step 206 may decrease sympathetic nervous system activity and help treat the related cardiovascular disease.
The denervation formulation 100 shown in
It should be understood that although certain methods and equipment are described below, other methods or equipment determined suitable by one of ordinary skill in the art may be alternatively utilized.
For each sample being evaluated, a 700 mL elution media was prepared including 0.5 w/v % sodium dodecyl sulfate, 22 mM sodium acetate, and 28 mM acetic acid (pH 4.6). To a Spectra-Por Float-A-lyzer G2 (Sigma Z727040 MWCO:100 kD) was added 2 mg of the formed microparticles. The Float-A-lyzer was added to a Sotax App 2 dissolution apparatus with 700 mL of media and equilibrated at 37° C. Aliquot samples (1 mL) of media were removed at specific time points (e.g., 4 hours and daily from 1 day to 14 days). The samples were then tested by High Performance Liquid Chromatography (HPLC)-Absorbance spectroscopy using USP protocols.
PVA/Water Solution: To a 1000 mL media flask was added 25 g of PVA (Mowiol; Sigma 81381) and 1000 g of deionized water.
DCM/Methanol Solution: To a 100 mL vial was added 98 g of DCM (Sigma Aldrich 270997) and 2 g of methanol (Burdick/Jackson LC230-1). The DCM/methanol solution was then shaken vigorously.
PLA:TMC Solution: To a 40 mL vial was added 24.2 g of the DCM/methanol solution followed by 0.650 g of a PLA:TMC copolymer (Gore LT-50).
PLA:TMC/PTX Solution: To another vial in a powder hood was added 0.100 g PTX powder (Indena). The PLA:TMC solution was added to the PTX powder and mixed for 30 minutes.
Formation: To a 400 mL PTFE beaker (80 mm×106 mm) with a mechanical homogenizer unit (VWR 25D) was added 250 g of the PVA/water solution. The homogenizer unit's probe (VWR 20 mm×125 mm) was inserted into the solution and rotated at a desired rate, specifically 3,015 or 5,035 rpm in this Example. The PLA:TMC/PTX solution was added rapidly to the PVA/water solution to form an emulsion, which was homogenized at the desired rate for 4 minutes. Then, the emulsion was vigorously stirred with a magnetic stir-bar within the isolator exposed to the isolator atmosphere for overnight (12 hours) to allow for formation and hardening of the microparticles and evaporation of residual solvent.
Isolation: To a 50 mL centrifuge tube was added 35 mL of the PLA:TMC/PTX emulsion. The centrifuge was spun at 3,450 rpm for 30 minutes. The centrifuge tube supernate was decanted and the tubes were filled to 35 mL with deionized water. These steps were repeated until the supernate was free of PVA.
Lyophilization: The microparticles were then re-suspended in a minimum amount of deionized water. The microparticle suspension was frozen at −20° C. for a minimum of 4 hours, preferably overnight. The samples were then lyophilized for 24 to 48 hours resulting in dry samples.
Microparticle Size: The dry PLA:TMC/PTX microparticles were subjected to scanning electron microscope (SEM) imaging, and the results are presented in
PTX Release Profile: The dry PLA:TMC/PTX microparticles were also subjected to sustained release testing as described above, and the results are presented in
Based on these results, the speed of rotation during emulsification was shown to have an indirect impact on particle size and an indirect impact on the PTX release rate.
Copolymers comprising varying mole ratios of vinyl acetate to tetrafluoroethylene (VAc:TFE) were prepared according the following general synthetic scheme. To a nitrogen purged 1 L pressure reactor under vacuum were added 500 g DI water, 2.0 g of 20% aqueous surfactant, 30 ml of distilled vinyl acetate, 10 g of n-butanol, and 0.2 g of ammonium persulfate. Tetrafluoroethylene monomer was then fed into the reactor until the reactor pressure reached 1500 KPa. The mixture was stirred and heated to 50° C. When a pressure drop was observed, 25 ml of additional vinyl acetate was slowly fed into the reactor. The reaction was stopped when the pressure dropped another 150 KPa after vinyl acetate addition. The copolymer was obtained from freeze-thaw coagulation of the latex emulsion, cleaned with methanol/water extraction, and air dried.
The copolymers' composition and molecular weight are listed in Table 1 below.
A denervation drug emulsion is added to a solution containing the WE-Vac of Example B by to form an emulsion, through a process similar to Example A, which is homogenized at the desired rate for 4 minutes. Then, the emulsion is vigorously stirred with a magnetic stir-bar within the isolator exposed to the isolator atmosphere for overnight (12 hours) to allow for formation and hardening of the microparticles and evaporation of residual solvent. The emulsion is then lyophilized and isolated as described in Example A.
The vinyl acetate groups of copolymer #100-0 of Example B were hydrolyzed to vinyl alcohol as follows. To a 50 ml round bottle flask were added 0.5 g of copolymer #100-0 (predissolved in 10 ml methanol) and 0.46 g NaOH (predissolved in 2 mI DI water). The mixture was stirred and heated to 60° C. for 5 hrs. The reaction mixture was then acidified to pH 4, precipitated in DI water, dissolved in methanol, again precipitated in DI water, and air dried. The resulting product was a copolymer of TFE-VOH.
Formation: To a disposable polystyrene cuvette, approximately 900 μL of DI water was added. Nanoparticles were immediately formed by adding approximately 100 μL TFE-VOH from Example D to DI water.
Nanoparticle Size: The cuvette containing the TFE-VOH nanoparticles was added to a Malvern ZetaSizer Ultra and diameter (or Z-Average) was obtained via dynamic light scattering (DLS).
Nanoparticle Chemical Properties: The TFE-VOH solution from Example D (Spectra A) and nanoparticles from this Example E (Spectra B) were added to a Nicolet 6700 FTIR with ATR for chemical characterization.
A denervation drug emulsion is added to a solution containing the TVE-VOH of Example E by to form an emulsion, through a process similar to Example A, which is homogenized at the desired rate for 4 minutes. Then, the emulsion is vigorously stirred with a magnetic stir-bar within the isolator exposed to the isolator atmosphere for overnight (12 hours) to allow for formation and hardening of the microparticles and evaporation of residual solvent. The emulsion is then lyophilized and isolated as described in Example A.
The invention of this application has been described above both generically and with regard to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments without departing from the scope of the disclosure. Thus, it is intended that the embodiments cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
This application is a national phase application of PCT Application No. PCT/US2021/014717, internationally filed on Jan. 22, 2021, which claims the benefit of Provisional Application No. 62/965,551, filed Jan. 24, 2020, which are incorporated herein by reference in their entireties for all purposes.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/014717 | 1/22/2021 | WO |
Number | Date | Country | |
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62965551 | Jan 2020 | US |