Patent Grant
11369741
The present disclosure relates to a microjet drug injection device that ejects an injected drug in a high-speed microjet form to penetrate the drug microjet into a target portion. More particularly, the present disclosure relates to an improved microjet drug injection device configured to prevent an ejection rate and penetration performance from being degraded due to creation of air bubbles in a drug solution contained within an injector after the microjet ejection.
In general, a variety of drug delivery systems have been applied as a method for parenterally administering a treatment drug solution into a patient's body in a medical field. In these drug delivery systems, the most commonly used method is a method using a needle-type syringe. In this method, a syringe having a syringe needle is pierced into a patient's skin, and a drug solution is directly injected. The conventional needle-type syringe as described above is advantageously simple in structure, easy to use, and has a merit that substantially quantitative drug injection is enabled because a piston-type injection port is used. However, such a conventional needle-type injection method has a great shortcoming in that the patient suffers from an inconvenience of feeling a pain during the injection. In addition, the injection method has many problems such as a wound caused by perforation of a skin layer, a risk of secondary infection through the wound, and waste of resources due to difficulty in reusing the syringe.
Due to the shortcomings of the conventional needle-type syringe, development of needle-free drug delivery systems as a substitute for the needle-type syringe has been widely researched. In an attempt to develop the needle-free drug delivery system, there has been proposed a drug delivery system of ejecting a drug solution in a form of a microjet having a micro diameter at a high speed and allowing the drug solution to be directly penetrated into an internal target spot through epidermis.
In the microjet drug delivery system, in order to produce a high-speed drug microjet, a strong propulsion force is applied (directly or indirectly) onto the ejected drug, so that the drug is forced out externally through a micro-nozzle orifice. In this microjet drug delivery system, the propulsion force generation approach has been variously developed since 1930s. Various ejection methods have been developed as follows. Until recently, piezoelectric ceramics were used for ejection. Alternatively, an ejection method using a shock wave induced by applying a laser beam to an aluminum foil, a method using a compression spring or a compressed gas, or an ejection method using Lorentz force has been employed.
In recent years, unlike the conventional microjet ejection methods, a laser-bubble type microjet ejection has been developed by the present applicant. In this laser-bubble type microjet ejection, the amount of ejected drug and the ejection rate (i.e. drug penetration depth) may be finely adjusted, and continuous injection and reusability may be achieved. This laser-bubble type technique has been filed as Korean Patent Application No. 10-2010-56637 (titled “microjet drug delivery system”). The above patent application is patented as KR registration number 1207977.
According to the above-described microjet drug delivery device as described in the above patent document, when the energy focusing unit 40 irradiates the pressure driving liquid 100 into the pressure chamber 10 with the strong energy of the laser beam or the like in a concentrated manner, the pressure driving liquid 100 evaporates momentarily, thus, a bubble is generated therein. Then, during rapid expansion and disappearance of the generated bubble, the elastic membrane 30 is expanded. Due to the expansion of the elastic membrane, the drug solution in the drug chamber 20 is rapidly pressured and ejected through the nozzle, so that the microjet of the drug solution is injected at an enough speed to penetrate soft tissue of the body.
However, in the microjet drug delivery device as disclosed in the above patent document, after drug microjet ejection, unintended and unnecessary bubbles are created in the drug chamber 20 containing the drug liquid therein. Due to the growth of the bubble, the pressure resulting from the expansion deformation of the elastic membrane is not transferred to the drug solution. As a result, microjet ejection characteristics and efficiency are lowered, and as a result, the penetration performance is greatly deteriorated.
Particularly, in the case of using a laser device as an energy source in a microjet drug delivery device as disclosed in the above patent document, by continuously ejecting a small amount of drug using a laser oscillating at several times (more than 10 times) per second, the dose of the injected drug is adjusted as necessary. However, as the number of ejections increases in such continuous ejection, the bubble in the drug chamber grows. After many repetitive ejections, a problem has been found that the device becomes unusable. The present applicant found from the test result that the jet speed of the conventional microjet drug delivery device is 140 m/s at an initial stage, decreases to 60 m/s after 200 shots, and then to 20 m/s after 600 shots.
The bubble generation in the drug chamber after the ejection is predicted to be caused by the external air inflow due to the decrease of the internal pressure of the drug chamber immediately after the ejection. That is, due to the vapor bubble 120 generated in the pressure-driving liquid 100 in the pressure chamber 10 during microjet ejection, the elastic membrane is initially expanded in the direction to pressurize the drug solution, but, the bubble 120 disappears, so that the pressure in the drug chamber becomes lower than the atmospheric pressure during the recovery of the elastic membrane 30 to its original position. Thus, due to the pressure difference between the internal pressure of the drug chamber and the external atmospheric pressure, back-pressure is generated and thus air flows into the drug chamber from the outside of the nozzle.
At this time, the air introduced into the drug chamber floats upward due to the specific gravity difference with the drug solution and air, and then occupies a location beneath the elastic membrane 30. The air bubble gradually grows beneath the elastic membrane due to air entering the chamber each time the ejection is repeated (the air enters the chamber at the same volume as the ejected drug). This leads to a significant reduction in the pressure delivered from the elastic membrane to the drug liquid during subsequent ejection. As a result, the ejection characteristics of the microjet and the penetration performance of the skin of the microjet are deteriorated.
Therefore, the present applicant discloses a method to solve the ejection efficiency deterioration due to the air bubble generation in the drug chamber after microjet ejection. In this method, before back-pressure occurs after microjet ejection, the operation of a drug supply device connected to the injector is controlled to supply the same amount of drug as the amount of previously ejected drug into the drug chamber in a timely manner. As a result, it is possible to suppress the inflow of external air into the drug chamber by the back-pressure and to suppress the generation of bubbles in the drug chamber. This method was filed as Korean Patent Application No. 10-2013-0061485 (titled “method to control drug supply in microjet drug delivery device, and microjet drug delivery system using the method). The above patent application was patented as Korean Patent No. 10-1500568.
However, according to the method of controlling the drug supply in the microjet drug delivery device as disclosed in the patent document, in order to achieve the above effect, the drug supply device and the laser device should be controlled so that the timings of driving the drug supply device and the laser device are accurately correlated with each other. However, in practical implementation, the control of these devices is very difficult, and therefore the desired effect has not been achieved satisfactorily. That is, according to the method as disclosed in the above patent document, an appropriate effect will be achieved only by supplying the exact amount of drug from the exact time point at which the internal pressure is reduced due to the disappearance of the bubble generated in the pressure chamber after ejection of the microjet. Actually, however, the behavior of the bubble inside the pressure driving liquid, and the elastic membrane, and thus the internal pressure change may vary depending on the type of drug, and environmental conditions such as the ambient temperature, and the condition of use. Therefore, it has been difficult to achieve the expected effect as described above.
Further, according to the method described in the above patent document, the operation of the drug supply device must be synchronized with the operation of the laser device. Thus, when a microjet injector unit is mounted on a conventional laser device, simply attaching the injector to the laser tip may not suffice. Therefore, additional technical measures are needed. As a result, in the construction of the drug supply device, there is a disadvantage in terms of the structure of the device, since driving means such as a micro pump (piezoelectric drive, pneumatic drive, etc.) must be additionally provided to supply the drug.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify all key features or essential features of the claimed subject matter, nor is it intended to be used alone as an aid in determining the scope of the claimed subject matter.
The present disclosure has been made in order to solve the problems in the above-described microjet ejection type drug injector. The present disclosure provides a microjet drug injection device that ejects an injected drug in a high-speed microjet form to penetrate the drug microjet into a target portion, whereby after the ejection of the drug solution, unwanted air bubbles are prevented from being created in the drug chamber where the drug is stored, and, thus, degradation of ejection characteristics and efficiency due to bubble creation in the drug chamber after microjet drug ejection is suppressed, and even with many repetitive ejections, constant speed and penetration performance is maintained irrespective of the number of ejection times.
Further, the present disclosure provides a microjet drug injection device whereby, without the need for additional precise control devices or complicated mechanical mechanisms, the amount of the drug solution equal to the amount of the drug ejected each time is automatically refilled into the chamber, thereby enabling automatic refilling with a simple configuration.
In a first aspect of the present disclosure, there is provided a microjet drug injection device comprising: a pressure chamber having a sealed inner space defined therein, wherein a pressure driving liquid is hermetically filled in the pressure chamber; a drug chamber having a drug solution contained therein, wherein the drug chamber has a micro nozzle defined in a wall thereof for discharging the drug solution out of the drug chamber; an elastic membrane configured to be elastically expandable and restorable and to separate the pressure chamber and the drug chamber from each other; an energy-focusing unit configured to concentrates energy on the pressure driving liquid in the pressure chamber to create a bubble in the pressure chamber; a drug storage unit being in fluid communication with the drug chamber through a drug supply channel, wherein the drug storage unit contains a drug solution stored therein, and the storage unit is configured to supply the drug solution into the drug chamber through the drug supply channel, wherein the drug chamber has a partial inner space defined therein, wherein the partial inner space is in fluid communication with the drug supply channel and is partially defined by the membrane; and a nozzle closure disposed inside or outside the drug chamber, wherein the nozzle closure is configured to block inflow of air outside the micro-nozzle into the partial inner space after the elastic membrane has expanded and before elastic recovery of the membrane is completed.
In one embodiment of the first aspect, the nozzle closure is disposed inside the drug chamber, wherein the drug chamber is partitioned into a first inner space and a second inner space by an intermediate wall, and the first space and the second space are in fluid communication through an opening defined in the intermediate wall, wherein the nozzle is defined in the wall defining the second space, wherein the partial inner space corresponds to the first space.
In one embodiment of the first aspect, the nozzle closure includes a check valve, wherein the check valve is configured to allow movement of the drug solution from the first space to the second space, but to block movement of the drug solution from the second space to the first space.
In one embodiment of the first aspect, the nozzle closure includes: a bearing ball having a diameter greater than the opening; and a support spring configured for elastically supporting the bearing ball such that the bearing ball closes the opening.
In one embodiment of the first aspect, when an inner pressure of the first space drops due to ejection of the drug solution from the first space out of the drug chamber, the drug solution is sucked from the storage unit into the first space by a pressure difference between the first space and an inner space of the storage unit.
In one embodiment of the first aspect, the energy-focusing unit includes a laser unit configured to irradiate a laser beam to the pressure driving liquid in the pressure chamber.
In one embodiment of the first aspect, the laser beam emitted from the laser unit is focused at one point in the pressure driving liquid.
In one embodiment of the first aspect, the laser unit include an Er:YAG laser unit.
In a second aspect of the present disclosure, there is provided a microjet drug injection device comprising: a pressure chamber having a sealed inner space defined therein, wherein a pressure driving liquid is hermetically filled in the pressure chamber; a drug chamber having a drug solution contained therein, wherein the drug chamber has a micro nozzle defined in a wall thereof for discharging the drug solution out of the drug chamber, wherein the drug chamber fluid-communicates with an external drug supply channel, wherein the drug chamber is partitioned into a first inner space and a second inner space by an intermediate wall, and the first space and the second space are in fluid communication through an opening defined in the intermediate wall, wherein the nozzle is defined in the wall defining the second space, wherein the drug supply channel fluid-communicates with the first space; an elastic membrane configured to be elastically expandable and restorable and to separate the pressure chamber and the drug chamber from each other, wherein the first space is partially defined by the membrane; an energy-focusing unit configured to concentrates energy on the pressure driving liquid in the pressure chamber to create a bubble in the pressure chamber; and a nozzle closure disposed in the second space, wherein the nozzle closure includes a check valve, wherein the check valve is configured to allow movement of the drug solution from the first space through the opening to the second space, but to block movement of the drug solution from the second space to the first space.
In one embodiment of the second aspect, the nozzle closure includes: a bearing ball having a diameter greater than the opening; and a support spring configured for elastically supporting the bearing ball such that the bearing ball closes the opening.
In a third aspect of the present disclosure, there is provided a microjet drug injection device, wherein the device is removably mounted to a laser tip of a laser unit to emit a laser beam, wherein the device comprises: a pressure chamber having a sealed inner space defined therein, wherein a pressure driving liquid is hermetically filled in the pressure chamber, wherein when the laser unit is mounted to the laser tip and the laser beam is irradiated into the pressure driving liquid in the pressure chamber to create a bubble in the pressure chamber; a drug chamber having a drug solution contained therein, wherein the drug chamber has a micro nozzle defined in a wall thereof for discharging the drug solution out of the drug chamber; an elastic membrane configured to be elastically expandable and restorable and to separate the pressure chamber and the drug chamber from each other; a drug storage unit being in fluid communication with the drug chamber through a drug supply channel, wherein the drug storage unit contains a drug solution stored therein, and the storage unit is configured to supply the drug solution into the drug chamber through the drug supply channel, wherein the drug chamber has a partial inner space defined therein, wherein the partial inner space is in fluid communication with the drug supply channel and is partially defined by the membrane; and a nozzle closure disposed inside or outside the drug chamber, wherein the nozzle closure is configured to block inflow of air outside the micro-nozzle into the partial inner space after the elastic membrane has expanded and before elastic recovery of the membrane is completed.
In one embodiment of the third aspect, the nozzle closure is disposed inside the drug chamber, wherein the drug chamber is partitioned into a first inner space and a second inner space by an intermediate wall, and the first space and the second space are in fluid communication through an opening defined in the intermediate wall, wherein the nozzle is defined in the wall defining the second space, wherein the partial inner space corresponds to the first space.
In one embodiment of the third aspect, the nozzle closure includes a check valve, wherein the check valve is configured to allow movement of the drug solution from the first space to the second space, but to block movement of the drug solution from the second space to the first space.
In one embodiment of the second aspect, the nozzle closure includes: a bearing ball having a diameter greater than the opening; and a support spring configured for elastically supporting the bearing ball such that the bearing ball closes the opening.
In the microjet drug injection device according to the present disclosure, after ejection of the drug solution, external air is prevented from being introduced into the drug chamber and, thus, unintended air bubbles are prevented from being created. This may prevent deterioration of ejection characteristics and efficiency due to bubble generation in the drug chamber after microjet drug ejection. Accordingly, even in the case of continuous ejections of many repetitions, regardless of the number of ejections, a constant ejection rate, ejection volume, and skin penetration performance may be maintained.
Further, in the microjet drug injection device according to the present disclosure, without the need for additional precise control devices or complicated mechanical mechanisms, the amount of the drug solution equal to the amount of the drug ejected each time is automatically refilled into the chamber, thereby enabling automatic refilling with a simple configuration.
The accompanying drawings, which are incorporated in and form a part of this specification and in which like numerals depict like elements, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure.
For simplicity and clarity of illustration, elements in the figures are not necessarily drawn to scale. The same reference numbers in different figures denote the same or similar elements, and as such perform similar functionality. Also, descriptions and details of well-known steps and elements are omitted for simplicity of the description. Furthermore, in the following detailed description of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be understood that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present disclosure.
Examples of various embodiments are illustrated and described further below. It will be understood that the description herein is not intended to limit the claims to the specific embodiments described. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the present disclosure as defined by the appended claims.
It will be understood that, although the terms “first”, “second”, “third”, and so on may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section described below could be termed a second element, component, region, layer or section, without departing from the spirit and scope of the present disclosure.
It will be understood that when an element or layer is referred to as being “connected to”, or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or layer, or one or more intervening elements or layers may be present. In addition, it will also be understood that when an element or layer is referred to as being “between” two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers may also be present.
Spatially relative terms, such as “beneath,” “below,” “lower,” “under,” “above,” “upper,” and the like, may be used herein for ease of explanation to describe one element or feature's relationship to another element s or feature s as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or in operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “above” the other elements or features. Thus, the example terms “below” and “under” can encompass both an orientation of above and below. The device may be otherwise oriented for example, rotated 90 degrees or at other orientations, and the spatially relative descriptors used herein should be interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context dearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes”, and “including” when used in this specification, specify the presence of the stated features, integers, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, operations, elements, components, and/or portions thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expression such as “at least one of” when preceding a list of elements may modify the entire list of elements and may not modify the individual elements of the list.
Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. The present disclosure may be practiced without some or all of these specific details. In other instances, well-known process structures and/or processes have not been described in detail in order not to unnecessarily obscure the present disclosure.
Referring to
In the embodiment of
As illustrated, the microjet injector unit 100 has an overall structure where two chambers are formed to be consecutive in one housing as shown in
As a partition wall which partitions the drug chamber 120 and the pressure chamber 110, an elastic membrane 130 is formed of an elastic material. The elastic membrane 130 is configured to be elastically expanded and deformed according to a change in a physical state (evaporation and, thus, overall volume increase) of the pressure driving liquid 110 in the pressure chamber 10 to apply pressure to the drug solution 200 in the adjacent drug chamber 20, so that the drug solution can be ejected.
In the microjet injector unit 100 according to the present disclosure, the driving force for ejecting the drug solution 125 in a microjet form is created from the pressure driving liquid 115 filled hermetically in the pressure chamber 110. According to the present disclosure, a vapor bubble 115b is rapidly generated in the hermetically filled pressure driving liquid 115. Thus, the elastic membrane 130 is momentarily strongly urged toward the drug chamber due to an increase in the total volume of the pressure driving liquid 115 due to the generation of the bubble. This allows the propulsion pressure to be applied to the to-be-ejected drug solution 125 within the drug chamber 120.
As shown in
Hereinafter, the components constituting the microjet drug delivery system according to the present disclosure as described above will be described in more detail with reference to the accompanying drawings.
With reference to
The pressure chamber 110 has an enclosed structure as a whole and has an accommodation space of a certain volume therein. In the interior space thereof, the pressure driving liquid 115 as a fluid for creating propulsion force is hermetically filled without voids therein.
According to the embodiment shown in
As the pressure driving liquid 115 filling the inside of the pressure chamber 110, basically, ordinary water may be used. In addition to the water, various liquid materials such as polymers sol and gel, such as alcohol or polyethylene glycol, may also be used as the pressure driving liquid 115. Further, the pressure driving liquid 115 may preferably include a degassed liquid for minimizing the residual bubble in the generation of the bubble 115b.
Furthermore, the pressure driving liquid may be prepared by adding an electrolyte (such as salt) to pure water. In this case, since the molecules are ionized and, thus, the energy required for the collapse of the molecular structure of the liquid is small, the bubble may be formed with better efficiency.
The drug chamber 120 is adjacent to the chamber 110 under the pressure chamber 110. The drug solution 125 is stored in the inside of the drug chamber 120. A micro nozzle 140 having a fine diameter is formed in the lower end of the drug chamber 120. As described above, the drug solution 125 may be ejected in the form of a high-speed microjet through the micro nozzle 140 by a propulsion force by which the pressure driving liquid 115 in the pressure chamber 110 pushes the elastic membrane 130. The diameter of the micro nozzle 140 may be varied according to a desired ejection speed, a target ejection amount, and the like. The diameter may be, for example, in a range of 150 μm to 300 μm.
Further, according to the embodiment shown in
Referring to
According to the present disclosure, the nozzle closure 150 temporarily seals a space (in the embodiment shown in
The nozzle closure 150 is basically in an opening mode during creation of the bubble 115b in the pressure driving liquid 115 and during the ejection of the drug solution 125 out of the micro nozzle 140 by expansion of the elastic membrane 130. To the contrary, as the bubble 115b created in the pressure driving liquid 115 in the pressure chamber no disappears, and, thus, the internal pressure of the pressure chamber no is lowered due to recovery of the elastic membrane 130 to its original state, the closure 150 closes the connection neck 128 in a closing mode. Accordingly, the first space 120a partially defined by the elastic membrane 130 is fluidly blocked from the atmospheric pressure outside the micro nozzle 140.
According to the present disclosure, the nozzle closure 150 as described above may be implemented as a check valve. The check valve allows the drug solution 125 to move from the first space 120a to the second space 120b, but blocks the solution 125 from moving from the second space 120b to the first space 120a. In the embodiment shown in
According to the embodiment shown in
Although, in the embodiment shown in
Further, according to the embodiment shown in
According to the drug delivery device according to the present disclosure, as shown in
According to the illustrated embodiment, the drug storage unit 200 may include an ample cylinder 210 having a constant internal volume and a piston 220 slidably moving within the ample cylinder 210, as in the embodiment shown in
In the case of the embodiment of the drug storage unit 200 shown in
Thus, according to the embodiment shown in
The drug supply channel 250 connecting the drug chamber 120 and the drug storage unit 200 may be connected to a side face of the first space 120a defined by the elastic membrane 130 and may be more advantageously disposed adjacent to the elastic membrane 130. This allows the drug to be supplied directly to the point of creation of the back-pressure as the elastic membrane 130 retracts. Further, the drug supply channel 250 is not limited to one channel as shown in
Next, the elastic membrane 130 may be embodied as a thin film having elastic restoring force, and may be disposed between the pressure chamber no and the drug chamber 120 to form a boundary therebetween. That is, the pressure chamber 110 and the drug chamber 120 are separated from each other via the elastic membrane 130, and, at the same time, at least one of the pressure chamber 110 and the drug chamber 120 is brought into contact with the elastic membrane 130. Accordingly, when the volume of the pressure driving liquid 115 in the pressure chamber 110 expands due to the creation of the bubble 115b, the deformation of the elastic membrane 130 may apply pressure to the drug solution 125 in the drug chamber 120.
The elastic membrane 130 may be made of a thin rubber material, preferably a silicone rubber. The silicone rubber not only has excellent stretchability but also has a low thermal conductivity, thereby effectively shielding the heat generated by the laser irradiation and preventing the deterioration and corruption of the drug due to heat transfer. Alternatively, the material of the elastic membrane 130 may employ any material having elasticity and liquid impermeability, depending on the choice of a person skilled in the art. An example of such a material may be nitrile butadiene rubber (NBR).
Next, the laser unit 300 concentrates the laser light (energy) on the pressure driving liquid 115 in the pressure chamber 110 to create a bubble 115b therein. The laser unit constitutes the energy-focusing unit according to the present disclosure. In this embodiment, the laser unit 300 is illustrated as the energy-focusing unit, but the present invention is not necessarily limited thereto. For example, the energy focusing unit may employ an electric electrode configured to apply electric energy.
As the light source of the laser unit 300, any type of laser may be used. For example, various types of laser sources as known in the art, such as Er: YAG laser (wavelength 2.94 μm), Nd: YAG laser (wavelength 1.06 μm), ruby laser, alexandrite laser, Nd: Glass laser, Er: Glass fiber laser may be employed. In particular, the Er: YAG lasers produce the most absorbable wavelength into water. Thus, when water is used as the pressure driving liquid, the Er: YAG laser may be used suitably for the present disclosure, since bubble generation and expansion may occur well.
Further, as shown in
Hereinafter, with reference to
First, regarding the basic operation principle of the microjet drug injection device according to the present disclosure, the microjet drug injection device according to the present disclosure basically blocks external air from entering the first space defined by the elastic membrane before the drug is re-ejected after initial ejection thereof, which may otherwise cause ejection pressure reduction of the drug. This will prevent ejection speed and penetration performance degradation. As described above, the bubble formation resulting from the external air which may adversely affect the ejection pressure may be caused by the back-pressure generated in the drug chamber in the process of the elastic membrane retracting after the initial microjet ejection. As described above, according to a preferred aspect according to the present disclosure, prior to re-ejection after the initial microjet ejection, the same amount of drug as the initially ejected drug may be automatically charged into the drug chamber, thereby maintaining the internal pressure therein. This may prevent the introduction of external air into the drug chamber that may otherwise cause a significant reduction in the propulsion force of the drug microjet.
The specific operations of the microjet drug injection device according to the present disclosure having the above-described technical feature will be described step by step with reference to
First, the laser unit 300 is driven to create a bubble 115b in the pressure driving liquid 115 in the pressure chamber 110. In the embodiment shown, a handheld laser unit 300 using the Er: YAG laser was used as a laser source with a wavelength of 2940 nm and a pulse width of 150-200 μs. Referring to
The pressure driving liquid 115 containing water as a main component is filled in the pressure chamber no of the microjet injector unit 100. Water as the pressure driving liquid 115 has the property of absorbing light having a wavelength of 2900 nm most effectively. As the irradiated laser beam 350 is absorbed into the pressure driving liquid 115, the pressure driving liquid 115 changes from a liquid state to a gas state around a laser focus point on which energy is concentrated. Accordingly, a vapor bubble 115b is created inside the pressure driving liquid 115 as shown in
The vapor bubble 115b created in the pressure driving liquid 115 rapidly expands and has increased volume. Accordingly, the pressure of the entire pressure chamber 120 is increased. This results in the expansion of the elastic membrane 130 located below the pressure chamber 120 (see
As the internal pressure of the pressure chamber 120 increases and thus the elastic membrane 130 expands, the propulsion pressure is transferred to the drug solution 125 in the drug chamber 120 adjacent to the membrane. The drug solution 125 in the first space 120a, upon receiving direct pressure from the elastic membrane 130, is strongly pushed toward the bearing ball 152. The bearing ball 152 is resiliently pushed by the pressure of the drug solution. Thus, the connection neck 128 in the drug chamber 120 is opened. Thus, as shown in
The propulsion pressure and kinetic energy are transferred to the drug solution in the second space 120b of the drug chamber 120 by the movement flow of the drug solution 125 and urged movement of the bearing ball 152. Thus, the drug solution 125 is ejected through the micro nozzle 140 in the form of a microjet 125a.
Then, as shown in
As the bearing ball 152 closes the connection neck 128, the first space 120a of the drug chamber 120 is fluidly shut off from the atmosphere outside the micro nozzle 140. Therefore, even when the internal pressure of the first space 120a falls below the external atmospheric pressure as the elastic membrane 130 continuously recovers and returns to the original position, air from the atmosphere outside the micro nozzle 140 is prevented from flowing into the first space 120a.
Meanwhile, the amount of the drug solution is reduced by the amount of ejected drug in the first space 120a of the drug chamber 120 by microjet ejection. Thus, when the bearing ball 152 closes the connection neck 128 and the elastic membrane 130 is continuously retracted from the extended state to the original state, the internal pressure of the first space 120a is reduced. In this connection, in the case of the conventional microjet drug injection devices, because there is no configuration of the nozzle closure 150, which is a key feature of the present disclosure, when the elastic membrane 130 is restored to its original state, the pressure inside the drug chamber is lower than the external atmospheric pressure. Thus, there is a problem that air is introduced into the drug chamber from the outside by back-pressure. However, according to the present disclosure, due to the action of the nozzle closure 150, the problem of inflow of external air into the chamber after such ejection may be effectively prevented.
As shown in
In the case of the embodiment shown in
In order to confirm the performance and the improved effect of the microjet drug injection device according to the present disclosure as described above, a test device according to the present disclosure was fabricated. Then, a comparison test was conducted between the test device and the conventional microjet drug injection device. Hereinafter, the above-described comparison test results will be described with reference to the accompanying drawings.
The laser unit used in the comparative test is a medical handheld laser unit 300 using an Er: YAG laser as a laser source with a wavelength of 2940 nm and a pulse width of 150-200 μs. In this regard, the nozzle diameter of the microjet injector unit was 300 μm. Further, the laser operation was configured to have an ejection rate of 10 times per second for each of the conventional device and the present test device. In
To the contrary, in the case of the drug injection device according to the present disclosure, air bubbles were not created in the drug chamber even though the number of ejections increased, as shown in
Further, referring to
In particular, according to the result graph of
To the contrary, in the case of the drug injection device according to the present disclosure, as shown in
Table 1 below shows measurements of microjet ejection speed and penetration performance of the drug injection device according to the present disclosure. The drug injection device used in
Penetration performance of drug injection device according to the present disclosure
As seen from
Therefore, according to the present disclosure microjet drug injection device, various medical drugs such as therapeutic drugs, anesthetics, hormones, vaccines, and various kinds of drugs such as cosmetic lotion, tattoo liquid and botulinum toxin (aka Botox) may be injected into human or animal body without pain such that the ejection amount may be accurately adjusted and correct dose may be administered in a repeated manner. Thus, the present device may be particularly advantageously used in various industrial fields such as the medical field, the cosmetic field, the tattoo field, and the livestock field.
On the other hand, in the explanation of the present disclosure, the term “drug” or “drug solution” has been used for illustrative purposes. The drug solution is not limited to a solution injected into a living tissue. Rather, drug solution may conceptually encompass liquid injections such as foods (bread, confectionery, jelly, etc.), soft synthetic resin, dyes and additives added to fibers, etc.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2016-0145666 | Nov 2016 | KR | national |
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