Local anesthetic dilating balloon system and method of making same

Abstract

The present application relates to a local anesthetic dilatation balloon system and a manufacturing method thereof, wherein the local anesthetic dilatation balloon system comprises a balloon having a dilatable balloon body, the balloon body has an inner side surface and an outer side surface, a drug loading unit is arranged on the outer side surface, the drug loading unit contains vesicles, the vesicles are provided with an anesthetic agent, and the vesicles are broken when subjected to a pressure exceeding a threshold value. The local anesthetic dilatation balloon system can achieve local anesthesia without injecting an anesthetic agent, thereby greatly simplifying the operation and system structure, for example, eliminating the injection step of the anesthetic agent and the fluid channel for injecting the anesthetic agent.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and in particular to a local anesthesia dilatation balloon system and its manufacturing method. Background Technology

[0002] Balloon compression of the trigeminal ganglion is a minimally invasive neurosurgical treatment for trigeminal neuralgia. During the procedure, the doctor inserts a balloon into the McMurray cavity through the foramen ovale in the face using a puncture needle. The balloon is then inflated to compress the target nerve for approximately 2-3 minutes, thus relieving pain. This treatment method is characterized by its effectiveness, low risk, and short duration.

[0003] Currently, in clinical practice, it is generally believed that the effectiveness of this treatment is closely related to the shape of the balloon dilation, with the mainstream view being that a "pear-shaped" balloon yields the best results. Therefore, in order to observe and control the shape of the balloon dilation, a fluid containing contrast agent is usually injected into the balloon to dilate it, thereby enabling observation and control of the balloon's shape.

[0004] In addition, current surgical procedures employ either general anesthesia or local anesthesia. General anesthesia is the mainstream method, but it is expensive and carries high risks. Some surgeons use puncture tools to create a percutaneous channel to the trigeminal nerve's semilunar node, then inject anesthetic using an injection device to achieve local anesthesia; the injection system is then removed, and a balloon is inserted for compression, but this procedure is cumbersome. Thirdly, a specialized local anesthesia balloon system has been designed specifically for administering anesthetic. This system requires two tubing lines: one for injecting a fluid containing contrast agent, and the other for injecting the anesthetic, thus still suffering from high manufacturing costs. Summary of the Invention

[0005] The purpose of this invention is to provide a local anesthesia dilatation balloon system that can achieve local anesthesia without the need for injection of anesthetic, thereby greatly simplifying operation and system structure, such as eliminating the need for anesthetic injection and fluid channels for injecting anesthetic. This objective is achieved through a local anesthesia dilatation balloon system comprising a balloon having an inflatable balloon body with an inner and outer surface. A drug-loaded unit containing vesicles of anesthetic is disposed on the outer surface of the balloon body, and the vesicles rupture upon exposure to pressure exceeding a threshold pressure. In this way, the balloon's inherent ability to compress human tissue during treatment allows the vesicles on the outer surface of the balloon body to release anesthetic over a controlled period for local anesthesia, without the need for additional fluid channels to deliver the anesthetic. Preferably, the drug-carrying unit is constructed as a multilayer structure and includes: a base plate membrane attached to the outer surface of the balloon body; a protective membrane capable of rupturing when the balloon body expands or dissolving upon contact with water; and a vesicle layer disposed between the base plate membrane and the protective membrane and comprising a plurality of the vesicles and a matrix for filling the gaps between the vesicles. Preferably, the local anesthesia dilatation balloon system further includes a catheter having only one fluid channel with a fluid inlet and a fluid outlet, the balloon being positioned at the fluid outlet with its inner surface facing the fluid outlet. Because a vesicle containing anesthetic is located on the outer surface of the balloon body to release the anesthetic upon pressure, a dedicated fluid channel for delivering the anesthetic can be eliminated, greatly simplifying the catheter's structure and making it easier to manufacture. Preferably, the vesicle is formed from a single layer of biodegradable glassy polymer or a single layer of brittle inorganic material, or a combination thereof. The biodegradable glassy polymer can be polylactic-co-glycolic acid copolymer (PLGA), polylactic acid (PLA), or polycaprolactone (PCL). By adjusting the crystallinity and molecular weight of the polymer, its brittleness can be precisely controlled, thereby adjusting the threshold pressure. The brittle inorganic material can be a thin layer of silica or calcium carbonate. Using composite materials allows for more precise setting of the pressure threshold. Preferably, the diameter of the vesicle is in the range of 1 micrometer to 50 micrometers, and / or the wall thickness of the vesicle is in the range of 100 nanometers to 10 micrometers. Preferably, the threshold pressure of the vesicle is in the range of 50 kPa to 100 kPa. Preferably, both the substrate membrane and the matrix are formed of a biocompatible elastic polymer. Preferably, the protective film is formed from polyvinyl alcohol, hydroxypropyl methylcellulose, trehalose, or gelatin. Preferably, the anesthetic is an anesthetic solution with a concentration in the range of 2% to 5%, or an anesthetic crystal suspension. This invention also proposes a method for a local anesthesia dilatation balloon system, the method comprising the following steps: providing a balloon comprising an inflatable balloon body having an inner surface and an outer surface; pretreating the outer surface of the balloon body; uniformly dispersing vesicles that rupture under pressure exceeding a threshold pressure in a volatile solvent and incorporating a biocompatible elastic polymer to form a vesicle layer suspension; coating the vesicle layer suspension onto the pretreated outer surface by dip coating, spray coating, or electrospinning; and evaporating the volatile solvent in the coated vesicle layer suspension to form drug-loaded units on the outer surface of the balloon body. This allows conventional balloons to be modified into balloons capable of releasing anesthetics using pressure, which can be used in existing conventional dilatation balloon systems without modifying existing equipment. Preferably, the method further includes the following steps before coating the vesicle layer suspension: dissolving a biocompatible elastic polymer in a volatile solvent to form a substrate membrane solution; spraying the substrate membrane solution onto a pretreated outer surface; and evaporating the volatile solvent in the sprayed substrate membrane solution to form a substrate membrane as part of the drug delivery unit. Preferably, the method further includes the following additional steps before the volatile solvent in the coated vesicle layer suspension is completely evaporated: dissolving a water-soluble material in water to form a protective film solution; spraying the protective film solution onto the outer surface of the coated vesicle layer suspension; and evaporating the water in the sprayed protective film solution to form a protective film as part of the drug delivery unit. Preferably, the volatile solvent is tetrahydrofuran or acetone. Preferably, the volatile solvent or water evaporates at an ambient temperature below 40°C. Preferably, the formation of the drug-loaded unit further includes curing using photocuring or thermal crosslinking. Preferably, the pretreatment includes plasma treatment of the outer surface or coating the outer surface with a silane coupling agent. Plasma treatment can generate active groups on the outer surface to increase surface energy, thereby facilitating coating adhesion. Preferably, the vesicle layer suspension is coated onto the pretreated outer surface by ultrasonic spraying. Ultrasonic spraying utilizes high-frequency vibration atomization, which minimizes the impact on suspended particles, thereby effectively preventing vesicle damage during coating. Preferably, the additional step is performed while evaporating 30% to 80% of the volatile solvent in the coated vesicle layer suspension. Preferably, the method further includes the following steps: providing a catheter having a fluid inlet and a fluid outlet; and mounting a balloon forming the drug-carrying unit at the fluid outlet of the catheter such that the inner surface of the balloon body faces the fluid outlet. Here, either a single-channel catheter or an existing multi-channel catheter can be used. Preferably, the method further includes the following steps before installing the balloon: sampling the balloon; observing under a microscope the uniformity of each coating in the drug-loading unit of the sampled balloon, the integrity of the vesicle, and whether there are cracks; and / or expanding the sampled balloon under the monitoring of a pressure sensor and a gas sensor until the gas sensor detects the release of anesthetic in the balloon, and determining whether the reading of the pressure sensor at this time meets the threshold pressure of the vesicle. Attached Figure Description

[0006] To better understand the above and other objects, features, advantages, and functions of the present invention, reference can be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate preferred embodiments of the invention and do not limit the scope of the invention in any way; the parts in the drawings are not drawn to scale.

[0007] Figure 1 A partial cross-sectional view of the local anesthesia dilatation balloon system according to the present invention is shown, wherein the balloon is in an inflated state;

[0008] Figure 2 An enlarged view of the front end of the local anesthesia dilatation balloon system according to the present invention is shown, wherein the balloon is in a contracted state;

[0009] Figure 3 An enlarged view of the balloon of the local anesthesia dilatation balloon system according to the present invention is shown;

[0010] Figure 4 An enlarged schematic diagram of the drug delivery unit of the local anesthesia dilatation balloon system according to the present invention is shown; and

[0011] Figure 5 A flowchart is shown for a method of manufacturing a local anesthesia dilatation balloon system according to the present invention. Detailed Implementation

[0012] Now, with reference to the accompanying drawings, specific embodiments of the present invention will be described in detail. The embodiments described herein are merely preferred embodiments of the invention; those skilled in the art can conceive of other ways to implement the invention based on these preferred embodiments, and such other ways also fall within the scope of the invention.

[0013] Figure 1A partial cross-sectional view of a local anesthesia dilatation balloon system 10 according to the present invention is shown, wherein the local anesthesia dilatation balloon system 10 includes a catheter 100 and a balloon 200, and the internal structure of the catheter 100 is clearly shown in cross-section.

[0014] The conduit 100 here has only one fluid passage and a fluid inlet 110 and a fluid outlet 120 provided for the fluid passage (see Figure 2 The fluid inlet 110 can be connected to a fluid supply device, such as a syringe, to supply fluid into the fluid channel, which passes through the fluid channel and enters the balloon 200 at the front end, i.e., near the patient end, via the fluid outlet 120, thereby inflating the balloon 200 to provide compression therapy to the target nerve. Conversely, the fluid supply device can also withdraw fluid from the fluid channel, thereby deflating the balloon 200 to allow removal of the local anesthesia inflation balloon system 10 from the body.

[0015] In this embodiment, the catheter 100 consists of a gripping portion 130 at the rear end, i.e., near the operator's end, and a tubular insertion portion 150 at the front end. This allows the gripping portion 130 and the insertion portion 150 to be manufactured separately and then assembled, for example, bonded together, during subsequent manufacturing processes. However, the catheter 100 can also be constructed integrally.

[0016] Figure 2 A further enlarged view of the front end of the local anesthesia dilatation balloon system 10 according to the present invention is shown. Figure 3 An enlarged view of the balloon 200 of the local anesthesia dilatation balloon system 10 according to the present invention is shown. Figure 4 An enlarged schematic diagram of the drug-carrying unit 220 of the local anesthesia dilatation balloon system 10 according to the present invention is shown, wherein all balloons 200 are in a contracted state.

[0017] from Figure 2 As can be seen, the fluid outlet 120 of the catheter 100 is disposed on the side wall of the catheter 100, or the insertion portion 150, and the end of the insertion portion 150 is closed by a plug 160. A balloon 200 is disposed at the fluid outlet 120 of the catheter 100 and includes an inflatable balloon body 210 and a fixing section 240. The balloon body 210 has an inner surface and an outer surface, wherein the inner surface faces the fluid outlet 120, and a drug-loaded unit 220 is disposed on the outer surface. The fixing section 240 is disposed on both sides of the balloon body 210 and is pressed against the outer wall of the catheter 100 by a fixing element 140, such as a metal clamp, thereby sealingly fixing the balloon 200 at the fluid outlet 120 of the catheter 100.

[0018] See Figure 3 and Figure 4The drug-carrying unit 220 has a multi-layered structure, comprising, from the outside to the inside, a protective layer 222, a vesicle layer 224, and a base plate membrane 226. The vesicle layer 224 contains multiple vesicles 225 and a matrix 223 for filling the gaps between the vesicles 225. Each vesicle 225 contains an anesthetic 227. When subjected to pressure exceeding a threshold pressure, the vesicles 225 rupture, releasing the anesthetic 227.

[0019] The pressure on vesicle 225 originates from the pressure generated when balloon body 210 expands and contacts human tissue and target nerves. The threshold pressure is typically set between 50 kPa and 100 kPa. This range covers the pressure interval from initial contact with human tissue to significant expansion of balloon 200. Precise release of anesthetic 227 during this period is highly advantageous for treatment. The anesthetic usually takes effect within tens of seconds, after which the pressure within balloon 200 can be further increased to the therapeutic pressure (typically approximately 200 kPa to 300 kPa) for painless or significantly reduced-pain compression therapy.

[0020] Therefore, vesicle 225 can be formed from a single layer of biodegradable glassy polymer, or a single layer of brittle inorganic material, or a combination thereof, such as a composite material consisting of one or more layers of biodegradable glassy polymer and one or more layers of brittle inorganic material.

[0021] The biodegradable glassy polymer can be polylactic-co-glycolic acid copolymer (PLGA), polylactic acid (PLA), or polycaprolactone (PCL), which exhibits brittleness below its glass transition temperature (Tg). By adjusting the polymer's crystallinity and molecular weight, its brittleness can be precisely controlled, thereby adjusting the threshold pressure. The brittle inorganic material can be a thin layer of silica or calcium carbonate. Using the composite material allows for more precise setting of the pressure threshold.

[0022] Another way to precisely set the pressure threshold is to control the wall thickness of vesicle 225. Uniform wall thickness control can be achieved through techniques such as microfluidics. Preferably, the wall thickness of vesicle 225 is controlled within the range of 100 nanometers to 10 micrometers.

[0023] The vesicle 225 is preferably a spherical or ellipsoidal microcapsule with a diameter preferably in the range of 1 micrometer to 50 micrometers. This size is much smaller than the microfolds on the outer surface of the balloon 200, thereby ensuring that the vesicle 225 does not rupture prematurely when the balloon 200 is folded for delivery.

[0024] The anesthetic 227 encapsulated inside the vesicle 225 can be a high-concentration (e.g., 2%-5%) local anesthetic solution (e.g., lidocaine, ropivacaine) or an anesthetic crystal suspension to increase drug loading.

[0025] In order to ensure that the vesicle 225, or the vesicle layer 224, is stably attached to the outer surface of the balloon body 210, a base plate membrane 226 is provided between the vesicle layer 225 and the outer surface of the balloon body 210.

[0026] The basement membrane 226 can be formed of a biocompatible elastic polymer, including hydrogels, silicone, or elastomer films such as polyvinyl alcohol (PVA) hydrogels or polyurethane films, similar to or similar to the matrix 223 of the vesicle layer 224. The basement membrane 226, formed of an elastic polymer, can stably adhere to the outer surface of the balloon body 210, and also facilitates the stable adhesion of the vesicle layer 224, which has a matrix 223 formed of the same or similar material, to the basement membrane 226.

[0027] To prevent the vesicle layer 224 from being scratched by external forces, a protective membrane 222 is provided on the outer side of the vesicle layer 224.

[0028] The protective membrane 222 can be an extremely thin, rapidly dissolving membrane. Depending on the environment in which it is applied, the protective membrane 222 can be formed from water-soluble materials such as polyvinyl alcohol, hydroxypropyl methylcellulose, trehalose, or gelatin to protect the vesicle 225 from blood flow in the early stages of the balloon 200 entering the body, and to dissolve rapidly upon contact with tissue after reaching its site of action.

[0029] The following describes a method for manufacturing the local anesthesia dilatation balloon system 10 according to the present invention. First, a balloon 200 is provided in step S100. This balloon can be a conventional PBC balloon (such as one made of silicone or polyurethane). Specifically, the balloon 200 includes an expandable balloon body 210 having an inner surface and an outer surface. A catheter 100 may also be provided simultaneously, having a fluid inlet 110 and a fluid outlet 120. Both a single-channel catheter 100 and an existing multi-channel catheter can be used to form the local anesthesia dilatation balloon system 10 according to the present invention. The manufacturing methods of single-channel or multi-channel catheters and conventional balloons 200 are well known in the art and will not be described in detail here. Then, in step S200, the outer surface of the balloon body 210 is pretreated. This pretreatment is used to improve the wettability and adhesion of the outer surface of the balloon body 210, ensuring that the coating does not peel off. In one embodiment, plasma treatment can be performed on the outer surface of the balloon body 210. For example, the balloon 200 can be placed in a plasma cleaner and argon or oxygen can be introduced to create micro-roughness on the outer surface of the balloon body 210 and introduce polar groups (such as -OH, -COOH), making it change from hydrophobic to hydrophilic, thereby allowing the coating solution to spread and adhere better. In an alternative embodiment, a silane coupling agent may be coated on the outer surface of the balloon body 210 to facilitate the spreading and adhesion of the coating solution. After completing the pretreatment step S200, the coating step S300 can be further performed. In a simplified embodiment, only coating is required to form the vesicle layer 224. In this case, the prepared pressure-responsive vesicles 225 (i.e., those that rupture when subjected to pressure exceeding a threshold pressure, for example, in the range of 50 kPa to 100 kPa) can be uniformly dispersed in a volatile solvent, such as tetrahydrofuran or acetone, and mixed in a precise ratio with a biocompatible elastic polymer as a matrix 223 to form a vesicle layer suspension. Here, the matrix 223 serves as a "framework" for the vesicles 225. The vesicle layer suspension is then coated onto the pretreated outer surface using dip coating, spray coating, or electrospinning. To prevent vesicle 225 breakage, a low-pressure, low-shear coating method must be employed. Ultrasonic spraying is an ideal choice, utilizing high-frequency vibration atomization with minimal impact on suspended particles. During coating, the balloon 200 can be rotated at a constant speed along multiple axes, and the nozzle can be manipulated to scan back and forth to ensure that the density of the vesicles 225 covering each area of ​​the outer surface of the balloon body is basically consistent. By controlling the number of sprays, suspension concentration, and spraying rate, the dry film thickness can be controlled within the range of 20-50 micrometers. Thickness directly affects the confinement level and trigger pressure of vesicle 225. exist Figure 5 In the illustrated embodiment, a protective layer 222 and / or a base plate layer 226 also need to be coated, thereby allowing the respective layers to be coated and formed in a layered coating manner, i.e., coating is performed in the order of base plate layer 226, vesicle layer 224, and protective layer 222. In this case, a biocompatible elastic polymer can be dissolved in a volatile solvent to form a substrate membrane solution before coating the vesicle layer suspension. The substrate membrane solution is then sprayed onto the pretreated outer surface. Accordingly, after coating the vesicle layer suspension, a water-soluble material can be dissolved in water to form a protective film solution. The protective film solution is then sprayed onto the pretreated outer surface, or more precisely, onto the outer surface already coated with the vesicle layer suspension. After each coating layer is applied, a curing step S400 can be performed. That is, the coating step S300 and the curing step S400 are performed alternately. During curing, preferably at room temperature or low temperature, especially below 40°C, the volatile solvents in the coated substrate layer solution, vesicle layer suspension, and / or water in the protective layer solution evaporate, causing them to dry and / or crosslink, thereby forming the substrate layer 226, vesicle layer 224, and / or protective layer 222, respectively, and ultimately forming the drug-loaded unit 220. Room temperature or low temperature can advantageously avoid high temperature damage to the vesicles 225 or inactivation of the anesthetic 227. If necessary, photocuring or thermal crosslinking can also be performed to ensure the coating is firmly cured. Particularly preferably, the protective film solution is sprayed after the vesicle layer suspension has been coated, but before the volatile solvents therein have completely evaporated, especially when 30% to 80%, particularly 50%, have evaporated. This allows for the formation of an extremely thin (approximately 2-10 micrometers) continuous protective film 222, facilitating rapid dissolution of the protective film 222 and ensuring a smooth transition in the treatment process. After all coatings are applied, final curing can be performed to ensure good bonding between the layers. The resulting drug-loaded unit 220 has a thickness of less than 0.5 mm, so it will not affect the use of the balloon, but it can modify all existing balloons into balloons with local anesthesia function according to needs; greatly expanding the application scenarios. Then, quality control step S500 can be performed. In quality control step S500, the functionality of the drug delivery unit 220 can be confirmed through microscopic inspection and functional testing. During microscopic examination, samples were taken and observed under a microscope to check the uniformity of each coating in the drug-carrying unit 220 of the balloon body 210, the integrity of the vesicles, and whether there were any cracks. In the functional test, a sample was subjected to an in vitro simulated pressure test. The sampled balloon 200 was expanded under the monitoring of pressure and gas sensors until the gas sensor detected the release of anesthetic 227 in the balloon 200. It was then determined whether the reading of the pressure sensor at this time met the threshold pressure of the vesicle 225, such as whether it matched the set threshold pressure or whether it was within the range of 50 kPa to 100 kPa. Finally, installation step S600 can be performed to install the balloon 200 forming the drug-loaded unit 220 at the fluid outlet 120 of the catheter 100 by means of, for example, a fixing element 140, such that the inner surface of the balloon body 210 faces the fluid outlet 120, thereby completing the manufacture of the local anesthesia dilatation balloon system 10.

[0030] This invention is not limited to the embodiments illustrated and described. Modifications and combinations of features may be made within the scope of the claims, even if these features are illustrated and described in different embodiments. List of reference numerals 10. Local anesthesia dilatation balloon system 100 catheters 110 Fluid inlet 120 Fluid Outlet 130 Grip section 140 Fixing Components 150 Penetration Section 160 plug 200 balloons 210 Balloon body 220 drug delivery units 222 Protective Film 223 Matrix 224 Vesicle layer 225 vesicles 226 Base Plate Membrane 227 Anesthetic 240 Fixed Section

Claims

1. A local anesthesia dilatation balloon system, characterized in that, The local anesthesia dilatation balloon system includes a balloon having an inflatable balloon body with an inner surface and an outer surface. A drug-carrying unit is disposed on the outer surface, the drug-carrying unit containing a vesicle containing an anesthetic agent, and the vesicle ruptures when subjected to pressure exceeding a threshold pressure.

2. The local anesthesia dilatation balloon system according to claim 1, characterized in that, The drug-carrying unit is constructed in a multi-layer structure and includes: A baseplate membrane, which is attached to the outer surface of the balloon body; A protective membrane, which is ruptured upon expansion of the balloon body or dissolves upon contact with water; and A vesicle layer is disposed between the base plate membrane and the protective membrane and includes a plurality of vesicles and a matrix for filling the gaps between the vesicles.

3. The local anesthesia dilatation balloon system according to claim 1, characterized in that, The local anesthesia dilatation balloon system also includes a catheter having only one fluid channel and a fluid inlet and a fluid outlet, the balloon being positioned at the fluid outlet with its inner surface facing the fluid outlet.

4. The local anesthesia dilatation balloon system according to claim 1, characterized in that, The vesicles are formed from a single layer of biodegradable glassy polymer or a single layer of brittle inorganic material or a combination thereof.

5. The local anesthesia dilatation balloon system according to claim 1, characterized in that, The diameter of the vesicle is in the range of 1 micrometer to 50 micrometers, and / or the wall thickness of the vesicle is in the range of 100 nanometers to 10 micrometers.

6. The local anesthesia dilatation balloon system according to claim 1, characterized in that, The threshold pressure of the vesicle is in the range of 50 kPa to 100 kPa.

7. The local anesthesia dilatation balloon system according to claim 2, characterized in that, Both the substrate membrane and the matrix are formed from a biocompatible elastic polymer.

8. The local anesthesia dilatation balloon system according to claim 2, characterized in that, The protective film is formed from polyvinyl alcohol, hydroxypropyl methylcellulose, trehalose, or gelatin.

9. The local anesthesia dilatation balloon system according to claim 1, characterized in that, The anesthetic is an anesthetic solution with a concentration in the range of 2% to 5%, or an anesthetic crystal suspension.

10. A method for manufacturing a local anesthesia dilatation balloon system, characterized in that, The method includes the following steps: A balloon is provided, the balloon comprising an inflatable balloon body having an inner surface and an outer surface; The outer surface of the balloon body is pretreated; Vesicles that rupture under pressure exceeding a threshold are uniformly dispersed in a volatile solvent and mixed with a biocompatible elastic polymer to form a vesicle layer suspension. The vesicle layer suspension is coated onto the pretreated outer surface using dip coating, spray coating, or electrospinning processes; and The volatile solvent in the coated vesicle layer suspension evaporates to form drug-loaded units on the outer surface of the capsule body.

11. The method according to claim 10, characterized in that, The method further includes the following steps before coating the vesicle layer suspension: A biocompatible elastic polymer is dissolved in a volatile solvent to form a substrate membrane solution; The substrate film solution is sprayed onto the pretreated outer surface; and The volatile solvent in the sprayed substrate film solution is evaporated to form a substrate film that is part of the drug-carrying unit.

12. The method according to claim 10, characterized in that, The method further includes the following additional steps before the volatile solvent in the coated vesicle layer suspension is completely evaporated: Dissolve water-soluble materials in water to form a protective film solution; The protective film solution is sprayed onto the outer surface of the suspension that has been coated with the vesicle layer; as well as The water in the sprayed protective film solution is evaporated to form a protective film that is part of the drug-carrying unit.

13. The method according to any one of claims 10 to 11, characterized in that, The volatile solvent is tetrahydrofuran or acetone.

14. The method according to any one of claims 10 to 12, characterized in that, The volatile solvent or water evaporates at an ambient temperature below 40°C.

15. The method according to any one of claims 10 to 12, characterized in that, The formation of the drug-loaded unit also includes curing using photocuring or thermal crosslinking.

16. The method according to claim 10, characterized in that, The pretreatment includes plasma treatment of the outer surface or coating the outer surface with a silane coupling agent.

17. The method according to claim 10, characterized in that, The vesicle layer suspension is coated onto the pretreated outer surface by ultrasonic spraying.

18. The method according to claim 12, characterized in that, The additional step is performed while evaporating 30% to 80% of the volatile solvent in the coated vesicle layer suspension.

19. The method according to claim 10, characterized in that, The method further includes the following steps: Provides a conduit having a fluid inlet and a fluid outlet; and The balloon forming the drug-carrying unit is mounted at the fluid outlet of the catheter, such that the inner surface of the balloon body faces the fluid outlet.

20. The method according to claim 19, characterized in that, The method further includes the following steps before installing the balloon: Sampling was performed on the balloon; Observe under a microscope the uniformity of the coatings in the drug-loaded units of the sampled capsules, the integrity of the vesicles, and the presence of cracks; and / or The sampled balloon is expanded under the monitoring of pressure and gas sensors until the gas sensor detects the release of anesthetic in the balloon, and it is determined whether the reading of the pressure sensor at this time meets the threshold pressure of the vesicle.

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