JP6198373B2 - Micro needle - Google Patents

Description

The present invention relates to a micro Needle for providing modifying effect and / or function effect on the skin surface and / or the stratum corneum

  Oral administration and transdermal administration are often used as methods for administering a drug into a human body. Injection is a typical transdermal method of administration. However, injection is an unacceptable technique for many people who must bother the hands of specialists such as doctors and nurses, can be painful, and can also be infected with AIDS or hepatitis B. . On the other hand, a transdermal administration method using a microneedle array without causing pain has recently attracted attention (Non-Patent Document 1).

During the transdermal administration of a drug, the skin stratum corneum acts as a barrier for drug permeation, and simply applying the drug to the skin surface does not necessarily provide sufficient permeability. On the other hand, by perforating the stratum corneum using a fine needle, that is, a microneedle, the drug administration efficiency can be significantly improved over the coating method. A microneedle array is a large number of microneedles integrated on a substrate. Microneedle patches are products that are easy to use by adding various tapes to the microneedle array, such as adhesive tape for attaching the microneedle array to the skin and a cover sheet for maintaining sterility until use. .
Here, the tape refers to a film in which an adhesive is applied.

Initially, metal or silicon was used as a material for the microneedle. A method of piercing the skin with a stainless needle, allowing a drug solution to flow through it and absorbing the drug from the hole (Patent Document 1), or a method of coating the drug on the surface of the stainless needle and inserting the drug ( Patent Document 2) has been proposed. Furthermore, it has also been proposed to inject a drug solution simply by using a hollow microneedle in which the injection needle is miniaturized (Patent Document 3).
However, the chemical solution casting method has poor drug uptake efficiency or sterilization, and the coating method peels off the coated drug at the time of insertion and the drug uptake efficiency is low, and the microinjection needle method has a complicated structure There were disadvantages such as. Furthermore, metal and silicon microneedles have the drawback of causing an accident when broken inside the body.

  On the other hand, if a microneedle is created using the substance which melt | dissolves in a body, such various problems can be solved (patent document 4). In addition, if a polymer (biosoluble polymer) that dissolves in the skin after administration is used as the material for the microneedle, the moisture in the skin diffuses into the needle due to the application of the microneedle and is inserted into the skin. The needle part swells and then dissolves. Anti-wrinkle action is expressed by diffusion of hyaluronic acid and collagen into the skin due to dissolution of the needle, or drugs and valuable substances previously dissolved in the needle are released into the skin (Patent Documents 5 and 6).

  A microneedle array made of a biosoluble polymer is often manufactured using a template (Patent Document 5). A microneedle pattern is formed by a lithography method using a photosensitive resin and then transferred to create a mold having a microneedle-forming recess. A microneedle array can be obtained by casting a microneedle material onto this mold and then heating to evaporate the moisture, and then separating the solidified material from the mold.

  Some drugs contained in the microneedle array are very expensive or only a small amount can be obtained. When such a precious drug is contained in a material and a microneedle array is prepared by a conventional method, the drug is contained not only in the microneedle part but also in the substrate part (Patent Document 7). When this microneedle array is inserted into the skin, the drug contained in the microneedle part is taken into the body and diffuses, but the drug present in the substrate part is discarded without being used, and the utilization efficiency of expensive drugs is low. Result.

  Several attempts to efficiently use expensive drugs are already known. In addition to the method of coating the surface of the microneedle (Patent Document 2), the method of attaching the drug to the tip of the microneedle (Patent Document 8), the method of collecting the drug at the tip of the needle by centrifuging the microneedle while it is soft (Patent Document) 9) A method (Patent Document 10), in which a template is filled with a drug-containing material solution, dried and then filled with a material solution that does not contain the drug, and the drug is held only at the tip of the microneedle has been reported. The method of Patent Document 8 for attaching the drug to the tip is characterized in that the drug is heated to about 100 ° C. and dissolved to adhere to the tip of the microneedle.

Japanese Patent Laid-Open No. 3-151982 JP 2008-029710 A Special Table 2002-517300 JP 2003-238347 A JP 2009-238772 A JP 2010-029634 A JP 2008-303162 A JP 2006-346127 A Special table 2009-507573 Japanese National Patent Publication No. 2009-066763

Gon Ei, Fumio Kamiyama “The Path to Microneedle Product”, Pharmacology, The Pharmaceutical Society of Japan, September 2009, Vol. 69, No. 4, p. 272-276.

The problem to be solved by the present invention is to solve the problems of the prior art and provide a new method for effectively using expensive drugs.
In the method of Patent Document 8 in which a drug is attached to the tip of a microneedle, if the drug is heated to 100 ° C. or higher, an expensive and valuable drug is often thermally decomposed. Therefore, warming should be avoided when attaching the drug to the microneedle tip.
In the method of Patent Document 8, since the drug is simply attached to the tip of the microneedle, the adhesion strength of the drug is weak, and when the microneedle is inserted into the skin, the attached part is broken and the drug is peeled off. There is a problem that it is not captured enough. These problems need to be solved.

The microneedle welding method according to the present invention made to solve the above problems is
a) Create a microneedle array using water-soluble polymer as a raw material,
b) creating a drug solution to be attached to the tip of the microneedle array;
c) bringing the tip of the microneedle array into contact with the drug solution for a short time;
When manufacturing a microneedle array with a drug attached to the tip,
In addition to the drug, a water-soluble polymer is dissolved in the drug solution,
The water-soluble polymer in the drug solution and the water-soluble polymer that is the material of the microneedle array include at least one same component,
The viscosity of the drug solution is 1.0 dPa · s or more and 90 dPa · s or less,
When pulling up the microneedle array from the drug solution, slowly pull up the thread from the drug solution, and further pull up to cut the thread.
And the drug is incorporated into the tip portion of the microneedle integrally with the water-soluble polymer,
A feature of producing a microneedle array with a drug attached to the tip (however, when the microneedle is immersed in the drug solution, the drug solution is held in an individual opening or recess for each microneedle. Except) .

  In order to efficiently attach the drug to the tip of the microneedle array, the microneedle array material and the drug solution are preferably compatible. For this purpose, it is preferable that both the drug and the microneedle material are water-soluble. The drug solution may be a mixture of water and an organic solvent that is mainly miscible therewith. Examples of the organic solvent miscible with water are ethanol and acetone.

Furthermore, it is preferable to increase the viscosity of the drug solution by dissolving the water-soluble polymer in the drug solution. This is because the viscosity increases due to dissolution of the water-soluble polymer, and the amount of drug solution deposited on the tip of the microneedle increases. The concentration of the water-soluble polymer in the aqueous solution is 1 to 20%, preferably 2 to 15%. If the concentration of the water-soluble polymer is small, the amount of the drug solution deposited by needle contact is small, and if the concentration is too high, the fluidity is lost and the welding operation is difficult to perform smoothly.
The appropriate concentration of the water-soluble polymer in the drug solution can be determined by the solution viscosity of the drug solution. The viscosity of the drug solution preferable for drug welding is in the range of 1.0 dPa · s to 90 dPa · s. When the viscosity of the drug solution is less than 1.0 dPa · s, the viscosity is too low and the amount of welding decreases. On the other hand, if it exceeds 90 dPa · s, stringing tends to occur even after pulling after contact with the drug solution. The viscosity is a value at room temperature (25 ° C.).

  When the tip of the microneedle array is brought into contact with the drug solution, the water-soluble microneedle material dissolves in the drug solution if it is too long.

By combining the drug and the water-soluble polymer, which is a microneedle material, into a drug aqueous solution, the tip is partially dissolved when the microneedle tip is immersed in the drug aqueous solution, so the drug is integrated with the water-soluble polymer. Therefore, it will be taken into the tip of the microneedle. In this way, the microneedle in which the drug and the material are integrated does not peel off the welded portion, that is, the drug when the skin is inserted, and the drug is completely taken into the body.
Here, “integral” means that there is no clear boundary surface between the original microneedle tip and the newly welded portion. At the border, the drug appears to have a concentration gradient. A method characterized by such integration is called a welding method.

The drug referred to in the present invention includes all substances that cause some effect when taken into the body.
It is appropriate to use this method when an expensive drug or a drug that is difficult to obtain in large quantities is to be transdermally administered to the human body. For inexpensive drugs and drugs that can be obtained in large quantities, the drug may be mixed with the microneedle material from the beginning and a microneedle may be prepared from the mixed material according to a conventional method.

  When the drug is dissolved only in the organic solvent, a solution in which the drug is dissolved in the organic solvent is mixed into the water-soluble polymer aqueous solution to prepare a drug aqueous solution, and the same procedure can be used. Even when the drug is not completely dissolved in the water-soluble polymer solution but suspended in the form of particles, if the suspension is uniform and the particle size is several μm or less, the drug is not welded or administered into the body. It behaves as if it had been dissolved.

  Examples of drugs suitable for the purpose of the present invention are all drugs that are effective when administered in the body of several mg, but are particularly effective for high-molecular drugs. For example, bioactive peptides and derivatives thereof, nucleic acids, oligonucleotides, various antigen proteins, bacteria, virus fragments and the like can be mentioned. Examples of the physiologically active peptides include insulin, exendin-4, exendin-4 derivatives, calcitonin, adrenocorticotropic hormone, parathyroid hormone (PTH), hPTH (1 → 34), secretin, oxytocin, angiotensin, β- Endorphin, glucagon, vasopressin, somatostatin, gastrin, luteinizing hormone releasing hormone, enkephalin, neurotensin, atrial natriuretic peptide, growth hormone, growth hormone releasing hormone, bradykinin, substance P, dynorphin, thyroid stimulating hormone, prolactin, interferon , Interleukin, G-CSF, glutathione peroxidase, superoxide dismutase, desmopressin, somatomedin, endothelin, E F, skin-related growth factors such as FGF, botulinum toxin, and salts thereof. Examples of the antigen protein or virus fragment include influenza antigen, tetanus antigen, diphtheria antigen, HBs surface antigen, HBe antigen and the like. Is mentioned. These are required to be uniformly dispersed in a solution or suspension in the aqueous drug solution of the present invention.

  As the microneedle material of the present invention, water-soluble natural polymer substances such as hyaluronic acid, collagen, dextrin, dextran, chondroitin sulfate, gelatin, and proteoglycan are suitable. Synthetic polymer materials such as polyvinyl pyrrolidone, polybille alcohol (partially saponified product), and polyacrylic acid (salt) can also be used. It is also possible to improve the physical properties of the microneedles by blending these polymers or blending low-molecular water-soluble substances. If various tapes such as adhesive tapes and bar sheets are added to the microneedle array manufactured as described above to make the product easy to use, a microneedle patch having a drug only at the tip is obtained.

In the method of impregnating both the needle portion and the substrate portion with a drug that has been reported in the past, there is a limit even if the substrate portion is thinned, and 50 μm is necessary. In that case, there is a disadvantage that more drug is present in the substrate part than the drug in the microneedle array, and the drug present in the substrate part is not administered into the skin (Patent Document 7).
In addition, in order to compensate for the above-mentioned drawbacks, a drug-containing material solution is cast on a microneedle mold, and after drying, the substrate material is removed leaving the microneedle, and then a drug-free material solution is cast and dried to dry the substrate. There is also an attempt to form (Patent Document 10). However, this method has a drawback in that the drug diffuses into the substrate material solution when the material solution is applied and the amount of the drug in the needle portion is reduced.
For these points, see Comparative Examples 1 and 2 in the Examples.

  By holding an expensive and precious drug only at the tip portion of the microneedle, the waste of the drug can be prevented and the drug can be used economically and effectively. This is because even if a drug is present in the substrate, it is not absorbed into the body by skin penetration of the microneedle.

In this method, since the drug is dissolved in a solvent and welded to the tip of the microneedle, it is not necessary to heat the drug. Many useful drugs decompose by heating at about 100 ° C., and it has been difficult to apply the conventional method, but this method has no weak point.
If the tip of the microneedle is brought into contact with a solution containing both the drug and the microneedle material and the drug is taken into the microneedle, the interface between the original part and the newly attached part disappears, and the microneedle is integrated. It becomes the target. When integrated, only the drug does not fall off when the microneedle is inserted into the skin.
In the present method, drying may be carried out as needed, such as air drying, air blowing, hot air blowing, nitrogen gas blowing, and the like. It is also possible to seal the aluminum pouch together with a desiccant without drying.
In this method, it is possible to adjust the length of the needle by changing the contact time with the drug solution, the contact depth of the needle, etc., which is larger than the other methods of this welding method. It is a feature.

Schematic of the microneedle welding method of the present invention. The figure which shows the time change of the blood glucose level after insulin administration of the diabetes model rat The figure which shows the time change of the blood glucose level after the exendin-4 administration of a GK rat. The figure which shows the time change of the drug concentration after exendin-4 administration of GK rat.   Microneedles after welding created by changing the contact depth of the microneedle array to the drug solution

There are the following methods for bringing the drug solution into contact with the tip of the microneedle.
(1) The microneedle array is immersed in the drug solution surface from above (FIG. 1).
(2) The microneedle array is placed face up, and the chemical solution impregnated in the sponge is brought into contact from above.
(3) The drug solution is flowed from above as a laminar flow, and the microneedle array is turned sideways and brought into contact for a short time.
In the following embodiments, the method (1) is used, but the methods (2) and (3) can also be adopted .

(Production of drug-containing microneedles by welding method)
The microneedle array of the present invention was manufactured using a template. After the frustoconical microneedle pattern is formed by the lithography method of irradiating the photosensitive resin with light, the frustoconical microneedle forming recess is formed by transferring the frustoconical microneedle pattern by electroforming. Used molds.

Microneedle forming mold recess root diameter 0.16 mm, tip diameter is 0.03 mm, a frustoconical depth 0.8 mm, are arranged in a lattice pattern on 0.6mm interval, per 1 cm ² 250 are formed. The microneedle array was formed in a circular shape having a diameter of 10 mm.

  Hyaluronic acid was used as the water-soluble polymer. Hyaluronic acid aqueous solution is a high molecular weight hyaluronic acid having a weight average molecular weight of 100,000 (product name “FCH-SU” manufactured by Kibun Food Chemifa Co., Ltd.), derived from culture) and 13.5 parts by weight and a low molecular weight hyaluron having a weight average molecular weight of 10,000. It was obtained by dissolving 1.5 parts by weight of acid (made by Kewpie Co., Ltd., trade name “Hialoligo”, derived from culture) in 85 parts by weight of water. This hyaluronic acid aqueous solution was cast on a mold, heated to evaporate water, and peeled off from the mold to obtain a hyaluronic acid microneedle array. The obtained microneedles reflected the shape of the mold, and had a truncated cone shape with a root diameter of 0.16 mm, a tip diameter of 0.03 mm, and a height of 0.8 mm. The microneedle array had a circular shape with a diameter of 10 mm, with microneedles arranged in a grid at intervals of 0.6 mm.

  Separately, bovine insulin (Nacalai Tesque Co., Ltd.) was dissolved in an aqueous hydrochloric acid solution having a pH of 2.5, and the aqueous solution was added to the aqueous hyaluronic acid solution to obtain a 1.0 unit (U) / ml concentration drug solution. The viscosity was 25 dPa · s.

  The microneedle array obtained was placed above the drug solution (FIG. 1 (a)), the microneedle array was lowered, and the tip of the microneedle was brought into contact with 100 μm for 1 second (FIG. 1 (b)). Thereafter, pulling up (FIG. 1 (c)), taking out (FIG. 1 (d)), and air drying, 20 tips of insulin-enriched microneedle arrays were obtained.

When the obtained microneedle array was observed with a microscope, the tip of the needle was swollen as shown in FIG. It was observed that the original microneedle and the insulin-containing hyaluronic acid as the welded part were completely integrated.
Using the three microneedle arrays obtained, the amount of insulin attached to the tip was measured. The measurement utilized the Grazyme insulin-EIA TEST kit (Wako Pure Chemical Industries, Ltd.). It was confirmed that one microneedle array contained 0.25 unit of insulin. The content variation was within 20%.

(Blood glucose measurement test)
Using the manufactured microneedle array, insulin was transdermally administered to rats.
The abdomen of a diabetic model rat (body weight: about 300 g) prepared by administration of streptozotocin was removed. After fasting this rat for 14 hours or more, the microneedle array was inserted into the hair removal skin, and the microneedle array was fixed to the skin with excellent skin bonds (manufactured by Nitto Denko). After administration of the microneedle array, blood was collected after 0.5, 1 and 2 hours, and blood glucose level was measured. Glucose CII-test kit (Wako Pure Chemical Industries, Ltd.) was used for blood glucose level measurement. The number of tests was 4.

Rats were administered insulin by subcutaneous injection.
After diabetic model rats were fasted for 14 hours or longer, 0.25 units of insulin was administered by subcutaneous injection. After insulin administration, blood was collected after 0.5, 1 and 2 hours and blood glucose level was measured. The blood glucose level was measured using Glucose CII-test kit as in Example 1. The number of tests was 4.

Control (without insulin administration) was measured as a reference for the blood glucose level measurement test.
After diabetic model rats were fasted for 14 hours or more, blood was collected after 0.5, 1, 2 hours and blood glucose levels were measured. The blood glucose level was measured using Glucose CII-test kit as in Example 1. The number of tests was 4.

(Results and discussion of blood glucose level test)
The above three test results are shown in FIG. 2 as changes in blood glucose level over time. Each 0 hour value (initial value) is 100, and the relative value of the blood glucose level is shown. As is clear from this figure, the blood glucose level decreased according to the microneedle administration method as in the subcutaneous injection administration method.

(Manufacture of drug-containing microneedles by welding method: When hyaluronic acid is the main component)
The water-soluble polymer solution contains 6 parts by weight of hyaluronic acid (manufactured by Kibun Food Chemifa Co., Ltd., weight average molecular weight 800,000, trade name FCH-80L) and 3 parts by weight of polyvinylpyrrolidone (trade name Kollidon 12PF, manufactured by BASF Japan Ltd.). Obtained by dissolving in 91 parts of water. A microneedle array was produced in the same manner as in Example 1 except that the composition of the water-soluble polymer solution and drying were not air drying but nitrogen gas blowing. The shapes and dimensions of the microneedles and the microneedle array are the same as those in the first embodiment.

Exendin-4 (Wako Pure Chemical Industries, Ltd.) was used as a drug. Exendin-4 is a type II diabetes therapeutic drug, a protein having a molecular weight of 4200, and has a blood glucose lowering effect. A drug solution is prepared by dissolving exendin-4 at 30 mg / ml in a 10% by weight aqueous solution of high molecular weight hyaluronic acid having a weight average molecular weight of 100,000 (manufactured by Kibun Food Chemical Co., Ltd., trade name: FCH-SU, derived from culture). did.
Using a jig, the tip of the microneedle array 200 μm was taken out immediately after coming into contact with the drug solution, and dried by blowing nitrogen gas to prepare 20 drug tip welded microneedle arrays.

(Production of drug-containing microneedles by the welding method: in the case of polymethyl methacrylate)
A microneedle array using polymethyl methacrylate (MMA) as a raw material was prepared using the same template as used in Example 1. A 10% toluene solution of MMA (Wako Pure Chemical Industries, Ltd.) was poured into a mold and dried at 40 ° C. for 48 hours to produce an MMA microneedle array having the same shape as in Example 2. A 200 μm tip of the microneedle array was brought into contact with the same drug solution as in Example 2 using a jig, and immediately taken out and dried by blowing nitrogen gas to produce a drug tip welded microneedle.

(Confirmation of abundance of exendin-4)
Exendin-4 abundance was determined by enzyme immunoassay. Using a solution obtained by dissolving drug-welded microneedles in ion-exchanged water or blood collected from a rat vein, the concentration of exendin-4 in the sample was determined by Exendin-4 EIA kit (Wako Pure Chemical Industries, Ltd.).
Using the prepared three microneedle arrays, the amount of exendin-4 adhering to the tip was measured by this method. Whether hyaluronic acid was the main component or MMA, it was confirmed that 10 μg of exendin-4 was contained in one microneedle array. The content variation was within 15%.

(Blood glucose measurement test)
Using the produced microneedle array, exendin-4 was transdermally administered to rats to perform a glucose tolerance test, and compared with the subcutaneous injection method and the control.
After anesthetizing a GK rat and a spontaneous type 2 diabetes model (8-week-old male, purchased from Shimizu Experimental Materials Co., Ltd.), the back was depilated. After fasting for 14 hours or more, a microneedle array was inserted into the depilatory skin and fixed to the skin with excellent skin bonds (manufactured by Nitto Denko). Glucose equivalent to 2 g / kg body weight was intraperitoneally administered 30 minutes after administration of the microneedle array. After administration, blood was collected after 15, 30, 60, 90 and 120 minutes, and blood glucose level was measured. The number of tests was 5.
Glucose CII-test kit (Wako Pure Chemical Industries, Ltd.) was used for blood glucose level measurement.

(Exendin-4 blood concentration change test)
Using the manufactured microneedle array, exendin-4 was transdermally administered to rats, and exendin-4 blood concentration change test was performed, and compared with the subcutaneous injection method and the control.
After anesthetizing a GK rat and a spontaneous type 2 diabetes model (8-week-old male, purchased from Shimizu Experimental Materials Co., Ltd.), the back was depilated. After fasting for 14 hours or more, the microneedle array was inserted into the hair removal skin, and fixed to the skin with excellent skin bonds (manufactured by Nitto Denko). Glucose equivalent to 2 g / kg body weight was intraperitoneally administered 30 minutes after administration of the microneedle array. After administration of sugar, blood was collected after 15, 30, 60, 90, and 120 minutes, and the concentration of exendin-4 was measured. The number of tests was 5.

In both the blood glucose level measurement test and the drug blood concentration change test, a subcutaneous injection administration method and a control test in which no drug was administered were performed for comparison with the microneedle transdermal administration method.
The subcutaneous injection administration method was performed as follows. A GK rat spontaneous type 2 diabetes model (8-week-old male, Shimizu Experimental Materials Co., Ltd.) was fasted for 14 hours or more, and then 10 μg exendin-4 was administered by subcutaneous injection. Thirty minutes later, 2 g / kg body weight equivalent of glucose was intraperitoneally administered. After administration of glucose, blood was collected after 15, 30, 60, 90, and 120 minutes, and blood glucose level and exendin-4 concentration were measured. The number of tests was 5.
Control was performed as follows. 30 minutes after fasting the GK rat spontaneous onset type 2 diabetes model (same as above) for 14 hours or more, glucose equivalent to 2 g / kg body weight was intraperitoneally administered. After administration of glucose, blood was collected after 15, 30, 60, 90, and 120 minutes, and blood glucose level and exendin-4 concentration were measured. The number of tests was 3 cases.

The time change of the blood glucose level after glucose load is shown in FIG. The symbols in the figure are as follows.
Control: no exendin-4 administration C. 10 μg: Exendin-4 administered by subcutaneous injection MN (HA) 10 μg: Exendin-4 administered by microneedle mainly composed of hyaluronic acid MN (MMA) 10 μg: Exendin-4 administered by MMA microneedle

  FIG. 4 shows the time course of blood exendin-4 concentration after 30 minutes after drug administration. The symbols in the figure are the same as those in FIG.

(Test results and discussion)
According to FIG. 3, the blood glucose level of the Control group after glucose loading is rapidly increased. C. In the 10 μg group and the MN (HA) 10 μg group, the increase in blood glucose level is suppressed. On the other hand, the blood glucose level of the MN (MMA) group is lower than that of the Control group, but is much higher than that of the MN (HA) 10 μg group. This result shows that the microneedle made of hyaluronic acid has a higher effect of suppressing the blood sugar level than the microneedle made of polymethylmethacrylate even if the microneedle is coated with the same 10 μg at the tip.

  According to FIG. 4, in 3 groups administered exendin-4 30 minutes before glucose load, C. In the 10 μg group and the 10 μg group of MN (HA), the blood exendin-4 concentration rapidly increased, and the concentration reached the maximum 45 minutes after administration (15 minutes after glucose loading). On the other hand, the blood exendin-4 concentration in the MN (MMA) 10 μg group is much lower than that in the MN (HA) 10 μg group.

The results of FIGS. 3 and 4 show that the drug (exendin-4) welded to the hyaluronic acid microneedle has a very large amount of penetration into the drug by applying the microneedle to the skin as compared with the case where the drug is attached to the polymethylmethacrylate microneedle. Thereby, it is shown that the blood glucose level lowering effect is also great. Administration with MN (HA) shows the same behavior as subcutaneous injection, indicating that all drugs welded to the microneedle penetrate into the body. On the other hand, in MN (MMA), only a fraction of the drug attached to the needle penetrates into the body.
This may be because the drug attached to the tip of the MN (MMA) has a weak adhesive strength, and the drug is peeled off from the microneedle and is not absorbed by the body when passing through the keratin during microneedle insertion. On the other hand, in MN (HA), since the drug is integrated with the microneedle during welding, it does not come off at the time of insertion, and the whole amount seems to be absorbed in the body.

A high-molecular-weight hyaluronic acid having a weight average molecular weight of 100,000 (manufactured by Kibun Food Chemifa Co., Ltd., trade name: FCH-SU, derived from culture) is prepared in various concentrations, and the ratios of hyaluronic acid and water are as follows. Adjusted. The viscosity of the prepared solution was 0.5, 1.0, 5.0, 20, 50, 90, 150 dPa · s. The room temperature was 25 degrees. Red No. 102 (Wako Pure Chemical Industries, Ltd.) was uniformly dissolved in these seven aqueous solutions having different concentrations to a concentration of 0.5%.
As for the microneedle array, a circular microneedle array having a diameter of 1.0 cm was prepared in the same manner as in Example 1.

  The microneedle array tip part 150 μm was brought into contact with the obtained hyaluronic acid aqueous solutions of various viscosities for 1 second, and then taken out and air-dried. In order to evaluate the amount of hyaluronic acid aqueous solution deposited by contact, one microneedle array was dissolved in 2 ml of ion-exchanged water, and the concentration of red No. 102 was measured by absorbance at 510 nm. The amount of welding per microneedle array of various aqueous solutions with different hyaluronic acid concentrations was calculated from the measured values, and the results are shown in the table below.

  When the aqueous solution viscosity is low, the amount of welding is low. The handling becomes worse as the height increases, and the shape of the needle becomes irregular. Appropriate aqueous solution viscosity was found to be 1.0 to 90 dPa · s, more desirably 5.0 to 50 dPa · s.

(Comparative Example 1)
Using the microneedle forming mold recess used in Example 1, the following microneedle array having a diameter of 1 cm was prepared.
The water-soluble polymer solution is composed of 14.995 parts by weight of hyaluronic acid (manufactured by Kibun Food Chemifa Co., Ltd., molecular weight 800,000, trade name FCH-80L), 0.005 parts by weight of red No. 102 dye as a model drug, and 85 parts of water. An aqueous solution was used. 0.3 ml of this aqueous solution was cast on a mold and dried at room temperature to form a microneedle array (diameter 1 cm). The microneedle array was taken out from the mold, and the needle part of the microneedle array was carefully scraped with a sharp cutter knife under observation with a microscope, and separated into a needle part and a substrate part. Each was dissolved in ion-exchanged water, and the absorbance at 510 nm was measured to determine the distribution ratio of the model drug to the needle portion and the substrate portion.
Needle part abundance: substrate part abundance = 0.048: 0.952
Therefore, when a microneedle array is produced by such a method, it is expected that most of the drug remains unused in the substrate portion.

(Comparative Example 2)
A microneedle array was molded on the mold in the same manner as in Comparative Example 1 except that the mold filling amount of the aqueous solution was 0.15 ml. Next, the substrate portion existing in the form of a film on the mold surface was carefully wiped with wet cotton.
Subsequently, 0.3 ml of an aqueous solution containing 15 parts by weight of hyaluronic acid (manufactured by Kibun Food Chemifa, molecular weight 800,000, trade name FCH-80L) and 85 parts of water and not containing red No. 102 dye was cast into a mold, and 40 ° C. And dried to form a microneedle array (diameter 1 cm). The microneedle array was taken out from the mold, and the needle portion of the microneedle array was carefully scraped with a sharp cutter knife under observation with a microscope, and separated into a needle portion and a substrate portion. Each was dissolved in ion-exchanged water, and the absorbance at 510 nm was measured to determine the distribution ratio of the model drug to the needle portion and the substrate portion.
Needle part abundance: substrate part abundance = 0.62: 0.38
Red No. 102 model drug was originally present only in the needle portion. However, this result shows that the drug diffuses from the needle part to the substrate part in the process of casting the hyaluronic acid aqueous solution on the mold and drying it to form the substrate part.
Therefore, with such a method, it is not possible to create a microneedle array that holds a drug only in the microneedle portion.

  An aqueous solution of high molecular weight hyaluronic acid having a weight average molecular weight of 100,000 (manufactured by Kibun Food Chemifa, trade name: FCH-SU, derived from culture) was prepared. The viscosity of the solution was 5.0 dPa · s. The room temperature was 25 ° C. In this aqueous solution, FD4 (fluorescene dextran, model compound, Wako Pure Chemical Industries, Ltd.) was uniformly dissolved to a concentration of 5%. A circular microneedle array having a diameter of 1.0 cm was prepared using the same mold as in Example 1 except that the height of the microneedle array was 0.65 μm.

  The tip of the microneedle array was brought into contact with the obtained hyaluronic acid aqueous solution for 1 second, and then taken out and air-dried. At that time, the needle length was adjusted by setting the contact depth of the tip to 150 μm and 250 μm. The microneedle with the model drug welded to the tip was shortened by partially dissolving the tip. The length of the needle when not in contact was 650 μm, but it could be about 640 μm and about 570 μm, respectively, by contact with 150 μm and 250 μm. See FIG. This shows that the needle length could be adjusted by changing the contact depth of the microneedle to the chemical solution.

  The microneedle patch according to the present invention is expected to be widely used in the fields of medicine and beauty.

Claims (4)

The microneedle tip, a microneedle array and having a drug welded portion drug dissolved liquid is microneedle materials and compatibility ing to dissolve wearing microneedle material in a water-soluble polymer There is a microneedle array in which the drug weld portion is 100-250 μm long at the tip of the microneedle.   The microneedle array according to claim 1, wherein the microneedle material and the material containing the deposited drug are the same water-soluble polymer.   The said drug is any one of PTH, interferon, insulin, exendin-4, exendin derivative, EGF, FGF, botulinum toxin, various antigenic proteins or virus fragments. Microneedle array.   The water-soluble polymer is one or more selected from hyaluronic acid, dextrin, dextran, carboxymethylcellulose, chondroitin sulfate, proteoglycan, polyacrylic acid (salt), polyvinylpyrrolidone, and polyvinyl alcohol. The microneedle array according to any one of claims 1 to 3.