# US 12,759,196 B2 · Solid microneedle comprising drug and method for manufacturing the same

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- Number: US 12,759,196 B2
- Document ID: US12759196B2
- Status: Granted
- Kind: B2
- Application number: 18/176,606
- Filed: 2023-03-01
- Published: 2023-09-07
- Granted: 2026-10-13
- Earliest claimed: 2022-03-03
- Assignees: LG Household & Health Care Ltd.
- Applicants: LG Household & Health Care Ltd.
- Inventors: Seong-Su Kang; Seung-Hyun Jun
- Web page: https://patentgrep.com/patent/US12759196B2

## CPC

- B29C 39/026: {characterised by the shape of the surface}
- A61K 9/0021: {Intradermal administration, e.g. through microneedle arrays or needleless injectors}
- B29K 2067/046: {PLA, i.e. polylactic acid or polylactide}
- B29L 2031/7544: {Injection needles, syringes}
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES

## Abstract

The present disclosure relates to a solid microneedle structure prepared using a water-insoluble polymer and a technique for manufacturing the same, wherein the technique can control the drug release rate of the microneedle: a rapid-release type or a sustained release type, the drug included in the microneedle may be various cosmetic or pharmaceutical active ingredients, and the microneedle can have an appropriate release rate suitable for the drug by the method of the invention.

## Claims

### Claim 1

A method for manufacturing a solid type microneedle comprising a water-insoluble polymer, sugar and drug by solvent casting, comprising:
(a) preparing a polymer solution by dissolving the water-insoluble polymer in a solvent;
(b) adding the sugar and the drug to the polymer solution, wherein the sugar is added in a powder form and stirring for 1 to 10 minutes to maintain the sugar in an undissolved, dispersed state in the polymer solution;
(c) injecting the polymer solution containing the sugar and the drug into a microneedle mold; and
(d) drying and separating the microneedle from the microneedle mold.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the sugar included in the microneedle is dissolved by moisture in the skin when the microneedle is applied to the skin and the drug is rapidly released.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the water-insoluble polymer is poly lactic acid (PLA).

### Claim 4 (depends on 3)

The method according to claim 3, wherein the PLA has an inherent viscosity (IV) of 0.25 to 1.7, and PLA in step (b) is added to have a final concentration of 5 to 15% by weight relative to the total weight of the polymer solution.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the sugar in step (b) is added to have a final concentration of 0.5 to 2% by weight relative to the total weight of the polymer solution.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the solvent is one or more selected from the group consisting of dimethyl sulfoxide (DMSO), acetone, and dimethylformamide (DMF).

### Claim 7 (depends on 1)

The method according to claim 1, wherein the solvent is dimethyl sulfoxide (DMSO).

### Claim 8 (depends on 1)

The method according to claim 1, wherein the drying is carried out by evaporating the solvent at a temperature of 40° C. to 60° C.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the sugar comprises one or more selected from glucose, sucrose and trehalose.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the sugar comprises glucose or sucrose.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the solid type microneedle form pores with an average diameter of 1 to 50 μm on the surface of the microneedle when the solid type microneedle is immersed in distilled water at 37° C. and observed after 48 hours.