Micro-needle sheet for reducing wrinkles

1. A method of cosmetic treatment of skin with at least one microneedle, comprising inserting the at least one microneedle into the skin, the at least one microneedle comprising:

a proximal end portion; and

a distal end portion extending from the proximal end portion and configured to penetrate the stratum corneum of the skin,

wherein:

the proximal end portion is configured to dissolve more rapidly in water than the distal end portion;

the proximal end portion comprises at least a first polymer that is water-dissolvable and selected from the group consisting of hyaluronic acid with a molecular weight of less than 50 kDa, disaccharide, oligosaccharide, dextrin, dextran, polyethyleneglycol, polyvinyl alcohol, polyvinylpyrrolidone, poly (methylvinylether/maleic acid) (PMVE/MA), poly (methylvinylether/maleic anhydride) (PMVE/MAH), or mixtures thereof;

the distal end portion is configured to detach from the proximal end portion following insertion into skin;

the distal end portion comprises at least one second polymer, different from the first polymer, wherein the second polymer is selected from the group consisting of hyaluronic acid with a molecular weight of about 500 kDa or more, cross-linked hyaluronic acid, polyethylene glycol cross-linked poly-lactic acid, polyethylene glycol cross-linked PVME/MA, or mixtures thereof, and

wherein the cosmetic treatment comprises reducing wrinkles on the skin.

2. The method of cosmetic treatment of the skin according to claim 1 , wherein the at least one second polymer in the distal end portion is selected from the group consisting of hyaluronic acid with a molecular weight of about 500 kDa or more, cross-linked hyaluronic acid, polyethylene glycol cross-linked PMVE/MA, or mixtures thereof.

3. The method according to claim 1 , wherein the at least one second polymer in the distal end portion has a molecular weight ranging from about 500 kDa to about 100000 kDa.

4. The method according to claim 1 , wherein the at least one second polymer in the distal end portion has a molecular weight ranging from about 2100 kDa to about 15000 kDa.

5. The method according to claim 1 , wherein the at least one second polymer in the distal end portion comprises polyethylene glycol cross-linked PMVE/MA.

6. The method according to claim 1 , wherein the distal end portion comprises a pore-forming carbonate agent.

7. The method according to claim 1 , wherein the proximal end portion is conical and the distal end portion tapers to a point.

8. The method according to claim 1 , wherein the distal end portion and the proximal end portion each have a diameter ranging from about 50 μm to about 300 μm.

9. The method according to claim 1 , wherein the distal end portion is formed of at least one active ingredient.

10. The method according to claim 1 , wherein the distal end portion comprises at least one active ingredient.

11. The method according to claim 1 , wherein the distal end portion is configured to swell upon insertion into the skin.

12. The method according to claim 1 , wherein the diameter of the distal end portion increases by at least 100% over a time period of one hour after insertion into the skin.

13. A method of forming a sheet comprising a plurality of microneedles, the method comprising:

filling a mold with a first material;

drying the first material to form distal end portions of the microneedles;

filling the mold with a second material; and

drying the second material to form proximal end portions of the microneedles that extend from respective ones of the distal end portions,

wherein the second material is more water soluble than the first material; and

wherein:

the distal end portions are configured to detach from the proximal end portion following insertion into skin;

the first material comprises at least one polymer selected from the group consisting of hyaluronic acid with a molecular weight of about 500 kDa or more, cross-linked hyaluronic acid, polyethylene glycol cross-linked poly-lactic acid, polyethylene glycol cross-linked poly(methyl/vinyl ether/maleic acid) (PMVE/MA), or mixtures thereof; and

the second material comprises at least one water-dissolvable polymer selected from the group consisting of hyaluronic acid with a molecular weight of less than 50 kDa, disaccharide, oligosaccharide, dextrin, dextran, polyethyleneglycol, polyvinyl alcohol, polyvinylpyrrolidone, PMVE/MA, poly(methylvinylether/maleic anhydride) (PVME/MAH), or mixtures thereof.

14. The method of forming a sheet according to claim 13 , wherein the first material comprises hyaluronic acid with a molecular weight of about 500 kDa or more, cross-linked hyaluronic acid, polyethylene glycol cross-linked PMVE/MA, or mixtures thereof.