Fabrication process of phase-transition microneedle patch
The application discloses a method to fabricate microneedle patches, comprising a) casting (painting and pasting) an aqueous polymer solution on a mold of array of micro-holes which is made of porous materials; b) sucking the polymer solution into the micro-holes by applying vacuum at the back of the mold; d) freezing and thawing the casted polymer solution to induce gelation; and e) drying the gelled polymer solution. Specifically, the present invention describes a process and composition of polymeric microneedlepatch which overcomes the limitations of existing microneedles systems and may be used for transdermal delivery system for therapeutics and other applications.
1. A method to fabricate microneedle patches, comprising:
a) casting (painting and pasting) an aqueous polymer solution on a mold of array of micro-holes, the mold being made of a plate of porous hydrophobic materials;
b) sucking the aqueous polymer solution into the micro-holes by applying vacuum at the back of the mold;
c) freezing and thawing the casted aqueous polymer solution to induce gelation whereby a gelled polymer solution is formed in the mold; and
d) drying the gelled polymer solution.
2. The method of claim 1 , wherein at least one bioactive agent is added in the aqueous polymer solution prior to the casting.
3. The method of claim 1 , wherein the mold is permeable to air and the aqueous polymer solution may be sucked into the micro-holes of the mold by applying a vacuum at the back side of the mold.
4. The method of claim 2 , wherein a pre-made gelled polymer sheet containing no bioactive agent may be placed as a supporter on the top of the newly casted polymer solution loaded with the bioactive agent.
5. The method of claim 2 , wherein a polymer solution free of bioactive agent may be pasted on the top of the casted polymer solution loaded with the bioactive agent as an adhesive prior to placing the pre-made polymer sheet on the top of the casted solutions.
6. The method of claim 1 , wherein the drying process may be carried out after detaching the gelled polymer solution in a form of a casted microneedle sheet/patch from the mold.
7. The method of claim 1 , wherein the mold is made of a porous Teflon plate.
8. The method of claim 1 , wherein after drying, the microneedle sheet/patch is punched to designed sizes.
9. The method of claim 8 , wherein microneedle patch of right size is sealed and packed within a moisture-proof bag.
10. The method of claim 1 may be sterilized by including the entire fabrication process within a sterile hood.
11. The method of claim 1 , wherein the polymeric material for forming the microneedles is soluble in water and able to form micro- or submicro-crystalline domain as the cross-linking junctions by physical treatment.
12. The method of claim 11 wherein the polymeric material comprises polyvinyl alcohol.
13. The method of claim 12 wherein the polyvinyl alcohol has a degree of hydrolysis of 80% or higher.
14. The method of claim 1 , wherein the drying comprises mounting the casted microneedle sheet on a holder to prevent curving of the sheet but allow it to shrink at X-Y (the plate) directions.