Drug-holding microneedle array and manufacturing method thereof
The present invention provides a drug-holding microneedle array in which a drug is applied and held only on a tip portion of microneedles for quantitatively holding the drug and for preventing the drug from falling away during insertion of the microneedles. The drug-holding microneedle array comprises: a microneedle array having a microneedle substrate 4 and microneedles, the microneedles being positioned in plural on the microneedle substrate 4 and a tip portion 1 of the microneedles projecting via steps 2 and a drug held on the tip portion of the microneedles and the steps 2.
1. A drug-holding microneedle array comprising:
a microneedle array having a microneedle substrate and microneedles, the microneedles being positioned in plural on the microneedle substrate, each microneedle comprising a tip portion projecting from a root portion via a step that narrows a width of the microneedle from the root portion to the tip portion, the step being arranged at a plane where the tip portion meets the root portion; and
a drug held on the tip portions and the steps of the microneedles,
wherein a first width is defined as a distance along the plane where the tip portion meets the root portion from a center of the microneedle to an outer edge of the tip portion,
a second width is defined as a distance along the plane where the tip portion meets the root portion from the center of the microneedle to an outer edge of the root portion,
a difference between the first width and the second width is more than 14 μm and less than 100 μm, and
the tip portion is cone-shaped.
2. The drug-holding microneedle array according to claim 1 , wherein the difference between the first width and the second width is less than 50 μm.
3. The drug-holding microneedle array according to claim 1 , wherein a base material of the microneedles is polymers which are injection-moldable or press-moldable.
4. The drug-holding microneedle array according to claim 1 , wherein a base material of the microneedles is at least one selected from a group consisting of nylon, polycarbonate, polylactic acid, copolymer of lactic acid and glycolic acid, polyglycolic acid, polyethylene terephthalate, and cyclic olefin polymer.
5. The drug-holding microneedle array according to claim 1 , wherein a base material of the microneedles is water-soluble polymers.
6. The drug-holding microneedle array according to claim 5 , wherein the base materials of the microneedles is at least one selected from a group consisting of hyaluronic acid, sodium chondroitin sulfate, carboxymethyl cellulose sodium salt, hydroxypropyl cellulose, and dextran.
7. The drug-holding microneedle array according to claim 1 , wherein the drug is added with a water-soluble polymer or a mixture of the water-soluble polymer and low molecular weight saccharides.
8. The drug-holding microneedle array according to claim 7 , wherein the water-soluble polymer is at least one selected from a group consisting of hyaluronic acid, collagen, dextrin, dextran, sodium chondroitin sulfate, carboxymethyl cellulose sodium salt, hydroxypropyl cellulose, and ethyl cellulose.
9. The drug-holding microneedle array according to claim 7 , wherein the low molecular weight saccharides are at least one selected from a group consisting of glucose, sucrose, maltose, and trehalose.
10. The drug-holding microneedle array according to claim 1 , wherein the microneedles are cone-shaped microneedles.
11. The drug-holding microneedle array according to claim 1 , wherein the root portion is one of cylinder-shaped and truncated cone-shaped.