A method of forming a microneedle array can include forming a sheet of material having a plurality of layers and micromilling the sheet of material to form a microneedle array. At least one of the plurality of layers can include a bioactive component, and the microneedle array can include a base portion and plurality of microneedles extending from the base portion.

The drill has a rake face, a flank face, and an outer circumferential surface. The flank face is continuous to the rake face. The outer circumferential surface is continuous to both the rake face and the flank face. A ridgeline between the rake face and the flank face constitutes a cutting edge. A ridgeline between the rake face and the outer circumferential surface constitutes an outer circumferential end. A groove is provided cyclically in the rake face to extend at an angle relative to an axis of the drill, the angle being larger than a helix angle of the drill. The groove has a depth of more than or equal to 1.5 μm.

A method of forming a microneedle array can include forming a sheet of material having a plurality of layers and micromilling the sheet of material to form a microneedle array. At least one of the plurality of layers can include a bioactive component, and the microneedle array can include a base portion and plurality of microneedles extending from the base portion.

The drill has a rake face, a flank face, and an outer circumferential surface. The flank face is continuous to the rake face. The outer circumferential surface is continuous to both the rake face and the flank face. A ridgeline between the rake face and the flank face constitutes a cutting edge. A ridgeline between the rake face and the outer circumferential surface constitutes an outer circumferential end. A groove is provided cyclically in the rake face to extend at an angle relative to an axis of the drill, the angle being larger than a helix angle of the drill. The groove has a depth of more than or equal to 1.5 m.

A method of forming a microneedle array can include forming a sheet of material having a plurality of layers and micromilling the sheet of material to form a microneedle array. At least one of the plurality of layers can include a bioactive component, and the microneedle array can include a base portion and plurality of microneedles extending from the base portion.

A method of forming a microneedle array can include forming a sheet of material having a plurality of layers and micromilling the sheet of material to form a microneedle array. At least one of the plurality of layers can include a bioactive component, and the microneedle array can include a base portion and plurality of microneedles extending from the base portion.

A method of forming a microneedle array can include forming a sheet of material having a plurality of layers and micromilling the sheet of material to form a microneedle array. At least one of the plurality of layers can include a bioactive component, and the microneedle array can include a base portion and plurality of microneedles extending from the base portion.