A method of molding a microneedle array comprising (i) providing a mold apparatus comprising a mold insert having the negative image of at least one microneedle, wherein the mold apparatus has an open position and a closed position； (ii) placing the mold apparatus in the closed position； (iii) applying acoustic energy having a frequency greater than about 5,000 Hz to the mold apparatus； (iv) injecting polymeric material into the closed mold apparatus； (v) opening the mold； and (vi) removing the molded microneedle array from the mold (Fig. 1).
