A problem to be solved of the present invention is to provide a drugformulation and a method of administering an active ingredient which allowthe active ingredient to be delivered evenly into the site of action in theskinwith high efficiency while ensuring stability of the active ingredient over along time, and which are easily handled and are less stressful for patients.Mean for solving the problem is a microneedle assembly formulation for skintreatment comprising a platform and a plurality of conical or pyramidalmicroneedles formed on the platform containing a base composed of abio-soluble and thread-forming polymer substance and an objectivesubstance retained in the base, wherein the objective substance is asubstance effective for prevention or treatment of skin senescence, ortreatment of skin scar.
