Abstract: Although modern biotechnology has produced extremely sophisticated and potent drugs, many of these compounds can not be effectively delivered by convention drug delivery techniques (e.g., pills and injections). Transdermal delivery is an attractive alternative, but it is limited by the extremely low permeability of skin. As the primary barrier of drug delivery is the upper skin in the thickness about 120 μm and the nerves is distributed in the tissue about 200 μm under the upper skin, the arrays of microneedles can be used to penetrate through the upper skin without stimulating the nerves. Therefore, the key technique of this drug delivery method is the fabrications of the of microneedle arrays. The silicon fabrica- tion processing based on the combination of isotropic and anisotropic etching is discussed.

Key words: Deep etching, Microneedles Isotropic etching, Transdermal drug delivery