Microcapsules comprising 2-piperazinone-1-acetic acid compounds

摘要

A microcapsule containing an amorphous water-soluble 2-piperazinone-1-acetic acid compound or salt thereof and a polymer and a method of preparing said microcapsule, which comprises dispersing in an aqueous phase a dispersion of the amorphous water-soluble 2-piperazinone-1-acetic acid compound or salt thereof in a solution of a polymer in an organic solvent to give an s/o/w type emulsion and subjecting the emulsion to in-water drying. The sustained-release microcapsule which is advantageous in entrapping 2-piperazinone-1-acetic acid compound or the salt thereof as a drug in a high concentration, and in the reduced initial release of the drug, thereby reducing undesirable side effects of the drug.