Mechanism of Enhancement of the Release Rate of Aclarubicin from Poly-β-hydroxybutyric Acid Microspheres by Fatty Acid Esters

Abstract

Poly-β-hydroxybutyric acid (PHB) microspheres containing aclarubicin hydrochloride were prepared by a solvent-evaporation process. The release rates of the drug from the microspheres were significantly increased by incorporating ethyl or n-butyl esters of fatty acids. In order to clarify the effects of fatty acid esters on drug release, the powder X-ray diffraction patterns of microspheres, contents of fatty acid esters in microspheres and other factors were investigated. Powder X-ray diffraction, scanning electron microscopy and differential scanning calorimetry indicated no significant differences due to incorporation of the esters in the microspheres. The contents of fatty acid esters in the microspheres and the solubility of aclarubicin hydrochloride in the fatty acid esters greatly affected the release rate of the drug from the microspheres. © 1988, The Pharmaceutical Society of Japan. All rights reserved.