Yoshioka Minoru

Mechanism of drug release from polyglycerol ester of fatty acid-based microspheres

Abstract The factors influencing the drug release and the mechanism of the drug release from the spherical, polyglycerol ester of fatty acid (PGEF)-based microspheres has been elucidated. The release rates of theophylline, phenylpropanolamine hydrochloride (PPA) and prednisolone were examined. The drug release could be regulated by choosing an appropriate hydrophile-lipophile balance value of PGEF. The drug solubility in water affected the release rate of the drug. The particle size of the microspheres did not change during drug release. In addition, the paddle speed did not affect the release rate. Since the release rate could be expressed by Janders equation which considers the change in the interfacial area where the actual release of a solid drug occurs, the release from the microspheres is found to be a diffusion controlled process within the micromatrix.