Y. Akiyama et al., MECHANISM OF DRUG-RELEASE FROM POLYGLYCEROL ESTER OF FATTY ACID-BASEDMICROSPHERES, Journal of controlled release, 27(1), 1993, pp. 37-45
The factors influencing the drug release and the mechanism of the drug
release from the spherical, polyglycerol ester of fatty acid (PGEF)-b
ased microspheres has been elucidated. The release rates of theophylli
ne, phenylpropanolamine hydrochloride (PPA) and prednisolone were exam
ined. The drug release could be regulated by choosing an appropriate h
ydrophile-lipophile balance value of PGEF. The drug solubility in wate
r affected the release rate of the drug. The particle size of the micr
ospheres did not change during drug release. In addition, the paddle s
peed did not affect the release rate. Since the release rate could be
expressed by Jander's equation which considers the change in the inter
facial area where the actual release of a solid drug occurs, the relea
se from the microspheres is found to be a diffusion controlled process
within the micromatrix.