K. Tojo et al., SURFACE DISSOLUTION-BULK EROSION MODEL OF DRUG-RELEASE FROM BIODEGRADABLE POLYMER RODS, Journal of Chemical Engineering of Japan, 31(4), 1998, pp. 648-651
A combined model of surface dissolution of the drug and bulk erosion o
f the polymer is developed for describing the biphasic release profile
of drugs from biodegradable polymer rod devices. The model parameters
are determined from the conventional moment analysis of the time cour
se of the release profile. The model describes well the typical biphas
ic phenomena of drug release, the initial bursting release due to diss
olution of the surface drug molecules, and the late bursting caused by
the bulk erosion of biodegradable polymers.