A reproducible accelerated in vitro release testing method for XXXX microspheres.

@entity7050 @entity1090
UNASSIGNED: The objective of the present study was to develop a discriminatory and reproducible accelerated in vitro release method for long-acting @entity7050 microspheres with inner structure/porosity differences. @entity1090 was chosen as a model drug. Qualitatively and quantitatively equivalent @entity7050 microspheres with different inner structure/porosity were obtained using different manufacturing processes. Physicochemical properties as well as degradation profiles of the prepared microspheres were investigated. Furthermore, in vitro release testing of the prepared @entity1090 microspheres was performed using the most common in vitro release methods (i.e., sample-and-separate and flow through) for this type of product. The obtained compositionally equivalent @entity1090 microspheres had similar drug loading but different inner structure/porosity. When microsphere particle size appeared similar, porous @entity1090 microspheres showed faster microsphere degradation and drug release compared with less porous microspheres. Both in vitro release methods investigated were able to differentiate @entity1090 microsphere formulations with differences in porosity under real-time (37  C) and accelerated (45  C) testing conditions. Notably, only the accelerated USP apparatus 4 method showed good reproducibility for highly porous @entity1090 microspheres. These results indicated that the accelerated USP apparatus 4 method is an appropriate fast quality control tool for long-acting @entity7050 microspheres (even with porous structures).
