Abstract:
A review, with 42 refs. The SUPAC-SS guidance, which governs scale-up and post-approval changes for semisolids, requires in vitro release data in certain instances of change in the amt. of an excipient, batch size or manufg. equipment, process or site. The kinetics of diffusion of an active ingredient through a semisolid into a liq. sink (the receptor) are measured; an inert, porous membrane phys. separates the 2 phases. Several com. instruments, some of which incorporate automated transfer to an anal. instrument, are available. The principal exptl. decisions involve selection of temp., membrane, receptor and timing of samples. These should be chosen to minimize undesired interactions and make diffusion through the semisolid rate-limiting, so that the intrinsic release is measured. Data treatment involves plotting the amt. released against the square root of time and using the slope of the linear plot as an index. Release profiles may be altered by certain changes in manufg. or formulation.