Stability of nifedipine-polyvinylpyrrolidone coprecipitate.

Publisher Website
Google Scholar
Abstract
The chemical and physicochemical stability of [the coronary vasodilator] nifedipine, [N] in N-polyvinylpyrrolidone (PVP) coprecipitate systems was studied. N in the coprecipitate systems was chemically stable to heat and humidity. Storage of the coprecipitate systems under humid conditions influenced the dissolution behavior. The X-ray diffraction pattern of coprecipitate which was stored under very humid conditions showed many sharp peaks attributable to N crystals. The inferior dissolution of the humidly stored coprecipitate systems resulted from the partial crystallization of amorphous N in the PVP matrix. Correlations between the in vitro dissolution behavior and the in vivo bioavailability parameters after oral administration to dogs were studied to confirm the effect of storage on the bioavailability. Coprecipitate systems of N with PVP should be stored so they are not exposed to humidity to avoid a decrease of drug bioavailability.