Accelerated stability study of sustained-release nifedipine tablets prepared with Gelucire

This paper describes an investigation of the chemical and physical stability of nifedipine sustained release dosage forms prepared with Gelucire® 53/10. Three formulations differing only in the applied tabletting force were stored for 6 months under four different controlled conditions of relative humidity (RH) and temperature (20°C/0% RH, 20°C/80% RH, 40°C/0% RH, 40°C/80%). It was found that nifedipine in the sustained release formulations was chemically stable against the effects of temperature and humidity. However, the variables, tabletting force, RH and storage time, exerted a significant influence on the dissolution behavior of nifedipine. The changes in dissolution behavior after storage under conditions of high humidity and temperature might be related to the formation of nifedipine microcrystals and to structural changes in the wax vehicle during storage. It is predicted that acceptable shelf-lives should result when moisture-resistant packaging is used for pharmaceutical formulations of this type.