Preparation and in-vitro evaluation of sustained-release metoclopramide hydrochloride microspheres.

Sustained-release metoclopramide microspheres were successfully prepared using cellulose propionate polymer at 1:2 drug to polymer ratio employing solvent evaporation technique and using acetone as the polymer solvent. The prepared microspheres at three stirring speeds were characterized with regard to their drug content, particle size distribution, surface topography using SEM and their release profiles at two different pHs at 37 degrees C. The surface of all samples was smooth with very few irregular elevations or depressions. The average particle size decreases as the rotational speed increases and was found to be 1320, 774 and 345 microns at 600, 900 and 1200 rpm, respectively. The average % drug entrapped was found to be 90.5, 100.1 and 60.0% at 600, 900 and 1200 rpm, respectively. Small differences in the release rate were observed due to different rotation speeds with an apparent lower dissolution for batches produced at 1200 rpm probably due to the properties of the coat. The effect of storage under accelerated conditions for 10 weeks on the release characteristics of these microspheres was also studied. The release properties of the microspheres did not change after storing them at 40 degrees C/80% relative humidity for 10 weeks.