Acta Pharm. 63 (2013) 85-98


full paper

Original research paper

Formulation and evaluation of mefenamic acid sustained release matrix pellets


Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Al-Azhar University, Assiut, Egypt

Accepted September 12, 2012


The objective of the study was to prepare mefenamic acid (MA) sustained release matrix pellets and investigate the formulation parameters affecting pellets attributes and the drug release in vitro. Mixer torque rheometer (MTR) was used to characterize the rheological properties of wet mass used in pellets formulation. Mefenamic acid pellets were prepared by extrusion/spheronization techniques using microcrystalline cellulose (MCC) in combination with lactose as pellet forming agents and water as the binding liquid. Also, the prepared pellets were characterized for their particle sizes and in vitro drug dissolution. The results revealed that the increase of lactose weight ratio mixed to MCC resulted in a significant reduction of both maximum torque and binder ratio, while the addition of 2 % (m/m) polyvinyl pyrolidone (PVP) to MCC-lactose influenced only the mean torque rather the wetting liquid (water) ratio. Particle size ranged from 945 to 1089 μm and had small span values (0.560.67). Furthermore, an inverse relation was observed the between rheological character of pellet wet masses (expressed by peak torque) and in vitro release rate. Increasing MA loading from 2.5 to 5 and 10 % was accompanied with a decrease in dissolution rates. In conclusion, the properties of MA matrix pellets could be successfully monitored by controlling the wet mass character characteristic by measuring torque.


Keywords: mefenamic acid, matrix pellets, mixer torque rheometer, sustained release