The effect of granulating liquid and curing on the physicomechanical and release properties of pellets containing ibuprofen and Eudragit RL prepared by extrusionspheronization

This study evaluates the effect of granulating liquid in production of ibuprofen, Eudragit RL and Avicel pellets. Pellets containing ibuprofen (30, 40 and 60%), Eudragit RL (48, 38 or 18% respectively), Avicel (20%) and PVP K30 (2%) were prepared by extrusion spheronisation using water or water/ethanol mixture. The physicomechanical properties (pellet shape, size distribution, crushing strength, elastic modulus) and drug release were examined. The pellets were stored at 60 C for 24 hour (cured) and the effect of curing on mechanical properties and drug release was investigated. The extrudability of the wetted mass decreased with addition of ethanol. The pellet shape changed from spherical to irregular and the yield of pellets decreased with increase in ethanol concentration. The size distribution for pellets shifted toward smaller particle size. Pellets showed different behavior under the mechanical test depending on the ethanol concentration in granulating liquid and percent of drug in formulation. The rate of drug release decreased with increase in ethanol concentration in granulating liquid. For those pellets with brittle behavior, curing changed the behavior of pellet to plastic deformation. Elastic modulus of all formulations decreased after curing. Besides curing decreased drug release rate. Interestingly the effect of curing on mechanical and release behavior of pellets decreased with increase in concentration of ethanol in granulating liquid. The results revealed that addition of ethanol to granulating liquid resulted in production of ibuprofen and Eudragit RL pellets with different properties from those prepared using water alone.