Effect of Various Grades of Hydroxypropylmethylcellulose (HPMC) on Drug Release from Naproxen Sodium Matrix Tablets

The objective of the present study was to design oral sustained release matrix tablets of Naproxen Sodium using different grades of hydroxypropyl methyl cellulose (HPMC) as rate retarding polymer and study the effect of various formulation factors such as polymer proportion and polymer viscosity, effect of different diluents (lactose monohydrate, microcrystalline cellulose), effect of preparation method (direct compression, wet granulation) on the invitro release of naproxen sodium. The release kinetics was analyzed using zero order equation, first order equation, Higuchi's square root equation and Korsmeyers-peppas equation. FTIR and DSC studies conducted for compatibility revealed that there was no interaction between drug and various excipients used in the study. In vitro release studies revealed that the release rate decreased with increase in polymer proportion and viscosity grade. MCC has more retardation of drug release than lactose monohydrate and wet granulation method has more retardation of drug release compared to direct compression. Mathematical analysis of release kinetics indicated the nature of drug release from matrix tablets was dependent on drug diffusion and polymer relaxation and therefore followed non-Fickian or anomalous release.