In vitro and in vivo studies on HPMC-K-100 M matrices containing naproxen sodium.

Controlled release (CR) matrix tablets of naproxen sodium were prepared by wet granulation using hydroxypropyl methyl cellulose (HPMC-K-100 CR) as the hydrophilic rate controlling polymer. The effect of the concentration of the polymer and different fillers on the in vitro drug release rate was studied. The studies indicated that the drug release can be modulated by varying the concentration of the polymer and the fillers. An optimized formulation subjected to accelerated stability studies for 3 months revealed that the developed CR tablets are stable. A complete cross-over bioavailability study of the optimized formulation of the developed CR tablets and marketed immediate release tablets was performed in 6 healthy male volunteers. The extent of absorption of drug from the CR tablets was significantly higher than that for the marketed naproxen sodium tablet due to lower elimination rate and longer half-life.