EFFECT OF pH ON DISSOLUTION BEHAVIOUR OF COMMERCIALLY AVAILABLE DICLOFENAC SODIUM TABLETS

Abstract

This study was performed at different pH on six brands of commercially available enteric-coated diclofenac sodium tablets. Dissolution behaviour of all the six brands was studied using USP type-II dissolution apparatus, working at 50 rpm. The data thus collected were plotted on standard curves constructed by using different concentrations of pure diclofenac sodium. Amount of diclofenac sodium dissolved in dissolution medium was obtained and the amount remaining undissolved was calculated. The data were analyzed using cube-root law to calculate the dissolution rate constants. The difference in dissolution behaviour among the brands may be due to the difference in film coating material, although other factors such as size and age of granules, compression force and the use of hydrophobic excepients may also play their part in causing variation in the dissolution behaviour of these brands.