Formulation and in vitro assessment of sustained release terbutaline sulfate tablet made from binary hydrophilic polymer mixtures.

In the present systematic study, a sustained release of terbutaline sulfate tablet (TBS) was developed and optimized by employing the hydrophilic polymers; chitosan and xanthan gum mixed with sodium bicarbonate as a release modifying agent. This formulation was developed using direct compression technology. In vitro release studies indicated rapid swelling and drug release in the initial period of the acid stage from a matrix composed of chitosan and xanthan gum solely. Addition of sodium bicarbonate to the matrix resulted in sustained drug release. Various formulation factors such as polymer to polymer ratio, polymer viscosity and particle size were altered and their effect on dissolution pattern was illustrated. Manufacturing variables such as compression force and lubricant percentage were investigated and found not to influence the drug release profile of the resulted tablets. The release mechanism follows Korsmeyer-Peppas equation with n value indicating non-Fickian diffusion. The release profiles were analyzed using statistical method (one-way ANOVA) and f2 metric values and found to be similar to the commercial product Bricanyl(®). Reproducible data were obtained when scale-up of the formulation was performed.