FORMULATION AND EVALUATION OF DICLOFENAC CONTROLLED RELEASE TABLETS EMPLOYING OLIBANUM RESINAbstract
The objective of the study is to evaluate Olibanum resin, a natural resin polymer as matrix polymer for controlled release tablets and to design matrix tablets of diclofenac for controlled release. Matrix tablets of diclofenac were formulated employing Olibanum resin in different proportions of drug and polymer and the tablets were evaluated for drug release kinetics and mechanism. Two diluents namely lactose (water soluble) and DCP (water insoluble) were included in the formulations to assess their influence on drug release characteristics of olibanum resin matrix tablets. Matrix tablets were found to be non- disintegrating in water, acidic (pH 1.2) and alkaline (pH 7.4) fluids and were considered suitable for oral controlled release. Diclofenac release from the matrix tablets formulated was slow and spread over 24 h and depended on the concentration (%) of olibanum resin in the matrix tablets and nature/type of diluent. As the concentration of olibanum resin in the matrix tablets was increased, drug release was decreased. Release was relatively faster with water soluble diluent lactose when compared to water insoluble diluent DCP at all concentrations of olibanum resin. Drug release from the tablets followed first order kinetics and followed non – Fickian (anomalous) diffusion release mechanism. Good linear relationships were observed between percent polymer and release rate in each case. The results of the study thus indicated olibanum resin could be used as rate controlling matrix in design of controlled release tablets. Both water soluble and water insoluble diluents can be included in the olibanum resin matrix tablets without affecting its rate controlling efficiency. Matrix tablets formulated employing olibanum resin(DF2) are considered suitable for controlled release of diclofenac over 24 h (i.e. once-a-day administration).