Boswellia papyrifera resin as microencapsulating agent for controlled release of diclofenac sodium: Formulation, evaluation and optimization study
International Journal of Pharmacy and Pharmaceutical Sciences
Department of Pharmaceutics and Social Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
Objective: The present study is aimed to investigate the resin from local olibanum (Boswellia papyrifera) as a wall material for microencapsulation using diclofenac sodium as a model drug. Methods: Microcapsule formulations were prepared by solvent evaporation method with varying polymer to drug ratio, stirring rate, temperature and dispersed phase volumes and their effects on percentage yield, particle size, encapsulation efficiency and release rate were evaluated. Results: The preliminary experiments revealed that the polymer to drug ratio and stirring rate significantly affect both the encapsulation efficiency and release rate while the other factors only affect one of the responses. Therefore, the effects of polymer to drug ratio and stirring rate on the encapsulation efficiency and release rate of the microcapsules were further studied and optimized by central composite design. The optimal conditions were obtained at 3.7:1 polymer to drug ratio and 1200 rpm stirring rate. Under these conditions, the encapsulation efficiency and release rate were 26.45 % and 27.87 h-1/2, respectively. The optimum formulation also provided discrete, spherical and freely flowing microcapsules. The in vitro drug release exhibited minimum burst release with sustained release for 12 h. The kinetic study showed the optimized formulation followed Higuchi square root kinetic model with non-Fickian diffusion release mechanism. Conclusion: The results of this study showed that the resin of B. papyrifera could be used as a potential alternative wall material for microencapsulation.
diclofenac; plant resin; analytic method; article; Boswellia papyrifera; central composite design; controlled release formulation; density; drug release; experimental design; kinetics; mathematical model; microcapsule; microencapsulation; microscopy; particle size; pH; physical parameters; solvent evaporation; stirring rate; temperature