Optimization of Formulation Process of Ginkgo Folium Bi-layer Osmotic Pump Controlled-release Tablets by Central Composite Design-response Surface Methodology
Objective: To optimize formulation of Ginkgo Folium bi-layer osmotic pump controlled-release tablets. Method: With accumulative release rate of total flavonol glycosides as index,single-factor tests were adopted to screen formulations of drug-layer,push-layer and coating solution,drug release behavior was evaluated by similarity factor method.Taking the amount of PEG4000 in coating solution,coating weight and the amount of polyoxyethylene in push-layer as independent variables,linearity of release curve and accumulative drug release in 16 h as dependent variables,central composite design-response surface methodology was applied to optimize formulation. Result: Optimum formula was as follows:polyoxyethylene amount of 120 mg,the amount of PEG4000 of 1.5 g,coating weight of 11%;accumulative release of total flavonol glycosides in 16 h was above 90%. Conclusion: Release curve of this preparation meets requirements with correlation coefficient of 0.996 4.This optimized formulation is stable and suitable for industrial production of Ginkgo Folium bi-layer osmotic pump controlled-release tablets.