Application of Experiential Design for Framing Gastroretentive Microsponges of Glipizide: Screening of Critical Variables by Plackett-Burman Design and Optimization by Box-Behnken Design

Introduction: Microsponges provides a proficient drug delivery system for specific delivery in the upper gastrointestinal tract with high drug loading capability. But the formulation is affected by numerous process and design related factors. The intention of the current research work was to formulate and optimize the floating gastroretentive microsponges of glipizide, an antidiabetic drug, with minimum number of experiments, by applying an appropriate experimental design. Methods: The decisive factors affecting formulation were screened by Plackett-Burman design and the final optimization were performed by applying Box-Behnken design. In Plackett-Burman design, Pareto ranking analyses indicated that polymer concentration, stirring speed and temperature significantly affected the formulation of microsponges. The influence of these independent variables was checked on the entrapment efficiency, buoyancy and cumulative drug release (12hr) of the formulation by Box-Behnken design. Results: The results of Box-Behnken design showed that after applying the desirability criteria and looking into overlay plots, formulation GBB-8 with medium drug- polymer ratio and maximum level of the other two variables was found to be optimum with desirability near 1. The formulation gave entrapment efficiency as 90.81%, buoyancy as 92.3% and CDR12 as 92.3%. Radiographic studies conducted on albino rabbits, indicated the presence of the microsponges in the stomach for 12hr. Conclusion: It could be concluded that application of experimental design is helpful tool for the development of floating microsponges of glipizide. The prepared formulation can offer the sustained release of the drug at its site of absorption which may provide the better control of the diabetes due to less fluctuation in plasma drug concentration.