A Quality by Design Approach of Metronidazole Bigel and Assessment of Antimicrobial Study Utilizing Box-Behnken Design.

OBJECTIVE The present investigation aimed to prepare metronidazole (MTZ) topical bigel for the effective delivery of MTZ and to study the effect of used variables as per statistical design. The study also signifies the implementation of the statistical method using the Quality by Design technique for MTZ bigel. METHODS The MTZ bigels were prepared as per the runs suggested by box behnken design (BBD) using statistical software. A total of 28 runs were suggested by the BBD considering sodium carboxymethylcellulose (Na CMC), guar gum, hydrogel, and RPM as independent variables. The prepared bigels were evaluated for organoleptic properties, percentage drug content, spreadability, viscosity, percentage in-vitro drug release, and antimicrobial efficacy. Model selectivity ascertained by pvalue considering responses along with predicted R2 and adjusted R2 value. Fitting of model ascertained by F-value as well as "lack of fit" carried out to find out the suitability of the experimental design. Furthermore, the characteristic distribution of data ascertained by the "normal plot of residual" method. The compatibility of MTZ and excipients in bigels were confirmed by FTIR and the crystalline nature of MTZ in formulations was studied by DSC and XRD studies. Furthermore, the dispersion of bigel was assessed by the SEM study. RESULTS The effect of independent variables on Spreadability (mm), Viscosity (cp), pH, Drug release in 6th hour (%), and Drug content (%) was evaluated. The optimized formulation was selected and evaluated by a polynomial equation while considering the p-value. These variables showed a significant effect on responses. A less significant difference was observed (6.37, 14463, 6.97, 86.29, and 67.47 respectively for spreadability, viscosity, pH, and percentage drug release and % drug content) was found between the observed and predicted values indicating that the model is suitable. The prepared bigels were compatible and globules were found to be uniformly dispersed throughout bigel. CONCLUSION The 3D response surface design ascertained the optimal MTZ bigel at 1.25g of NaCMC, 0.5g of guar gum, 37.5g hydrogel, and 1000 RPM. The selected showed good antimicrobial efficacy against S. Aureus and may be considered as better delivery vehicles for the effective delivery of MTZ.