Efficacy and Physicochemical Evaluation of an Optimized Semisolid Formulation of Povidone Iodine Proposed by Extreme Vertices Statistical Design; a Practical Approach

One of the most significant issues in pharmaceutical industries, prior to commercializationof a pharmaceutical preparation is the “preformulation” stage. However, far too attention hasbeen paid to verification of the software assisted statistical designs in preformulation studies.The main aim of this study was to report a step by step preformulation approach for a semisolidpreparation based on a statistical mixture design and to verify the predictions made by thesoftware with an in-vitro efficacy bioassay test.Extreme vertices mixture design (4 factors, 4 levels) was applied for preformulationof a semisolid Povidone Iodine preparation as Water removable ointment using differentPolyEthylenGlycoles. Software Assisted (Minitab) analysis was then performed using fourpractically assessed response values including; Available iodine, viscosity (N index andyield value) and water absorption capacity. Subsequently mixture analysis was performedand finally, an optimized formulation was proposed.The efficacy of this formulation was bioassayedusing microbial tests in-vitro and MIC values were calculated for Escherichia coli,pseudomonaaeruginosa, staphylococcus aureus and Candida albicans.Results indicated the acceptable conformity of the measured responses. Thus, it can beconcluded that the proposed design had an adequate power to predict the responses in practice.Stability studies, proved no significant change during the one year study for the optimizedformulation. Efficacy was eligible on all tested species and in the case of staphylococcusaureus;the prepared semisolid formulation was even more effective.