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

Document Type : Research article


1 Department of Pharmaceutical and Food Control, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.

2 Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.

3 Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.


One of the most significant issues in pharmaceutical industries, prior to commercialization
of a pharmaceutical preparation is the “preformulation” stage. However, far too attention has
been 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 semisolid
preparation based on a statistical mixture design and to verify the predictions made by the
software with an in-vitro efficacy bioassay test.
Extreme vertices mixture design (4 factors, 4 levels) was applied for preformulation
of a semisolid Povidone Iodine preparation as Water removable ointment using different
PolyEthylenGlycoles. Software Assisted (Minitab) analysis was then performed using four
practically assessed response values including; Available iodine, viscosity (N index and
yield value) and water absorption capacity. Subsequently mixture analysis was performed
and finally, an optimized formulation was proposed.The efficacy of this formulation was bioassayed
using 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 be
concluded 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 optimized
formulation. Efficacy was eligible on all tested species and in the case of staphylococcus
aureus;the prepared semisolid formulation was even more effective.


Main Subjects