Fatty alcohols are excipients that are abundantly used in various pharmaceutical formulations. The objective of the present study was to evaluate the impact of incorporating different fatty alcohols on microstructural and formulation characteristics of topical o/w clotrimazole cream formulation. The formulations containing different fatty alcohols as KolliwaxRTM CSA 50 (CSA 50), KolliwaxRTM CSA 70 (CSA 70), KolliwaxRTM MA (MA), KolliwaxRTM CA (CA), KolliwaxRTM SA (SA) were prepared by selecting suitable RPM and homogenization time. The M.P. of API and fatty alcohols were determined using DSC technique. The prepared cream formulations were evaluated for their phase separation. The various tests like pH, water activity measurement, work of adhesion measurement, globule size distribution, In vitro permeation study and rheological study were performed for the characterization of the formulation. All formulations were made in two batches and were subjected to stability conditions for 3 month at two conditions, 25°C/60% RH and 40°C/75% RH respectively. The initial and 3 month samples were characterized using tests like, pH, water activity measurement and globule size distribution.

The results for the tests like pH, water activity were found to be comparable in all cream formulations with different fatty alcohols. In phase separation study, the drug was found to have partitioned predominantly in the lipid phase with negligible amount present in the aqueous phase of the cream formulations. The work of adhesion values for all fatty alcohols except SA were found to be in the same range of values. From the results of globule size distribution, it can be concluded that CSA50, CSA70, MA and CA were found to form stable o/w cream formulation with a globule size range 2 to 6microm. SA when used alone in cream formulation, failed to produce a cream formulation with stable globules. All fatty alcohols containing creams showed yield stress values ∼ 10 Pa, except for the SA sample, which displayed a very low yield stress. The results of the rheological studies revealed that CSA 50 and CSA 70 form relatively stable microstructure. As, all products are shear thinning and have comparable yield stress, the rheological characteristics clearly reflect the microstructural similarities in the formulations. The results of finite and infinite IVPT studies revealed that the permeation of clotrimazole from all the o/w topical cream formulations could be enhanced when MA and CA are used in the formulation. The cream products prepared with different fatty alcohols maintained same characteristics at two storage conditions. SA was found to be one of the less efficient fatty alcohol in terms of forming a good o/w cream in the present case.