Preparation, Characterization and Optimization of Oromucosal Clotrimazole Emulgel Formulation

Mengesha, Mahilet (2015) Preparation, Characterization and Optimization of Oromucosal Clotrimazole Emulgel Formulation. Masters thesis, Addis Ababa University.

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Abstract

The topical applications of a drug to the oral mucosa offer the potential advantages of delivering the drug directly to the site of action and possibly delivering the drug for an extended period of time. The environment of the oral cavity and the continual secretion and swallowing of saliva are unique problems which need to be considered to ensure successful delivery of a drug via this route. Recently, emulgel has emerged as one of the most interesting topical preparations in the field of pharmaceutics. The use of emulgel as a delivery system has several advantages such as ease of administration, increased residence time of the drug at the applied site, and better drug release and diffusion. The objectives of this study were to formulate Clotrimazole, a practically insoluble imidazole antifungal, as oromucosal emulgel formulation, characterize, optimize, and to study the release profile and storage stability of the formulation. Different oils were compared for their solubilizing capacity of clotrimazole and phase diagrams were constructed using Tween 80 and ethanol as an emulsifier and co-emulsifier, respectively. Two of the commonly used polymers, sodium carboxymethyl cellulose (Na CMC) and hydroxypropylmethyl cellulose (HPMC), were studied for their gelling capacity. A systematic experimental design and optimization approach was carried out using central composite design (CCD) to select study points and generate polynomial equations which describe the relationship between the dependant and independent variables. The formulated emulgels were characterized by their physical behavior, content, pH, apparent viscosity, in vitro release, relative in vitro residence time, and spreadability using modified and standard methods. The mean globule size, release profiles, mechanisms, and kinetics of the optimized formulations were compared and studied. Based on relative solubility study oleic acid and virgin olive oil were chosen as oil phase and it was found that Tween 80 and ethanol at a ratio of 2:1 managed to emulsify the oil phase with greater area of transparent emulsions in the phase diagram. The emulsions were jellified using Na CMC without disrupting their phase behavior. Rheological studies revealed that the clotrimazole emulgels exhibited a shear-thinning behavior which is desirable for ease of administration. Based on the predicted responses and their desirability indices, threeformulations were selected as the optimum formulations with oil phase concentration of around 12.4%, surfactant solution concentration of 30%, and Na CMC concentration of 4%. The optimized clotrimazole emulsions exhibited 139-146 nm and 0.16-0.26 of mean globule size and polydispersity, respectively. When in-vitro drug release data were fitted to five commonly employed release kinetic models, zero order release model showed the best fit with high linearity for all the optimized formulations. The polymer relaxation and erosion were found to be the rate controlling steps when the first 60% drug releases were fitted to the Korsmeyer-Peppas model. From this, it can be concluded that clotrimazole can be formulated as an emulgel which can possibly enhance its release in aqueous media with acceptable spreadability and residence time at the target site.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Emulgel; Clotrimazole; Oral candidiasis; Optimization; Shear thinning
Subjects: R Medicine > RM Therapeutics. Pharmacology
R Medicine > RS Pharmacy and materia medica
Divisions: Africana
Depositing User: Emmanuel Ndorimana
Date Deposited: 17 Oct 2018 13:00
Last Modified: 17 Oct 2018 13:00
URI: http://thesisbank.jhia.ac.ke/id/eprint/6946

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