Development and Characterization of Sesame Oil Based Formulations for Controlled Drug Delivery

Abstract

The controlled delivery system has gained much importance in the last decade due to their ability to reduce the frequency of the dosage administration, toxicity and improve patient compliance. A large number of formulations employ vegetable oils to achieve desirable release profiles and/ or modulate the physical properties of the formulations. The present work explains the development and characterization of different types of sesame oil based formulations for controlled drug delivery applications. FDA (Food and Drugs Administration) approved “non-ionic surfactants” were used in the study. Two types of surfactants were chosen for developing the formulations from the large family of sorbitan esters and their derivatives. A liquid surfactant mixture of Span 80 and Tween 80 (1:2 w/w) was used which forms fluid-filled structures. The other surfactant was solid in nature (Span 60) and forms interconnecting solid fiber network structures. Mainly two types of formulations were developed, namely, emulsions (microemulsions and macroemulsions) and gels (organogels, emulsion gels, bigels and lyotropic gels). Organogels were prepared by mixing surfactants in sesame oil (70 °C, 500 rpm). Biphasic formulations were prepared by adding aqueous phase (70 °C) to the surfactant-oil mixture. Based on the composition, the formulations either formed emulsions or gels when cooled to room-temperature. The formulations were characterized in depth by stability testing, microscopic studies, Fourier Transform Infrared (FTIR) spectroscopy, viscosity measurement, mechanical testing, differential scanning calorimetry, electrical properties and biocompatibility studies. Metronidazole (model drug) loaded formulations were tested for in vitro drug release study and antimicrobial efficiency against model Gram negative microorganism, Escherichia coli. The microstructures of the formulation were studied using different microscopic techniques (phase contrast, fluorescence, confocal and polarized). FTIR spectra of the formulations suggested the absence of any interactions amongst the formulation components and the drug molecules. The formulations showed good biocompatibility against HaCaT cells. Metronidazole loaded formulations showed the diffusion-mediated controlled release of the drug. The developed formulations showed good antimicrobial properties against E. coli. Therefore, it may conclude that the developed formulations may be used as controlled delivery vehicles for pharmaceutical, nutraceutical and cosmetic applications.