Mapping the Impact of a Polar Aprotic Solvent on the Microstructure and Dynamic Phase Transition in Glycerol Monooleate/Oleic Acid Systems

The impact of incorporating a polar aprotic solvent, dimethyl sulfoxide (DMSO), in glycerol monooleate/oleic acid systems was evaluated briefly to map its influence on the gel microstructure and dynamic phase transition in controlling the performance of a polyene antifungal drug delivery system. An gelling fluid precursor system (IGFPS) exhibiting inverse lyotropic liquid crystalline phases was developed by simple solution add-mixture method. Polarized light microscopy, small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and oscillatory rheological assessments were performed to ascertain microstructural modulations. The developed system was examined for minimum gelling volume, gelling time, swelling behavior, mucoadhesion, antifungal activity, and drug release. The SAXS study identifies the coexistence of Im3m cubic phase with HCP P63/mmc hexagonal structures. The SAXS and DSC data highlight DMSO's unique ability to work both as a kosmotropic or chaotropic solvent and to be a function of its concentration. The antifungal test results indicate the concentration of DMSO to be a controlling factor in drug release and diffusion. The drug release kinetic studies reveal that most of the gel samples follow the matrix model and anomalous type release as implied by Peppas model. Finally, the antifungal IGFPS formulated was found to have the required low viscosity, responsive sol-gel phase transition, appreciative mechanical properties, and desirable antifungal effect with sustained drug release performance.