Date of Graduation

Summer 2021

Degree

Master of Science in Chemistry

Department

Chemistry

Committee Chair

G. Alan Schick

Keywords

oil-in-water, surfactant, crystal, lamellar, polarized, microscopy, birefringence, lyotropic, hot stage

Subject Categories

Dermatology | Lipids | Materials Chemistry | Medicinal-Pharmaceutical Chemistry | Pharmaceutical Preparations | Statistical, Nonlinear, and Soft Matter Physics

Abstract

Diethylene glycol monoethyl ether (DEGEE) is a promising solvent component in topical cream formulations due to its superior solubilizing abilities with certain active pharmaceutical ingredients. One of the goals of this study is to characterize the effects of pH on the physical and chemical stabilities of topical cream formulations containing particularly high concentrations of DEGEE by characterizing a full topical pH profile of 3.5 – 9.0. The second goal is to evaluate the presence, amount, and characteristics of lyotropic liquid crystals (LLCs), molecularly structured in a lamellar phase, in a model cream emulsion utilizing polarized light microscopy (PLM). The presence of lamellar structured LLCs has been found to improve the overall character and stability of cream formulations. In this study, it was found that the oil-in-water emulsion is physically stable at pH values under the inflection point. Chemical stability was confirmed by an accelerated temperature condition at 40°C where the pH value was stable throughout the topical profile. The presence and abundance of lamellar LLCs at the oil-water interface were found to be more abundant at pH values below the inflection point. The introduction of thermal studies provided interesting results when lamellar LLCs were heated and slow cooled to ambient conditions. It is possible a different crystalline structure was produced upon cooling the sample; however, continued research is needed to definitively determine these results.

Copyright

© Melinda Joanna Sutton

Open Access

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