Impact of Span surfactants on the physicochemical properties of stearic acid–sesame oil oleogels for topical drug delivery

The present study outlines the development of innovative oleogel carriers for topical formulations by combining stearic acid (SA) and sesame oil (SO). Different Span series surfactants, namely monolaurate, monopalmitate, monostearate, and monooleate, were added to the SA–SO oleogel at 3.2% to modify the crystal habit of the formulations. Moreover, mupirocin (MUP) was incorporated into this oleogel system. The prepared oleogels were analyzed for their surface and physicochemical characteristics. The oil-binding capacity suggested the excellent stability of the fabricated oleogel formulations. Microscopic analysis indicated a network between the oil, gelator, and surfactant. FTIR demonstrated the intermolecular bonding within the oleogel network. XRD provided detailed insights into the crystallographic properties of the developed oleogels. Oleogels exhibit significant antimicrobial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria. In vitro cell studies confirm the cytocompatibility of the developed oleogels. The Live/Dead assay on the fibroblast cell line showed high cell viability, confirming the biocompatibility of the oleogels for topical applications. In vitro and ex vivo drug release analysis suggested that the release of MUP from the prepared oleogel occurs in a sustained manner. In addition, the skin irritant properties of the oleogels were evaluated through animal studies. Both animal and cell studies indicated the positive effect of the oleogel drug combination on therapeutic applications. Thus, the developed oleogel is suitable for topical application.