Physicochemical Properties and Release Profiles of Lidocaine Hydrochloride in Microemulsion Gels

Abstract This study focuses on the development and characterization of microemulsion gel systems incorporating the model drug lidocaine. Microemulsions were prepared via the standard phase titration method using various oil phases, surfactants, and co-surfactants, with demineralized water as the aqueous component. The primary objective was to assess the physical properties of the resulting gels and compare their drug release profiles to conventional gel formulations. The study examined the impact of varying surfactant and co-surfactant types, as well as the presence of the active pharmaceutical ingredient, on gel characteristics. Physical properties were evaluated through texture analysis and rheological measurements, while drug release was determined using Franz diffusion cells. Results showed that while the physical properties of microemulsion gels remained largely consistent across formulations, significant differences were observed in lidocaine liberation, highlighting the potential of microemulsion gels to modulate drug release behavior.