(32e) Sepineo P600- Based Topical Semisolid Formulation- Relationship between Rheological Properties, Physical Stability, and Drug Release

The emulsion-based topical semisolid dosage forms present a high degree of complexity in their microstructures which is evident from their compositions made up of two or more immiscible phases as well as from mixing and interactions among multifunctional excipients and active substance. Rheological parameters are very crucial not only in determining the physical stability of the formulation during product development and the shelf life but also in influencing the release and skin permeation of drugs. In this present study, we develop Sepineo P600 based gel and emulsion gel (emulgel) topical formulations and evaluate the relationship between the rheological properties, physical instability due to phase separation, the in vitro release of drugs. We find that formulation parameters such as pH, nature of APIs and their concentration, concentration of dispersed phase and polymers can significantly affect the rheology as well as the physical stability and drug release. We also demonstrate rapid assessment and prediction of the long-term physical stability and shelf life of topical semisolid products using a dispersion analytical tool namely ‘LUMiSizer’. This study provides valuable insights into rheological behaviors of Sepineo P600 gel and emulgel which can be used to construct a framework for designing optimal topical drug delivery system.