Formulation and optimization of dimenhydrinate emulgels for topical delivery using response surface methodology

Development of dimenhydrinate (DMN) emulgel formulation has been described in this work with enhanced permeation for transdermal delivery of DMN for effective management of motion sickness. Various DMN emulgel formulations were prepared using central composite design in response surface methodology. Propylene glycol and olive oil were used in varying ratios as permeation enhancers along-with carbopol-934 as gelling agent. Prepared formulations were evaluated by physico-chemical properties, stability and Fourier transform infrared spectroscopy (FTIR) studies. In-vitro drug release was studied using cellophane membrane. Formulation F2 showed maximum drug permeation following diffusion-based release mechanism and was used in further studies. Rat skin was used in Franz cell for ex-vivo studies to determine various permeation kinetic parameters. FTIR studies provided no evidence of chemical interaction between DMN and polymers used, whereas molecular docking revealed formation of a stable complex in the presence of aqueous environment with stable intermolecular binding and the complex was well hydrated. No evidence of skin irritation was observed in human volunteers following application of the optimized formulation. Histopathology data of the rat skin showed a decreased proliferation of the lymphocytes whereas monocytes were induced. In conclusion, combination of propylene glycol and olive oil was successfully employed for delivery of DMN through transdermal route with good permeability and prolonged release time that can be highly beneficial in treating motion sickness in unusual circumstances.