Transdermal ethosomal gel nanocarriers; a promising strategy for enhancement of anti-hypertensive effect of carvedilol

The current study was conducted to develop vesicular ethosomal gel (ethogel) systems for upgrading the transdermal delivery of anti-hypertensive carvedilol. Ethosomes composed of Phospholipon 100 H, cholesterol, ethanol, and Transcutol P at different ratios, were prepared by thin-film hydration method with sonication. Carvedilol-loaded ethosomes were characterized by microscopic examinations followed by other in-vitro assessments. Selected ethosomal formulation (E10) was incorporated into different concentrations of gelling agents to prepare the ethogel formulations. Ethogels were subjected to physicochemical characterization, compatibility, and in-vitro drug release studies. Ex-vivo skin permeation and retention studies were performed followed by in-vivo studies in induced hypertensive rats. The smooth ethosomes demonstrated vesicular size of 201.55-398.55 nm, entrapment efficiency of 30.00-90.66% and loading capacity of 7.64-43.04% with zeta potential range of -30.30 to -44.90 mV. The homogeneous ethogels exhibited appropriate results of pH and drug content measurements. Spreadability was observed as a function of viscosity as the latter increased, the former decreased. The ethogel formulation (G2) manifested satisfactory physical appearance, spreadability, viscosity, and in-vitro release. In comparison to pure carvedilol gel, tested formulations (E10 and G2) developed high ex-vivo permeation, steady-state flux and drug retention through skin layers. The in-vivo study of G2 formulation revealed a significant gradual decline (p < 0.01) in the mean arterial pressure of rats at the second hour of experiment (146.11 mmHg) with continuous significant decrease (p < 0.001) after 6 h (98.88 mmHg). In conclusion, ethogels as promising lipid carriers proved their potential to enhance skin permeation with extended anti-hypertensive action of carvedilol.