Formulation development of ethosomes containing indomethacin for transdermal delivery

Abstract

2 Ethosomes containing indomethacin (8 mg/mL) were prepared with various concentrations of soybean phosphatidylcholine (SPC), ethanol and with different dispersion media and additives. The ethosomes with good colloidal appearance were obtained in the media containing 10%-30% ethanol in pH 7.4 phosphate buffer. The properties of ethosomes, including physical appearances, size, and entrapment efficiency (EE), were examined and discussed concerning their constituents. Notably significant decreases in vesicular size were observed at 20% ethanol (2% and 4% SPC) and 30% ethanol (6% SPC). The EE was varied relating to the vesicular size and concentration of SPC used. The optimized ethosomes were prepared from a dispersion of 4% w/v SPC:cholesterol:deoxycholic acid (6:2:1 M ratio) in 20% v/v ethanol in pH 7.4 phosphate buffer. The vesicular size was 55 ± 8 nm; the EE was 52.51% ± 4.09%, and the zeta potential was −39.06 ± 1.53 mV. These ethosomes led to significantly higher permeation of indomethacin through pig skin over 24 h than the commercial solution and the ethanolic solution of indomethacin. It was stable in terms of physical appearance, drug content, and EE when stored at ambient temperature for 3 months. These results indicated the feasibility of ethosomes as a transdermal drug carrier for indomethacin.