Effect of gel composition and phonophoresis on the transdermal delivery of ibuprofen: in vitro and in vivo evaluation.

The objective of this study was to evaluate the effect of formulation composition and continuous ultrasound at 1.5 W/Cm² intensity on the permeation of ibuprofen across polymeric and biological barriers. In vitro studies were performed using cellulose membrane and rabbit skin, whereas in vivo studies were performed on rabbits. Overall, higher transport data were obtained with the cellulose membrane. Nonetheless, with both barriers, transport was higher with the gel formulation than oleaginous or emulsion based preparations, which was also dependent on the viscosity of the gel and the concentration of the formulation additives. Transport increased with the increase in alcohol concentration and decreased with the addition of propylene glycol. Ultrasound had a significant effect on ibuprofen transport. For example, an 11-fold increase in drug permeation across cellulose membrane was observed after the application of ultrasound. Similar effect was observed in animal studies. Ibuprofen plasma concentration increased with the concentration of the drug in the gel, which significantly increased after the application of ultrasound. It was concluded that aqueous gel formulations act as ideal coupling agents for topical application of drugs. Nonetheless, in addition to ultrasound, the composition of the gel is expected to have a significant effect on the transdermal delivery of drugs.