Cardamom oil as a skin permeation enhancer for indomethacin, piroxicam and diclofenac

The effect of the penetration enhancer, cardamom oil, on percutaneous absorption was investigated. Three kinds of drugs, indomethacin, piroxicam and diclofenac, which have different solubility in a mixed solvent system (phosphate buffer/alcohol, 50:50, v/v), were selected to evaluate the drug permeation with or without cardamom oil. For all drugs, the flux, lag time, accumulated amount (at 48 h) and penetration parameters were also determined at various pH values by using an in vitro permeation technique through rabbit abdominal skin. The solubility of each of the three drugs in the solvent system containing 1% cardamom oil was similar to that without enhancer. The penetration index of piroxicam was extremely increased by 1% cardamom oil, about 81.9-fold at the pH 5.8 solvent system, compared with that of indomethacin or diclofenac. The shorter lag time of indomethacin and diclofenac was observed in in vitro permeation experiments with 1% cardamom oil. These results suggest that the enhancing effect of cardamom oil is not due to changing the solubility of the drug in the solvent system and was dependent on the kind of drug, pH value of solvent system and concentration of cardamom oil.