Effect of pretreatment by cardamom oil on in vivo percutaneous absorption of piroxicam gel: Pharmacokinetic analysis in rabbits

The effect of pretreatment by 5% cardamom oil in an alcohol-H2O vehicle on the percutaneous absorption of piroxicam gel was investigated. The area under the curve of plasma concentration from 0 to 24 h (AUC(0-24)h) of piroxicam for 30 min pretreatment with cardamom oil was about 67.09-fold higher than that of non-pretreatment and the absolute bioavailability obtained was 83.23% and was similar to that for 60 min pretreatment. On increasing the pretreatment period from 0 to 30 min, the AUC(0-24h) value increased linearly. In addition, a pharmacokinetic model with two consecutive first-order processes was developed and successfully described the plasma level after topical administration of piroxicam by penetration enhancer for pretreatment. A good correlation was observed between the AUC(0-24h) and the absorption rate constant.