Enhancement of Intestinal Absorption of few Cox-2 Inhibitors Through Interaction with β-Cyclodextrin

Complexing a drug may alter the rate and extent of drug absorption. The complex formation is very well applied in the administration of poorly water-soluble drugs. The drugs selected for the study are cyclooxygenase-2 inhibitors, are potent anti-infl ammatory drugs with very low water solubility. The water solubility of these drugs was enhanced by complexing with β-cyclodextrin. In vitro absorption studies using isolated inverted bovine gut technique showed greater rate of transport of these drugs when complexed with β-cyclodextrin. The increase in the rate of transport is due to the formation of inclusion complexes with β-cyclodextrin that in turn increases the absorption. Studies also reveal that as the concentration of complexing agent increases the rate of absorption also increases proportionately. A statistical correlation was attempted between the mean percent drug dissolved at time ‘t’ and quantity of drug absorbed at time ‘t/2’. When relation of in vitro drug dissolution and in vitro drug absorptions were studied, it was found that the r-values for all formulations are within 0.947 to 0.997. This indicates a strong positive correlation between the in vitro drug dissolution and absorption of the drug through everted gut.