Objective: To investigate the absorption mechanism of palmatine chloride by using Caco-2 monolayer model. Method: A Caco-2 cell monolayer model was used to investigate the bi-directional transport of palmatine chloride. The effect of time

drug concentration

temperature

pH and inhibitors on the absorption of palmatine chloride was studied. Apparent permeability coefficient (Papp) of palmatine was calculated based on quantitation by HPLC. Result: Directional flux studies with palmatine chloride suggested transport with the permeability in the apical to basolateral direction higher than that in the basolateral to apical direction. Transport of palmatine chloride could be of saturation with time and concentration

and it was also effected by P-glycoprotein inhibitor

pH and temperature. Conclusion: The absorption of palmatine chloride in Caco-2 cell model was an active transportation mediated by transporter

which mainly located in the apical side of Caco-2 cell monolayer.