Abstract:Abstract:Objective: to investigate the absorption mechanism of palmatine chloride by using Caco-2 monolayer mode1.Methods: 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. Drug concentration was measured by HPLC and the apparent permeability coefficients (Papp) were calculated. Results: The apical to basolateral permeability (Papp) of palmatine chloride was bigger than the basolateral to apical permeability(Papp).Transport of palmatine chloride was time and concentration dependent, 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.