ABSTRACT
To investigate the inhibitory effect of Pluronic on P-glycoprotein (P-gp) drug efflux pump, Caco-2 cells and animal models were established to study the influence of Pluronic on celiprolol transport across Caco-2 cell monolayer and intestinal mucous membrane with verapamil set as a positive control. Drug concentration was measured by HPLC and the apparent permeability coefficient (P(app)), absorption rate constant (k(a)) and the effective permeability coefficient (P(eff)) were calculated. P(app) of basolateral to apical side and apical to basolateral side was (2.10 +/- 0.13) x 10(-6) and (0.333 +/- 0.018) x 10(-6) cm x s(-1), respectively. Transports of celiprolol across Caco-2 cell monolayer were influenced by both verapamil and Pluronic. The absorption constants (k(a)) of celiprolol at duodenum, jejunum, ileum, and colon were (0.09 +/- 0.03), (0.14 +/- 0.04), (0.11 +/- 0.03) and (0.05 +/- 0.02) h(-1), k(a) of celiprolol in verapamil group were (0.14 +/- 0.03), (0.24 +/- 0.02), (0.25 +/- 0.03) and (0.23 +/- 0.02) h(-1), and k(a) of celiprolol in Pluronic group were (0.13 +/- 0.02), (0.22 +/- 0.02), (0.22 +/- 0.03) and (0.20 +/- 0.03) h(-1), respectively. Pluronic showed significant effect on inhibiting P-gp of Caco-2 cell and intestinal mucosa in rats.