ACTA Pharmaceutica Sciencia 2008 , Vol 50 , Num 3
INFLUENCE OF SILYMARIN PRETREATMENT ON ABSORPTION OF NITRENDIPINE
KANDHAGATLA RAJNARAYANA, ALLENKI VENKATESHAM, MARTHA SRINIVAS, MALOTHU NAGULU, DEVARAKONDA R KRISHNA
Dept of Pharmacology and Clinical Pharmacy, University College of Pharmaceutical Sciences, Kakatiya University, Warangal, Andhra Pradesh, INDIA Silymarin was a flavonoid extracted from the medicinal plant Silybum marianum. Male albino rats were used for the study. Silymarin (50mg/kg, p.o) was given orally for 9 days and on day 10, animals were fasted overnight prior to sacrifice. The whole small intestine was flushed with 50 ml of ice-cold saline after sacrificing the animal with an over dose of pentobarbital. The small intestine was isolated and divided in to duodenum, jejunum and ileum. Each segment was everted and a 5 cm long sac was prepared and 1ml of nitrendipine solution introduced into the everted sac (serosal side) and both ends of the sac were ligated tightly. The sac containing nitrendipine solution was immersed in 30 ml of Dulbecco‘s phosphate buffer solution (D-PBS) containing 25 mM glucose. The transport of nitrendipine from serosal to mucosal surfaces across the intestine was determined by collecting samples from the mucosal medium periodically at different intervals 0, 10, 20, 30, 60, 90 and 120 minutes. The samples were analyzed by HPLC. Silymarin pretreatment significantly increased the transport rate of nitrendipine to greater extent in ileum than jejunum and with no effect in duodenum. It might be due to induction of P-glycoprotein (P-gp) in the intestine, with highest expression of P-gp being found in ileum followed by jejunum and duodenum. Keywords : SILYMARIN, NITRENDIPINE, EVERTED RAT INTESTINE, P-GLYCOPROTEIN

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