Effects of Berberine on Pharmacokinetics of Amlodipine in Rats and its Potential Mechanism

This study investigates the pharmacokinetic interactions between berberine and amlodipine in rats. Twelve male Sprague-Dawley rats were randomly assigned into two groups: amlodipine group (1 mg/kg of amlodipine) and berberine (20 mg/kg) + amlodipine (1 mg/kg) group. Plasma concentrations of amlodipine were determined by using a sensitive and reliable LC-MS/MS method. The effects of berberine on the metabolic stability of amlodipine were investigated by using rat liver microsome incubation systems. The results indicated that when the rats were pretreated with berberine, the C-max of amlodipine increased from 13.78 +/- 3.57 to 19.96 +/- 4.56 ng/mL (p < 0.05), the T-max increased from 4.04 +/- 1.15 to 5.89 +/- 1.64 h (p < 0.05), and the AUC(0-t) increased by approximately 104% (p < 0.05), which suggested that the pharmacokinetic behavior of amlodipine was affected after oral co-administration of berberine. Additionally, the metabolic half-life was prolonged from 35.2 +/- 6.5 to 56.8 +/- 11.7 min (p < 0.05) with the pretreatment of berberine. It can be speculated that the drug-drug interaction between berberine and amlodipine might occur, which might have resulted from inhibiting the metabolism of amlodipine by berberine when they were co-administered.