The Pharmacokinetic Interaction Between JBP485 And Cephalexin In Rats

Objective:Drug-drug interactions (DDIs) arising from inhibition of the same transporters may lead to adverse effects. JBP485 (cyclo-trans-4-L-hydroxyprolyl-L-serine) is a dipeptide with obvious liver protective effect after oral administration. Cephalexin has a broad spectrumof antibacterial activity. It has already been demonstrated that dipeptides and cephalexin share certain structural features such as a peptide bond with an a-amino group and a terminal carboxylic acid group. In this study we investigated the mechanism of interaction between JBP485 and cephalexin when they were co-administered in rats.Methods:A sensitive, quick and high performance method was used to determine the concentration of JBP485 and cephalexin in rat biologic samples with internal standard by LC-MS/MS. (1) JBP485 (25 mg/kg) alone, cephalexin (50 mg/kg) alone and JBP485 (25 mg/kg)+cephalexin (50 mg/kg) were oral administered in vivo. Blood samples were collected via jugular for determination. (2) Using everted small intestinal preparations in vitro to investigate the interaction between JBP485 (0.5 mM) and cephalexin (1 mM), and the effect of Gly-sar (20 mM) and JBP923 (1 mM) on JBP485 were also detected. (3) In situ intestine perfusions were applied to further demonstrate the absorption mechanism of JBP485 with cephalexin. (4) Blood arid urine samples were collected to investigate the interaction in kidney, when JBP485 (25 mg/kg) and cephalexin (50 mg/kg) were administered intravenously. And the effect of probenicid (100 mg/kg) on the excretion of JBP485 and cephalexin were also investigated. (5) Kidney slices experiments were operated to clarify the mechanism of DDI. (6) Uptake in hOAT1-or hOAT3-HEK293 cells was performed to investigate the definite mechanism of the interaction.Results:(1) When JBP485 and cephalexin were co-administered orally, the plasma concentrations of the two drugs were decreased significantly. Nonetheless, little differences were observed after simultaneously intravenous administration, suggesting that the interaction target localized in intestine during absorption process. (2) Uptakes of JBP485 and cephalexin in everted intestinal sacs in vitro were significantly reduced. (3) The absorption in situ jejunal perfusions was also dramatically reduced when they were perfused simultaneously. Absorption of JBP485 could be inhibited by Gly-sar or JBP923. (4) When intravenously co-administered, the renal clearances of JBP485 and cephalexin were both decreased (2.89 to 1.87ml/min/kg of JBP485 versus 2.23 to 1.58ml/min/kg of cephalexin) indicated that other transporter(s) involved in the process of excretion except PEPT2. Probenecid (a typical substrate of OATs) could reduce renal excretion of JBP485 and cephalexin in vivo. (5) Uptake of JBP485 and cephalexin had significantly dropped when they were administered together in kidney slices. Moreover, Uptake of JBP485 was decreased.by adding PAH, PCG or Gly-Sar. (6) The uptake in hOATl-or hOAT3-HEK293 cells showed an obvious greater accumulation of JBP485 than that in vector-HEK. And the uptake could be inhibited in the presence of probenecid, PAH or PCG.Conclusion:(1) There are significant interaction between JBP485 and cephalexin when they administered together. (2) The pharmacokinetic mechanism of drug-drug interaction between JBP485 and cephalexin could be explained by inhibiting the same transporters in intestinal mucosa (PEPT1) and kidney (PEPT2 and OATs). (3) We provide the first evidence that JBP485 is not only a substrate of PEPTs but also is excreted through OATs.