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ABSTRACT: Cyclo-trans-4-L-hydroxyprolyl-L-serine (JBP485) is a dipeptide with anti-hepatitis activity that has been chemically synthesized. Previous experiments in rats showed that JBP485 was well absorbed by the intestine after oral administration. The human peptide transporter (PEPT1) is expressed in the intestine and recognizes compounds such as dipeptides and tripeptides. The purposes of this study were to determine if JBP485 acted as a substrate for intestinal PEPT1, and to investigate the characteristics of JBP485 uptake and transepithelial transport by PEPT1. The uptake of JBP485 was pH dependent in human intestinal epithelial cells Caco-2. And JBP485 uptake was also significantly inhibited by glycylsarcosine (Gly-Sar, a typical substrate for PEPT1 transporters), JBP923 (a derivative of JBP485), and cephalexin (CEX, a β-lactam antibiotic and a known substrate of PEPT1) in Caco-2 cells. The rate of apical-to-basolateral transepithelial transport of JBP485 was 1.84 times higher than that for basolateral-to-apical transport. JBP485 transport was obviously inhibited by Gly-Sar, JBP923 and CEX in Caco-2 cells. The uptake of JBP485 was increased by verapamil but not by cyclosporin A (CsA) and inhibited by the presence of Zn(2+) or the toxic metabolite of ethanol, acetaldehyde (AcH) in Caco-2 cells. The in vivo uptake of JBP485 was increased by verapamil and decreased by ethanol in vivo, which was consisted with the in vitro study. PEPT1 mRNA levels were enhanced after exposure of the cells to JBP485 for 24h, compared to control. In conclusion, JBP485 was actively transported by the intestinal oligopeptide transporter PEPT1. This mechanism is likely to contribute to the rapid absorption of JBP485 by the gastrointestinal tract after oral administration.
Peptides 01/2011; 32(4):747-54. · 2.43 Impact Factor
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ABSTRACT: To investigate the pharmacokinetics and mechanism of intestinal absorption of JBP485 in rats, the pharmacokinetics of JBP485 were investigated in vivo both intravenously and orally. The effects of glycylsarcosine (Gly-Sar) on the uptake and transepithelial transport of JBP485 were examined in everted intestinal sacs, in situ jejunal perfusion, Caco-2 cells and PEPT1 transfected Hela cells. The gastrointestinal absorption of JBP485 was rapid. T(1/2β) was 2.25 ± 0.06 h, CL(plasma) was 2.99 ± 0.002 ml/min/kg, V(d) was 0.22 ± 0.05 l/kg and bioavailability was about 30% at a dosage of 25 mg/kg. JBP485 underwent rapid distribution in the tissues. Gly-Sar significantly decreased JBP485 uptake and transport in these models. A kinetic study showed that JBP485 was transported by PEPT1 in Caco-2 cells with Km and Vmax values of 0.33 ± 0.13 mM and 0.72 ± 0.06 nmol/mg protein/10 min, respectively. JBP485 appeared to have linear pharmacokinetics at intravenous doses of 6.25-100 mg/kg with minor first-pass effect, and JBP485 was mainly distributed in the kidney; JBP485 is a substrate for PEPT1 which is involved in the absorption of JBP485 in rat intestine.
Drug Metabolism and Pharmacokinetics 09/2010; 25(5):500-7. · 2.32 Impact Factor
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ABSTRACT: The purpose of this study was to investigate the pharmacokinetic mechanism of interaction between JBP485 (cyclo-trans-4-L-hydroxyprolyl-L-serine, a dipeptide) and cephalexin when they were coadministered in rats. The plasma concentrations of JBP485 and cephalexin were both decreased significantly after oral combination, but little difference was observed after simultaneous intravenous administration of the two agents, suggesting that the interaction target localized in the intestine during the absorption process. The uptake in everted intestinal sacs and absorption in jejunal perfusions of JBP485 and cephalexin were dramatically reduced after drug combination. When JBP485 and cephalexin were coadministered, both the decrease in accumulative renal excretion (81.9-68.1% of JBP485 and 91.8-74.5% of cephalexin) and in renal clearance (2.89-1.87 ml/min/kg JBP485 and 2.23-1.58 ml/min/kg cephalexin) indicated that transporter(s) other than H(+)/peptide transporter (PEPT) 2 are involved in the process of excretion. Probenecid could reduce renal excretion of JBP485 and cephalexin. Moreover, the decreased uptake of JBP485 with probenecid, p-aminohippuate, or benzylpenicillin in kidney slices could be explained by an inhibition in the kidney via organic anion transporters (OATs), at least in part. The accumulation of JBP485 in human (h) OAT1- or hOAT3-human embryonic kidney (HEK) 293 cells was greater than that in vector-HEK293 cells, and the uptake could be inhibited by probenecid. These findings further confirmed that the pharmacokinetic mechanism of the drug-drug interaction between JBP485 and cephalexin could be explained by their inhibition of the same transporters in the intestinal mucosa (PEPT1) and kidneys (PEPT2 and OATs). We provide the first evidence that JBP485 is not only a substrate of PEPTs but also is excreted through OATs.
Drug metabolism and disposition: the biological fate of chemicals 03/2010; 38(6):930-8. · 3.74 Impact Factor
