抄録
The transport characteristics of β-lactam antibiotics was investigated in rat jejunum using the Ussing-type chambers in vitro. Not only the transmural flux rate, but also the influx rate and accumulation into the mucosal epithelium were measured to clarify the sequential processes of drug transport. β-Lactam antibiotics examined were cephalexin (CEX), cephradine (CED), ampicillin (AB-PC) and cefazolin (CEZ). The transport characteristics of these drugs were compared with that of L-phenylalanine (L-Phe). The results suggested that specialized transport systems are involved in all processes of mucosal-to-serosal transport for CEX and CED. From the kinetical analysis, it was demonstrated that these two drugs have similar capacity and affinity to carriers in the influx process or components which contribute to the cellular accumulation, while their transmural flux rates were different from each other. L-Phe was shown to have a much greater activity, affinity and capacity in the intestinal transport process than those of CEX, CED, AB-PC and CEZ.
