1975 Volume 27 Issue 1 Pages 34-52
The inactivation of antibiotics in the liver is one of the most important problems in the field of chemotherapy. Serial estimation of the in vitro recovery rate of the activities of antibiotics in rat liver homogenate kept at 0°C were made by bioassay (OKUBO's band culture method). The results obtained were as follows:
1) The changes in antibacterial activity of the various antibiotics in rat liver ho mogenate could be divided into four types:
(1) H (CER, CEZ) - no significant decrease in activity, more than 80% recovery throughout 24 hours preservation;
(2) L (JM) - immediate decrease down to 20%, no activity recurrence;
(3) SD (MCI-PC) - gradual decrease, no recurrence; and
(4) V (TC, PC-G) - gradual decrease followed by recurrence of activity up to more than 80% after 24 hours. This“recurrence phenomenon”is a new finding, hitherto unreported. The antibiotics kept in rat blood displayed similar patterns to those kept in the liver homogenate but not so clearly.
2) The mechanism of the recurrence phenomenon was further studied as follows:
(a) Influence of heat treatment: The antibacterial activity of TC added to liver homogenate previously treated with heat (56 °C,20 min. ) gradually decreased without recurrence, while that of PC-G showed no decrease during 24 hours.
(b) Influence of EDTA addition: PC-G presented activity recurrence despite the previous addition of EDTA to the liver homogenate, but TC did not.
(c) Bio-autograms revealed that the recurrence phenomenon of both antibiotics was not due to the production of metabolites.
