[Penetration, distribution and retention of chlortetracycline in the body of pregnant rabbits and their fetuses]. / Proniknovenie, raspredelenie i sokhranenie khlortetratsiklina v organizme beremennykh krol'chikh i ikh plodov

Chlortetracycline was administered to the rabbits per os in a single dose of 150000 Units/kg. After 29-30 days of pregnancy the rabbits were sacrificied 1--3--6--9--12--24-hours and 2--3--4 days after the drug administration. Three-four rabbits were examined in every experiment. The antibiotic levels were determined by the agar-diffusion method. It was found that chlortetracycline was present in bactericidal concentrations in all 60 tissues of the rabbits and fetus examined except the rabbits eye lens. In some tissues of the rabbit and fetus chlortetracycline persisted up to 3 and 2 days respectively. The antibiotic levels in the organs, tissues and fluids of the fetus were many times lower than those in the rabbits. The concentration peak in the fetus was attained somewhat later and the rate of the concentration decrease was lower as compared to the same indices in the rabbit. The highest concentrations of chlortetracycline in the fetus were registered in the amniotic membranes, joints, bones, urine and amniotic fluid.

[Absorption, distribution and the duration of retention of neomycin in the body of pregnant rabbits and their fetuses]. / Vsasyvanie, raspredelenie i prodolzhitel'nost' sokhraneniia neomitsina v organizme beremennykh krol'chikh i ikh plodov

Neomycin was administered intramuscularly to rabbits in single doses of 50000 gamma/kg 24--25-day gravid rabbits were sacrificed 1.5-2-3-4-6-12-24 hours and 2-3-6 days after the drug administration. 3--4 rabbits were used in every experiment. The antibiotic concentration was determined with the agar-diffusion method. It was found that the drug was present in various bactericidal concentrations in all 55 organs, tissues and fluids of the rabbits and the fetus examined except the crystalline lens in the rabbits and the brain, liver and bile cyst of the fetus. In some material of the rabbits and their fetus, high levels of neomycin were detected during 6 days, i. e. up to the end of the experiment. The highest neomycin levels in the organs, tissues and fluids of the fetus were detected somewhat later than in those of the rabbits. However, their retention time was longer. It is necessary to forbear from using antibiotics, such as neomycin, monomycin and others, which retained for long periods of time in the organism.