Abstract
The transfer of sulfonamides to eggs and its relationship to sulfonamide levels inthe plasma and other tissues were examined in hens fed a diet containing sulfadi-methoxine (SDM), sulfamonomethoxine (SM[NI), or sulfamerazine (SMR).When hens were fed diets containing 0.005% sulfonamide, it was hardly possibleto find both SDM and SMM in both egg-albumen and yolk.When O.2% sulfonamide diets were fed, a rise in sulfonamide level was observed inplasma>egg-albumen>egg-yolk, as listed in the decreasing order of rapidity, with apeak level appearing 2 to 4, 6 to 8, and 8 to 10 days, respectively, after the start of theexperimental feeding. SDM levels in the egg-albumen were nearly a half of those inthe plasma, while SMM levels, as well as SMR levels, were almost the same both in theegg-albumen and in the plasma. In every case of the plasma, egg-albumen and yolk, SDM levels were higher than SMM and SMR levels. The withdrawal of SDM andSMM after a 30-day period of medication accompanied the disappearance of these drugsfrom the plasma, egg-albumen, and yolk after 4, 6, and 10 days, respectively. On theother hand, SMR could not be detected after 4 days in these tissues. The drug levelswere relatively high in the gall-bladder, plasma, and kidney, but were low in the ovary, ileum, and thoracic muscle. The level in the egg-albumen was as high as that in thekidney, while the egg-yolk showed the lowest level of 15 tissues tested. A considerablylarge difference was found in the proportion of acetylated sulfonamide arnong the drugs, as well as the tissues tested.Evidences have been obtained that the differences observed in plasma level andtransferability to eggs among the sulfonamides studied depended more on the durabilityof these drugs and the degree of plasma-protein binding than the rapidity of absorptionfrom the alimentary tract.
