Abstract
The effect of terephthalic acid (TPA) upon sulfadimethoxine contents in blood plasma was studied. The drug contents in blood plasma were increased by TPA feeding both in the rat and in the rabbit. The maximum contents of the drug in blood plasma were not so affected. However, 24 and 48 hr. after a single administration, they showed significant increases from that of the control. The drug excretion amounts in the urine of the TPA group was lower than those of the control and the plasma half-life of the drug was elongated by TPA administration, about 1.5 times in the rat and 1.9 times in the rabbit. Absorption of the drug through the gastrointestinal tract decreased with TPA administration and high contents of TPA might have a hindering effect on drug absorption from the small intestine. The contests of N4-acetate of the drug were increased by TPA administration. This increasing effect of TPA upon sulfadimethoxine seems to be concerned with excretion from the kidney. As a result, it is supposed that the plasma half-life of the drug is elongated.
