[Experimental pharmacodynamic study of rifampicin administered by various methods]

The experimental study was performed on 80 male albino rats. The dose of rifampicin was 10 mg per 1 kg of the body weight. The highest rifampicin levels in the lung tissue were determined at all periods after intrabronchial administration of the drug. Thus, 2 hours after intrabronchial instillation of rifampicin its level in the lung tissue was 10--12 times higher than that after its enteral use. In 4 hours the antibiotic level decreased. Still, it remained 10 times higher than that after the enteral use. In 8 hours the level of rifampicin administered intrabronchially was almost the same as its maximum concentration in the lung tissue attained after the enteral use in 2 hours. By the 12th hour of the intrabronchial administration of rifampicin its concentration in the lung tissue markedly decreased. Still, it was 5--6 times higher than that after the enteral use. The rifampicin levels in the liver tissue after intrabronchial administration of the drug were at all periods much lower than those after the enteral use. The levels of rifampicin in the blood serum after its intrabronchial and enteral administration, as well as those in the liver tissue did not significantly differ.