Abstract
The results of laboratory studies on doxycycline intravenous are summarized as follows:
1. The standard curves of doxycycline in five dilution systems were compared. Zones of growth inhibition were largest in the phosphate buffer solution at pH 7.2 and smallest in human serum. Lung system was close to the buffer system, liver system close to the serum system, and kidney system intermediate.
2. The doxycycline concentrations in blood of healthy male adults were compared by crossover method. The concentration following intravenous injection of 200 mg, dissolved in 40 ml of 20% glucose and injected in 5 minutes, was higher than that after oral administration of 200 mg immediately after the injection, but was same after 3 hours and thenafter.
3. No tendency of accumulation was observed in six volunteers injected intravenously with 100-200 mg of doxycycline daily for three days.
4. In a patient with chronic broncho-bronchitis injected intravenously with 200 mg, the blood level reached a peak of 4.8 mcg/ml after 30 minutes, while the sputum- level reached a peak of 1.8 mcg/ml after 90 minutes. The sputum level was 30-40% that of serum.
5. The urinary excretion of doxycycline was 94 mg/day (47.0%) after a single intravenous injection of 200 mg, and 53 mg/day (26.5%) after a single oral administration of 200 mg.
