Human safety and pharmacokinetics of a single intramuscular dose of a novel spectinomycin analog, trospectomycin (U-63,366F).

In this study, local and systemic tolerance and pharmacokinetics of trospectomycin sulfate in human beings were evaluated for the first time. Trospectomycin sulfate (U-63,366F; trospectomycin) or sterile saline was administered to 96 healthy male volunteers in doses ranging from 0.25 ml (75 mg) to 3.3 ml (1,000 mg) in a single intramuscular injection in a double-blind, randomized design. Volunteers were screened to establish baseline vital signs and laboratory test values. Pain and tenderness at the injection site, which occurred at doses of 450 mg and above, were the most common side effects; they were mild in severity and transient. Adverse drug experiences reported by subjects included nausea, dizziness, light-headedness, diaphoresis, costal pain, and perioral numbness. The perioral numbness (paresthesia) experienced at doses of 750, 900, and 1,000 mg was probably drug related. No Clostridium difficile toxin was detected in fecal samples. Pharmacokinetic calculations based on data obtained by high-performance liquid chromatography showed that after a 1,000-mg intramuscular dose of trospectomycin (3.3 ml), the serum mean half-life was 1.85 h (1.70 to 2.02 h), mean area under the serum concentration-time curve was 140.2 micrograms.h/ml and was linear with dose, mean peak concentration was 28.3 micrograms/ml (20.4 to 34.7 micrograms/ml), mean time to maximum concentration was 71 min (30 to 120 min), and the elimination rate constant was 0.307 h-1. The elimination rate constant and half-life did not vary with dose. Little trospectomycin was detected in 2-day fecal collections. A few randomly occurring abnormal clinical laboratory test values and vital signs were observed. For the trospectomycin-treated group, creatinine phosphokinase increased substantially for 24 h after injection and then decrease through day 5, while serum glutamic oxalacetic transaminase and lactate dehydrogenase increased slightly.