Pharmaceutical Applications
3″-Propionyl leucomycin A5. A semisynthetic macrolide. Unstable in acid media.
The antibacterial spectrum is identical to that of erythromycin, but it is less active against Gram-positive cocci. It is poorly active against H. influenzae (MIC50 8 mg/L) and Mor. catarrhalis (MIC50 4 mg/L). It displays good activity against Campylobacter spp. (MIC50 0.1 mg/L), L. pneumophila (MIC50 0.1 mg/L) and M. pneumoniae (MIC50 0.003 mg/L). It is active against anaerobes, including some Bacteroides spp. (MIC50 <0.05 mg/L).
After a single oral dose of 600 mg, the peak plasma concentration was 1.9 mg/L after 0.6 h. Oral doses of 5, 10 and 15 mg/kg of a syrup formulation given to children achieved plasma concentrations of 0.26, 0.55 and 0.79 mg/L, respectively, after about 40 min. The half-life is around 2 h.
It is mainly eliminated in the bile; only about 2% appears in the urine. Its major metabolites are leucomycin A7, 10″-OH-rokitamycin (which show some antibacterial activity) and leucomycin V. In healthy adult volunteers, the proportions of rokitamycin and its metabolites in serum 30 min after a single oral dose of 1200 mg were 18% (leucomycin A7), 33% (10″-OH-rokitamycin) and 9% (leucomycin V). The pharmacokinetic behavior is not altered in patients with liver cirrhosis. It is available in Italy and Japan.
