ABSTRACT
Erythromycin is particularly effective against most Gram-positive bacteria and some Gram-negative bacteria, including Neisseria, Campylobacter, Clamydia, and Mycoplasma. S. Morimoto et al. prepared a new semisynthetic macrolide, 6-0-methylerythromycin A, by the chemical modification on the C-6 hydroxy group of Erythromycin A (EM). The potency of clarithromycin is generally equal to or two-fold greater than that of EM, and two-to eight-fold greater than that of josamycin against aerobic Gram-positive bacteria, including Stapylococcus aureus, Staphylococcus epidermidis, and Streptococcus pneumoniae. Clarithromycin has demonstrated improved pharmacokinetic profiles in laboratory animals, such as mice, rats, and dogs. The in vitro and in vivo antibacterial activity of clarithromycin was also reported by P. B. Fernandes et al. Clarithromycin was more acid-resistant than EM. One of the limitations of EM is poor absorption after p.o. administration because of its liability at the gastric pH. EM, discovered in 1952, was a clinically useful macrolide antibiotic.
