Preparation and evaluation of erythromycin fumarate--a new derivative of erythromycin.

Erythromycin fumarate, a new water-soluble derivative of erythromycin, was prepared and its physicochemical and biological properties were evaluated. The derivative also has considerable solubility in organic solvents. Its partition coefficient data in different organic solvent-water systems may indicate that it is well-distributed in various tissues in vivo. Antimicrobial potency in vitro of the derivative, 725 micrograms/mg, is much higher than that of the existing derivatives and its antimicrobial spectrum is comparable to that of the parent antibiotic. The LD50 value of the new derivative in mice intraperitoneally is 402.7 mg/kg. Results of this and the previous investigation on pharmacokinetics and protein binding indicate that erythromycin fumarate has high potential for possible clinical application and further investigation may be undertaken.