Erythromycin estolate was synthesized by the Lilly Research Laboratories in 1959. It shows a higher and longer lasting serum level than erythromycin and the other esters, ethylsuccinate and stearate, when administered orally. This antibiotic is stable against gastric acids, and after oral absorption it is hydrolyzed gradually into erythromycin. Long-term usage of erythromycin estolate is toxic to the liver. Erythromycin ethylsuccinate [41342-53-4], (C43H75NO16, Mr 862.07) and erythromycin stearate [643-22-1] (C37H67NO13 · C18H36O2, Mr 1018.43) also have been used orally, and erythromycin lactobionate [3847-29-8] (C37H67NO13 · C12H22NO12, Mr 1092.25) has been used by intravenous administration and opthalmic topical application
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Long Needles
World Health Organization (WHO)
Erythromycin estolate, a macrolide antibiotic, was introduced in
1958 for the treatment of gram-positive infections. By the early 1970s its use had
been associated with a higher incidence of hepatic toxicity than that seen with
other salts and esters of erythromycin. This led to its withdrawal by some
regulatory authorities whereas others required the addition of a warning in the
product information. Evidence that the estolate ester is more hepatotoxic than
other salts or esters has subsequently been disputed. It has been claimed to be the most effective ester for treatment of Legionnaire's disease and preparations remain
widely available.
(Reference: (BMJOAE) British Medical Journal, 286, 1954, 1983)
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Erythromycin estolate, erythromycin propionate lauryl sulfate(Ilosone), is the lauryl sulfate salt of the 2＇-propionateester of erythromycin. Erythromycin estolate is acid stableand absorbed as the propionate ester. The ester undergoesslow hydrolysis in vivo. Only the free base binds to bacterialribosomes. Some evidence, however, suggests that theester is taken up by bacterial cells more rapidly than thefree base and undergoes hydrolysis by bacterial esteraseswithin the cells. The incidence of cholestatic hepatitis is reportedlyhigher with the estolate than with other erythromycinpreparations. Erythromycin estolate occurs as long needles that aresparingly soluble in water but soluble in organic solvents. administration for the treatment of serious infections,such as Legionnaires disease, or when oral administrationis not possible. Solutions are stable for 1 week whenrefrigerated.
