Enhancement of the properties of a drug by mono-deuteriation: reduction of acid-catalysed formation of a gut-motilide enol ether from 8-deuterio-erythromycin B.

Erythromycin B is structurally very similar to erythromycin A, and also shares its clinically important antibacterial activity. Its potential advantage is that it is much more stable to acid. Both compounds are susceptible to 6-9-enol ether formation, involving loss of a proton from C-8.

Mechanism for the degradation of erythromycin A and erythromycin A 2'-ethyl succinate in acidic aqueous solution.

A major drawback of the antibiotic erythromycin A is its extreme acid sensitivity, leading to rapid inactivation in the stomach. The accepted model for degradation in aqueous acidic solution has erythromycin A in equilibrium with erythromycin A enol ether and degrading to anhydroerythromycin A. We report a detailed kinetic study of the acidic degradation of erythromycin A and of erythromycin A 2'-ethyl succinate (the market-leading pediatric prodrug), investigating the reaction rates and degradation products via NMR.

Pediatric erythromycins: a comparison of the properties of erythromycins A and B 2'-ethyl succinates.

The antibiotic erythromycin A is generally administered to children as a suspension of the pro-drug erythromycin A 2'-ethyl succinate. The success of the pro-drug depends on (a) elimination of the unacceptably bitter taste of free erythromycin, (b) its stability against stomach acid, and (c) its smooth (base-catalyzed) hydrolysis in the body to yield active erythromycin. We have investigated the rates and pathways of acid-catalyzed degradation and base-catalyzed hydrolysis of the 2'-ethyl succinates of erythromycins A and B.

Synthesis and antibacterial activity of N-(5-benzylthio-1,3,4-thiadiazol-2-yl) and N-(5-benzylsulfonyl-1,3,4-thiadiazol-2-yl)piperazinyl quinolone derivatives.

A series of N-(5-benzylthio-1,3,4-thiadiazol-2-yl) and N-(5-benzylsulfonyl-1,3,4-thiadiazol-2-yl) derivatives of piperazinyl quinolones was synthesized and evaluated for antibacterial activity against Gram-positive and Gram-negative microorganisms. Some of these derivatives exhibit high activity against Gram-positive bacteria; Staphylococcus aureus and Staphylococcus epidermidis, comparable or more potent than their parent N-piperazinyl quinolones norfloxacin and ciprofloxacin as reference drugs. The SAR of this series indicates that both the structure of the benzyl unit and the S or SO(2) linker dramatically impact antibacterial activity.