Evaluation of the dose-effect curves of dimethindene maleate enantiomers in various animal models

Abstract

Dimethindene maleate (Fenistil®), an, H1-receptor blocker, exists in the form of two enantiomers: S-(−)-dimethindene maleate and R-(+)-dimethindene maleate. These two enantiomers were tested for their antihistaminic and anti-anaphylactic properties in guinea-pigs. The S-enantiomer was much more active than the R-enantiomer. The ED50 for protection against a standard lethal dose of histamine 3 h after S-(−)-dimethindene maleate application was 0.056 mg/kg b.w. p.o. and against fatal anaphylactic shock 0.273 mg/kg b.w. p.o. Values of 14.32 mg/kg b.w. p.o. and >31.6 mg/kg b.w. p.o. were determined for the R-(+)-enantiomer.