Trace decomposition of selegiline. Use of worst-case kinetics for a stable drug.
A solution of selegiline hydrochloride reference standard, which contained no detectable impurities at the time of its preparation, was found by HPLC to contain a trace of a compound at the locus of methamphetamine when analyzed after 1 year. Heating selegiline solutions at pH 7 and 105 degrees C produced methamphetamine as the major product at a rate which closely followed the first-order rate equation. Using only these data and worst-case assumptions, rate constants were estimated at various temperatures; the activation energy was estimated to be about 25 kcal, and the stability-indicating validity of the assay used was reaffirmed. Selegiline undergoes degradation at a negligibly slow rate.
Chafetz
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L
Center for Pharmaceutical Technology, School of Pharmacy, University of Missouri-Kansas City 64110-2499.
Desai
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MP
Sukonik
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L
D002849:Chromatography, Gas; D002853:Chromatography, Liquid; D002855:Chromatography, Thin Layer; D004355:Drug Stability; D004356:Drug Storage; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007700:Kinetics; D008694:Methamphetamine / Q000737:chemistry; D012642:Selegiline / Q000737:chemistry*; D013237:Stereoisomerism; D013696:Temperature
D007202:Indicators and Reagents; D012642:Selegiline; D008694:Methamphetamine