Liquid chromatography of dansyl derivatives of some alkaloids and the application to the analysis of pharmaceuticals.
Derivatization of the alkaloids cephaeline, codeine, emetine, ephedrine, morphine, narcotine and others with dansyl chloride has been studied with the aim of developing a sensitive and specific liquid chromatographic method for these substances in complex pharmaceutical dosage forms. While codeine and narcotine do not react, the other compounds form completely substituted derivatives which possess maxima in their fluorescence emission spectra between 470 and 500 nm. The structure of the derivatives has been confirmed by nuclear magnetic resonance spectroscopy. The dansylated compounds have been separated by thin-layer chromatography and high-pressure liquid chromatography. The improved selectivity and sensitivity have permitted an analysis of these substances present in low concentrations in 10- 100-fold excesses of other drugs. Direct derivatization of syrups and aqueous slurries of capsules having a complex excipient and drug composition is feasible and time saving and serves as a pre-clean-up step. Detection limits are in the 1-10-ng range or better, depending on the efficiency of the detection device. The reproducibility of the method is limited by the derivatization step, but a relative standard deviation of less than 2% can be obtained. The analysis time for these pharmaceuticals may be reduced by at least one fifth of that required by conventional techniques.
D000470:Alkaloids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003061:Codeine / Q000032:analysis; D003619:Dansyl Compounds / Q000032:analysis*; D004640:Emetine / Q000032:analysis; D009020:Morphine / Q000032:analysis; D009665:Noscapine / Q000032:analysis; D013057:Spectrum Analysis; D013997:Time Factors
D000470:Alkaloids; D003619:Dansyl Compounds; D009020:Morphine; D009665:Noscapine; D003061:Codeine; D004640:Emetine