Sensitive determination of D-carnitine as enantiomeric impurity of levo-carnitine in pharmaceutical formulations by capillary electrophoresis-tandem mass spectrometry

In this work, capillary electrophoresis-electrospray ionization-tandem mass spectrometry was applied to the determination of and D-carnitine in pharmaceutical formulations A simple sample treatment procedure consisting of the use of a dilution or an extraction step with water was employed prior to :derivatization with 9-fluorenylmethoxycarbonyl (FMOC) The method was validated in terms of selectivity. linearity, accuracy, precision and sensitivity, with a LOD of 10 ng mL(-1) for each enantiomer. which was enough to detect enantiomeric impurities up to 0 002% of D-carnitine with respect to the main enantiomer (L-carnitine). Eleven pharmaceutical formulations were analyzed including ampoules, oral solutions, sachets, and tablets Results showed contents for carnitine comprised between 77 and 101% with respect to the labeled ones in the case of those formulations marketed with the racemate, and from 97 to 102% in those cases where the single enantiomer (L-carnitine) was employed as active ingredient. Percentages for the enantiomeric impurity (D-carnitine) ranging from 06 to 1 3% were obtained exceeding the limits established for impurities in drug products These results corroborate the need of validated analytical methodologies enabling the quality control of pharmaceutical formulations containing carnitine. (C) 2010 Elsevier B V All rights reserved.