Algorithmen zum automatischen Vergleich von Spektren in der HPLC/UV-Kopplung: 3. Spektrenvergleich

Estimation of impurity profiles of drugs and related materials. Part 14: the role of HPLC/diode-array UV spectroscopy in the identification of minor components (impurities, degradation products, metabolites) in various matrices

The possibility of the rapid identification of drug related minor components by HPLC/diode-array UV spectroscopy is demonstrated by three examples. Hydroxylated impurities (degradation products) of norgestrel (6 alpha and beta, 10 beta-hydroxy derivatives) were identified on the basis of their UV spectra and retention matching with the synthesized impurities. The position of the phenolic hydroxyl groups in the mono- and dihydroxylated metabolites of bisaramil was established by UV spectroscopy and retention matching with the synthesized metabolites. The discrimination between the isomeric 4-ene-3-ketone and 1-ene-3-ketone components in crude 19-nortestosterone, product of the Birch reduction of 3-methoxy-1,3,5(10)-oestratriene-17 beta-ol, was also based on the diode-array UV spectra.

Quantification of chlorprothixene, levomepromazine and promethazine in human serum using high-performance liquid chromatography with coulometric electrochemical detection

Isocratic reversed-phase high-performance liquid chromatography with coulometric electrochemical detection was optimised to quantify the neuroleptic drugs chloroprothixene, levomepromazine, and promethazine in human serum. The method involves extraction of the neuroleptic drugs in n-heptane-isoamylalcohol from the alkalinized serum, followed by chromatographic separation on a Nucleosil CN column with acetonitrile-pyridine-sodium acetate buffer as the mobile phase. The extraction recovery was > 85% for each neuroleptic drug. The sensitivity and selectivity required for pharmacokinetic studies was obtained with a dual coulometric analytical cell operating in the oxidative screen mode. The lower limit of detection in human serum for chlorprothixene, levomepromazine, and promethazine, was 0.5, 0.2 and 0.1 ng/ml, respectively. A linear relationship (r2 > 0.99) was obtained between the concentrations of each neuroleptic drug and the detector signal. The accuracy of the quality control samples was +/- 7% for each neuroleptic drug with a precision within 9.5%, 8.1% and 13.5% for chlorprothixene, levomepromazine, and promethazine, respectively. The neuroleptic drugs were stable in acetonitrile and human serum for at least six months when stored at -20 degrees C. This method is applicable to analyze a large number of serum samples for pharmacokinetic studies of the neuroleptic drugs.