RESUMEN
D-penicillamine is a thiol drug mainly used for Wilson's disease, rheumatoid arthritis and cystinuria. Adverse effects during normal use of the drug are frequent and may include skin lesions. To evaluate its toxic effects in clinical cases an original method based on high performance liquid chromatography coupled to amperometric detection in a specific biological matrix such as skin has been developed. The chromatographic analysis of D-penicillamine was carried out on a C18 column using a mixture of acid phosphate buffer and methanol as the mobile phase. Satisfactory sensitivity was obtained by oxidizing the molecule at +0.95 V with respect to an Ag/AgCl reference electrode. A chemical reduction of D-penicillamine-protein disulphide bonds using dithioerythritol combined with microwaves was necessary for the determination of the total amount of D-penicillamine in skin specimens. A further solid-phase extraction procedure on C18 cartridges was implemented for the sample clean-up. The whole analytical procedure was validated: high extraction yield (>91.0%) and satisfactory precision (RSD<6.8%) values were obtained. It was successfully applied to skin samples from a patient who was previously under a long-term, high-dose treatment with the drug and presented serious D-penicillamine-related dermatoses. Thus, the method seems to be suitable for the analysis of D-penicillamine in skin tissues.
Asunto(s)
Cromatografía Líquida de Alta Presión , Electroquímica , Penicilamina/análisis , Enfermedades de la Piel/metabolismo , Piel/metabolismo , Estudios de Casos y Controles , Disulfuros/química , Disulfuros/metabolismo , Electrodos , Femenino , Degeneración Hepatolenticular/complicaciones , Degeneración Hepatolenticular/tratamiento farmacológico , Humanos , Persona de Mediana Edad , Penicilamina/efectos adversos , Penicilamina/química , Enfermedades de la Piel/inducido químicamente , Extracción en Fase SólidaRESUMEN
A fast analytical method has been developed for the determination of nine amino acids, together with serotonin, in wine samples of different origin and vintage. The method is based on capillary electrophoresis coupled to laser-induced fluorescence detection. Separation was obtained by using a fused-silica capillary (75 µm id, 74.0 cm total length, 60.0 cm length to detector) and a background electrolyte composed of carbonate buffer (20 mM, pH 9.2), applying a 20 kV voltage. Direct hydrodynamic injection of wine samples was made after an original microwave-assisted derivatisation step with 5-(4,6-dichlorotriazinyl)aminofluorescein. Fluorescence was induced by an Ar-Ion laser, exciting at 488 nm. Good linearity (r(2) >0.9990) was obtained for all considered analytes and sensitivity was also good, with limits of detection in the 7-50 ng/mL range. The method was successfully applied for the analysis of commercial Italian wines and thus seems to be suitable for the determination of the relevant amino acids and serotonin, providing good results in terms of accuracy and precision, together with the advantage of a very fast, microwave-assisted derivatisation procedure. Future applications of the method are planned to check for wine adulterations and commercial frauds.
Asunto(s)
Aminoácidos/análisis , Electroforesis Capilar/métodos , Vino/análisis , Láseres de Gas , Límite de Detección , Modelos Lineales , Reproducibilidad de los Resultados , Espectrometría de FluorescenciaRESUMEN
A sensitive method based on capillary electrophoresis with laser-induced fluorescence detection has been developed for the analysis of the non-ergoline dopamine agonist pramipexole in human urine. Separation was carried out in uncoated fused silica capillaries (75microm internal diameter, 75.0 and 60.0cm total and effective length, respectively), with a background electrolyte composed of borate buffer (50mM, pH 10.3), tetrabutylammonium bromide (30mM), and acetone (15%, v/v). Applying a 20kV voltage, the electrophoretic run is completed within 12min. A sample pre-treatment procedure based on liquid/liquid extraction with ethyl acetate, followed by derivatisation of pramipexole with fluorescein isothiocyanate at pH 9, allows the complete removal of biological interferences, with extraction yields always higher than 94.5%. Method validation gave good linearity (r(2)=0.9992) in the 25.0-1000ngmL(-1) range; limit of detection and limit of quantitation were 10.0 and 25.0ngmL(-1), respectively; precision was
Asunto(s)
Antiparkinsonianos/orina , Benzotiazoles/orina , Fluorescencia , Rayos Láser , Métodos Analíticos de la Preparación de la Muestra , Antiparkinsonianos/uso terapéutico , Benzotiazoles/uso terapéutico , Electroforesis Capilar , Salud , Humanos , Pramipexol , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
A capillary electrophoretic method has been developed for the enantioselective analysis of amisulpride in pharmaceutical formulations, using beta-cyclodextrin sulfate as the chiral selector. Several parameters, such as cyclodextrin type and concentration, buffer concentration and pH and capillary temperature were investigated for method optimisation. Baseline enantioseparation of the racemic compound was achieved in less than 10 min using a fused silica capillary (50 microm i.d. and 33.0, 8.5 cm, total and effective length, respectively), filled with a background electrolyte consisting of a 10mM citrate buffer at pH 3.5 supplemented with 0.22% (w/v) beta-cyclodextrin sulfate at 20 degrees C and applying a voltage of +15 kV. Formulation analysis was carried out after analyte extraction by methanol. The method was fully validated, with good results in terms of precision, selectivity, accuracy and amount of drug found with respect to the label claim. Thus, the method seems to be suitable for the enantiomeric analysis of amisulpride in pharmaceutical formulations.