RESUMEN
A micellar electrokinetic chromatography method (MEKC) has been developed and validated for the determination of bile acids (BA) such as ursodeoxycholic acid (UDCA), dehydrocholic acid (DHCA) and deoxycholic acid (DCA) in pharmaceuticals for quality control purpose. The background electrolyte consisted of 20 mM borate-phosphate buffer containing 50 mM sodium dodecylsulfate (SDS), and acetonitrile as additive. UV detection was set at 185 nm. Selectivity, linearity, range, repeatability, intermediate precision and accuracy showed good results. Comparison of the values obtained by MEKC and HPLC methods were in close agreement.
Asunto(s)
Ácidos y Sales Biliares/análisis , Cromatografía Capilar Electrocinética Micelar/métodos , Preparaciones Farmacéuticas/química , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrofotometría UltravioletaRESUMEN
A cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) method has been developed and validated for purity determination of two bile acids, ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA). Quantitation of related impurities such as lithocholic acid (LCA), chenodeoxycholic acid (CDCA), cholic acid (CA), and DCA in UDCA and CA in DCA was performed. A running buffer containing 20 mM borate-phosphate, 50 mM sodium dodecyl sulfate (SDS), 2.0 mM beta-cyclodextrin, and acetonitrile was used. Modifiers were added to improve resolution and selectivity. The applied voltage was 25 kV and detection was performed at 185 nm. Validation parameters such as selectivity, linearity, repeatability, intermediate precision, limit of detection, limit of quantitation, and robustness were evaluated. The method was simple and proved to be useful for the purity testing of bile acids in bulk drugs. Good results were obtained for related impurities at concentration levels from 0.05 to 1.5% with respect to the main component, according to international requirements.
Asunto(s)
Cromatografía Capilar Electrocinética Micelar/métodos , Ciclodextrinas , Ácido Desoxicólico/análisis , Ácido Ursodesoxicólico/análisis , beta-Ciclodextrinas , Cromatografía Capilar Electrocinética Micelar/normas , Estructura MolecularRESUMEN
The determination of active compounds in samples of dissolution tests of oral solid dosage forms based on the USP 23 methods was performed by capillary electrophoresis after the use of solid-phase extraction disks for the preconcentration of drugs. Enrichment factors of 20:1 allowed the determination of betamethasone and ergotamine tartrate at levels of 0.33 microgram/mL and 1.0 microgram/mL, respectively. CE analysis was performed using fused-silica capillaries (35 or 60 cm length x 75 microns i.d.) and the operating conditions consisted of 15 kV applied voltage and UV detection at 254 nm. The background electrolyte was 20-mM phosphate borate buffer, pH 9.0, containing 50 mM of sodium cholate for the separation of betamethasone and 25 mM phosphate buffer, pH 3.0, for ergotamine tartrate. Validation of the methods was also performed. Accuracy and precision of the intraday and interday assays showed comparable results with those obtained by HPLC.
Asunto(s)
Betametasona/análisis , Electroforesis Capilar/métodos , Ergotamina/análisis , Preparaciones Farmacéuticas/química , Administración Oral , Cromatografía Líquida de Alta Presión/métodos , Formas de Dosificación , Indicadores y Reactivos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrofotometría Ultravioleta/métodosRESUMEN
A liquid chromatographic method was developed for the simultaneous separation and determination of noscapine hydrochloride, hexylresorcinol and anethole in cough lozenges. Analysis was performed on a phenyl column with phosphate buffer- acetonitrile as mobile phase and the separated components were detected at 282 mm. Recoveries obtained for the analytes were of 94.6% for noscapine hydrochloride, 99.1% for hexylresorcinol and 96.3% for anethole. The values of the relative standard deviation were 0.8% for noscapine hydrochloride, 1.5% for hexylresorcinol and 1.1% for anethole. The analytical method was validated and a system suitability test was accomplished for the chromatographic method.
Asunto(s)
Anetol Tritiona/análisis , Antitusígenos/análisis , Hexilresorcinol/análisis , Noscapina/análisis , Cromatografía Liquida , Indicadores y Reactivos , ComprimidosRESUMEN
Sample preparation procedures using octadecyl (C18) extraction disks were developed to obtain accurate and reproducible results for determinations of clenbuterol(20 micrograms per dose) and levothyroxine (100 micrograms per dose) in dissolution media of solid oral dosage forms. Preconcentration of samples allowed final concentrations of 1.1 micrograms/ml of clenbuterol and 4.0 micrograms/ml of levothyroxine to be reached prior to CE analysis. The results obtained by CE were in good agreement with those of HPLC. The precision of the migration time, peak area, peak height and accuracy were determined in both intra-day (n = 6) and inter-day (n = 18) assays. Linearity was demonstrated over the ranges 0.5-80.0 micrograms/ml of clenbuterol and 1.0-30.0 micrograms/ml of levothyroxine. The mean recoveries were higher than 94.0%, ranging from 50 to 125% levels with respect to dose potencies. The proposed methodology may be generally applied to determine drugs at ng/ml concentrations.