RESUMO
This report presents an extension of a method developed for determination of dextran sulfate in rat serum. The drug is a negatively charged polysaccharide with a molecular mass of 8000. It is fractionated by molecular size and separated from serum components by high-performance size-exclusion chromatography. Sensitive detection is achieved by the post-column complexation of the analyte with 1,9-dimethylmethylene blue (DMMB). A metachromatic complex is formed; the absorbance maximum of the complex is shifted from that of the free dye. Various glycosaminoglycans and other macromolecular polyanions interact with DMMB. Several can be determined using the chromatographic conditions developed for dextran sulfate. The method provides a simple procedure for quantitation of these compounds. Compared to spectrophotometric assays, less sample preparation is required, selectivity is enhanced, and molecular mass information is provided. With modification of eluent composition, dye concentration, and detection wavelength, the method can be validated for determination of additional compounds.
Assuntos
Polissacarídeos/sangue , Animais , Cromatografia em Gel , Sulfato de Dextrana/sangue , Glicosaminoglicanos/sangue , Indicadores e Reagentes , Lasers , Peso Molecular , Ratos , Valores de Referência , Espalhamento de RadiaçãoRESUMO
A sensitive and selective method for the determination of dextran sulfate in rat serum has been developed. The analysis is suitable for quantitation of the drug and for monitoring molecular mass changes occurring during biotransformation. Dextran sulfate is resolved from higher molecular mass serum components by high-performance aqueous size-exclusion chromatography. The method has been validated for the direct injection of serum. Sensitive detection is achieved by post-column reaction of the polyanionic drug with the dye 1,9-dimethylmethylene blue. Components of serum which inhibit complex formation are separated chromatographically from dextran sulfate. Absorbance of the metachromatic complex is monitored at 525 nm.
Assuntos
Antivirais/sangue , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão/métodos , Sulfato de Dextrana/sangue , Animais , Cromatografia Líquida de Alta Pressão/estatística & dados numéricos , HIV-1/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Masculino , Peso Molecular , Concentração Osmolar , Ratos , Ratos Sprague-Dawley , Sensibilidade e Especificidade , EspectrofotometriaRESUMO
The chemical stability of cefonicid sodium in infusion fluids was analyzed. Cefonicid sodium vials were reconstituted and diluted with sterile water for injection and other commonly used intravenous fluids to concentrations of 325, 220, 40, 20, and 5 mg/mL. Cefonicid concentration was analyzed by high-performance liquid chromatography initially and after storage at room temperature and 5 degrees C. Reconstituted vials were frozen as long as eight weeks, thawed, and kept at room temperature and 5 degrees C and then analyzed. Cefonicid sodium reconstituted in each of the diluents studied exhibited no change in clarity and very little change in potency after 24 hours at room temperature and after 72 hours at 5 degrees C. Some vials with high concentrations became turbid between 72 and 96 hours at 5 degrees C. The thawed vials were chemically stable for 24 hours at room temperature and for 96 hours at 5 degrees C. When reconstituted with sterile water for injection and other commonly used intravenous fluids, cefonicid sodium vials and small-volume infusions are chemically stable for 24 hours at room temperature and for 72 hours at 5 degrees C. Reconstituted cefonicid sodium vials can be frozen and stored for as long as eight weeks, thawed, and then kept at room temperature for 24 hours or at 5 degrees C for 72 hours.
