Desenvolvimento de métodos cromatográficos para o controle de qualidade e para a análise de resíduos em leite bovino de medicamentos veterinários

Abstract

This work reports the investigation of a series of bovine serum albumin (BSA) restricted access media columns (RAM) for on-line milk samples deproteinization using water, phosphate and acetate buffer as mobile phase. The retention factor (k) of aminoglycosides antibiotics (streptomycin, neomycin and gentamycin) on the RAM columns was evaluated using buffers and ion pair chromatography. The results showed a wide variation on aminoglicosides antibiotics retentions time; a RAM-ADS column was also investigated and the same results was observed. During the RAM columns studies, an investigation of two analytical columns, C18 and phenyl (Hyperil 15 x 0,46 cm i.d.), were performed using ion pair chromatography. Perfluorinated acids (TFA, HFBA and PFPA) were evaluated as moblile phase and the detection was accomplished by an evaporative light scattering detector (ELSD). This study allowed the development of analytical methods for quality control of gentamycin, neomycin and streptomycin in veterinary pharmaceutical formulations. The developed methods showed good selectivity, sensibility, accuracy and precision for all compounds allowing it to be successfully used to commercials phormulation. This works also presents a study for on line determination of cephalosporinic antibiotics in bovine milk by multidimentional chromatography using RAM-BSA column for sample clean-up. The chromatographic conditions optimzed for these compounds were not adequate for the MS/MS quantification due to suppression and/or enhancement of compound s ionization. Still a sensitive and enantioselective multidimensional high performance liquid chromatography (HPLC) method for determination of albendazole metabolites: albendazole sulphoxide, albendazole sulphone and albendazole 2-aminesulphone in bovine milk was development and validated at this work. The compounds, (±)-albendazole sulphoxide, albendazole sulphone and 2-aminesulphone were extracted from bovine milk using a octyl restricted access media bovine serum albumin column (C8-RAM-BSA) (5.0 x 0.46 cm i.d.) and analyzed on a chiral column containing amylose tris(3,5-dimethylphenylcarbamate) coated onto APS-Nucleosil support, as stationary phase (15.0 x 0.46 cm i.d.). The validated method showed linearity, precision, accuracy and adequate sensitivity, allowing it to be appropriate for pharmacokinetics studies and residual limits control. A matrix effect study was conducted to investigated its influence on the LC-MS method development.