Avaliação de fungos e complexos de salen na obtenção do metabólito quiral e ativo terbutalina
ZANÂO, L. R. Evaluation of fungi and salen complexes in the obtention of the chiral and active metabolite terbutaline. 2013. 101 f. Thesis (Master). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto -Universidade de São Paulo, Ribeirão Preto, 2013. Enantiomers may interact differently in the organism causing pharmacological sundry effects. For these reason, enantiomeric pure drugs are very important for the pharmaceutical industries. Synthetic models employing chiral reagents, like
... l reagents, like salen complexes, and biological models using fungi are been very studied in this context. Fungi present as main advantage the fast growing up, low costs and easily application, moreover, their metabolites are produced in huge quantities. Salen complexes are efficient and stable. They have a wide application and the possibility of production of high enantiomeric excess. The aim of this work was to evaluate fungi and salen complex as alternatives to the enantioselective production of terbutaline, the chiral and active metabolite of your prodrug, bambuterol. The analytes' enantioselective separation was done employing high performance liquid chromatography with UV-Vis detector (LC/UV). The method validation and the studies of biotransformation were done using high performance liquid chromatography coupled with mass spectrometry (LC-MS). The resolution of bambuterol and terbutaline by LC/UV was accomplished using the Chirobiotic T column and acetonitrile: methanol (80:20, v/v) + 0.3% formic acid and 0.1% triethylamine as mobile phase at a flow rate of 1.5 mL min -1 and by LC-MS employing the same column and the mobile phase was composed by 96% of methanol in water + 0,2% acetic acid and 0,1% ammonium acetate at a flow rate of 0.1 mL min -1 . The analytes' extraction of the culture medium (Czapek, 2 mL) was done using the dispersive liquid liquid microextraction (DLLME), in the following conditions: dispersive solvent, isopropanol (600 µL); extractor solvent, dichloromethane (50 µL); ionic-pair reagent; di(2-ethylhexyl)phosphate (100 µL); and sodium phosphate buffer (2 mL, pH 7.6). The recoveries were 92% for the bambuterol and estimated in 55% for terbutaline. The method was validated for the analysis of bambuterol in the culture medium and was linear over the concentration range of 500 -17500 ng mL -1 for each enantiomer (r > 0.998). The quantification limit was 500 ng mL -1 . Among the evaluated fungi, none was able to do the biotransformation process of bambuterol at terbutaline in the employed conditions and so do the studies employing asymmetric catalyses. Because the complexity of bambuterol's metabolism for producing terbutaline (hydrolysis and/or oxidation reactions) and the formation of several intermediates before the terbulaline's formation step, the evaluated conditions in this study were not able to produce the chiral active metabolite, terbutaline.