Estudos fundamentais e aplicações envolvendo hormônios esteróides por meio de eletroforese capilar / Fundamental study and applications involving steroids hormones by capillary electrophoresis

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

In the first chapter of this work, the classification and importance of the sexual steroids for maintenance of the life human is presented. The next chapter presents general aspects on capillary electrophoresis, such as operation, terminology and considerations on the electroosmotic flow and electroforetic mobility. The third chapter shows a study of interaction solvent/ SDS micelle /solute, based on the optimization of molecule geometry, conformational analysis, with molecular descriptors and regression models, based in the partition coefficient. The retention times were measured experimentally for eleven steroids, in MEKC electrolytes modified by solvents. The solvent effect in modulating the retention of solute was explaned in terms of LSER, which indicated the total organic solvent percentage in the electrolyte as the main factor controlling retention. The separation of selected compounds, in the best condition, was tested in urine extract sample from a human volunteer - feminine -1 sex - in puberty phase. The composition of the proposed electrolyte (20 mmol L-1 SDS, 20% (v/v) EtOH and 20 mmol L-1 sodium tetraborate, pH 9.4) can potentially be applied for determination of estrogens in clinical studies (0.80% C.V. for migration time and 2.5% C.V. for peak area, n = five consecutive injections). Later, in fourth chapter, the use of factorial design was introduced to optimize the composition of the electrolyte to separate a mixture-test with eleven steroids. The selection of variable indicated that the concentrations of ACN, SDS and β-CD influenced the most resolution and analysis time. The study of the effect showed that interaction ACN/ β-CD and ACN were important for resolution of the critical pairs. The micelle system constituted of 20 mmol L-1 SDS, 10% (v/v) ACN, 5 mmolL-1 β-CD and 20 mmolL-1 TBS, pH 9.2, was composition to achieve resolution of the critical pairs and analysis time. This method was used to evaluate the presence of the steroids in fecal ethanolic extract of Pantera onca. In another work a MEEKC method was developed and validated for determination of 17 β-estradiol in transdermical adhesive using a microemulsion containing 0.5% (w/w) ethyl acetate, 1.2% (w/w) butan-1-ol, 0.6% (w/w) sodium dodecyl sulfate, 15% (v/v) ACN and 82.7% (w/w) 12 mmol L-1 sodium tetraborate aqueous buffer at pH 9.4. Acceptable precision (<1.2% RSD), linearity, sensitivity (LOD=0.89 µg/mL; LOQ=2.68 µg/mL) and recovery (100.4± 0.9 % at three concentration levels) were obtained. The last chaper, the development and validation of MEKC method for determination of ethynylestradiol in a commercial tablet formulation using a micellar medium containing, 25 mmol L-1 sodium dodecyl sulfate, 22,5% (v/v) ACN and 10 mmol L-1 sodium tetraborate aqueous buffer at pH 9.2 was presented. Acceptable precision (<1.0% RSD), linearity, sensitivity (LOD=0.84 µg/mL; LOQ=2.55 µg/mL) and recovery (99.8± 1.8 % at three concentration levels) were obtained. A MEEKC method for the simultaneous determination of ethynylestradiol and levonorgestrel using microemulsion containing 0.5% (w/w) ethyl acetate, 1.2% (w/w) butan-1-ol, 0.6% (w/w) sodium dodecyl sulfate, 15% (v/v) ethanol and 82.7% (w/w) 12 mmol L-1 sodium III tetraborate aqueous buffer at pH 9.2 was developed. High precision (<0.8% RSD), linearity, sensitivity (LOD=1.04 µg/mL; LOQ=3.15 µg/mL to ethynylestradiol and LOD=1.35 µg/mL; LOQ=4.10 µg/mL to levonorgestrel) and recovery (98.6± 0.8 % at three concentration levels of ethynylestradiol) were obtained.

ASSUNTO(S)

meekc hormônios esteróides lser planejamento com misturas mixture designs mekc steroids hormones lser meekc eletroforese capilar mekc

ACESSO AO ARTIGO

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