Direct Quantitative Determination of Optically Active Absorbing Drugs in Human Urine by Circular Dichroism. Simultaneous Direct Determination of β-Ractam Antibiotics and Proteins

□ Over 200 urine samples from 61 subjects were analyzed by circular dichroism spectroscopy. The results proved that this technique can be applied to the direct determination of optically active absorbing drugs in urine of subjects under multiple drug administration, independently of the presence of proteins, which can simultaneously be determined. A list of noninterfering drugs is included. The validity of the present method was confirmed by analysis of variance, the β-Mactam antibiotics ampicillin, cefoxitin, and cephalexin being chosen as model drugs and human albumin as the analytical standard for protein determination. The results demonstrated that the proposed method is accurate and precise, the correlation coefficients being higher than 0.9996. A circular dichroism and HPLC data comparison was successfully performed. The principal advantages of this method are simplicity, quickness, and economy, no derivatization or chromatographic separation steps being needed.