Simultaneous spectrophotometric determination of ampicillin and penicillin in human plasma using multivariate calibration

An analytical methodology based on spectrophotometric and partial least squares (PLS) algorithm for the simultaneous determination of ampicillin and penicillin in human plasma was developed and validated. The multivariate model was developed as a binary calibration model and it was built and validated with an independent set of synthesis and real samples in presence of matrix. It is shown how a developed technique for signal filtering, orthogonal signal correction (OSC), can be applied in multivariate calibration to enhance predictive power. The experimental calibration matrix was constructed with 25 samples. The concentration ranges considered were 1.0-40.0 and 0.5-20.0 μg mL-1 for ampicillin and penicillin, respectively. This procedure allows the simultaneous determination of ampicillin and penicillin in synthetic and human plasma good reliability of the determination was proved. The results obtained by the OSC-PLS and HPLC were statistically compared. Very similar values were found by two methods. No time consuming pretreatment was needed and this method also provides rapid, accurate and economical analysis of these drugs.