Quantitative analysis of a mixture containing ampicillin sodium and sulbactam sodium by ratio spectra-first and ratio spectra-second derivative methods

Abstract

Two signal processing approaches, ratio spectra- first and ratio spectra-second derivative, are proposed for quantitative analysis of a mixture containing ampicillin sodium (AP) and sulbactam sodium (SB) in two different commercial pharmaceutical preparations for injection. These new methods have the advantage that no chemical priory separation step is required In this investigation, the UV-absorption spectra of the analyzed drugs and their samples are recorded in the spectral range of 210-340 nm. The ratio spectra are obtained by dividing the absorbance values of SB to standard divisor (50 mu g/mL) AP and by dividing the absorbance values of AP to standard divisor (40 mu g/mL) of SB. Both first and second derivatives of the obtained ratio spectra are calculated by using Delta lambda=8 nm intervals for both AP and SB. In order to minimize the deformations of the first derivative graph, we used a smooth function for Delta lambda=8. The appropriate graphs of second derivative method are obtained after multiplication with two scaling factors, namely 50 for AP and 40 for SB, but without any smoothing process. Calibration graphs are obtained by measuring the amplitudes at 233.5 nm for AP and 252.2 rim, 275.0 nm and 288.2 nm of the first derivative of the ratio spectra, and by measuring the amplitudes at 246.9 nm for AP and 248.4 nm, 274.2 nm, 285.4 nm and 300.0 nm for SB of the second derivative of the ratio spectra, respectively. The proposed approaches are validated by analyzing the synthetic mixtures and are used to determine AP and 0 in their pharmaceutical preparations