Simultaneous determination of metoclopramide and aspirin by spectrofluorimetric technique: application to pharmaceutical formulations and human plasma

A simple, sensitive and rapid spectrofluorimetric method for the simultaneous determination of metoclopramide (MET) and aspirin (ASP) was executed. The method was based on the application of a second derivative synchronous fluorescence spectroscopy technique for the simultaneous determination of the studied drugs without prior separation or pre-derivatization procedures. The synchronous fluorescence of both drugs was measured in methanol at Delta lambda of 100 nm, and the second derivative peak amplitudes (D-2) were estimated to be at 260 nm for ASP and at 285 nm for MET. The method was rectilinear over the concentration ranges of 0.01-0.1 mu g mL(-1) and 0.01-0.2 mu g mL(-1) for ASP and MET with detection limits of 0.002 mu g mL(-1) and 0.001 mu g mL(-1) and quantitation limits of 0.007 mu g mL(-1) and 0.004 mu g mL(-1) for ASP and MET, respectively. The proposed method was successfully applied for the determination of the studied drugs in their pharmaceutical formulations without interference from common excipients. The results were in good agreement with those obtained by the reference HPLC method. The method was further extended to the in vitro determination of ASP and MET in spiked human plasma.