Simultaneous LC-ESI-MS/MS PMT method development and validation of cefixime, ornidazole and dicloxacillin in human blood plasma.

A simple, selective method was developed for simultaneous estimation of Cefixime, Ornidazole and Dicloxacillin in blood plasma and validated as per the US FDA guidelines. Extraction process was accomplished by protein precipitation method. By employing cefixime as internal standard in methyl alcohol solvent, the proteins got precipitated. Single method can be used for separating combination drugs, where any one drug can act as an internal standard. The drugs were analyzed by triple quadrupole mass spectrometer using photomultiplier tube as detector, with the electron spray ionization technique of positive and negative mode on a shim-pack solar C18(50 x 4.6mm i.d, 5µm) column. The mobile phase comprising of 10mM ammonium acetate and Methyl alcohol with the ratio 10:90v/v, pH 6.0. After the evaluation of different sample pretreatment techniques, protein precipitation was found to be satisfactory, offering good recovery values. The linearity of Ornidazole and Dicloxacillin found within range of 4.0 - 80.0µg/ml and 1.5 - 30.0µg/ml respectively which is consistently accurate for plotting curve. The correlation coefficient of Ornidazole and Dicloxacillin were 0.9936 and 0.9994 respectively. The Limit of detection of Ornidazole and Dicloxacillin was found to be 330ng/ml and 123.5ng/ml respectively and their Limit of quantification values were 1000ng/ml and 375ng/ml respectively. Different constituents of plasma will not affect the effective recovery of the drugs. The established method can be used for the quantification of drugs in plasma for BA-BE studies and biopharmaceutical sciences. [ABSTRACT FROM AUTHOR]