Structure of chemical compounds, methods of analysis and process control

A procedure for the rapid determination of nimesulide (N) and its active metabolite (M1) [4′-nitro-2′-(4-hydroxyphenyloxyphenyl)methanesulfonamide] in human serum that includes solid-phase extraction with octylsilyl-silica gel followed by gradient reverse-phase HPLC with diode-array detection has been developed and validated. The ranges of linearity for the determination of M1 and N were 20.0 – 4,000.0 and 50.0 – 10,000.0 ng/mL, respectively; the limits of detection (3σ), 13 and 10 ng/mL, respectively. Long-term stability of the analytes in biosamples and the stability of samples after the preparation procedure were 1 month and 48 h, respectively. The procedure was used for bioequivalence studies of drugs containing N.