Background: In this study, a rapid, simple, and advanced reverse phase high-performance liquid chromatography (RP-HPLC) method was developed for the quantification of sulfasalazine in human plasma.

Materials and methods: Sulfasalazine was extracted from plasma matrices using a simple protein precipitation method by acetonitrile. Chromatographic conditions were optimized (mobile phase compositon, flow rate, injection volume and temperature of the oven). The method was validated in protein precipitated human plasma for linearity, selectivity, accuracy, precision, limit of detection, limit of quantification.

Results: The chromatographic separation was conducted on C₁₈ brisa LC₂ column (250 mm × 4.6 mm, 5μ) using isocratic elusion with mobile phase consisting of the mixture of acetonitrile: 10mM Ammonium acetate pH adjusted to 4.6 (30:70 v/v) with a flow rate of 1.0 ml/min at ambient temperature. Detection was carried out by UV detector at 361 nm. Calibration curves made in the human plasma were linear in the range of 3.125-50 μg/ml with the value of r² > 0.9999. The LOD and LOQ was 0.5 and 2.5 µg/ml, repectively.

Conclusion: The developed and validated HPLC-UV method is suitable for accurately determining sulfasalazine levels in pharmacokinetic studies of new formulations.