Novel LC–MS/MS method for estimation of niacin with negligible matrix effect and its application to the BE study

A liquid chromatography coupled with tandem mass spectrometry method for the quantification of the cholesterol lowering drug niacin in human plasma was developed and validated according to the current bioanalytical guidelines. Following solid phase extraction niacin and the internal standard nicotinic-d4 acid were extracted from an aliquot of 100 µL of human plasma. Chromatographic separation achieved on Inertsil ® CN-3 column (100 × 4.6 mm, 5 µm) by using mobile phase consisting of acetonitrile and solution-1 (0.002 % Formic acid water, v/v) in the ratio of 70:30, v/v was delivered at a flow rate of 1.0 mL/min with 25 % split ratio. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization source. The mass transitions of niacin and IS were m/z 124.1/80.1 and m/z 128.1/84.1 respectively. The linear calibration curves were obtained in the concentration range of 50.6–25022.7 ng/mL (r2 ≥ 0.99) for niacin. The intra- and inter-day precision and relative error were all within 11 %. Despite achieving high mean recovery (>80 %), no interference peaks or matrix effects were observed. Detailed stability exercises including drug stability in blood, hemolyzed, lipemic and normal plasma were conducted to extend the method applicability in vast majority of clinical studies using 750 mg niacin oral dosage form.