Estimation of Mesalamine in Human Plasma Using Rapid and Sensitive LC-ESI-MS/MS Method

A sensitive, selective and rapid liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method has been developed for the estimation of mesalamine in human plasma using a derivatization technique. Aliquid-liquid extraction technique with ethyl acetate was used for the extraction of mesalamine and mesalamine-D3 internal standard (IS). Mesalamine and mesalamine-D3 were analyzed on Thermo BetaBasic C8 (100 mm x 4.6 mm, 5 mu m) column using acetonitrile and 10 mM ammonium formate in 70 : 30 v/v ratio under isocratic elution mode. The MS detection and quantitation were performed under multiple reaction monitoring using positive ESI for mesalamine (m/z, 210.1 -> 191.9) and mesalamine D3 (m/z, 213.2 -> 195.1). Main advantages of the proposed method include higher sensitivity (5.00 ng/mL), superior extraction efficiency (>= 79%), and small volume (200 mu L) of sample for processing. The calibration curve was linear in the concentration range of 5.00 - 2957.17 ng/mL with a good correlation coefficient (r(2) >= 0.9980) for mesalamine. The intra-batch (within day) and inter-batch (between days) precision (% CV) and accuracy (% nominal) values varied from 2.09 to 4.44% and from 96.02 to 103.23%, respectively. The method was validated as per the US FDA guidelines and the results were found accurate and precise.