Bioanalytical Method for Estimation of Nitrofurantoin in Human Plasma Using Liquid Chromatography–Tandem Mass Spectrometry

An ultra-performance liquid chromatography-tandem mass spectrometry method for estimating nitrofurantoin in K₂EDTA human plasma has been developed using the liquid-liquid extraction technique. This method used electrospray ionization in negative mode for nitrofurantoin using triple quadruple mass spectrometry, with nitrofurantoin-¹³C₃ employed as an internal standard. Nitrofurantoin was extracted via the liquid-liquid extraction method and separated on an analytical column Xbridge C18 (4.6 × 100 mm, 3.5 μm). Nitrofurantoin and nitrofurantoin-¹³C₃ were performed using multiple-reaction monitoring acquisition modes with the transition of m/z from 237.06 to 152.05 (nitrofurantoin) and from 240.04 to 152.04 (nitrofurantoin-¹³C₃). The linearity range for nitrofurantoin was optimized from 5 to 800 ng/mL, respectively. The average recovery of nitrofurantoin and nitrofurantoin-¹³C₃ was 82.9 and 93.8%, respectively. The inter-precision ranged from 2.5 to 5.5%, and the inter-run accuracy range (deviation) ranged from –0.5 to 3.6% across quality control levels. The method was validated following USFDA guidelines and was determined to be straightforward, highly sensitive, precise, robust, and accurate. Therefore, it is suitable for routine quantification of nitrofurantoin in bulk drug and formulation.