Comparison of the quantification of acetaminophen in plasmacerebrospinal fluid and dried blood spots using high-performance liquidchromatography-tandem mass spectrometry

摘要

Acetaminophen (paracetamol, N-(4-hydroxyphenyl) acetamide) is one of the most commonly prescribed drugs for the management of pain in children. Quantification of acetaminophen in pre-term and term neonates and small children requires the availability of highly sensitive assays in small volume blood samples.We developed and validated an LC-MS/MS assay for the quantification of acetaminophen in human plasma, cerebro-spinal fluid (CSF) and dried blood spots (DBS). Reconstitution in water (DBS only) and addition of a protein precipitation solution containing the deuterated internal standard were the only manual steps. Extracted samples were analyzed on a Kinetex 2.6 μm PFP column using an acetonitrile/formic acid gradient. The analytes were detected in the positive multiple reaction mode. Alternatively, DBS were automatically processed using direct desorption in a sample card and preparation (SCAP) robotic autosampler in combination with online extraction.The range of reliable response in plasma and CSF was 3.05-20,000 ng/ml (r² > 0.99) and 27.4-20,000 ng/ml (r² > 0.99) for DBS (manual extraction and automated direct desorption). Inter-day accuracy was always within 85-115% and inter-day precision for plasma, CSF and manually extracted DBS were less than 15%. Demingregression analysis comparing 167 matching pairs of plasma and DBS samplesshowed a correlation coefficient of 0.98. Bland Altman analysis indicated a26.6% positive bias in DBS, most likely reflecting the blood: plasmadistribution ratio of acetaminophen.DBS are a valid matrix for acetaminophen pharmacokinetic studies.