title: Comparison of the quantification of acetaminophen in plasma, cerebrospinal fluid and dried blood spots using high-performance liquid chromatography-tandem mass spectrometry.
abstract: 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 (r(2)>0.99) and 27.4-20,000 ng/ml (r(2)>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%. Deming regression analysis comparing 167 matching pairs of plasma and DBS samples showed a correlation coefficient of 0.98. Bland Altman analysis indicated a 26.6% positive bias in DBS, most likely reflecting the blood: plasma distribution ratio of acetaminophen. DBS are a valid matrix for acetaminophen pharmacokinetic studies.
authors.affiliation: iC42 Clinical Research and Development, Department of Anesthesiology, University of Colorado Denver, and The Children's Hospital of Colorado, Aurora, CO 80045-7503 , USA.
authors.forename: Rachel R
authors.initials: RR
authors.lastname: Taylor
authors.forename: Keith L
authors.initials: KL
authors.lastname: Hoffman
authors.forename: Björn
authors.initials: B
authors.lastname: Schniedewind
authors.forename: Claudia
authors.initials: C
authors.lastname: Clavijo
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Galinkin
authors.forename: Uwe
authors.initials: U
authors.lastname: Christians
mesh_terms: D000082:Acetaminophen / Q000097:blood* / Q000737:chemistry*; D002555:Cerebrospinal Fluid / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D059788:Dried Blood Spot Testing / Q000379:methods*; D006801:Humans; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000082:Acetaminophen