A simple assay of paracetamol based on dried blood spot suitable for paediatric pharmacokinetic studies

Abstract

Dried blood spots in Guthrie cards are a reliable means of blood sampling suitable for pharmacoki-netic analysis in children. The aim of this study was to develop a simple and reliable bioanalytical method to measure the concentration of paracetamol in dried blood spots. Paracetamol was ex-tracted from dry blood spots by precipitation using 30% perchloric acid and separated on Hichrom 3.5 μ C18column. Detection was by a Waters 486 Tunable Absorbance Detector, at a wavelength of 244 nm. From five adult volunteers blood samples were collected as dried blood spots before and at 15, 30, 60, 120, 240 and 420 minutes after 1 g oral paracetamol was administered. C_max, T_max, t_1/2 and CL/F were calculated using non-compartmental analysis. The standard curve for the method was linear in the range 0 – 100 μg ml^-1. The LLOD and LLOQ were 550 pg and 1100 pg, respectively, on column. The median (min., max) C_max, T_max, t_1/2 and CL/F, were 14.6 μg ml^-1 (9, 19.1), 45 minutes (15, 60), 2.3 hours (1.1, 2.7) and 0.31 L kg^-1 (0.21, 0.36), respectively. We report a simple assay for the analysis of paracetamol that can be used for monitoring blood concentration of paracetamol in young children.

Keywords: Bioanalytical, concentration, children, Guthrie, neonates