Serum samples were analysed for their lignocaine and MEGX content in a single batch, using liquid chromatography; tandem mass spectrometry (liquid chromatography-mass spectrometer-mass-spectrometer) with methodology adapted from Abdel-Rehim M et al (6).
The principal study measurements were maximum concentration ([C.sub.max]) and area under the curve recorded from 0 to 24 hours ([[AUC.sub.0-24h]) for both lignocaine and MEGX. Area under the time-concentration curve from 0 to 24 hours was computed using NCSS 2007 Statistical Software (NCSS LLC, East Kaysville, Utah, USA) by linear trapezoidal integration in the following form:
We now describe a reliable, simple, sensitive, and rapid procedure for determining MEGX in serum by LC-MS-MS.
MEGX hydrochloride and lidocaine hydrochloride were kind gifts from Astra (Stockholm, Sweden).
Because, for ethical reasons, pharmacological treatment of uremic patients could not be suspended, patients were excluded from this study if they were receiving drugs known to induce or inhibit CYP3A4 (11) or in any case suspected to alter MEGX
An automated fluorescence polarization immunoassay (FPIA; Abbot Diagnostics Division, Chicago, IL) is widely available for MEGX
determination in serum.
Various HPLC and gas-liquid chromatographic methods capable of measuring lidocaine, MEGX
, and GX in serum have been reported (61, 62).
(1) Nonstandard abbreviations: PK, pharmacokinetics; PD, pharmacodynamics; DUS, digoxin-like immunoreactive substances; MEGX
, monoethylglycinexylidide; and IV, intravenous.
All hepatitis patients in the study had a percutaneous liver biopsy within 1 week of MEGX
 Nonstandard abbreviations: anti-LKM, liver/kidney microsome antibodies; UDPGT, uridine diphosphate glucuronyltransferase; NAPQl, N-acetyl-p-benzoquinone itnine; UDPGA, uridine diphosphate glucuronic acid; NAT, N-acetyltransferase; AST, aspartate atninotransferase; ALT, alanine arninotransferase; GGT, [gamma]-glutamyltransferase; PT, prothrombin time; and MEGX
Donor hyaluronic acid and MEGX
levels do not accurately predict posttransplant liver function.
Chicago, IL) of MEGX
in serum is almost universally available and widely used.