Assay of an active metabolite of 6-thioguanine, 6-thioguanosine 5′-monophosphate, in human red blood cells

Differences in Nucleotide Hydrolysis Contribute to the Differences between Erythrocyte 6-Thioguanine Nucleotide Concentrations Determined by Two Widely Used Methods

“…In a third set of experiments, we carefully investigated the effect of the duration of hydrolysis (15,30,45,60, and 75 min at 100°C) in both protocols. In addition, we repeated time course studies with the Lennard method using perchloric acid (1 mol/L) instead of sulfuric acid.…”

Liquid chromatographic methods for the determination of endogenous nucleotides and nucleotide analogs used in cancer therapy: A review

“…Other chromatographic methods which analyzed phosphorylated metabolites of thiopurine without hydrolysis pre-treatment were earlier than 2000s. These methods were based on an anion exchange liquid chromatography with UV [108] or fluorimetric detection after oxidation of the thioguanine nucleotides [109][110][111].…”

Liquid chromatography–mass spectrometry for measuring deoxythioguanosine in DNA from thiopurine-treated patients

“…Given a low therapeutic index and the wide variation in clinical response, including potential for life-threatening toxicity in patients with very low or absent TPMT activity, it is important to monitor and optimise thiopurine drug levels. Assays have been developed to measure metabolites in a range of cellular compartments including erythrocytes [17] , [18] , [19] , [20] , whole blood [21] and leukocyte DNA [22] , [23] but ease of access to erythrocytes coupled with simple HPLC separation techniques has meant that quantifying thiopurine metabolites in erythrocytes has become the standard method for therapeutic monitoring. However, despite its value for assessing patient compliance, there is significant debate about concordance with therapeutic response in IBD [24] , [25] , [26] .…”