Main author: Unnur A. Þorsteinsdóttir
Institution or Company: Faculty of Pharmaceutical Sciences, University of Iceland
Co-Authors, Institution or Company:
Hrafnhildur L. Runolfsdóttir, Internal Medicine Services, Landspitali–The National University Hospital of Iceland. Finnur F. Eiríksson, ArcticMass, Reykjavík. Vidar Ö. Eðvarðsson, Children’s Medical Center, Landspitali–The National University Hospital of Iceland. Runólfur Pálsson, Faculty of Medicine, University of Iceland; Internal Medicine Services, Landspitali–The National University Hospital of Iceland. Margrét Þorsteinsdóttir, Faculty of Pharmaceutical Sciences, University of Iceland; ArcticMass, Reykjavík.
Introduction: Adenine phosphoribosyltransferase deficiency (APRTd) results in excessive urinary excretion of poorly soluble 2,8-dihydroxyadenine (DHA), that leads to nephrolithiasis and chronic kidney disease (CKD). Treatment with the xanthine oxidoreductase (XOR) inhibitors allopurinol or febuxostat reduces DHA excretion and prevents or slows CKD progression. A reliable method for comprehensive therapeutic drug monitoring of patients with APRTd is needed. The aim of this study was to optimize a UPLC-MS/MS method for quantification of DHA, purine metabolites and the XOR inhibitors allopurinol and febuxostat in human plasma, utilizing the chemometric approach design of experiments (DoE).
Methods: The UPLC-MS/MS quantification method was optimized, employing the chemometric software MODDE Pro 12 (Sartorius Stedim Data Analytics, Umeå, Sweden). Fractional factorial (FF) design was used to reveal significant factors influencing retention time, resolution and peak area for all analytes, using partial least square (PLS) regression. Plasma samples from untreated and treated APRTd patients and healthy controls were analyzed using the UPLC-MS/MS assay.
Results: The FF design revealed significant factors and factor interactions effecting the peak response and resolution. Following optimization of the assay, the sensitivity was improved and chromatographic resolution between the purine analytes was achieved. Preliminary data revealed that the median (range) plasma DHA concentration was 248 (224-395) ng/ml in the untreated patients and below limit of quantification (BLQ) in those on treatment. DHA was not detected in the plasma samples from healthy controls.
Conclusion: A UPLC-MS/MS assay for quantification of DHA, purine metabolites and XOR inhibitors in human plasma was developed and optimized using DoE.
