title: Determination of urinary 6-mercaptopurine and three of its metabolites by HPLC-UV coupled with the iodine-azide reaction.
abstract: BACKGROUND
  The presented method is able to determine 6-mercaptopurine (6-MP), 6-thioguanine, 6-mercaptopurine riboside and 6-thioguanine riboside in urine, and is thereby dedicated to control of thiopurine therapy of children with acute lymphoblastic leukemia. Good separation of the mentioned compounds was achieved on a C18 stationary phase with a sodium azide and sodium heptane sulfonate solution, acetonitrile and water at ratio of 50:1:49 (v/v/v).
  
  
  RESULTS
  Coefficient of regression is >0.99 for all linearity ranges. LOD and LOQ are 0.3, 0.4, 0.3, 0.8 and 0.4, 0.6, 0.5 and 0.9 nmol/ml of urine for 6-MP, 6-thioguanine, 6-mercaptopurine riboside and 6-thioguanine riboside, respectively. Intra- and inter-day recovery and RSD are close to 100% and less than 10%, respectively, for all investigated thiopurines.
  
  
  CONCLUSIONS
  The elaborated method was successfully applied for detection and quantitation of 6-MP and its selected metabolites in patients' urine samples.
authors.affiliation: Department of Inorganic & Analytical Chemistry, University of Łódź, 12 Tamka St, 91-403 Łódź, Poland.
authors.forename: Robert
authors.initials: R
authors.lastname: Zakrzewski
authors.forename: Kamila
authors.initials: K
authors.lastname: Borowczyk
authors.forename: Adam
authors.initials: A
authors.lastname: Łuczak
authors.forename: Wojciech
authors.initials: W
authors.lastname: Młynarski
authors.forename: Joanna
authors.initials: J
authors.lastname: Trelińska
mesh_terms: D001386:Azides / Q000737:chemistry*; D002648:Child; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D007455:Iodine / Q000737:chemistry*; D057230:Limit of Detection; D015122:Mercaptopurine / Q000378:metabolism* / Q000652:urine*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013997:Time Factors; D016482:Urinalysis / Q000379:methods*
chemical_list: D001386:Azides; D007455:Iodine; D015122:Mercaptopurine