title: Analysis of tacrolimus and creatinine from a single dried blood spot using liquid chromatography tandem mass spectrometry.
abstract: Long term therapeutic drug monitoring and assessment of renal function are required in renal transplant recipients on immunosuppressant therapy such as tacrolimus. Dry blood spots (DBS) have been used successfully in the clinic for many years and offers a convenient, simple and non-invasive method for repeated blood tests. We developed and performed a preliminary validation of a method for the analysis of tacrolimus and creatinine from a single DBS using liquid chromatography-tandem mass spectrometric (LC-MS/MS). Tacrolimus and creatinine were extracted from a 6mm punch with a mixture of methanol/acetonitrile containing ascomycin and deuterated creatinine as internal standards. A 10 μl aliquot of the extract was analyzed directly after dilution for creatinine with normal phase high performance liquid chromatography and multiple reaction monitoring. The remainder of the extract was processed and analyzed for tacrolimus. The lower limit of quantification for tacrolimus was 1 ng/ml with accuracy of 0.34% bias and precision (CV) of 11.1%. The precision ranged from 1.33% to 7.68% and accuracy from -4.44% to 11.6% bias for the intra- and inter-day analysis. The lower limit of quantification of creatinine was 0.01 mg/dL with precision of 7.94%. Accuracy was based on recovery of additional creatinine spiked into whole blood samples and ranged from -2.45% bias at 5 mg/dL to 3.75% bias at 0.5 mg/dL. Intra- and inter-day precision was from 3.48 to 4.11%. The assay was further validated with DBS prepared from pediatric renal transplant recipients. There was excellent correlation between the levels of tacrolimus and creatinine obtained from the clinical laboratory and the DBS method developed. After additional validation, this assay may have a significant impact on compliance with medication intake as well as potentially lowering the cost associated with intravenous blood draws in clinical laboratories.
authors.affiliation: Department of Physiology and Pharmacology and Bioanalytical Shared Resource/Pharmacokinetics Core, Oregon Health and Science University, Portland, OR 97239, USA. koopd@ohsu.edu
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Koop
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Bleyle
authors.forename: Myrna
authors.initials: M
authors.lastname: Munar
authors.forename: Ganesh
authors.initials: G
authors.lastname: Cherala
authors.forename: Amira
authors.initials: A
authors.lastname: Al-Uzri
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D003404:Creatinine / Q000097:blood*; D006801:Humans; D057230:Limit of Detection; D015203:Reproducibility of Results; D016559:Tacrolimus / Q000097:blood*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D003404:Creatinine; D016559:Tacrolimus
references.citation: Am J Transplant. 2004 Sep;4(9):1509-13
references.pmid: 15307839
references.citation: Drugs. 2007;67(10):1463-81
references.pmid: 17600393
references.citation: Ther Drug Monit. 2002 Dec;24(6):757-67
references.pmid: 12451294
references.citation: Rapid Commun Mass Spectrom. 2005;19(21):2995-3001
references.pmid: 16193530
references.citation: Kidney Int. 1996 Jul;50(1):235-42
references.pmid: 8807593
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2002 Dec 5;781(1-2):93-106
references.pmid: 12450655
references.citation: Health Policy. 1998 Jun;44(3):215-32
references.pmid: 10182294
references.citation: Nat Clin Pract Nephrol. 2009 Mar;5(3):E1
references.pmid: 19240724
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2003 Aug 25;794(1):125-36
references.pmid: 12888205
references.citation: Lancet. 1986 Feb 8;1(8476):307-10
references.pmid: 2868172
references.citation: J Pharm Biomed Anal. 2007 Jul 27;44(3):658-64
references.pmid: 17184953
references.citation: AAPS J. 2010 Sep;12(3):290-3
references.pmid: 20383669
references.citation: Ther Drug Monit. 2009 Apr;31(2):187-97
references.pmid: 19258929
references.citation: Clin Biochem. 2010 Sep;43(13-14):1158-62
references.pmid: 20553888
references.citation: Clin Chim Acta. 2008 Feb;388(1-2):189-91
references.pmid: 18028890
references.citation: Biomed Chromatogr. 2010 Jan;24(1):49-65
references.pmid: 20017122
references.citation: Transplantation. 2007 Jan 27;83(2):237-8
references.pmid: 17264824
references.citation: Transpl Int. 2008 Feb;21(2):140-5
references.pmid: 17944802
references.citation: Pediatr Transplant. 2005 Dec;9(6):729-33
references.pmid: 16269043
references.citation: Pediatrics. 2004 Apr;113(4):825-32
references.pmid: 15060234
references.citation: Pediatr Clin North Am. 2009 Jun;56(3):505-13, Table of Contents
references.pmid: 19501689
references.citation: J Chromatogr B Biomed Sci Appl. 2001 Aug 15;759(2):343-8
references.pmid: 11499488
references.citation: Clin Chem. 1976 Oct;22(10):1664-71
references.pmid: 10095
references.citation: Transplantation. 2007 Apr 15;83(7):858-73
references.pmid: 17460556
references.citation: Int Urol Nephrol. 1978;10(1):59-64
references.pmid: 649287
references.citation: Clin Chim Acta. 1973 Feb 12;43(3):305-10
references.pmid: 4690902
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2010 Oct 1;878(27):2582-92
references.pmid: 20462809
references.citation: Nephrol Dial Transplant. 2010 Aug;25(8):2757-63
references.pmid: 20190242
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2007 May 1;850(1-2):471-80
references.pmid: 17239667
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2005 Aug 5;822(1-2):27-32
references.pmid: 15993663
references.citation: Pediatr Nephrol. 2011 Jan;26(1):133-8
references.pmid: 20972803
references.citation: Clin Transplant. 2006 Mar-Apr;20(2):221-5
references.pmid: 16640530
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2012 Feb 1;883-884:33-49
references.pmid: 21992751
references.citation: Clin Transplant. 2012 May-Jun;26(3):E293-9
references.pmid: 22686953
references.citation: Biochim Biophys Acta. 1980 Jul 16;600(1):212-27
references.pmid: 7397170
references.citation: Clin Biochem. 2011 Jan;44(1):14-20
references.pmid: 20599871
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2012 Feb 1;883-884:102-7
references.pmid: 21680259
references.citation: Pediatr Transplant. 2010 Dec;14(8):968-75
references.pmid: 21040278
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2012 Feb 1;883-884:108-12
references.pmid: 21727051
references.citation: Bioanalysis. 2010 Nov;2(11):1883-91
references.pmid: 21083496
references.citation: Clin Chem. 1981 Feb;27(2):272-5
references.pmid: 7460278
references.citation: Pediatr Transplant. 2008 May;12(3):284-8
references.pmid: 18331387
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2004 Sep 25;809(1):153-8
references.pmid: 15282106
references.citation: Clin Biochem. 2011 Jan;44(1):110-8
references.pmid: 20599869
references.citation: Ann Clin Biochem. 1986 Jan;23 ( Pt 1):1-25
references.pmid: 3532908
references.citation: Pediatr Transplant. 2007 Sep;11(6):608-14
references.pmid: 17663682
references.citation: Am J Transplant. 2009 Nov;9(11):2497-504
references.pmid: 19681814