Analysis of creatine, creatinine, creatine-d3 and creatinine-d3 in urine, plasma, and red blood cells by HPLC and GC-MS to follow the fate of ingested creatine-d3

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 827; no. 2; pp. 210 - 215
• Main Authors: MACNEIL, Lauren, HILL, Lisa, MACDONALD, Daniel, KEEFE, Lori, CORMIER, James F, BURKE, Darren G, SMITH-PALMER, Truis
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 05.12.2005
• Subjects: Adult; Analysis; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Chromatography, High Pressure Liquid - methods; Chromatography, Ion Exchange; Creatine - blood; Creatine - metabolism; Creatine - urine; Creatinine - blood; Creatinine - metabolism; Creatinine - urine; Deuterium; Erythrocytes - metabolism; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry - methods; General pharmacology; Humans; Male; Medical sciences; Pharmacology. Drug treatments; Creatinine; Urine; Biological fluid; Plasma; Deuterated creatine; HPLC chromatography; Red blood cell; Creatine; Deuterated creatinine; Blood plasma; GC-MS; Blood cell; Red blood cells
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2005.09.011

Creatine, which is increasingly being used as an oral supplement, is naturally present in the body. Studies on the fate of a particular dose of creatine require that the creatine be labeled, and for studies in humans the use of a stable isotopic label is desirable. The concentrations of total creatine and total creatinine were determined using HPLC. Creatine and creatinine were then separated using cation exchange chromatography and each fraction was derivatized with trifluoroacetic anhydride and the ratio of the deuterated:undeuterated species determined using GC-MS. Ratios of creatine:creatine-d(3), and creatinine:creatinine-d(3), and the concentrations of each of these species, were able to be determined in urine, plasma and red blood cells. Thus, the uptake of labeled creatine into plasma and red blood cells and its excretion in urine could be followed for a subject who ingested creatine-d(3). Creatine-d(3) was found in the plasma and red blood cells 10 min after ingestion, while creatine-d(3) and creatinine-d(3) were found in the urine collected after the first hour.