title: Validation of a simple liquid chromatography assay for creatine suitable for pharmacokinetic applications, determination of plasma protein binding and verification of percent labeled claim of various creatine products.
abstract: Creatine has been quantified in various tissues by a range of methodologies. This paper reports on the development and validation of a simplified HPLC assay to determine plasma creatine, plasma protein binding of creatine, creatine in microdialysate and creatine in over-the-counter products. An isocratic, reversed-phase (C(18)) HPLC assay, using potassium phosphate monobasic (pH 4) as a mobile phase, was validated in human plasma and microdialysis perfusion fluid (normal saline). The lower limit of quantification for the assay was 1 mg l(-1) in saline and 5 mg l(-1) in plasma. The RSD was below 6% and accuracy was below 12% in both matrices. Protein binding in human plasma was found to be negligible (<10%). Over-the-counter creatine monohydrate products tested contained 100% creatine monohydrate. This assay was found to be suitable for pharmacokinetic studies and the assessment of plasma creatine and skeletal muscle microdialysate.
authors.affiliation: Department of Pharmaceutics, University of Florida, College of Pharmacy, Gainesville, FL 32610, USA. apersky@email.unc.edu
authors.forename: Adam M
authors.initials: AM
authors.lastname: Persky
authors.forename: Günther
authors.initials: G
authors.lastname: Hochhaus
authors.forename: Gayle A
authors.initials: GA
authors.lastname: Brazeau
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003401:Creatine / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D017551:Microdialysis; D011485:Protein Binding; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003401:Creatine