I. Athanasiadou(1,2), A. Dokoumetzidis(1), C. Georgakopoulos(3), G. Valsami(1)
(1)Laboratory of Biopharmaceutics & Pharmacokinetics, Faculty of Pharmacy, National & Kapodistrian University of Athens, Panepistimiopolis-Zographou 15771, Athens, Greece, (2)Doping Control Laboratory of Athens, Olympic Athletic Center of Athens ‘Spiros Louis’, 37 Kifissias Ave., 15123 Maroussi, Greece, (3)Anti Doping Lab Qatar, P.O. Box 27775, Doha, Qatar
Objectives: To study the effect of hyperhydration on the urine pharmacokinetic profile of recombinant human erythropoietin (rHuEPO) and its possible role as a doping masking procedure used by athletes.
Methods: 1000 subjects administered subcutaneously a single dose of 3000 IU rHuEPO were simulated, by a two-compartment popPK model taken from literature [1], using MatLab SimBiology toolbox. Urine production was modelled based on the renal regulation of urine volume [2] and the conditions of water retention [3]. The normal rHuEPO PK urine profile and additional PK profiles simulating hyperhydration effect were simulated for 3 hydration levels, expressed as 10, 20 and 30 ml of water consumption/kg of body weight. Simulation of urine sampling collection schedule was used to evaluate the effect of hyperhydration on measured rHuEPO urine concentration during doping control analysis.
Results: Simulation analysis revealed that rHuEPO urine concentration follows the circadian rhythm of urine production regardless of hydration state. Moreover, at the time points of hyperhydration, a significant decrease on rHuEPO concentrations was observed compared to the normal profile; the difference was more pronounced as the hydration level increased. Cases of undetectable rHuEPO have been reported in literature, attributed to inhibition of EPO production following EPO doping, highly diluted urine, and/or manipulation of urine samples with proteases [4]. However, our simulations results showed that even in the normal PK profile, low concentrations compared to the sensitivity of the applied analytical methods [5] may exist, due to the circadian rhythm of urine production. The effect of rHuEPO dose and different hyperhydration intake scenarios on rHuEPO PK urine profile is also studied.
Conclusions: Clear effect of hyperhydration on rHuEPO urine profile was shown, supporting the reported cases of undetectable EPO urine levels. These findings may have practical implications regarding the timing of urine collection during anti-doping control sampling procedure and the subsequent detection of doping agents if hyperhydration could be used by athletes as a masking procedure. To verify this hypothesis, a single dose rHuEPO PK study in healthy male athletes with or without hyperhydration is designed, based on the present simulation analysis.
References:
[1] Olsson-Gisleskog P, Jacqmin P, Perez-Ruixo JJ. Population pharmacokinetics meta-analysis of recombinant human erythropoietin in healthy subjects, Clin Pharmacokinet. 2007, 46:159-173.
[2] Robertson GL, Norgaarg JP. Renal regulation of urine volume: potential implications for nocturia, BJU International 2002, 90:7-10.
[3] Shafiee MA, Charest AF, Cheema-Dhadli S, Glick DN, Napolova O, Roozbeh J, Semenova E, Sharman A, Halperin ML. Defining conditions that lead to the retention of water: The importance of the arterial sodium concentration, Kidney International 2005, 67:613-621.
[4] Lamon S, Robinson N, Sottas PE, Henry H, Kamber M, Mangin P, Saugy M. Possible origins of undetectable EPO in urine samples, Clin. Chim. Acta 2007 385:61-66.
[5] WADA Technical Document-TD2013EPO: Harmonization of analysis and reporting of recombinant erythropoietins (i.e. epoetins) and analogues (e.g. darbepoetin, pegserpoetin, peginesatide, epo-fc) by electrophoretic techniques. (2013). http://www.wada-ama.org/Documents/World_Anti-Doping_Program/WADP-IS-Laboratories/Technical_Documents/WADA-TD2013EPO-Harmonization-Analysis-of-Recombinant-Erythropoietins-EN.pdf
Reference: PAGE 22 (2013) Abstr 2794 [www.page-meeting.org/?abstract=2794]
Poster: Other Modelling Applications