title: Determination of xanthines by high-performance liquid chromatography and thin-layer chromatography in horse urine after ingestion of Guaraná powder.
abstract: The seeds of Guaraná are rich in xanthines and are used for the preparation of guaraná powder which is very commonly given to horses as a 'tonic' in Brazil. In this paper, the xanthine content of guaraná powder was determined, in addition to its clearance time in horses. Thin-layer chromatography was used as a screening procedure and high-performance liquid chromatography was performed to quantify the drugs in both the powder and urine samples. The guaraná powder was found to contain 2.16, 1.10 and 36.78 mg g-1 of theobromine (TB), theophylline (TP) and caffeine (CF), respectively, and in urine it was possible to detect TB and TP up to 13 d and CF up to 9 d after the administration of guaraná powder.
authors.affiliation: Antidoping Lab-Jockey Club de São Paulo, Brazil.
authors.forename: M C
authors.initials: MC
authors.lastname: Salvadori
authors.forename: E M
authors.initials: EM
authors.lastname: Rieser
authors.forename: L M
authors.initials: LM
authors.lastname: Ribeiro Neto
authors.forename: E S
authors.initials: ES
authors.lastname: Nascimento
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002110:Caffeine / Q000008:administration & dosage* / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002855:Chromatography, Thin Layer / Q000379:methods; D004338:Drug Combinations; D006736:Horses; D012044:Regression Analysis; D015203:Reproducibility of Results; D012639:Seeds; D013805:Theobromine / Q000008:administration & dosage* / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D013806:Theophylline / Q000008:administration & dosage* / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D014970:Xanthines / Q000032:analysis / Q000652:urine*
chemical_list: D004338:Drug Combinations; D014970:Xanthines; C092099:guarana powder; D002110:Caffeine; D013806:Theophylline; D013805:Theobromine