title: Bioavailability of tramadol hydrochloride from tramadol--capsules 50 mg.
abstract: The aim of this study was to investigate the bioavailability of tramadol hydrochloride after oral administration of Tramadol--50 mg capsules, made in Synteza Pharmaceutical-Chemical Company in Poznań. As a reference preparation of Tramadol was used Tramal--50 mg capsules, (Grünenthal, Germany). The preparations were investigated in 20 healthy volunteers, according to a randomised two-way, cross-over design in the fasted state. Blood samples for determination of tramadol plasma concentrations were collected at pre-defined time points up to 24 h following drug administration. A washout period of one week separated both treatment periods. Tramadol plasma concentrations were determined by means of a validated HPLC method (fluorescence detector, verapamil as an internal standard). Values of 1,226.4 ng h/ml (Tramadol) and 1,397.01 ng x h/ml (Tramal) for the parameter AUC(0-infinity) demonstrate a nearly identical extent of drug absorption. Maximum concentrations--Cmax (217.81 ng/ml and 246.0 ng/ml) and time to reach maximum plasma concentration--Tmax (2.14 and 2.31 h) achieved for Tramadol and reference preparation did not differ significantly.
  
  
  CONCLUSIONS
  the bioavailability of tramadol hydrochloride after administration of Tramadol is the same as after administration of Tramal, whose clinical efficacy was tested before.
authors.affiliation: Department of Clinical Pharmacy, K. Marcinkowski University of Medical Sciences, Poznań, Poland.
authors.forename: S
authors.initials: S
authors.lastname: Dyderski
authors.forename: D
authors.initials: D
authors.lastname: Szkutnik
authors.forename: M
authors.initials: M
authors.lastname: Zgrabczyńska
authors.forename: L
authors.initials: L
authors.lastname: Drobnik
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D001682:Biological Availability; D002214:Capsules; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D006801:Humans; D008297:Male; D013810:Therapeutic Equivalency; D014147:Tramadol / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000701:Analgesics, Opioid; D002214:Capsules; D014147:Tramadol