High-performance liquid chromatographic determination of tramadol and its O-desmethylated metabolite in blood plasma. Application to a bioequivalence study in humans.
Simultaneous HPLC determination of the analgetic agent tramadol, its major pharmacodynamically active metabolite (O-desmethyltramadol) in human plasma is described. Simple methods for the preparation of the standard of the above-mentioned tramadol metabolite and N1,N1-dimethylsulfanilamide (used as the internal standard) are also presented. The analytical procedure involved a simple liquid-liquid extraction of the analytes from the plasma under the conditions described previously. HPLC analysis was performed on a 250x4 mm chromatographic column with LiChrospher 60 RP-selectB 5-microm (Merck) and consists of an analytical period where the mobile phase acetonitrile-0.01 M phosphate buffer, pH 2.8 (3:7, v/v) was used, and of a subsequent wash-out period where the plasmatic ballast compounds were eluted from the column using acetonitrile-ultra-high-quality water (8:2, v/v). The whole analysis, including the equilibration preceding the initial analytical conditions lasted 19 min. Fluorescence detection (lambda(ex) 202 nm/lambda(em) 296 nm for tramadol and its metabolite, lambda(ex) 264 nm/lambda(em) 344 nm for N1,N1-dimethylsulfanilamide) was used. The validated analytical method was applied to pharmacokinetic studies of tramadol in human volunteers.
Nobilis
M
M
Institute of Experimental Biopharmaceutics, Joint Research Center of Academy of Sciences of the Czech Republic and PRO.MED.CS Praha a.s., Hradec Králové.
Kopecký
J
J
Kvetina
J
J
Chládek
J
J
Svoboda
Z
Z
Vorísek
V
V
Perlík
F
F
Pour
M
M
Kunes
J
J
D000701:Analgesics, Opioid / Q000097:blood* / Q000493:pharmacokinetics; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D013810:Therapeutic Equivalency; D014147:Tramadol / Q000097:blood* / Q000493:pharmacokinetics
D000701:Analgesics, Opioid; D014147:Tramadol