Levallorphan

DM hydrobromide, dextrorphan (DX) tartrate, 3methoxymorphinan (3-MM) hydrochloride, OZ, CAF, 1,7-dimethylxanthine (paraxanthine; 1,7-X), the internal standard (IS) levallorphan, and β-glucuronidase were purchased from Sigma-Aldrich (MO, USA). LOS, losartan carboxylic acid (E-3174) and 5-hydroxyomeprazole (5-OZ) sodium salt were obtained from Santa Cruz Biotechnology (CA, USA). LC-MS-grade methanol, acetonitrile and formic acid, and analytical-grade sodium acetate, acetic acid used to prepare the β-glucuronidase treatment buffer, ammonium formate, and SOLA ® cartridges for solid phase extraction (SPE) were purchased from Fisher Scientific (Geel, Belgium). Analyticalgrade potassium dihydrogen phosphate and sodium hydroxide were used to prepare the SPE buffer and were purchased from Merck (Darmstadt, Germany). Deionized water was purified through a water purification system from Millipore (MA, USA).
Other compounds used were: carboxymethyl cellulose sodium salt (Sigma-Aldrich, MO, USA), sodium chloride 0.9% solution for injection (Labesfal, Portugal), heparin sodium 5000 I.U./mL for injection (B. Braun Medical, Portugal), and pentobarbital (Eutasil® 200 mg/mL, Ceva Saúde Animal) used as anaesthetic drug. Introcan ® Certo IV in dwelling cannula (22G; 0.9 x 2.5 mm) made of polyurethane from B. Braun Melsungen AG (Melsungen, Germany) and heparin-lithium tubes were also used.