title: Determination of L-ephedrine, pseudoephedrine, and caffeine in rat plasma by liquid chromatography-tandem mass spectrometry.
abstract: A rapid and simple liquid chromatography tandem mass spectrometry method was developed and validated for the simultaneous determination of L-ephedrine, pseudoephedrine, and caffeine in male Fisher-344 rat plasma at nanogram-per-milliliter concentrations for use in support of toxicology studies. Only 25 μL of plasma is required, and extraction is performed using a simple, single-step protein precipitation. The method was validated over a range of 2.09 to 5460 ng/mL for L-ephedrine, 2.09 to 5050 ng/mL for pseudoephedrine and 2.03 to 5340 ng/mL for caffeine. A binary gradient elution at 0.3 mL/min was used with a Waters XBridge Phenyl (2.1 × 150 mm, 3.5 μm) column and a Waters XBridge Phenyl 2.1- × 10-mm guard column at ambient temperature. The mobile phase consisted of 10 mM ammonium acetate in water (pH 5.0) and methanol. Caffeine trimethyl-(13)C(3) was used as the internal standard. The method was evaluated for linearity, recovery, precision, accuracy, and stability, and it was successfully applied in toxicokinetic studies of ephedrine, administered alone, in combination with caffeine, and in the herbal source Ma Huang.
authors: RTI International, Research Triangle Park, North Carolina 27709-2194, USA.
authors: Stephen D
authors: SD
authors: Cooper
authors: Brenda L
authors: BL
authors: Fletcher
authors: Melanie A Rehder
authors: MA
authors: Silinski
authors: Sherri S
authors: SS
authors: Brown
authors: Jon W
authors: JW
authors: Lodge
authors: Reshan A
authors: RA
authors: Fernando
authors: Bradley J
authors: BJ
authors: Collins
mesh_terms: D000818:Animals; D002110:Caffeine / Q000097:blood*; D002853:Chromatography, Liquid; D004809:Ephedrine / Q000097:blood*; D008297:Male; D054199:Pseudoephedrine / Q000097:blood*; D051381:Rats; D015813:Substance Abuse Detection / Q000379:methods*; D053719:Tandem Mass Spectrometry
chemical_list: D002110:Caffeine; D054199:Pseudoephedrine; D004809:Ephedrine