title: Pharmacokinetic study of the oral administration of procaterol hydrochloride hydrate 50 µg in healthy adult Japanese men.
abstract: BACKGROUND
  The pharmacokinetics of procaterol, a selective beta2-adrenergic agonist with a high intrinsic efficacy in man, could not be determined in humans when the drug was launched because of the low therapeutic dose and the low sensitivity of the analytical methods available at the time. However, a recently established analytical method using LC-MS/MS has been refined to enable the determination of the pharmacokinetic profile of procaterol and its metabolites in humans.
  
  
  METHODS
  Procaterol hydrochloride hydrate 50 µg was administered orally to 8 healthy adult Japanese men. Plasma and urine samples collected from the subjects were analyzed by use of LC-MS/MS for procaterol and its metabolites.
  
  
  RESULTS
  Following the oral administration of procaterol hydrochloride hydrate 50 µg, the plasma concentration of procaterol reached a Cmax of 136.4 pg/ml at ~1.44 h post-dose. The mean apparent terminal elimination half-life was ~3.83 h. DM-251 and DM-252, glucuronides of the optical isomers of procaterol, were the main metabolites and both were present in plasma at higher levels than procaterol in the plasma. The 24 h urinary excretion rates of unchanged procaterol, DM-251 and DM-252 were 15.7%, 12.4% and 11.2% of the procaterol administered, respectively.
  
  
  CONCLUSIONS
  This study describes the pharmacokinetic profiles of procaterol and its metabolites following the oral administration of procaterol hydrochloride hydrate 50 µg. Procaterol and its glucuronides were found at high levels in the plasma and urine.
authors.affiliation: Shinanozaka Clinic, Shinanokai, Medical Corporation, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: M
authors.initials: M
authors.lastname: Masuda
authors.forename: E
authors.initials: E
authors.lastname: Kashiyama
authors.forename: N
authors.initials: N
authors.lastname: Koga
authors.forename: Y
authors.initials: Y
authors.lastname: Yasuda
authors.forename: T
authors.initials: T
authors.lastname: Shibutani
authors.forename: K
authors.initials: K
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Funaki
authors.forename: T
authors.initials: T
authors.lastname: Miyamoto
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000328:Adult; D044466:Asian People; D002853:Chromatography, Liquid / Q000379:methods; D020719:Glucuronides / Q000493:pharmacokinetics; D006207:Half-Life; D006801:Humans; D007564:Japan; D008297:Male; D017265:Procaterol / Q000008:administration & dosage / Q000493:pharmacokinetics*; D053719:Tandem Mass Spectrometry / Q000379:methods; D055815:Young Adult
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D020719:Glucuronides; D017265:Procaterol