title: Effect of age on toxicokinetics among human volunteers exposed to propylene glycol methyl ether (PGME).
abstract: Aging adults represent the fastest growing population segment in many countries. Physiological and metabolic changes in the aging process may alter how aging adults biologically respond to pollutants. In a controlled human toxicokinetic study (exposure chamber; 12 m³), aging volunteers (n=10; >58 years) were exposed to propylene glycol monomethyl ether (PGME, CAS no. 107-98-2) at 50 ppm for 6 h. The dose-dependent renal excretion of oxidative metabolites, conjugated and free PGME could potentially be altered by age.
  
  
  OBJECTIVE
  (1) Compare PGME toxicokinetic profiles between aging and young volunteers (20-25 years) and gender; (2) test the predictive power of a compartmental toxicokinetic (TK) model developed for aging persons against urinary PGME concentrations found in this study.
  
  
  METHODS
  Urine samples were collected before, during, and after the exposure. Urinary PGME was quantified by capillary GC/FID.
  
  
  RESULTS
  Differences in urinary PGME profiles were not noted between genders but between age groups. Metabolic parameters had to be changed to fit the age adjusted TK model to the experimental results, implying a slower enzymatic pathway in the aging volunteers. For an appropriate exposure assessment, urinary total PGME should be quantified.
  
  
  CONCLUSIONS
  Age is a factor that should be considered when biological limit values are developed.
authors.affiliation: Institute for Work and Health (IST), University of Lausanne, 1011 Lausanne, Switzerland. Nancy.Hopf@hospvd.ch
authors.forename: Nancy B
authors.initials: NB
authors.lastname: Hopf
authors.forename: David
authors.initials: D
authors.lastname: Vernez
authors.forename: Aurelie
authors.initials: A
authors.lastname: Berthet
authors.forename: Nicole
authors.initials: N
authors.lastname: Charriere
authors.forename: Christine
authors.initials: C
authors.lastname: Arnoux
authors.forename: Catherine
authors.initials: C
authors.lastname: Tomicic
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D011409:Propylene Glycols / Q000493:pharmacokinetics / Q000633:toxicity* / Q000652:urine; D012737:Sex Factors; D055815:Young Adult
chemical_list: D011409:Propylene Glycols; C005216:propylene glycol methyl ether