title: Upper gastrointestinal pH in seventy-nine healthy, elderly, North American men and women.
abstract: Gastric and duodenal pH levels were measured in 79 healthy, elderly men and women (mean +/- SD = 71 +/- 5 years) under both fasted and fed conditions using the Heidelberg capsule technique. The pH was recorded for 1 hr in the fasted state, a standard liquid and solid meal of 1000 cal was given over 30 min, then the pH was measured for 4 hr postprandially. Results are given as medians and interquartile ranges: fasted gastric pH, 1.3 (1.1-1.6); gastric pH during the meal, 4.9 (3.9-5.5); fasted duodenal pH, 6.5 (6.2-6.7); and duodenal pH during the meal, 6.5 (6.4-6.7). Although fasted gastric pH, fasted duodenal pH, and duodenal pH during the meal differ statistically from those observed in young subjects, the differences are not expected to be clinically significant in terms of drug absorption for the majority of elderly subjects. Following a meal, gastric pH decreased from a peak pH of 6.2 (5.8-6.7) to pH 2.0 within 4 hr in most subjects. This rate of return was considerably slower than in young, healthy subjects. Nine subjects (11%) had a median fasted gastric pH > 5.0, and in five of these subjects the median pH remained > 5.0 postprandially. In this group, drugs and dosage forms which require an acidic environment for dissolution or release may be poorly assimilated.
authors.affiliation: College of Pharmacy, University of Michigan, Ann Arbor 48109.
authors.forename: T L
authors.initials: TL
authors.lastname: Russell
authors.forename: R R
authors.initials: RR
authors.lastname: Berardi
authors.forename: J L
authors.initials: JL
authors.lastname: Barnett
authors.forename: L C
authors.initials: LC
authors.lastname: Dermentzoglou
authors.forename: K M
authors.initials: KM
authors.lastname: Jarvenpaa
authors.forename: S P
authors.initials: SP
authors.lastname: Schmaltz
authors.forename: J B
authors.initials: JB
authors.lastname: Dressman
mesh_terms: D000126:Achlorhydria / Q000453:epidemiology; D000368:Aged; D000369:Aged, 80 and over; D004064:Digestive System / Q000378:metabolism*; D004386:Duodenum / Q000378:metabolism; D005215:Fasting / Q000378:metabolism; D005260:Female; D005745:Gastric Acidity Determination; D005755:Gastrins / Q000097:blood; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D009656:North America; D012016:Reference Values; D012727:Sex Characteristics
chemical_list: D005755:Gastrins