Measurement of gastrointestinal pH profiles in normal ambulant human subjects.
Level 4 - case-series / case-control
Prospective observational physiological study / case series in healthy volunteers without a comparator group
PubMed 3410329 · doi:10.1136/gut.29.8.1035
What was done
Gastrointestinal pH was measured in 66 normal ambulant subjects for up to 48 hours using an ingested pH-sensitive radiotelemetry capsule and a portable solid-state recording receiver. Capsule location within the gastrointestinal tract was tracked using an external directional surface detector.
What was found
Gastric pH ranged from 1.0 to 2.5 in all subjects. Mean (SD) pH values across the gastrointestinal tract were: - Proximal small intestine (first hour): 6.6 (0.5) - Terminal ileum: 7.5 (0.4) (p < 0.001) - Caecum: 6.4 (0.4), showing a sharp drop upon entry in all subjects (p < 0.001) - Left colon: 7.0 (0.7), following a progressive rise from the right colon (p < 0.001)
Why it matters
This study provides normative reference values for regional gastrointestinal pH gradients in freely moving healthy humans, directly informing the design and evaluation of pH-dependent oral drug delivery formulations.
Limits
The study is purely descriptive without comparison to patients with gastrointestinal pathology. The abstract does not report participant demographics such as age and sex, nor does it describe dietary controls during the 48-hour ambulatory recording period.
Cited by
- context Blood pH is slightly alkaline, the stomach is highly acidic, the large intestine is acidic, and the small intestine is alkaline.