Studies using a pH sensitive radiotelemetry capsule in normal, ambulatory volunteers have shown that the mean pH in the colonic lumen is 6.4 ± 0.6 in the ascending colon, 6.6±0.8 in the transverse colon and 7.0±0.7 in the descending colon10.
Many factors such as disease, diet, pharmaceutical formulations or therapeutic agents may alter the pH or the difference in pH between the ascending and descending colon. For example, administration of the laxative disaccharide lactulose causes the production of large amounts of lactic acid by the caecal bacteria, acidifying the proximal colon to 5.5-5.0. Less pronounced decreases are produced by guar gum and isphagula. Evidence exists suggesting that there are substantial changes in gastrointestinal pH in patients with malabsorption due to cystic fibrosis and in ulcerative colitis the pH may drop below 511. Current dosage forms designed for release in the proximal bowel employ enteric coatings, and are therefore dependent on luminal pH. Alteration of the pH profile of the gastrointestinal tract in various disease states may be an important factor influencing the bioavailability of drugs delivered in this form.
Was this article helpful?
Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...