Advertisement

Pharmaceutisch Weekblad

, Volume 11, Issue 1, pp 9–12 | Cite as

A study on the buffering activity of the human rectum

In vivo demonstration of HCO3 and H+ secretion after rectal application of fluids with an unphysiological pH
  • Wendelien M. Böttger
  • Bert J. M. Schoonen
  • Frits Moolenaar
  • Jan Visser
  • Dirk K. F. Meijer
Original Articles

Abstract

The buffering activity of the human rectum was evaluated in various pilot studies, using a rectal lumen perfusion method. Quantitative alkaline and acid secretion was measured, respectively, by direct titration according to the pH-stat method. The change in composition of the perfusate with regard to the test drug benzoate and the concentration HCO 3 was detected. The pilot studies suggest that rectal mucosa is capable of neutralizing a pH deviating from the physiological value within a remarkably short time. In the acid region, at least a part of the alkalizing activity is the result of HCO 3 secretion. It has been shown that this process is stimulated by the H as well as Cl ions. In the basic region neutralization very likely occurs by means of H secretion.

Keywords

Acid-base imbalance Buffers Hydrogen Hydrogen carbonate Neutralization Perfusion, rectal Rectum Secretion 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Böttger WM, Schoonen AJM, Visser J, Meijer DKF. Lumen perfusion of the human rectumin situ; a method to study to mechanisms for rectal drug transport in humans. J Pharm Sci 1984;73:95–9.PubMedGoogle Scholar
  2. 2.
    McNeil NI. Differences in electrolyte handling through the human large intestine. In: Skadhauge E, Heintze K, eds. Intestinal absorption and secretion. Hinghaus: MTP Press Limited, 1984:111–6.Google Scholar
  3. 3.
    Schurgers N. Mechanistic studies on the absorption of drugs: factors influencing absorption of drugs from the small intestine of the rat. Utrecht: Utrecht University, 1983. Dissertation.Google Scholar
  4. 4.
    Crommelin DJA, Modderkolk J, De Blaey CJ. pH-Dependence of rectal absorption of theophylline from solutions of aminophyllinein situ in rats. Int J Pharm 1979;3:299–309.CrossRefGoogle Scholar
  5. 5.
    Rask-Madsen J. Simultaneous measurement of electrical polarization and electrolyte transport by the entire normal and inflamed human colon duringin vivo perfusion. Scand J Gastroenterol 1973;8:327–36.PubMedGoogle Scholar
  6. 6.
    Moolenaar F, Yska JP, Visser J, Meijer DKF. Drastic improvement in the rectal absorption profile of morphine in man. Eur J Clin Pharmacol 1985;29:119–21.CrossRefPubMedGoogle Scholar
  7. 7.
    Vromans H, Moolenaar F. Effects of solvents on rectal absorption rate of paracetamol in man: anin vitro approach. Int J Pharm 1985;26:5–13.CrossRefGoogle Scholar
  8. 8.
    Flemström G, Kivilaakso E. Demonstration of a pH gradient at the luminal surface of rat duodenumin vivo and its dependence on mucosal alkaline secretion. Gastroenterology 1983;84:787–94.PubMedGoogle Scholar
  9. 9.
    Garner A, Flemström G, Allen A. Gastroduodenal alkaline and mucus secretions. Scand J Gastroenterol 1983;18:25–41.Google Scholar
  10. 10.
    Smeaton LA, Hirst BH, Allen A, Garner A. Gastric and duodenal HCO3 transportin vivo: influence of prostaglandins. Am J Physiol 1983;245:G751–9.PubMedGoogle Scholar

Copyright information

© Royal Dutch Association for Advancement of Pharmacy 1989

Authors and Affiliations

  • Wendelien M. Böttger
    • 1
  • Bert J. M. Schoonen
    • 2
  • Frits Moolenaar
    • 3
  • Jan Visser
    • 3
  • Dirk K. F. Meijer
    • 3
  1. 1.St. Maartens HospitalBL VenloThe Netherlands
  2. 2.Department of Technology, Faculty of PharmacyUniversity of GroningenAW GroningenThe Netherlands
  3. 3.Department of Pharmacology and Therapeutics, Faculty of PharmacyUniversity of GroningenAW GroningenThe Netherlands

Personalised recommendations