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


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.


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


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  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

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