Effect of bicarbonate buffer on artificial membrane permeation of drugs

Background and purpose: The pH value of the small intestine is physiologically maintained by bicarbonate buffer (BCB). However, the effect of BCB on the membrane permeation of drugs has not been investigated. The purpose of this study was to investigate the effect of BCB on the passive membrane per...

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Main Authors: Shiori Ishida, Sam Lee, Balint Sinko, Karl Box, Kiyohiko Sugano
Format: Article
Language:English
Published: International Association of Physical Chemists (IAPC) 2025-01-01
Series:ADMET and DMPK
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Online Access:https://pub.iapchem.org/ojs/index.php/admet/article/view/2603
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author Shiori Ishida
Sam Lee
Balint Sinko
Karl Box
Kiyohiko Sugano
author_facet Shiori Ishida
Sam Lee
Balint Sinko
Karl Box
Kiyohiko Sugano
author_sort Shiori Ishida
collection DOAJ
description Background and purpose: The pH value of the small intestine is physiologically maintained by bicarbonate buffer (BCB). However, the effect of BCB on the membrane permeation of drugs has not been investigated. The purpose of this study was to investigate the effect of BCB on the passive membrane permeation of drugs. Experimental approach: The μFlux apparatus (pION Inc.) was used for permeability measurements. To avoid a pH change of BCB, a floating lid was newly developed for μFlux. The membrane filter was coated with a 10 % soybean lecithin-decane solution. The flux measurement was performed in an iso-pH condition (pH 6.5, BCB = 10 mM, buffer capacity ()= 4.4 mM pH-1). Phosphate buffer (PPB) with the same pH and β was used for comparison (PPB = 8 mM). Key results: The floating lid suppressed the pH increase to less than 0.1 for 120 min. The effective permeability (Pe) values of lipophilic weakly acidic and basic drugs were lower in BCB than in PPB (ketoprofen, naproxen, and propranolol). On the other hand, the Pe values in BCB and PPB were similar for unionizable drugs (caffeine and antipyrine) and hydrophilic weakly basic drugs (metoprolol and procainamide). Conclusion: Passive membrane permeation of lipophilic weakly acidic and basic drugs was slower in BCB than in PPB. This was suggested to be attributed to the slow neutralization rate of BCB, which affects the pH value adjacent to the membrane surface.
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publisher International Association of Physical Chemists (IAPC)
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spelling doaj-art-8bdf9fa66f1e4d04a516877d8f2cdddb2025-01-21T07:44:53ZengInternational Association of Physical Chemists (IAPC)ADMET and DMPK1848-77182025-01-0110.5599/admet.2603Effect of bicarbonate buffer on artificial membrane permeation of drugsShiori Ishida0Sam Lee1Balint Sinko2Karl Box3Kiyohiko Sugano4Molecular Pharmaceutics Lab., College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga 525-8577, JapanPion Inc. (UK) Ltd. Forest Row Business Park, Station Road, East Sussex, RH18 5DW, United KingdomPion Inc. (UK) Ltd. Forest Row Business Park, Station Road, East Sussex, RH18 5DW, United KingdomPion Inc. (UK) Ltd. Forest Row Business Park, Station Road, East Sussex, RH18 5DW, United KingdomMolecular Pharmaceutics Lab., College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga 525-8577, Japan Background and purpose: The pH value of the small intestine is physiologically maintained by bicarbonate buffer (BCB). However, the effect of BCB on the membrane permeation of drugs has not been investigated. The purpose of this study was to investigate the effect of BCB on the passive membrane permeation of drugs. Experimental approach: The μFlux apparatus (pION Inc.) was used for permeability measurements. To avoid a pH change of BCB, a floating lid was newly developed for μFlux. The membrane filter was coated with a 10 % soybean lecithin-decane solution. The flux measurement was performed in an iso-pH condition (pH 6.5, BCB = 10 mM, buffer capacity ()= 4.4 mM pH-1). Phosphate buffer (PPB) with the same pH and β was used for comparison (PPB = 8 mM). Key results: The floating lid suppressed the pH increase to less than 0.1 for 120 min. The effective permeability (Pe) values of lipophilic weakly acidic and basic drugs were lower in BCB than in PPB (ketoprofen, naproxen, and propranolol). On the other hand, the Pe values in BCB and PPB were similar for unionizable drugs (caffeine and antipyrine) and hydrophilic weakly basic drugs (metoprolol and procainamide). Conclusion: Passive membrane permeation of lipophilic weakly acidic and basic drugs was slower in BCB than in PPB. This was suggested to be attributed to the slow neutralization rate of BCB, which affects the pH value adjacent to the membrane surface. https://pub.iapchem.org/ojs/index.php/admet/article/view/2603phosphate bufferfloating lidlipophilic weakly acidic and basic drugs
spellingShingle Shiori Ishida
Sam Lee
Balint Sinko
Karl Box
Kiyohiko Sugano
Effect of bicarbonate buffer on artificial membrane permeation of drugs
ADMET and DMPK
phosphate buffer
floating lid
lipophilic weakly acidic and basic drugs
title Effect of bicarbonate buffer on artificial membrane permeation of drugs
title_full Effect of bicarbonate buffer on artificial membrane permeation of drugs
title_fullStr Effect of bicarbonate buffer on artificial membrane permeation of drugs
title_full_unstemmed Effect of bicarbonate buffer on artificial membrane permeation of drugs
title_short Effect of bicarbonate buffer on artificial membrane permeation of drugs
title_sort effect of bicarbonate buffer on artificial membrane permeation of drugs
topic phosphate buffer
floating lid
lipophilic weakly acidic and basic drugs
url https://pub.iapchem.org/ojs/index.php/admet/article/view/2603
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