A new concept in colonic drug targeting: a combined pH‐responsive and bacterially‐triggered drug delivery technology

Ibekwe, Valentine C.; Khela, Mandeep; Evans, David F.; Basit, Abdul W.

doi:10.1111/j.1365-2036.2008.03810.x

Cited by 95 publications

(65 citation statements)

References 25 publications

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“…The small intestinal transit times for the tablet administered without food (fasted) and after food (fed) are statistically similar; this is what has been described previously (1,22). The pre-feed dose, which was administered 45 min before food, shows differences in small intestinal transit.…”

Section: Discussionsupporting

confidence: 59%

Meal-Induced Acceleration of Tablet Transit Through the Human Small Intestine

et al. 2008

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Section: Discussionsupporting

confidence: 59%

Meal-Induced Acceleration of Tablet Transit Through the Human Small Intestine

et al. 2008

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“…These differences may significantly influence the performance of drugs during their residence in the lower parts of the intestine. Unraveling the composition of colonic fluids led to better insights in colonic drug delivery strategies, resulting in pH-responsive and bacterially-triggered drug delivery technology (Basit et al, 2004(Basit et al, , 2009Ibekwe et al, 2008;McConnell et al, 2008;Vertzoni et al, 2010a), as well as optimized dissolution media to assess the performance of for instance colontargeted drug formulations in the lower intestine. These findings have led to the development of biorelevant fasted and fed state simulated colonic fluid (FaSSCoF and FeSSCoF, respectively), developed to mimic the fluids collected from the ascending colon in healthy adults (Vertzoni et al, 2010b).…”

Section: Invasive Methodologiesmentioning

confidence: 99%

Exploring gastrointestinal variables affecting drug and formulation behavior: Methodologies, challenges and opportunities

Hens

Corsetti

Spiller

et al. 2017

International Journal of Pharmaceutics

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(2017) Exploring gastrointestinal variables affecting drug and formulation behavior: methodologies, challenges and opportunities. International Journal of Pharmaceutics, 519 (1-2). pp. 79-97. ISSN 1873-3476Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/39960/1/FinalVersion-Revised-FOR_EPRINTS_1_YEAR_EMBARGO_ELSEVIER.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the Creative Commons Attribution Non-commercial No Derivatives licence and may be reused according to the conditions of the licence. For more details see: http://creativecommons.org/licenses/by-nc-nd/2.5/ A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. After oral intake, a drug formulation is challenged by several gastrointestinal (GI) barriers. Complex variables such as pH, GI secretions and GI transit/motility along the GI tract can affect drug release and absorption in a positive or negative way depending on the physicochemical properties of the drug compound (e.g. pH/pKa interplay for ionizable drugs) and/or the formulation characteristics (e.g. pHsensitive coating). In addition, inter-subject variability in characteristics of the GI environment may cause variable drug absorption and systemic drug availability (Riethorst et al., 2015). Determining the median and range for specific GI variables, and understanding how they influence oral drug behavior along the GI tract, will be helpful in the field of drug development. 2The present review provides an overview of different methodologies that can be applied to study physiological variables of the human GI tract and their impact on oral drug absorption in healthy and patient populations. The methodologies have been subdivided into two groups: (i) noninvasive and (ii) invasive methodologies. Although some of the methodologies are more historical than operational, they have been of paramount importance for innovations in drug and formulation development; in addition, they have created the basis for several novel methodologies, leading to an in-depth comprehension of different GI variables: gastric emptying (magnetic resonance imaging (MRI), scintigraphy, acetaminophen absorption technique, ultrasonography, breath test, intraluminal sampling and telemetry), motility (MRI, small intestinal/colonic manometry and telemetry), GI volume changes (MRI and ultrasonography), temperature (telemetry) and GI pH (intraluminal sampling and telemetry). Noninvasive methodologiesa. Scintigraphy Disturbances in the normal movement of food along the GI tract can be associated with abdominal pain, early satiety and nausea. Measurement of GI transit, es...

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“…pHsensitive systems exhibit unpredictable site specificity of drug release because of inter-and intrasubject variation and almost similar pH values of small intestinal and colonic fluids (5). A time-dependent system seems difficult for accurate prediction of site for drug release because of wide variation in gastric retention time (6) though the small intestinal transit time (3± 1 h) is relatively constant and less variable (7). Prodrugs based on azo polymers are specifically reduced by azoreductase enzymes.…”

Section: Introductionmentioning

confidence: 99%

Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release

Maity

2015

AAPS PharmSciTech

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Abstract. This work was envisaged to develop compression-coated tablets using a blend of Ca +2 ion crosslinked carboxymethyl xanthan gum (CMXG) and sodium alginate (SAL) for delayed release of immediate pulse release tablets of prednisolone (PDL) in the colon without the need of colonic bacterial intervention for degradation of the polysaccharide coat. The core tablets containing PDL and other compatible excipients were prepared by direct compression method and subsequently compression coated with different ratios of CMXG and SAL. Long T lag , the time required to restrict the drug release below 10%, and short T rap , the time required for immediate release following the T lag , were considered as suitable release parameters for evaluation of colon targeting of PDL tablets. Among the various compression coats, a blend of CMXG and SAL in a ratio of 1.5:3.5 provided T lag of 5.12±0.09 h and T rap of 6.50±0.05 h. The increase in microcrystalline cellulose (MCC) and crospovidone (CP) in the core tablets did not change T lag significantly although decreased the T rap marginally. Inclusion of an osmogen in the core tablets decreased the T lag to 4.05±0.08 h and T rap to 3.56±0.06 h. The increase in coat weight to 225 mg provided a reasonably long T lag (6.06±0.09 h) and short T rap (4.36±0.20 h). Drug release from most of the formulations followed the Hixson-Crowell equation and sigmoidal pattern as confirmed by the Weibull equation. In conclusion, tablets, compression coated with CMXG and SAL in a ratio of 1.5:3.5 and having 225-mg coat weight, were apparently found suitable for colon targeting.

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A new concept in colonic drug targeting: a combined pH‐responsive and bacterially‐triggered drug delivery technology

Cited by 95 publications

References 25 publications

Meal-Induced Acceleration of Tablet Transit Through the Human Small Intestine

Meal-Induced Acceleration of Tablet Transit Through the Human Small Intestine

Exploring gastrointestinal variables affecting drug and formulation behavior: Methodologies, challenges and opportunities

Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release

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