In vivo models to evaluate ingestible devices: Present status and current trends

Abstract

Link to publication on Research at Birmingham portal General rightsUnless a licence is specified above, all rights (including copyright and moral rights) in this document are retained by the authors and/or the copyright holders. The express permission of the copyright holder must be obtained for any use of this material other than for purposes permitted by law.• Users may freely distribute the URL that is used to identify this publication.• Users may download and/or print one copy of the publication from the University of Birmingham research portal for the purpose of private study or non-commercial research.• User may use extracts from the document in line with the concept of 'fair dealing' under the Copyright, Designs and Patents Act 1988 (?) • Users may not further distribute the material nor use it for the purposes of commercial gain.Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document.When citing, please reference the published version. Take down policyWhile the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

In vitro models to evaluate ingestible devices: Present status and current trends

“…It is known that there is wide variability in the transit time within the colon of adults with range of 12-72 hours reported in a normal population [306]. The technique used to measure the transit can affect measurements reported and this is discussed in further detail in the second part of this review paper [8]. There is a meta-analysis on colonic transit times of ingested solid oral dosage forms that may also be useful for the reader [136]; particularly as this highlighted that larger units can move more quickly through the colon compared to multi-units.…”

“…A comprehensive understanding of the human gastro-intestinal tract is required as the basis for the development of suitable models. There have been several relevant reviews on GI conditions that the reader is referred to for completeness [4][5][6][7], further details on human GI anatomy and physiology are presented in our other paper within this edition [8]. Key factors for in vitro models are fluid volume and composition and these details are reviewed here, similarly, this review highlights current progress with microscale models, with evaluation of models that involve relevant cell types, luminal flow and microbiota.…”

“…Furthermore, several studies have demonstrated the functional orthotopic transplantation of murine [77] and human [78][79][80][81][82] GI organoid-derived monolayer epithelial tissue into mice, where they were observed to develop into mature tissues with morphological semblance of the original tissue [83]. This approach to manipulating organoids and animal models for use as advanced preclinical models may be valuable for the development of ingestible devices and is reviewed in more detail here [8].…”

“…Liquids will ordinarily empty faster than solids, and smaller objects faster than larger [137]. Further details on gastric emptying can be found in [8] where there is a full discussion on gastric emptying rates and how this relates to ingestible devices.…”

“…Ingestion of food also influences colonic motility and fatty meals have been shown to have a stronger influence on motility compared to carbohydrate based meals [307]. Further details on colonic motility are presented in the second part of this review paper [8], alternatively detailed information can be found in this paper [292].…”