MRI of the Colon in the Pharmaceutical Field: The Future before us

Abstract

Oral solid drug formulation is the most common route for administration and it is vital to increase knowledge of the gastrointestinal physiological environment to understand dissolution and absorption processes and to develop reliable biorelevant in vitro tools. In particular, colon targeted drug formulations have raised the attention of pharmaceutical scientists because of the great potential of colonic drug delivery. However, the distal bowel is still a relatively understudied part of the gastrointestinal tract. Recently, magnetic resonance imaging (MRI) has been gaining an emerging role in studying the colon. This article provides a comprehensive; contemporary review of the literature on luminal MRI of the colonic environment of the last 15 years with specific focus on colon physiological dimensions; motility; chyme and fluids; transit and luminal flow. The work reviewed provides novel physiological insight that will have a profound impact on our understanding of the colonic environment for drug delivery and absorption and will ultimately help to raise the in vitro/in vivo relevance of computer simulations and bench models.

Dynamic Colon Model (DCM): A Cine-MRI Informed Biorelevant In Vitro Model of the Human Proximal Large Intestine Characterized by Positron Imaging Techniques

“…The data here were analyzed using freely available image analysis software. It is worth mentioning that more sophisticated semi-automated analysis methods have been recently developed and reported [ 22 ]. The use of machine learning is developing in this field and could make this type of data analysis quicker and suitable, for example, for population- and disease-based and investigations and modeling.…”

“…MRI imaging of the colon provides insights into the undisturbed colon environment, including wall motion and fluid distribution [5,22,23]. MRI is non-invasive; thus, there is no disruption to the physiological, physical state of the colon.…”

Quantification of Fluid Volume and Distribution in the Paediatric Colon via Magnetic Resonance Imaging

“…Data on intestinal fluid (amount, distribution and composition) are necessary for in vitro and in silico models in drug development [ 3 , 5 , 8 , 11 , 14 , 25 , 26 ]. Despite recent efforts, there is no consensus on the volume of water or its distribution throughout the colon of adults [ 27 ], which translates in poor estimations for the standardised volume employed for colonic dissolution testing ( Table 1 ). Currently, in vitro and in silico models of the colon use a range of volumes for dissolution assays, ranging from 1 mL to 200 mL [ 28 , 29 , 30 ].…”

Photometric Stereo-Based Depth Map Reconstruction for Monocular Capsule Endoscopy

“…For experiments, more comparable experiments will be verified not only by the camera, but also by MRI and CT devices. For object surfaces with more practical reflection properties, more complex phantom structures [ 36 , 37 ] and experimental techniques [ 38 , 39 ] will also be considered in experiments.…”