Bioavailability

Transepithelial transport in the cell model

 

The transport of an active ingredient through the mucous membrane of the small intestine is a prerequisite for it to develop its effect in the body. In vitro tests can provide an important building block during product development or further development. The determination of the transport rate of an analyte can be carried out with or without prior simulated gastric and intestinal passage.

The model is particularly suitable for the simultaneous comparative determination of the transport rate during product development, quality assurance during a product changeover, or in comparison to a benchmark product.

Our modular package solution:

Simulated GASTRO-INTESTINAL PASSAGE:
The processes occurring during residence time in the stomach and small intestine are simulated using enzyme addition and pH adjustments in the in vitro setup. The test substances introduced are subjected to potential metabolic processes (e.g., cleavage of sugar residues) similar to those observed in vivo. Water-insoluble active components are incorporated into micelles by the added enzymes and bile salts, making them soluble for subsequent transport studies.

Particle size determination:
Information on the solubility and stability of the drug formulation is obtained via the concomitant determination of particle size by dynamic light scattering (DLS) at different time points before and during the gastric or intestinal phase.

Transepithelial transport:
Transepithelial transport is determined in the Caco-2 model (optionally also with EpiIntestinal™). In the model, the epithelium of differentiated cells separates two sides on a membrane: the apical side, which represents the intestinal lumen with the active ingredients it contains, and the underlying basal side, which symbolizes the systemic side of the body into which the active ingredients are to be released. To determine the transport, the concentration of the analyte in the basal compartment is measured and the apparent transport coefficient (Papp) is calculated.

Analysis:
The marker substance of mixtures is analyzed at the start of supplementation and after transport on the basal side. The analyses are carried out in-house using UHPLC and optical detection or LC-MS/MS, depending on the analyte:

• Vitamins
• Polyphenols and flavonoids
• Terpenes
• Curcuminoids
• Silymarin
• Cannabinoids
• Trace elements

PAMPA assay:
Cell-free alternative for determining the passive permeation of active substances through an artificial membrane.