Current Methodologies for Membrane Permeability Assessment

Abstract

Orally administrated drugs permeate the biological membrane by various transport mechanisms. The oral absorption potential is closely related to the physicochemical properties of the drug and interaction with the physiological factors surrounding the site of absorption. Assessment of the drug membrane permeability is an integral part of the early stage drug developmental process. Appropriate selection of the permeability screening method at the right stage of drug development process is important in achieving successful developmental outcomes. This review aims at introducing currently available in vitro and in vivo screening methods for the membrane permeability assessment.

Water and Molecular Exchange in Biological Cells Studied Using 1H Pulsed Field Gradient NMR

“…In Equation (7), P(r 0 |r,∆) is the propagator that determines the probability of a molecule, initially at position r 0 , being found at position r after time ∆, where ρ(r 0 ) is the initial density of the molecules. For free isotropic diffusion, the propagator is Gaussian, and the integration in Equation ( 7) yields the following expression relating the echo intensity to the diffusion coefficient D:…”

“…In the study of the permeability of biomembranes for various compounds, a number of physicochemical methods are used: osmotic, based on measuring the change in cell volume when placed in hyper- or hypo-tonic solutions; indicator, based on a change in the color of the cellular contents with the introduction of certain substances; chemical, based on the analysis of the composition of intracellular contents; and the method of labeled atoms, based on the use of radioactive and stable isotopes, among others [ 7 ]. A wide range of opportunities for the non-invasive study of local molecular mobility and molecular diffusion in living biological cells is provided by the pulsed field gradient NMR method (PFG NMR) [ 8 ].…”