Static and Dynamic Permeability Assay for Hydrophilic Small Molecules Using a Planar Droplet Interface Bilayer

Area of Science:

• Biophysics
• Drug Discovery
• Membrane Transport

Background:

• Oral drug administration necessitates accurate prediction of intestinal drug permeability.
• Existing in vitro methods like Caco-2 assays are time-consuming and expensive.
• Other assays lack defined structures, limiting their versatility.

Purpose of the Study:

• To develop a simpler, more accurate, and versatile platform for measuring small molecule permeability across lipid bilayers.
• To overcome the limitations of current in vitro permeability assays.

Main Methods:

• Constructed a planar freestanding lipid bilayer within a UV spectrometer cell.
• Measured drug molecule transport across the bilayer via UV absorbance over time.
• Computed permeability using the time-dependent diffusion equation.

Main Results:

• The new assay demonstrated significantly higher permeability values compared to existing techniques.
• Higher permeability was correlated with the lipid bilayer's thickness.
• The assay successfully measured dynamic permeability changes upon surfactant addition, indicating real-time detection capabilities.

Conclusions:

• The developed UV-spectrometer-based assay offers a simpler, more accurate, and versatile alternative for drug permeability assessment.
• The assay's ability to measure dynamic changes provides valuable insights into drug-membrane interactions.
• This platform has the potential to enhance early-stage drug discovery and development.