Studying the interactions of drugs and hydrophobic model membranes using contact angle goniometry

This study demonstrates a method where contact angle goniometry combined with surface tension measurements is used to assess the interactions of drugs with the hydrophobic core of a biological membrane. To this end, self-assembled monolayers (SAMs) of two alkanethiol and one thiolipid on Au(1 1 1) surfaces are used as model membranes and their interaction with six β-blockers is studied. The Gibbs equation and the Langmuir adsorption isotherm are used to determine the partition coefficients for the adsorption of the drugs, which are compared to the octanol–water partition coefficients as well as the liposome–water partition coefficients. The ability of the different SAMs to serve as model membranes in partitioning of drugs is discussed.