Abstract: This invention improves the PAMPA (parallel artificial membrane permeability assay) method used in pharmaceutical, biotechnological, and agrochemical R&D. This new high-throughput method and apparatus for measurement of permeability and membrane retention of compounds overcomes shortcomings of prior art and includes sensitivity and speed enhancing reagents. The phospholipid membranes used here consist of 10–74% wt/vol soybean lecithin extract dissolved in dodecane. Concentrations are measured by direct UV spectroscopy. To reduce membrane retention, surfactants, cyclodextrins, or water-soluble lipophilic polymers with low UV absorption are used in the acceptor comparment of the permeation cells and create an artificial sink state. A pH gradient established between donor and acceptor solutions creates a secondary sink state. This “double-sink” makes successful modeling of passive-diffusion transport of molecules possible.

Abstract: The invention described here improves the PAMPA (parallel artificial membrane permeability assay) high-throughput method used in lead compound selection and optimization in pharmaceutical and biotechnological research and development, and for identifying active compounds with the right plant distribution properties in agrochemical research and development. The invention described here is a robust method and apparatus for measurement of two physical properties, permeability and membrane retention of compounds, which overcomes several of the shortcomings in the prior art. This invention includes reagents specifically designed for enhancing the sensitivity of the assay, to allow a UV detection system to be used for concentration measurements, to accurately estimate and compensate for the effects of membrane retention and unstirred water layer, and to increase the speed of the assay.