PAMPA

PAMPA (Parallel Artificial Membrane Permeability Assay) is a method which determines the permeability of substances from a donor compartment, through a lipid-infused artificial membrane into an acceptor compartment. Read-out is a permeation coefficient Peff drug as well as test compound concentrations in donor, membrane and acceptor compartments⁶⁷.

A 96-well microtiter plate completely filled with aqueous buffer solutions (pH 7.4/ 6.5) is covered with a microtiter filterplate like a sandwich construction. The hydrophobic filter material (Durapore/Millipore; pore size 0.22–0.45 μm) of the first 48 wells (sample) of the filterplate is impregnated with a 1–20% solution of lecithin in an organic solvent (dodecane, hexadecane, 1,9-decadiene). The filter surface of the remaining 48 wells (reference) is wetted with a small volume (4–5 μl) of a 50% (v/v) methanol/buffer solution. Transport studies were started by the transfer of 100–200 μl of a 250 or 500 μM stock solution on top of the filterplate in the sample and in the reference section, respectively. In general 0.05 M TRIS, pH 7.4, or 0.05 M phosphate, pH 6.5, buffers were used. The maximum DMSO content of the stock solutions was 5%.