Fluorescence assay of dipyridamole in RBC membranes.

Excitation spectra with emission at 480 nm are shown. After exposure to dipyridamole, intact RBCs were washed before lysis and preparation of membranes (see text). Membrane protein concentration was 0.10 mg/mL in assay samples. For quantification of dipyridamole, the difference between peak fluorescence at 293 nm and minimum fluorescence at 265 nm was calculated (depicted in panel B).