BD140 [for Albumin binding assay]

Human Serum Albumin (HSA) binds to a wide variety of drugs at two primary binding sites (I: blue and II: yellow), and can have a significant impact on their pharmacokinetics and pharmacological effects. The fluorescent probes, dansylamide (1) and dansylglycine (2) selectively interact with sites I and II, respectively.^1,2) BD140 (3) also binds to drug binding site II specifically.³⁾ Changes in probe fluorescence are analyzed by fluorescence titrations as a result of competitive displacient by drugs and pharmaceuticals. The pattern of fluorescent probe displacient by these reagents enabled the identification of two specific drug binding sites, which illustrates their usefulness for the characterization of the binding sites in HSA.

Binding of BD140 to HSA is not inhibited completely or nearly by warfarin and phenylbutazone, which bind to HSA drug binding site 1. On the other hand, binding of BD140 to HSA is inhibited sufficiently by ibuprofen, flurbiprofen and triiodobenzoic acid, which bind to drug binding site 2. Thus, BD140 is available for checking whether drugs bind to HSA drug binding site 2.

[Assay Condition]
Buffer: 1% DMSO in phosphate buffer (pH7.2 - 7.5), HSA: 20 µM (50 µL/well), Drugs: each concentration (50 µL/well), BD140: 20 µM(50 µL/well), Incubation: 20-25°C for 30 min, Measurement: plate-reader; excitation=365 nm, emission=585 nm.