Studies of drug—protein binding interactions by flow injection analysis with fluorimetric detection

The applicability of single-channel and merging-zones flow injection systems with fluorimetric detection to the study of drug-protein binding interactions has been demonstrated. A study of the binding of the fluorescent probe 8-anilinonaphthalene-1-sulphonic acid (ANS) to human serum albumin by means of such systems gave results identical to those obtained by a static procedure, but the flow injection procedure was much more convenient. The flow injection methods were also used in pure albumin solution and in diluted serum to study the displacement of ANS by acidic drugs. The flow injection procedures were extended to investigate the binding of basic drugs to α₁-acid glycoprotein. A recent fluorescence probe derived from propanolol permitted calculations of the number and strength of the binding sites on this protein for propanolol and other drugs.