In this paper, applying fluorescence quenching method and energy transfer technique, we have firstly studied the interaction of human serum albumin (HSA) with cardiovascular drugs such as dilthiazem, tetramethylpyrazine and glycyrrhizic acid. The results show that dilthiazem and tetramethylpyrazine can form association molecules with HSA in the solution. The mechanism of quenching belongs to static quenching and the association constants between tetramethylpyrazine and HSA are Ks=1.12×10^4(mol/L)^-^1(25℃), 6.95×10^3 (mol/L)^-^1(40℃), and those between dilthiazem and HSA are 4.71×10^2(mol/L)^-^1(25℃), 3.00×10^2(mol/L)^-^1(40℃), respectively. The interaction between HSA and glycyrrhizic acid is dynamic quenching. The dynamic quenching constants are KD=4.76×10^(mol/L)^-^1(25℃), 6.19×10^2(mol/L)^-^1(40℃ ).Based on the mechanism of energy transfer of dipole-dipole interaction between the donor and acceptor, we have determined the distance between 214--tryptophane residue of HSA and drug molecule tetramethylpyrazine to be R=1.76nm(25℃) and .nm(40℃), respectively.

Key words: SERUM, ALBUMINE, CARDIOVASCULAR DRUG, FLUOROSPECTROPHOTOMETRY, GLYCYRRHETINIC ACID