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Bumetanide binding to normal albumins and to albumin in renal failure
Author(s) -
Howlett M. R.,
Auld W. H. R.,
Murdoch W. R.,
Skellern G. G.
Publication year - 1993
Publication title -
biopharmaceutics and drug disposition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 58
eISSN - 1099-081X
pISSN - 0142-2782
DOI - 10.1002/bdd.2510140606
Subject(s) - bumetanide , albumin , human serum albumin , chemistry , binding site , plasma protein binding , serum albumin , diuretic , chromatography , endocrinology , biochemistry , biology , membrane , ion transporter
Binding of bumetanide, a loop diuretic, to partially purified albumins from renal failure patients (RF‐HA), and healthy subjects (N‐HA), human serum albumin (HSA) and defatted‐HSA (D‐HSA), was studied with equilibrium dialysis at a constant albumin concentration and various ligand concentrations. Binding parameters ( n and K ) were estimated from Scatchard plots and with a nonlinear two‐binding site model computer program, assuming two classes of independent sites. The binding capacities ( n 1 K 1 ) decreased in the order N‐HA>RF‐HA>D‐HSA>HSA. Computer estimates of K 1 for the partially purified albumin preparations were not markedly different. However, the graphical estimate of K 1 for N‐HA was greater than that for RF‐HA. When the degree of binding ( r ) was plotted as a function of the logarithm of the free bumetanide concentration, an asymptotic plateau was not observed, indicating that the protein binding sites were not saturated. Consequently, the calculated binding estimates may not adequately describe the binding of bumetanide.