title: Plasma protein binding of furosemide in the elderly.
abstract: The protein binding of furosemide was investigated in plasma from 22 old and 11 young subjects by equilibrium dialysis. The unbound fraction of furosemide was 3.16% in plasma from the elderly and 1.7% in plasma from the young. A significant correlation was found between the unbound fraction of furosemide and the plasma concentration of albumin. The average number of binding sites was 3.8 (elderly) and 2.7 (young) 10(-6) mol/g albumin. The average association constant (K) was 4.3 (elderly) and 4.2 (young) 10(5) M-1. By increasing the concentration of furosemide up to 200 micrograms/ml buffer the unbound fraction of the drug rose to 5.2% (elderly) and 3.5% (young).
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001798:Blood Proteins / Q000378:metabolism*; D005260:Female; D005665:Furosemide / Q000097:blood*; D006801:Humans; D008297:Male; D011485:Protein Binding
chemical_list: D001798:Blood Proteins; D005665:Furosemide