title: Assessment of the contribution of alpha 1-acid glycoprotein to the serum binding of basic drugs using serum treated with sulphosalicylic acid and DEAE-cellulose.
abstract: Treatment of human serum with DEAE-cellulose in acid conditions almost completely removed alpha 1-acid glycoprotein (alpha 1-AG) with little change in the concentration of albumin and beta-lipoprotein, while treatment with sulphosalicylic acid removed almost all the proteins except alpha 1-AG. The binding of various drugs to serum treated as above was measured by equilibrium dialysis and the contribution of alpha 1-AG to drug binding by human serum was assessed. Sulphosalicylic acid-treated serum exhibited a saturable binding for propranolol, which was considered to be due to the binding to alpha 1-AG while DEAE-cellulose-treated serum mostly exhibited non-saturable binding, for which albumin and beta-lipoprotein may be responsible. With this treated serum, alpha 1-AG was estimated to contribute approximately 40% to the binding of therapeutic concentrations of propranolol, 15% to that of imipramine and 15-20% to that of desipramine, respectively, in serum samples pooled from healthy adults. However, no contribution of alpha 1-AG was observed in the binding of salicylic acid to the serum. Dissociation constants of the propranolol binding to the high affinity site in control serum, sulphosalicylic acid-treated serum and purified alpha 1-AG showed similar values (3.7-6.7 microM). These results suggest that treatment of serum with sulphosalicylic acid and DEAE cellulose is useful in assessing the contribution of alpha 1-AG to the serum binding of basic drugs.
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Sugiyama
authors.forename: Y
authors.initials: Y
authors.lastname: Sawada
authors.forename: T
authors.initials: T
authors.lastname: Iga
authors.forename: M
authors.initials: M
authors.lastname: Hanano
mesh_terms: D001557:Benzenesulfonates; D001798:Blood Proteins / Q000378:metabolism; D002021:Buffers; D002482:Cellulose / Q000031:analogs & derivatives; D003636:DEAE-Cellulose; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009961:Orosomucoid / Q000378:metabolism*; D004364:Pharmaceutical Preparations / Q000097:blood*; D011433:Propranolol / Q000097:blood; D011485:Protein Binding; D012459:Salicylates; D013696:Temperature; D014462:Ultrafiltration
chemical_list: D001557:Benzenesulfonates; D001798:Blood Proteins; D002021:Buffers; D009961:Orosomucoid; D004364:Pharmaceutical Preparations; D012459:Salicylates; D002482:Cellulose; D003636:DEAE-Cellulose; D011433:Propranolol; C003366:sulfosalicylic acid