Interaction between Drugs and Water-Soluble Polymers. Part VI. Binding of Warfarin with Quaternized Poly(4-vinylpyridinium bromide)s.

Abstract

The interaction between warfarin (WF) and ionic synthetic polymer was investigated using an equilibrium dialysis method. Polymers used were quaternized poly(4-vinylpyridinium bromide)s (QPV), in which N-alkyl groups were butyl (QBu), methyl (QMe) and benzyl (QBz), and degree of quaternization of polymer was shown in parentheses as a percentage. The nature of bindings depended on both the hydrophilic property of the pyridinium part and the hydrophobic property of the alkyl and pyridine parts. The bindings of WF to QBu(100) and QMe(100) were assumed to be due to hydrophilic interaction. The binding capacity of WF to QBu decreased with increase of the degree of quaternization of QBu. The binding of WF to QBu(24) was attributed to both hydrophobic and hydrophilic parts. The binding of WF to QBz(80) was due to hydrophobic interaction because of the hydrophobic property of the benzyl group. N-Butyl-4-ethylpyridinium bromide (BEP) monomer and WF formed an equimolar complex. Phenylbutazone (PB) competed with WF for the hydrophobic binding to QBz(80).