Application of spin labeling to drug assays. II. Determination of the binding of [14C]-phenytoin and spin-labeled phenytoins to albumin and human serum
Chou, D.; Polnaszek, C.F.; Yost, Y.; Leppik, I.E.; Holtzman, J.L.
Molecular Pharmacology 20(3): 674-680
1981
ISSN/ISBN: 0026-895X PMID: 7329409 Document Number: 170250
The concentration-dependent binding of 4 nitroxide spin-labeled derivatives of phenytoin (I) to bovine serum albumin and human sera was investigated. The spin label moiety was attached to phenytoin either at position 3-N via a carbimidomethyl linkage (II) or at a 4'-phenyl position via an amide linkage (III-V). Two of the phenyl labels (III and IV) differed only in the presence of a double bond in the pyrroline ring in IV, and V had the amide linkage reversed as compared with III. The results of the binding studies were compared with those obtained by equilibrium dialysis of levels in sera.