US 4,788,136 A · Diagnostic immunoassay by solid phase separation for digoxin

Abstract

A method for performing a diagnostic immunoassay by solid phase separation for digoxin. To a reaction mixture of a test sample and labeled anti-digoxin antibody, which forms a complex of any digoxin present in the test sample, is added a solid phase material having an immobilized ouabain triacetate derivative compound capable of binding any excess labeled antibody. The solid phase material is chosen to rapidly settle whereby a solid and liquid phase is formed. The liquid phase can then be extracted to measure the amount of digoxin-labeled antibody present therein. Ouabain triacetate derivative compounds possess sufficient affinity for anti-digoxin antibodies, and are therefore useful in a solid phase separation based digoxin immunoassay for settling out such antibodies without contributing to undesired background interference. These compounds are also less deleterious to assay performance because of low recognition when leached from the solid phase matrix thereby providing solid phase material with extended shelf life.

Claims21

Dependent claims

A method for conducting a diagnostic immunoassay for digoxin, comprising:

(a) forming a reaction mixture of a test sample with a molar excess of labeled anti-digoxin antibodies whereby said labeled antibodies are capable of forming complexes with digoxin present in said sample;
(b) contacting said reaction mixture with a solid phase material having immobilized thereon a compound of formula I:
##STR4## wherein R.sup.1 .dbd.R.sup.2 .dbd.R.sub.3 .dbd.Ac, X.dbd.O, Y.sub.1 .dbd.Y.sub.2 .dbd.OH, Z.sub.1 .dbd.Z.sub.2 .dbd.H;
or R.sub.1 .dbd.R.sub.2 .dbd.R.sub.3 .dbd.Ac, X.dbd.O, Y.sub.1 .dbd.OH, Z.sub.1 .dbd.H, Y.sub.2 and Z.sub.2 .dbd.a bond connecting the two carbon atoms to which they are attached;
or R.sub.1 .dbd.R.sub.2 .dbd.R.sub.3 .dbd.Ac, X.dbd.O, Y.sub.1, Z.sub.1 and Y.sub.2, Z.sub.2 .dbd.a bond connecting the two carbon atoms to which they are attached;
or R.sub.1 .dbd.R.sub.2 .dbd.R.sub.3 .dbd.H, X.dbd.N, Y.sub.1 .dbd.Y.sub.2 OH, Z.sub.1 .dbd.Z.sub.2 .dbd.H, said compound present in an amount capable of complexing with any of said excess labeled antibodies, to form solid phase complexes;
(c) separating said solid phase material from said reaction mixture;
and
(d) determining the presence of digoxin in the test sample by measuring the amount of complex present in said liquid phase.

6 more elements

Dependencies are inferred from the claim text.

Diagnostic immunoassay by solid phase separation for digoxin

Life of this patent

Diagnostic immunoassay by solid phase separation for digoxin

Life of this patent

Abstract

Claims21