Immunoassay for phencyclidine

An improved immunoassay for detecting the drug of abuse phencyclidine is described. This immunoassay is characterized in utilizing as reagents (i) an antibody elicited with a novel immunogen comprising 4-[(1-piperidinyl)cyclohexyl] benzoic acid covalently bonded to an immunogenic carrier material through the carboxyl group and (ii) a novel radiolabeled derivative of phencyclidine, namely .sup.125 I N-(4-hydroxy-2-phenylethyl)-4-[1-(1-piperidinyl)cyclohexyl] benzamide.

We claim:

1. N-(4-hydroxy-2-phenylethyl)-4-[1-(1-piperidinyl)cyclohexyl] benzamide.

2. .sup.125 I-N-(4-hydroxy-2-phenylethyl)-4-[1-(1-piperidinyl) cyclohexyl] benzamide.

3. An immunogen consisting of 4-[1-(piperidinyl) cyclohexyl] benzoic acid covalently liked through its carboxyl group to an immunogenic carrier material.

4. The immunogen of claim 3 wherein said immunogenic carrier material is bovine serum albumin.

5. A method for the assay of phencyclidine in a sample which method comprises mixing said sample with known amounts of a .sup.125 I-labelled phencyclidine derivative and an antibody which will selectively complex with phencyclidine, said antibody being elicited in the blood of a host animal by immunization with the immunogen of claim 3, separating antibody bound antigen from free antigen and then measuring the radioactivity of either the free or bound antigen and comparing said value to values obtained previously with samples containing known amounts of phencyclidine.

6. The method of claim 5 wherein said .sup.125 I-labelled derivative is .sup.125 I-N-(4-hydroxy-2-phenylethyl)-4-[1-(-piperidinyl) cyclohexyl] benzamide.

7. The method of claim 6 wherein the antibody bound antigen is separated from free antigen by precipitation by ammonium sulfate, the precipitate is centrifuged and the supernatant counted.

8. The method of claim 7 wherein phencyclidine is assayed qualitatively by comparing the counts obtained to a positive control, whereby counts equal or greater to said control value indicates the presence of phencyclidine in the sample.

9. The method of claim 7 wherein phencyclidine is assayed quantitatively by comparing the counts obtained to a standard curve.