# US 8,785,204 B2 · Methods of assaying for tetrahydrocannabinol

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- Number: US 8,785,204 B2
- Document ID: US8785204B2
- Status: Granted
- Kind: B2
- Application number: 13/201,446
- Filed: 2010-01-28
- Published: 2012-05-17
- Granted: 2014-07-22
- Earliest claimed: 2009-02-13
- Assignees: Oxtox Limited
- Applicants: Dimitrios Konstantinos Kampouris; Patrick Robinson Huddleston; Craig Edward Banks
- Inventors: Dimitrios Konstantinos Kampouris; Patrick Robinson Huddleston; Craig Edward Banks
- Web page: https://patentgrep.com/patent/US8785204B2

## CPC

- G01N 33/948: {Sedatives, e.g. cannabinoids, barbiturates (opiates G01N33/9486)}
- Y10T 436/142222: Hetero-O [e.g., ascorbic acid, etc.]
- Y10T 436/145555: Hetero-N
- Y10T 436/147777: Plural nitrogen in the same ring [e.g., barbituates, creatinine, etc.]
- Y10T 436/17: Nitrogen containing
- Y10T 436/173845: Amine and quaternary ammonium
- Y10T 436/200833: Carbonyl, ether, aldehyde or ketone containing
- Y10T 436/203332: Hydroxyl containing
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The invention provides a method of assaying for tetrahydrocannabinol in a body fluid. The method includes contacting a sample of body fluid with an imine capable of reacting with tetrahydrocannabinol to yield a quinone imine, and detecting the formation of a quinone imine, where the sample is contacted with the reagent compound at a pH of at least 10.5.

## Claims

### Claim 1

A method of assaying for tetrahydrocannabinol in a body fluid, said method comprising the steps of contacting a sample of body fluid with an imine capable of reacting with tetrahydrocannabinol to yield a quinone imine, and detecting the formation of a quinone imine, wherein said sample is contacted with said imine at a pH of at least 10.5.

### Claim 2 (depends on 1)

The method as claimed in claim 1 wherein said imine capable of reacting with tetrahydrocannabinol is a compound of formula I
R′—N═C*—(X*—C*)n—C*-Q-R′ (I)
where Q is —O—, —S—, ═N— or —NR′—; each R′, which may be the same or different, is H or an electron-withdrawing or -donating group; X* is N* or C*; n is 0 or 1; and * indicates that the carbons or nitrogens are part of a delocalised electron system.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein said imine is formed from an imine precursor.

### Claim 4 (depends on 3)

The method as claimed in claim 3, wherein the imine is formed from the imine precursor by oxidation or by application of an electric potential.

### Claim 5 (depends on 3)

The method as claimed in claim 3, wherein the imine precursor is an amine of formula (II)
R′—HN—C*—(X*—C*)n—C*-Q-R′ (II)
where Q is —O—, —S—, ═N— or —NR′—; each R′, which may be the same or different, is H or an electron-withdrawing or -donating group: X* is N* or C*; n is 0 or 1; and * indicates that the carbons or nitrogens are part of a delocalised electron system, or wherein the imine precursor is a cyclic hydrazide.

### Claim 6 (depends on 3)

The method as claimed in claim 3, wherein the imine precursor is selected from the group consisting of 1-(substituted-amino)-4-amino benzenes, 1-(substituted-amino)-4-hydroxy benzenes, 1-(substituted-amino)-2-amino benzenes, 1-(substituted-amino)-2-hydroxy benzenes, 1,4-di(substituted-amino)-benzenes, 1,2-di(substituted-amino)-benzenes, 2,3-diaminopyridines, 2,5-diaminopyridines, 3,4-diaminopyridines, 2-amino-3-hydroxypyridines, 4,5-diaminopyrimidines, 4-aminopyrazolones and maleic hydrazides and substituted derivatives thereof.

### Claim 7 (depends on 3)

The method as claimed in claim 3, wherein the imine precursor is a 4-amino pyrazolone.

### Claim 8 (depends on 1)

The method as claimed in claim 1, wherein the sample is contacted with the imine at a pH of from 10.5 to 12.

### Claim 9

A method of assaying for a phenol analyte in a body fluid sample, said method comprising contacting said sample with a 4-imino-pyrazolone and electrochemically detecting any resulting quinone imine.

### Claim 10 (depends on 9)

The method as claimed in claim 9, wherein the phenol analyte is tetrahydrocannabinol.