# US 8,785,205 B2 · Detection of nicotine metabolites

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- Number: US 8,785,205 B2
- Document ID: US8785205B2
- Status: Granted
- Kind: B2
- Application number: 13/697,446
- Filed: 2011-05-13
- Published: 2013-05-23
- Granted: 2014-07-22
- Earliest claimed: 2010-05-13
- Assignees: GFC Diagnostics Ltd.
- Applicants: Charles John Knill; John Frederick Kennedy
- Inventors: Charles John Knill; John Frederick Kennedy
- Web page: https://patentgrep.com/patent/US8785205B2

## CPC

- G01N 33/52: Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper {and including single- and multilayer analytical elements (immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72)}
- G01N 33/94: involving narcotics {or drugs or pharmaceuticals, neurotransmitters or associated receptors}
- Y10T 436/14: Heterocyclic carbon compound [i.e. , O, S, N, Se, Te, as only ring hetero atom]
- Y10T 436/145555: Hetero-N
- 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 present invention relates to assays for detection of nicotine metabolites, in particular cotinine, in fluid samples and uses of these assays in quantification of smoking habits. The assays comprise contacting a body fluid sample with a cyanogen halide and a pyrazolone compound and detecting a change in light absorbance of the pyrazolone compound which is associated with the presence of nicotine metabolites. Also provided are assay kits including a cyanogen halide or cyanogen halide-precursor(s) and a pyrazolone compound.

## Claims

### Claim 1

A method of detecting or measuring a nicotine metabolite in a sample comprising contacting the sample with a cyanogen halide and a pyrazolone compound and detecting a change in light absorbance of the pyrazolone compound; wherein the pyrazolone compound is a compound according to formula I
in which:
R1 is —C(═O)—;
R2 is —CH2—;
R3 is —C(R6)—;
R5 is phenyl substituted with —S(═O)2OH;
R6 is C1-6alkyl;
z is a single bond and a is 1; and
y is a double bond and b is 0.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the pyrazolone compound has formula III

### Claim 3 (depends on 1)

A method according to claim 1, wherein the pyrazolone compound is 1-(4-sulfophenyl)-3-methyl-5-pyrazolone (SPMP).

### Claim 4 (depends on 1)

A method according to claim 1, wherein the cyanogen halide is cyanogen chloride.

### Claim 5 (depends on 1)

A method according to claim 1, wherein the change in light absorbance is quantitatively correlated to the level of nicotine metabolite in the sample.

### Claim 6 (depends on 1)

A kit for detection or measurement of a nicotine metabolite in a sample, the kit comprising:
a cyanogen halide or cyanogen halide-precursor(s);
and
a pyrazolone compound as defined in claim 1.

### Claim 7 (depends on 6)

A kit according to claim 6, comprising reagents KCN, chloramine-T and SPMP.

### Claim 8 (depends on 7)

A kit according to claim 7, wherein the reagents of KCN, chloramine-T and SPMP are present in a KCN:chloramine-T:SPMP ratio of about 1:1:0.2 w/w.