# US 9,039,878 B2 · Mediator for test sensor

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- Number: US 9,039,878 B2
- Document ID: US9039878B2
- Status: Granted
- Kind: B2
- Application number: 13/717,024
- Filed: 2012-12-17
- Published: 2013-05-23
- Granted: 2015-05-26
- Earliest claimed: 2007-12-10
- Assignees: Bayer HealthCare LLC
- Applicants: Bayer Healthcare LLC
- Inventors: Karen L. Marfurt; Henry C. Arndt
- Web page: https://patentgrep.com/patent/US9039878B2

## CPC

- C07D 279/20: with hydrogen atoms directly attached to the ring nitrogen atom
- C07D 265/38: [b, e]-condensed with two six-membered rings
- C07D 279/18: [b, e]-condensed with two six-membered rings
- C12Q 1/004: {mediator-assisted}
- G01N 27/3271: {Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood (amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001)}
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- 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)

## Abstract

A method of forming a 3-phenylimino-3H-phenothiazine or a 3-phenylimino-3H-phenoxazine mediator includes providing a first reactant including phenothiazine or phenoxazine, providing a first solvent, providing a second reactant and providing a second solvent. The first reactant, first solvent, second reactant and second solvent are combined to form a reactants solution. Sodium persulfate is added to the reactants solution to couple the first and second reactants resulting in a reaction solution including the 3-phenylimino-3H-phenothiazine or the 3-phenylimino-3H-phenoxazine mediator.

## Claims

### Claim 1

A test sensor including a base, the base including an enzyme adapted to react with an analyte, and a mediator, the mediator having a background current being less than 200 nA after being exposed to a temperature of 50° C. for a duration of two weeks and further including a neutralizing agent, the neutralizing agent being present in an amount to obtain a pH in a range below 7 to about 5.5 in a mediator solution.

### Claim 2 (depends on 1)

The test sensor of claim 1 wherein the neutralizing agent is sodium hydroxide.

### Claim 3 (depends on 1)

The test sensor of claim 1 wherein the neutralizing agent is sodium bicarbonate.

### Claim 4 (depends on 1)

The test sensor of claim 1 further including a buffer.

### Claim 5 (depends on 4)

The test sensor of claim 4 wherein the buffer is sodium phosphate.

### Claim 6 (depends on 1)

The test sensor of claim 1 wherein the test sensor is an electrochemical test sensor.

### Claim 7 (depends on 1)

The test sensor of claim 1 wherein the test sensor is an optical test sensor.

### Claim 8 (depends on 1)

The test sensor of claim 1 wherein the mediator is a 3-phenylimino-3H-phenothiazine mediator.

### Claim 9 (depends on 1)

The test sensor of claim 1 wherein the neutralizing agent is sodium phosphate.

### Claim 10 (depends on 1)

The test sensor of claim 1 wherein the neutralizing agent is present in an amount to obtain a pH in a range below 7 to about 6 in the mediator solution.

### Claim 11 (depends on 1)

The test sensor of claim 1 wherein the neutralizing agent is present in an amount to obtain a pH of from about 5.5 to about 6 in the mediator solution.

### Claim 12

A test sensor including a reagent, the reagent including a mediator and a neutralizing agent, the reagent having a % bias being within 2.4% between 0 and 400 mg/dL of glucose after being exposed to a temperature of 50° C. for a duration of two weeks, the neutralizing agent being present in an amount to obtain a pH in a range below 7 to about 5.5 in a mediator solution.

### Claim 13 (depends on 12)

The test sensor of claim 12 wherein the reagent includes a 3-phenylimino-3H-phenothiazine mediator.

### Claim 14 (depends on 12)

The test sensor of claim 12 wherein the reagent further comprises glucose dehydrogenase (GDH) and a cellulose polymer.

### Claim 15 (depends on 12)

The test sensor of claim 12 wherein the test sensor includes electrodes.

### Claim 16 (depends on 12)

The test sensor of claim 12 wherein the % bias is within 1.8% between 0 and 100 mg/dL of glucose after being exposed to a temperature of 50° C. for a duration of two weeks.

### Claim 17 (depends on 12)

The test sensor of claim 12 wherein the neutralizing agent is present in an amount to obtain a pH in a range below 7 to about 6 in the mediator solution.

### Claim 18 (depends on 12)

The test sensor of claim 12 wherein the neutralizing agent is present in an amount to obtain a pH of from about 5.5 to about 6 in the mediator solution.

### Claim 19

A test sensor including electrodes and a reagent including glucose dehydrogenase (GDH), a mediator and a neutralizing agent, the reagent having a % bias being within 2.4% between 0 and 400 mg/dL of glucose after being exposed to a temperature of 50° C. for a duration of two weeks, the neutralizing agent being present in an amount to obtain a pH in a range below 7 to about 5.5 in a mediator solution.

### Claim 20 (depends on 19)

The test sensor of claim 19 wherein the reagent further includes 3-phenylimino-3H-phenothiazine mediator and a cellulose polymer.

### Claim 21 (depends on 19)

The test sensor of claim 19 wherein the % bias is within 1.8% between 0 and 100 mg/dL of glucose after being exposed to a temperature of 50° C. for a duration of two weeks.

### Claim 22 (depends on 19)

The test sensor of claim 19 wherein the neutralizing agent is present in an amount to obtain a pH of from about 6 to about 7 in the mediator solution.

### Claim 23 (depends on 19)

The test sensor of claim 19 wherein the neutralizing agent is present in an amount to obtain a pH of from about 5.5 to about 6 in the mediator solution.

### Claim 24

A test sensor including a base, the base including an enzyme adapted to react with an analyte, and a 3-phenylimino-3H-phenothiazine mediator, the 3-phenylimino-3H-phenothiazine mediator having a background current being less than 200 nA after being exposed to a temperature of 50° C. for a duration of two weeks and further including a neutralizing agent, the neutralizing agent being present in an amount to obtain a pH in a range below 7 to about 6 in a mediator solution.

### Claim 25 (depends on 24)

The test sensor of claim 24 wherein the neutralizing agent is present in an amount to obtain a pH of from about 5.5 to about 6 in the mediator solution.

### Claim 26 (depends on 24)

The test sensor of claim 24 wherein the neutralizing agent is sodium hydroxide.

### Claim 27 (depends on 24)

The test sensor of claim 24 wherein the neutralizing agent is sodium bicarbonate.

### Claim 28 (depends on 24)

The test sensor of claim 24 wherein the neutralizing agent is sodium phosphate.

### Claim 29 (depends on 24)

The test sensor of claim 24 further including a buffer.

### Claim 30 (depends on 29)

The test sensor of claim 29 wherein the buffer is sodium phosphate.

### Claim 31 (depends on 24)

The test sensor of claim 24 wherein the test sensor is an electrochemical test sensor.

### Claim 32 (depends on 24)

The test sensor of claim 24 wherein the test sensor is an optical test sensor.

### Claim 33

A test sensor including a base, the base including an enzyme adapted to react with an analyte, and a 3-phenylimino-3H-phenothiazine mediator, the 3-phenylimino-3H-phenothiazine mediator having a background current being less than 200 nA after being exposed to a temperature of 50° C. for a duration of two weeks and further including a neutralizing agent, the neutralizing agent being present in an amount to obtain a pH of about 6.1 in a mediator solution.

### Claim 34 (depends on 33)

The test sensor of claim 33 wherein the neutralizing agent is sodium hydroxide.

### Claim 35 (depends on 33)

The test sensor of claim 33 wherein the neutralizing agent is sodium bicarbonate.

### Claim 36 (depends on 33)

The test sensor of claim 33 wherein the neutralizing agent is sodium phosphate.

### Claim 37 (depends on 33)

The test sensor of claim 33 further including a buffer.

### Claim 38 (depends on 37)

The test sensor of claim 37 wherein the buffer is sodium phosphate.

### Claim 39 (depends on 33)

The test sensor of claim 33 wherein the test sensor is an electrochemical test sensor.

### Claim 40 (depends on 33)

The test sensor of claim 33 wherein the test sensor is an optical test sensor.