Method for preserving leuco chromogen-containing aqueous solution

Abstract

The present invention provides a method for preserving a leuco chromogen-containing aqueous solution comprising: adding at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound to a leuco chromogen-containing aqueous solution; a method for stabilizing a leuco chromogen in an aqueous solution comprising: adding at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound to a leuco chromogen-containing aqueous solution; and a liquid reagent comprising a leuco chromogen and at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound.

Claims

1. A method for preserving a leuco chromogen-containing aqueous solution comprising: adding at least one acid compound selected from the group consisting of a first compound, a second compound, a third compound, and a fourth compound to the leuco chromogen-containing aqueous solution, wherein the first compound is selected from the group consisting of alkyl phosphoric acid, polyoxyethylene alkyl ether phosphoric acid, polyoxyethylene polycyclic phenyl ether phosphoric acid, and salts thereof, wherein the second compound is selected from the group consisting of polyoxyethylene alkyl ether fatty acid, N-acylamino acid in which a hydrogen atom of the amino group may be substituted with a substituent, and salts thereof, wherein the third compound is selected from the group consisting of N-acyl taurine in which a hydrogen atom of the amino group may be substituted with a substituent, ?-olefin sulfonic acid, alkyl sulfocarboxylic acid, polyoxymethylene alkyl sulfocarboxylic acid, and salts thereof, wherein the fourth compound is selected from the group consisting of alkyl sulfuric acid, polyoxyethylene alkyl ether sulfuric acid, and salts thereof, and wherein the leuco chromogen comprises a phenothiazine chromogen.

2. The method according to claim 1, wherein the phenothiazine chromogen comprises 10-(carboxymethylaminocarbonyl)-3, 7-bis(dimethylamino)phenothiazine or a salt thereof.

3. A method for stabilizing a leuco chromogen in an aqueous solution comprising: adding at least one acid compound selected from the group consisting of a first compound, a second compound, a third compound, and a fourth compound to a leuco chromogen-containing aqueous solution, wherein the first compound is selected from the group consisting of alkyl phosphoric acid, polyoxyethylene alkyl ether phosphoric acid, polyoxyethylene polycyclic phenyl ether phosphoric acid, and salts thereof, wherein the second compound is selected from the group consisting of polyoxyethylene alkyl ether fatty acid, N-acylamino acid in which a hydrogen atom of the amino group may be substituted with a substituent, and salts thereof, wherein the third compound is selected from the group consisting of N-acyl taurine in which a hydrogen atom of the amino group may be substituted with a substituent, ?-olefin sulfonic acid, alkyl sulfocarboxylic acid, polyoxymethylene alkyl sulfocarboxylic acid, and salts thereof, wherein the fourth compound is selected from the group consisting of alkyl sulfuric acid, polyoxyethylene alkyl ether sulfuric acid, and salts thereof, and wherein the leuco chromogen comprises a phenothiazine chromogen.

4. The method according to claim 3, wherein the phenothiazine chromogen comprises 10-(carboxymethylaminocarbonyI)-3, 7-bis(dimethylamino)phenothiazine or a salt thereof.

5. The method according to claim 1, wherein the first compound is selected from the group consisting of sodium lauryl phosphate, polyoxyethylene tridecyl ether phosphoric acid, polyoxyethylene octyl ether phosphoric acid, polyoxyethylene lauryl ether phosphoric acid, polyoxyethylene lauryl ether phosphate-monoethanolamine salt, and polyoxyethylene styrenated phenyl ether phosphoric acid.

6. The method according to claim 1, wherein the second compound is selected from the group consisting of sodium polyoxyethylene lauryl ether acetate, polyoxyethylene lauryl ether acetic acid, sodium polyoxyethylene tridecyl ether acetate, N-lauroyl-N-methyl-?-alanine sodium, N-palmitoyl sarcosine sodium, sodium N-lauroyl sarcosine, N-myristoyl sarcosine sodium, and N-oleoyl sarcosine.

7. The method according to claim 1, wherein the third compound is selected from the group consisting of N-lauroyl-N-methyl taurine sodium, N-palmitoyl-N-methyl taurine sodium, N-myristoyl-N-methyl taurine sodium, N-stearoyl-N-methyl taurine sodium; ?-olefin sulfonic acid, sodium lauryl sulfoacetate, sodium dioctyl sulfosuccinate, lauryl polyoxyethylene sulfosuccinate disodium, sodium lauryl sulfosuccinate, and alkyl polyoxyethylene sulfosuccinate disodium.

8. The method according to claim 1, wherein the fourth compound is sodium lauryl sulfate or sodium polyoxyethylene lauryl ether sulfate.

9. The method according to claim 1, wherein the leuco chromogen-containing aqueous solution comprises from 0.0001 mmol/L to 2.0 mmol/L of the leuco chromogen.

10. The method according to claim 3, wherein the first compound is selected from the group consisting of sodium lauryl phosphate, polyoxyethylene tridecyl ether phosphoric acid, polyoxyethylene octyl ether phosphoric acid, polyoxyethylene lauryl ether phosphoric acid, polyoxyethylene lauryl ether phosphate-monoethanolamine salt, and polyoxyethylene styrenated phenyl ether phosphoric acid.

11. The method according to claim 3, wherein the second compound is selected from the group consisting of sodium polyoxyethylene lauryl ether acetate, polyoxyethylene lauryl ether acetic acid, sodium polyoxyethylene tridecyl ether acetate, N-lauroyl-N-methyl-?-alanine sodium, N-palmitoyl sarcosine sodium, sodium N-lauroyl sarcosine, N-myristoyl sarcosine sodium, and N-oleoyl sarcosine.

12. The method according to claim 3, wherein the third compound is selected from the group consisting of N-lauroyl-N-methyl taurine sodium, N-palmitoyl-N-methyl taurine sodium, N-myristoyl-N-methyl taurine sodium, N-stearoyl-N-methyl taurine sodium; ?-olefin sulfonic acid, sodium lauryl sulfoacetate, sodium dioctyl sulfosuccinate, lauryl polyoxyethylene sulfosuccinate disodium, sodium lauryl sulfosuccinate, and alkyl polyoxyethylene sulfosuccinate disodium.

13. The method according to claim 3, wherein the fourth compound is sodium lauryl sulfate or sodium polyoxyethylene lauryl ether sulfate.

14. The method according to claim 1, wherein the method comprises adding the first compound to the leuco chromogen-containing aqueous solution.

15. The method according to claim 1, wherein the method comprises adding the second compound to the leuco chromogen-containing aqueous solution.

16. The method according to claim 1, wherein the method comprises adding the third compound to the leuco chromogen-containing aqueous solution.

17. The method according to claim 1, wherein the method comprises adding the fourth compound to the leuco chromogen-containing aqueous solution.

18. The method according to claim 3, wherein the method comprises adding the first compound to the leuco chromogen-containing aqueous solution.

19. The method according to claim 3, wherein the method comprises adding the second compound to the leuco chromogen-containing aqueous solution.

20. The method according to claim 3, wherein the method comprises adding the third compound to the leuco chromogen-containing aqueous solution.

Description

EXAMPLES

(1) Hereinafter, the present invention will be described in more detail with reference to examples, but these examples do not limit the scope of the present invention in any way. In this examples and comparative examples, the reagents and enzymes of the following manufacturers were used.

(2) Bis-Tris (manufactured by Dojindo Molecular Technologies, Inc.), peroxidase (manufactured by TOYOBO CO., LTD.), 30% hydrogen peroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.), and bovine serum albumin (BSA, manufactured by PLOMELAIN).

(3) Phosphoric Acid Compound

(4) Sodium phosphate (manufactured by Wako Pure Chemical Industries, Ltd.)

(5) NIKKOL SLP-N [alkyl phosphoric acid salt (sodium lauryl phosphate); manufactured by Nikko Chemicals Co., Ltd.)]

(6) PLYSURF A212C [polyoxyethylene alkyl ether phosphoric acid (polyoxyethylene tridecyl ether phosphoric acid); manufactured by DKS Co. Ltd.]

(7) PLYSURF A215C [polyoxyethylene alkyl ether phosphoric acid (polyoxyethylene tridecyl ether phosphoric acid); manufactured by DKS Co. Ltd.]

(8) PLYSURF A208F [polyoxyethylene alkyl ether phosphoric acid (polyoxyethylene octyl ether phosphoric acid); manufactured by DKS Co. Ltd.]

(9) PLYSURF A219B [polyoxyethylene alkyl ether phosphoric acid (polyoxyethylene lauryl ether phosphoric acid); manufactured by DKS Co. Ltd.]

(10) PLYSURF DB-01 [polyoxyethylene alkyl ether phosphoric acid (polyoxyethylene lauryl ether phosphate.Math.monoethanolamine salt); manufactured by DKS Co. Ltd.]

(11) PLYSURF AL [polyoxyethylene polycyclic phenyl ether phosphoric acid (polyoxyethylene styrenated phenyl ether phosphoric acid); manufactured by DKS Co. Ltd.]

(12) Carboxylic Acid Compound

(13) NIKKOL AKYPO RLM 45 NV [polyoxyethylene alkyl ether fatty acid salt (sodium polyoxyethylene lauryl ether acetate); manufactured by Nikko Chemicals Co., Ltd.]

(14) NIKKOL AKYPO RLM 100 [polyoxyethylene alkyl ether fatty acid salt (sodium polyoxyethylene lauryl ether acetate); manufactured by Nikko Chemicals Co., Ltd.]

(15) NIKKOL ECTD-3NEX [polyoxyethylene alkyl ether fatty acid salt (sodium polyoxyethylene tridecyl ether acetate); manufactured by Nikko Chemicals Co., Ltd.]

(16) NIKKOL ECTD-6NEX [polyoxyethylene alkyl ether fatty acid salt (sodium polyoxyethylene tridecyl ether acetate); manufactured by Nikko Chemicals Co., Ltd.]

(17) NIKKOL ALANINATE LN-30 [N-acyl-N-alkylalanine salt (N-lauroyl-N-methyl-?-alanine sodium); manufactured by Nikko Chemicals Co., Ltd.]

(18) NIKKOL SARCOSINATE PN [N-acyl sarcosine salt (N-palmitoyl sarcosine sodium); manufactured by Nikko Chemicals Co., Ltd.]

(19) NIKKOL SARCOSINATE OH [N-acyl sarcosine salt (N-oleoyl sarcosine); manufactured by Nikko Chemicals Co., Ltd.]

(20) Sulfonic Acid Compound

(21) NIKKOL LMT [N-acyl-N-alkyl taurine salt (N-lauroyl-N-methyl taurine sodium); manufactured by Nikko Chemicals Co., Ltd.]

(22) NIKKOL MMT [N-acyl-N-alkyl taurine salt (N-myristoyl-N-methyl taurine sodium); manufactured by Nikko Chemicals Co., Ltd.]

(23) NIKKOL PMT [N-acyl-N-alkyl taurine salt (N-palmitoyl-N-methyl taurine sodium); manufactured by Nikko Chemicals Co., Ltd.]

(24) NIKKOL SMT [N-acyl-N-alkyl taurine salt (N-stearoyl-N-methyl taurine sodium); manufactured by Nikko Chemicals Co., Ltd.]

(25) NIKKOL OS-14 (?-olefin sulfonic acid; manufactured by Nikko Chemicals Co., Ltd.)

(26) NIKKOL LSA-F [alkyl sulfocarboxylate (sodium lauryl sulfoacetate); manufactured by Nikko Chemicals Co., Ltd.]

(27) NEOCOL SW-C [alkyl sulfocarboxylic acid salt (sodium dioctyl sulfosuccinate); manufactured by DKS Co. Ltd.]

(28) NEOHITENOL L-30 [polyoxyethylene alkyl sulfocarboxylic acid salt (lauryl polyoxyethylene sulfosuccinate.Math.disodium); manufactured by DKS Co. Ltd.]

(29) Sulfuric Acid Compound

(30) NIKKOL SLS [alkyl sulfuric acid salt (sodium lauryl sulfate); manufactured by Nikko Chemicals Co., Ltd.]

(31) NIKKOL SBL-2N-27 [polyoxyethylene alkyl ether sulfuric acid salt (sodium polyoxyethylene lauryl ether sulfate); manufactured by Nikko Chemicals Co., Ltd.]

Example 1

(32) A DA-67-containing aqueous solution having the following composition was prepared.

(33) TABLE-US-00001 Bis-Tris (pH 6.5) 50 mmol/L DA-67 40 ?mol/L

(34) Phosphoric acid compound (refer to Table 1)

Example 2

(35) A DA-67-containing aqueous solution having the following composition was prepared.

(36) TABLE-US-00002 Bis-Tris (pH 6.5) 50 mmol/L DA-67 40 ?mol/L

(37) Carboxylic acid compound (refer to Table 1)

Example 3

(38) A DA-67-containing aqueous solution having the following composition was prepared.

(39) TABLE-US-00003 Bis-Tris (pH 6.5) 50 mmol/L DA-67 40 ?mol/L

(40) Sulfonic acid compound (refer to Table 1)

Example 4

(41) A DA-67-containing aqueous solution having the following composition was prepared.

(42) TABLE-US-00004 Bis-Tris (pH 6.5) 50 mmol/L DA-67 40 ?mol/L

(43) Sulfuric acid compound (refer to Table 1)

Comparative Example 1

(44) A DA-67-containing aqueous solution having the following composition was prepared.

(45) TABLE-US-00005 Bis-Tris (pH 6.5) 50 mmol/L DA-67 40 ?mol/L

Example 5

(46) (1) Preparation of Sample for Evaluation of DA-67 Stability

(47) The aqueous solution containing DA-67 prepared in Example 1 was irradiated with 1,100 lux of light for 10 hours, and the stability of DA-67 against light was evaluated. The aqueous solution containing DA-67 after light irradiation was used as a sample for evaluation of DA-67 stability.

(48) (2) Preparation of Reagent for DA-67 Stability Assay

(49) A reagent for DA-67 stability assay having the following composition was prepared.

(50) <Reagent for DA-67 Stability Assay>

(51) TABLE-US-00006 Bis-Tris (pH 7.0) 50 mmol/L BSA 0.005%

(52) (3) Evaluation for Stability of DA-67 in DA-67-Containing Aqueous Solution

(53) 120 ?L of reagent for DA-67 stability assay prepared in (2) was added to 30 ?L of the freshly-prepared DA-67-containing aqueous solution in Example 1, and the mixture was heated at 37? C. for 5 minutes. Then, the absorbance (E.sub.freshly-prepared) of the solution was measured at Hitachi 7170S with a main wavelength of 660 nm and a sub-wavelength of 800 nm. Similar measurement was carried out using the reagent for DA-67 stability assay of (2) instead of the freshly-prepared DA-67-containing aqueous solution to determine the absorbance (E.sub.blank). E.sub.blank was subtracted from E.sub.freshly-prepared to determine the absorbance (?E.sub.freshly-prepared) for the freshly-prepared DA-67-containing aqueous solution.

(54) The absorbance (?E.sub.light) for the DA-67-containing aqueous solution after light irradiation was calculated by the same method except for using the DA-67-containing aqueous solution after light irradiation (sample for DA-67 stability evaluation) prepared in (1) instead of the freshly-prepared DA-67-containing aqueous solution in Example 1, as a sample. ?E.sub.freshly-prepared was subtracted from the calculated ?E.sub.light to determine ?E.sub.1 as an indicator of the stability of DA-67 against light. The results are shown in Table 1 below. The closer the value of ?E.sub.1 is to 0, the more suppressed coloring of DA-67 by light irradiation is.

Example 6

(55) ?E.sub.1 was measured in the same manner as in Example 5 except that the DA-67-containing aqueous solution of Example 2 was used instead of the DA-67-containing aqueous solution of Example 1. The results are shown in Table 1 below.

Example 7

(56) ?E.sub.1 was measured in the same manner as in Example 5 except that the DA-67-containing aqueous solution of Example 3 was used instead of the DA-67-containing aqueous solution of Example 1. The results are shown in Table 1 below.

Example 8

(57) ?E.sub.1 was measured in the same manner as in Example 5 except that the DA-67-containing aqueous solution of Example 4 was used instead of the DA-67-containing aqueous solution of Example 1. The results are shown in Table 1 below.

Comparative Example 21

(58) ?E.sub.1 was measured in the same manner as in Example 5 except that the DA-67-containing aqueous solution of Comparative Example 1 was used instead of the DA-67-containing aqueous solution of Example 1. The results are shown in Table 1 below.

(59) TABLE-US-00007 TABLE 1 Compound ?E.sub.1* Comparative 0.101 Example 2 Example 5 Phosphoric acid compound Sodium phosphate (0.04% = 2.5 mmol/L) 0.025 Example 5 Phosphoric acid compound Sodium phosphate (0.08% = 5 mmol/L) 0.023 Example 5 Phosphoric acid compound Sodium phosphate (0.16% = 10 mmol/L) 0.052 Example 5 Phosphoric acid compound NIKKOL SLP-N (0.05%) 0.021 Example 5 Phosphoric acid compound PLYSURF A212C (0.2%) 0.052 Example 5 Phosphoric acid compound PLYSURF A215C (0.5%) 0.077 Example 5 Phosphoric acid compound PLYSURF A208F (0.5%) 0.027 Example 5 Phosphoric acid compound PLYSURF A219B (0.5%) 0.064 Example 5 Phosphoric acid compound PLYSURF DB-01 (0.5%) 0.029 Example 5 Phosphoric acid compound PLYSURF AL (0.5%) 0.091 Example 6 Carboxylic acid compound NIKKOL AKYPO RLM 45 NV (0.5%) 0.049 Example 6 Carboxylic acid compound NIKKOL AKYPO RLM 100 (0.5%) 0.063 Example 6 Carboxylic acid compound NIKKOL ECTD-3NEX (0.1%) 0.048 Example 6 Carboxylic acid compound NIKKOL ECTD-6NEX (0.5%) 0.062 Example 6 Carboxylic acid compound NIKKOL ALANINATE LN-30 (0.5%) 0.035 Example 6 Carboxylic acid compound NIKKOL SARCOSINATE PN (0.05%) 0.026 Example 6 Carboxylic acid compound NIKKOL SARCOSINATE OH (0.25%) 0.030 Example 7 Sulfonic acid compound NIKKOL LMT (0.1%) 0.066 Example 7 Sulfonic acid compound NIKKOL MMT (0.05%) 0.053 Example 7 Sulfonic acid compound NIKKOL PMT (0.05%) 0.055 Example 7 Sulfonic acid compound NIKKOL SMT (0.025%) 0.045 Example 7 Sulfonic acid compound NIKKOL OS-14 (0.1%) 0.063 Example 7 Sulfonic acid compound NIKKOL LSA-F (0.05%) 0.046 Example 7 Sulfonic acid compound NEOCOL SW-C (0.1%) 0.055 Example 7 Sulfonic acid compound NEO HITENOL L-30 (0.5%) 0.048 Example 8 Sulfuric acid compound NIKKOL SLS (0.05%) 0.030 Example 8 Sulfuric acid compound NIKKOL SBL-2N-27 (0.25%) 0.042 *Change of absorbance after light irradiation for 10 hours

(60) As shown in Table 1, in the DA-67-containing aqueous solution comprising at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound, the coloring by light irradiation was remarkably suppressed as compared with the DA-67-containing aqueous solution which does not comprise any compound of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound. From this result, it was clearly found that DA-67 in the DA-67-containing aqueous solution comprising at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound is stable against light, and the DA-67-containing aqueous solution is stably preserved by at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound, and the DA-67 is stabilized in the aqueous solution by at least one acid compound selected from the group consisting of a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a sulfuric acid compound.

INDUSTRIAL APPLICABILITY

(61) The present invention provides a method for preserving a leuco chromogen-containing aqueous solution, a method for stabilizing a leuco chromogen in an aqueous solution, and a liquid reagent comprising a leuco chromogen. The methods and reagent of the present invention are useful for measurement of glycated hemoglobin used for diagnosis of diabetes.