JPH084616B2 - Sterilization confirmation indicator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sterilization confirmation indicator for confirming whether or not sterilization is completed in sterilization treatment with formaldehyde.

2. Description of the Related Art Sterilization with formaldehyde gas is performed for items that cannot be sterilized by heat, such as endoscopes and large-scale medical devices, and those that are difficult to sterilize.

In order to confirm the completion of sterilization with formaldehyde gas, an indicator in which a pH indicator and an amino acid are impregnated in paper or the like is known (US Pat. No. 4,328,182). In this method, the completion of sterilization is confirmed by confirming with a pH indicator that the amino acid has reacted with formaldehyde gas and the pH of the system has shifted to the acidic side. However, in this method, even before the amino acid completely reacts with formaldehyde, discoloration occurs when the pH of the system shifts to acidic, so there is a problem in determining whether or not sterilization is completely performed. is there. Furthermore, since pH changes are reversible, neutralization of excess formalin with ammonia gas at the end of sterilization may restore the original color, making it impossible to distinguish whether or not sterilized. As an indicator utilizing irreversible color change, a method of reacting an azo compound with formaldehyde to utilize the color change of the azo compound has been proposed (US Pat. No. 4,298,569). However, this method does not indicate whether or not sterilization is completely performed, but is merely for confirming whether or not the object to be treated has been subjected to formaldehyde treatment (column 1, columns 45 to 45).
(Line 49) does not indicate whether sterilization has been completed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
It is intended to provide an indicator for irreversibly confirming whether or not sterilization is completed.

Means for Solving the Problems The present invention relates to an indicator for confirmation of sterilization by formaldehyde containing the following components as essential components (i) an azo dye and (ii) a discoloration rate adjusting agent which exhibits acidity by reacting with formaldehyde.

The indicator of the present invention is based on the principle that the reaction between an azo dye and formaldehyde is promoted under acidic conditions. When the indicator comes into contact with formaldehyde gas, first, a color change rate adjusting agent, for example, amino acids, selectively reacts with it, and after the color change rate adjusting agent is consumed and the system becomes acidic, the azo dye reacts with formaldehyde. Irreversibly discolors. Therefore, the color change rate can be controlled by appropriately selecting the type and amount of the color change rate adjusting agent, and the completion of sterilization can be confirmed.

As the azo dye used in the present invention, CI22120 Direct Red 28, CI23500 Direct Red 2, C.
I.22310 Direct Red 1, CI22240 Direct Red 37, CI23380 Direct Orange 7, CI30140 Direct Brown 6, CI30235 Direct Black 38,
CI30245 Direct Black 4, CI36300 Direct Brown 74, CI36030 Direct Brown 25, CI302
80 Direct Green 1, CI35520 Direct Brown 33, CI24895 Direct Yellow 12 and the like are exemplified. Particularly preferably, CI22120 Direct Red 28
(Generic name Congo Red), CI23500 Direct Red 2 (generic name Benzo Purpurin 4B), CI30235 Direct Black 38 (generic name Direct Deep Black Extra), CI30245 Direct Black 4
(Generic name direct deep black RL), CI
36300 Direct Brown 74 (generic name diamine / catechin 3G) and the like.

The amount of azo dye used is the dye used, the required hue,
Depending on the concentration, it is about 0.01 to 20 g per 1 m ^{2 of} coating area, and 0.05 to 5 g for normal applications.

The discoloration speed adjusting agent used in the present invention is a substance which reacts with formaldehyde to exhibit an acidity, and examples of such a substance include amino acids. Amino acids used in the present invention are amino acids, amino acid alkali salts, amino acid acid addition salts and the like, and amino acids include monoamino monocarboxylic acids such as glycine, alanine, valine, leucine and isoleucine, aspartic acid, glutamic acid and the like. Aminodicarboxylic acids, oxyamino acids such as serine and threonine, sulfur-containing amino acids such as cystine and methionine,
Examples thereof include aromatic amino acids such as phenylalanine and tyrosine, and heterocyclic amino acids such as histidine and tryptophan. The amino acid may be β-type, γ-type, etc. as well as α-type. It may be either D type or L type.
Particularly preferred are α-amino acids such as glycine, alanine, valine, leucine, isoleucine, histidine and phenylalanine.

It may be an amino acid, alkali salt type or acid addition salt type. Alkali salts include glutamic acid sodium salt,
Examples of potassium glutamate and acid addition salts include glutamate hydrochloride and glutamate sulfate.

These amino acids may be used alone, or if necessary, a plurality of amino acids may be appropriately combined and used.

Amino acids can be used in the same liquid because they do not discolor when mixed with an azo dye.

The amount of the discoloration speed adjuster used varies depending on the type of discoloration speed adjuster and the required sterilization conditions, but when treated at a formaldehyde concentration of 3,000 to 15,000 ppm at a temperature of 40 to 60 ° C for 30 minutes, the coating area per amino acid is 1 m ² About 0.01 to 2g is required.

If desired, the indicator of the present invention is not discolored by other components such as a binder or formalin, and is an auxiliary dye for further clarifying the discoloration of the azo dye, a solvent for dissolving or dispersing the azo dye or amino acid, and a thickening agent. Agents and binder resins.

The indicator of the present invention can take various forms. Specifically, it is an ink composition, a coating composition, an impregnated sheet, a label, a card, a bag-making product or the like.

The ink composition is obtained by dissolving or dispersing the azo dye and the color change speed adjusting agent in a suitable solvent and vehicle. The vehicle blended in the ink composition may be one that does not deteriorate in a sterilizing atmosphere with formaldehyde but permeates formaldehyde and is brought into contact with a discoloration speed adjusting agent or an azo dye. Examples of such vehicle resins include polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, ethyl cellulose, gelatin, acrylic ester resin, polyvinyl butyral and the like. Solvents are water, alcohols (methanol,
Ethanol, isopropyl alcohol), ketones (acetone, methyl ethyl ketone), ethers (ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether),
Examples thereof include esters (ethyl acetate, butyl acetate) and the like. The ink composition may be used for printing a label or the like, or may be impregnated with a felt-tip pen or the like, a predetermined item may be written on the label, and the label may be attached to an article to be sterilized.

The coating composition can be obtained by dispersing an azo dye and a discoloration speed adjusting agent in an appropriate vehicle resin. Examples of such binder resins are shellac, rosin, ester gum,
There are linseed oil, phenol resin, butyral resin, urethane resin, etc.

In use, the coating composition is applied to a predetermined portion of the article to be sterilized, applied to a panel or plate attached to the article, or when the article itself does not need to be sterilized,
It is used by applying it to another sterilization display panel such as one inserted in the sterilizer.

The impregnated sheet is obtained by impregnating paper, felt, cloth, non-woven fabric or the like with an azo dye or a discoloration speed adjusting agent. The back surface of the sheet may be coated with an adhesive or the like and sterilized and may be used by sticking it on the instrument.

 Hereinafter, examples will be described.

Example 1 Adjustment of sterilization indicator The composition of the following formulation was thoroughly stirred and mixed to obtain a brown uniform solution.

Weight part Primula Turkis Blue GL ^{* 1} (Hodogaya Chemical Co., Ltd.) 2.0 CI23500 Direct Red 2 (Brand name: Benzoperpurin-4B ^{* 2} Nippon Kayaku) 6.0 Glycine 1.2 Polyvinyl alcohol (20% aqueous solution) 30.0 Water 60.8 Total 100.0 This was applied to high-quality paper and dried to obtain an indicator having a coating amount of 3 g / m ² .

Sterilization test A syringe contaminated with B. Subtilis bacteria (spore volume 10 ⁶ ), together with the above indicator (10 × 10 mm ² ), was placed in 3 dicators, and the RH72 vaporized at 40 ° C inside this dicator.
%, Formaldehyde content 4.0 mg / l Replace with gas, temperature 40
30 minutes (A), 1 hour (B), 2 hours (C) and 3 at ℃
Hold for time (D). The (A) indicator does not show discoloration, the (B) indicator is slightly discolored,
The indicators of (C) and (D) turned blue.

A syringe was taken out from each desiccator under a sterile environment and individually immersed in 80 ml of sterile water. Immersion water was flowed in a standard manner on a standard agar medium on a petri dish in an amount of 0.1 ml. Similarly, 10 for each of (A), (B), (C) and (D)
Individual petri dishes were obtained and these were cultured at 37 ° C for 7 days. B.
The observed sheer numbers of Subtilis colonies are shown below.

Examples 2 and 3 Preparation of Sterilization Indicator The compositions having the following formulations were sufficiently mixed by stirring to obtain brown uniform solutions.

As Comparative Example 1, a glycine-free product was prepared.
Each solution obtained was applied to high-quality paper and dried,
It was 3 g / m ² .

This indicator was subjected to a sterilization test simultaneously with Example 1 and the following results were obtained.

In Comparative Example 1, a normal sterilization time (from (C) to
It did not show a clear change even after (D)) and could not be used as an indicator.

Examples 4, 5 and 6 The compositions having the following formulations were thoroughly mixed with stirring to obtain brown uniform solutions.

Each solution obtained was applied to a high-quality paper, dried, and the coating amount was 4 g / m.
Got ² indicators.

[Sterilization test] A syringe contaminated with B. Stearothermophilus bacterium (spore amount 10 ⁴ ) was placed in 3 desiccators together with the above indicator (10 × 10 mm ² ), and the RH 63% and formaldehyde content vaporized at 50 ° C were stored in the desiccator. The atmosphere was replaced with a gas of 4.2 mg / l, and the temperature was kept at 50 ° C. for 1 hour (E), 2 hours (F), 3 hours (G), and 4 hours (H).

The syringe was taken out from each desiccator under a sterile environment and separately immersed in 80 ml of sterile water.

Immerse water on a standard agar medium on a petri dish by a conventional method.
0.1 ml was poured. Similarly, 10 petri dishes were obtained for each of (E), (F), (G) and (H).
Cultured for a day.

The observed petri dish number of the colony of B. Stearothermophilu and the discoloration degree of the indicator are shown below.

Effect of the Invention When the indicator of the present invention is used, completion of sterilization with formaldehyde can be confirmed by discoloration, and discoloration is irreversible, so it is easy to confirm whether or not it is a sterilized instrument. Further, since the indicator components are not used mutually, it can be a one-liquid indicator.

Claims (1)

[Claims] 1. An indicator for confirmation of sterilization by formaldehyde, which comprises the following components as essential components: (i) an azo dye and (ii) a discoloration rate adjusting agent which reacts with formaldehyde to exhibit acidity.