WO2024252035A1 - Disinfectant and sporicidal composition containing a low concentration of glutaraldehyde for cleaning and disinfection of medical, veterinary or industrial equipment - Google Patents

Abstract

Disinfectant and sporicidal composition containing a low concentration of glutaraldehyde for cleaning and disinfection of medical, veterinary or industrial equipment in short times.

Description

Disinfectant and sporicidal composition containing a low concentration of glutaraldehyde for cleaning and disinfecting material for medical, veterinary or industrial use.

Field of the invention:

The present invention relates to a disinfectant and sporicidal composition containing a low concentration of glutaraldehyde, which is useful for cleaning and disinfecting materials used in medical, veterinary or industrial environments, including the food industry. The composition of the present invention is highly effective in eliminating a wide range of bacteria, viruses, fungi and spores.

Description of the state of the art:

Traditionally, 2% alkaline glutaraldehyde has been used as a high-level disinfectant (HLD), normally activating it with bicarbonate at a concentration of approximately 0.3%, obtaining a HLD that was not sporicidal except over very long periods (3-8 h) and also failed to disinfect with M. avium intracellulare unless it was left to act for 45 minutes, more than double the time normally recommended for high-level disinfection with 2% glutaraldehyde, which is 20 minutes.

Furthermore, this composition, due to its high concentration of glutaraldehyde, was toxic or a respiratory irritant, since at 2% it produces vapours that require forced ventilation to prevent their accumulation, which is not always the case in rooms where instrument disinfection is carried out. On the other hand, this composition is not aggressive on hospital material, but if it contained traces of organic matter, it fixed it to the substrate and, on the one hand, altered the instrument and, on the other, caused a reduction in the diameter of narrow lumens, to the point of requiring repair of the fomite. Attempts have been made to reduce the toxicity of glutaraldehyde by using it together with other substances that amplify its action, such as phenolic derivatives, in order to dilute it to 0.25% or even 0.13%, but its effectiveness against mycobacteria was insufficient to be considered DAN, so it is not recommended at concentrations less than 1%, and this concentration still produces toxic effects.

In the state of the art it is possible to find documents such as US5863547, which describes compositions with glutaraldehyde in a concentration closer to that traditionally used, specifically from 1.0% to 2.5%, and which also uses phosphate salts instead of carbonate/bicarbonate as in the present invention.

There are also other documents such as CN105394034 A and CN101579330 A that disclose high-level aqueous disinfectant compositions containing glutaraldehyde between 1% and 1.5%, accompanied by different salts and alcohols.

It is also possible to find some documents that disclose the use of very low concentrations of glutaraldehyde, such as:

US3968250 describes aqueous sporicidal and disinfectant compositions comprising glutaraldehyde in a concentration of from 0.02% to 5%, an alcohol, a sodium bicarbonate buffer and a nonionic or anionic surfactant which is an ethoxylate of linear isomeric alcohols in a concentration between 0.01% and 1%. These compositions are used in conjunction with ultrasonic irradiation over a wide range of frequencies (10 to 850 kHz). The latter greatly complicates and reduces its use in various settings, whether hospital or not, and does not eliminate the toxicity of glutaraldehyde, since in the examples it is preferably used at concentrations greater than 1%, typically 2%.

Document CN111955488A describes aqueous disinfectant compositions comprising 0.1 to 1.5% glutaraldehyde, isopropanol, a salt such as sodium nitrite, isopropyl alcohol and the surfactants dodecyl-dimethyl-benzyl-ammonium chloride and didecyl-dimethyl-ammonium chloride (chlorinated quaternary ammonium compounds). This document discloses that this composition is of low toxicity both for humans and for the environment and that it does not corrode materials such as aluminum, stainless steel and carbon steel.

However, it is still necessary to provide disinfectant and sporicidal compositions with low concentration glutaraldehyde that overcome the disadvantages of those already known in the prior art, and in particular that exhibit a sporicidal DAN in very short times at very low concentrations of glutaraldehyde, which significantly improves their toxicity and reduces their aggressiveness towards the material on which they are applied.

The inventor of the present invention has found that, with the compositions of the invention, it is possible to achieve a sporicidal DAN in very short times, of the order of 10-15 minutes at a concentration of glutaraldehyde of only 0.25%. For this purpose, activators that have demonstrated a synergistic effect with glutaraldehyde are used in combination with glutaraldehyde at a very low concentration. The effectiveness of the compositions of the invention against mycobacteria and other more sensitive (hospital) bacteria, which are found on germ carriers with a rough surface (endodontic files), has been proven. It is completely effective in 10 minutes and is not aggressive on metal or after 7 days of immersion.

Experimental tests have shown that it is possible to use a 1/2 dilution of the above for surface disinfection, i.e. only 0.13% glutaraldehyde, and achieve a 3.6 log reduction of B atrophaeus spores after 30 minutes of contact, something similar to 4000 ppm hypochlorite, but without its toxicity and aggressiveness to metal. If instead of spores we use mycobacteria or bacteria of hospital origin on glass germ carriers (smooth surface model), this synergistic combination completely destroys microbial inocula in just 10 minutes. Detailed description of the invention:

The disinfectant and sporicidal composition of the present invention comprises glutaraldehyde, water, a low concentration alcohol and at least one surfactant. Glutaraldehyde is present in a concentration range of 0.1% to 1% w/v, more preferably 0.1% to 0.5% w/v, and even more preferably about 0.25% w/v. The surfactant is a non-chlorinated cationic quaternary ammonium surfactant, and is present in a concentration range, in use, of 0.1% to 5%, more preferably 1 to 3%. Water is used as a diluent, and is present in sufficient quantity to reach 100% vol.

In the experiments carried out with the composition investigated, it has been shown that it achieves a DAN of sporicidal level that is the highest possible, using B atrophaeus 3M spores in the experiments in very short times, 10-15 minutes at a concentration of glutaraldehyde of only 0.25%. For this purpose, different activators are used that have demonstrated a synergistic effect and non-aggressiveness on the material to be disinfected with glutaraldehyde, a synergistic effect or harmlessness that has not been demonstrated by other activators with which comparative tests have been carried out. Its effectiveness has also been proven against mycobacteria and other (hospital) bacteria that are more sensitive to disinfectants, which are on rough germ carriers (endodontic files), being completely effective in 10 minutes and not aggressive on metal or in 7 days of immersion.

For surface disinfection, a 1/2 dilution of the above can be used (only 0.13% aldehyde) and achieves 3.6 log reduction of B atrophaeus spores after 30 minutes of contact, something similar to 4000 ppm hypochlorite, but without its toxicity and aggressiveness to metal. If mycobacteria or hospital-origin bacteria on glass germ carriers (surface model) are used instead of spores, this synergistic combination completely destroys microbial inocula in just 10 minutes. Accordingly, in a first aspect, the invention is directed to a disinfectant and sporicidal composition comprising:

- water;

- glutaraldehyde at a concentration, in use, between 0.1% w/v and 1% w/v;

- at least one alcohol selected from the group consisting of n-propanol, isopropanol and ethanol, alone or in any combination between them, in a concentration, in use, of 6-20% v/v;

- at least one alkaline or alkaline earth salt in a concentration, in use, between 0.05% w/v and 0.5% w/v, and

- at least one non-chlorinated cationic quaternary ammonium surfactant selected from didecyl methyl polyoxyethyl ammonium propionate in a concentration, in use, of 0.1-5% v/v, or tetradecyl trimethyl ammonium bromide in a concentration, in use, of 0.1-5% w/v.

In a second aspect, the invention is directed to a method for cleaning and disinfecting materials for medical or veterinary use using the above composition, comprising diluting the composition with water to the desired concentration, applying the diluted composition to the surface and/or passages of the material to be disinfected, leaving the composition on the surface for a predetermined time, rinsing the material with water, and drying the material.

In a third aspect, the invention is directed to the use of the above-mentioned composition in the high-level disinfection of medical or veterinary instruments or in the medium/low-level disinfection of surfaces or medical or veterinary instruments or even in the food industry.

In a fourth aspect, the invention is directed to a kit for the in situ reconstitution of the disinfectant and/or sporicidal composition, indicated above, in which the glutaraldehyde is in a first container, the alcohol and the surfactant in a second container, and the (at least one) salt, in a third container.

In a fifth aspect, the invention is directed to a process for the in situ reconstitution of a disinfectant and/or sporicidal composition, indicated above, which includes the step of providing the glutaraldehyde, the alcohol and/or the salt at a concentration higher than that necessary to generate the reconstituted composition, and then diluting them, in situ, to a concentration according to said claims.

Material and methods

For the current experimental tests, a base formulation with 0.25% glutaraldehyde was used (1/100 dilution of 1 ml of 25% Panreac glutaraldehyde), to which one of the following combinations of activators was added:

s+t8+a activator

s+B+a activator

s+T+a activator

s+Q+a activator

s+E+a activator

s+D+a activator

s+I+a activator

The remainder, up to 100 vol%, is sterile distilled water. where: "s" is the mixture of sodium bicarbonate 0.5% w/w and potassium carbonate 0.18% w/w,

"a" is n-propanol, 6 ml per 100 ml (%v/v),

"T8" is tetranil T80 (coco-alkyl-dimethyl-benzyl-ammonium chloride), 1% v/v,

"B" is Bardap 26 (didecyl-methyl-polyoxy-ethyl-ammonium propionate), 1% v/v,

"T" is Tetradecyl-trimethyl ammonium bromide, 0.125% w/v,

"Q" is alkylpropylenediamine-guanidinoacetate, 1% v/v,

"E" is Emal 40 (triethanolamine lauryl sulfate), 2% v/v,

"D" is dodecyl sulfate, 0.1% w/v,

"I" is copolymer of ethylene and propylene oxide, 2% v/v,

The function of the "s" component (salts) is to make glutaraldehyde alkaline in a stable manner. Experimental tests carried out by the inventor have shown that, with the double salt sodium bicarbonate + potassium carbonate, the result is better and the pH is more stable than sodium bicarbonate alone.

As for component "a" (alcohol), its main function is as a diluent of the accompanying surfactant, so that it dissolves better in the water of the final composition. In the experimental tests carried out by the inventor, the alcohols that give the best results are the 3-carbon alcohols, such as isopropyl and n-propyl alcohol.

These formulations were used on:

- Spores of B atrophaeus (former B subtilis), commercial (3M).

- M fortuitum ATCC.

- P aeruginosa obtained from an ICU patient. The first step is to assess the sporicidal effect on commercial spores (3M) and then determine its bactericidal effect on material with a rough surface (endodontic files) or smooth surface (glass) to check its effectiveness on mycobacteria and other more sensitive bacteria. Its aggressiveness on the scalpel with human blood at different times is also studied. All these techniques are described in various works by doctors Herruzo, Vizcaíno and cois, between 1999-2004.

Figures 1 and 2 show the difference in efficacy between classical glutaraldehyde (2% alkaline glutaraldehyde) and solutions with a lower concentration of aldehyde that have been activated, in this case, with the activator s+T+a, which we will call Activatorl (Actil) from now on. The tests in Figure 1 show that a sporicidal action can be achieved in 5 minutes with 1% glutaraldehyde (G+1%), or in 15 minutes if only 0.25% is used (G+0.25%). With mycobacteria (Figure 2) the efficacy is even greater, despite being on a rough germ carrier, since 1% glutaraldehyde (G+1%) only requires 3 minutes to destroy the entire mycobacterial inoculum, 0.5% (G+0.5%) needs 5 minutes and 0.25% (G+0.25%), 10 minutes.

With P. aeruginosa the result is even better, since it destroys the entire inoculum in just 5 minutes with any of the three concentrations of glutaraldehyde tested (1%, 0.5% and 0.25%).

Figures 3 and 4 describe the sporicidal and bactericidal results with 0.25% glutaraldehyde without activator and the 2 activators preferred for their efficacy and safety (Actil=s+T+a and Act¡2=s+B+a), both without and with glutaraldehyde in 5-15 minutes. The sporicidal effect is expressed as a logarithmic reduction of B. atrophaeus spores in 15 minutes and the bactericidal effect (on rough germ carriers) as a logarithmic reduction of M. fortuitum in 10 minutes and of P. aeruginosa in 5 minutes.

In comparative tests carried out by the inventor (not shown), the components s+a together with each of the activators T8 0 Q 0 D 0 E 0 I Tested independently, they either gave lower microbicidal results (3.5-4.5 logios reduced) than the two preferred activators (s+a together with T or B), or were more aggressive on metal instruments (in 24 hours of immersion or less).

Furthermore, Figures 3 and 4 show that activators alone (Actil or Act¡2) or glutaraldehyde without activators (Gluta 0.25%) barely produce a quantifiable microbicidal effect, while synergistic combinations (Gluta 0.25%+Actil or Gluta 0.25%+Act¡2) manage to destroy more than 5 logios (both spores, in 15 min, and mycobacteria, in 10 min). This maximum efficacy occurs even at the low concentration of glutaraldehyde, which is very useful to avoid its toxicity.

Given the great antimicrobial activity obtained, the sporicidal effect was tested again with B. atrophaeus, in a shorter time, 10 min, and only with 0.25% glutaraldehyde, with the two types of activators, namely, Act2 which carries a liquid surfactant (B) and Actl which carries a solid surfactant (T), reaching the following conclusions:

-The version with Actil activator (s+T+a) fails to reduce the 5 logio of B atrophaeus spores in just 10 min, while the version with Act¡2 (s+B+a) does.

-Therefore, the first version of the activator (Gluta 0.25% + Actil) would be left with the indication of 15 min and the second (Gluta 0.25% + Act¡2) could be reduced to only 10 minutes.

It is also verified that classic glutaraldehyde alone (Gluta 0.25%), or the two activators alone (Actil and Act¡2) do not manage to go beyond 2 log of reduced spores in 15 min, and its effectiveness against Mycobacteria or P aeruginosa, in shorter times, is also scarce.

Figure 5 summarizes the sporicidal efficacy of the various components of the liquid activator (Acti2), i.e. components "a", "B" and "s" in a manner independently each one of them together with 0.25% glutaraldehyde, (columns Gluta 0.25%+Acti-a, Gluta 0.25%+Acti-B and Gluta 0.25%+Acti-s for 0.25% glutaraldehyde together with each of the components, a, B and s respectively), or these 3 components of the Act¡2 activator together, but without glutaraldehyde (column Activ a+B+s), to compare them with the combination of glutaraldehyde and the sum of the 3 components of this Act¡2 activator (column Gluta 0.25%+Acti a+B+s), showing the synergistic effect achieved with this combination of 0.25% glutaraldehyde and the Act¡2 activator.

With this latest version of activator (Act¡2 = s+B+a) combined with 0.25% glutaraldehyde, we have also attempted to go one step further: to destroy more than ¹⁰⁶ B. atrophaeus spores, that is, the threshold with which we define "sterilization" by chemical methods. For this purpose, commercial 3M spores were used, which have a certified load of 3-5 million B. atrophaeus spores, and were introduced into the disinfectant. After 15 or 20 min (50% or 100% more than the time for the sporicidal action described above) they were inhibited in a suitable inhibitor and, instead of shaking to release the surviving spores, the germ carrier was introduced into culture broth (Nutrient-Broth, Difeo) for 7 days. If one or more spores had survived, growth would appear in the broth, so the absence of such growth would indicate that no spores survived, i.e. that the level of spore destruction required for sterilization has been achieved.

The result of this test is also excellent. In just 15 minutes the spore load was completely eliminated from the commercial germ carrier, so it can be concluded that in this time the sterilization of the material immersed in this diluted solution of glutaraldehyde (0.25%) with this last activator is achieved.

Furthermore, and this must also be highlighted, in no case, either with the activator s+T+a (Actil) or with this last activator s+B+a (Act¡2), was any aggression obtained to metallic material, not even in 7 days of immersion. (equivalent to 700 15-minute disinfections), so the resulting compounds are very harmless on the disinfected material.

For the disinfection of surfaces, where evaporation of glutaraldehyde may be greater, it could be useful to use an even lower concentration of this product in order not to contaminate the environment. For this reason, the efficacy of the different activators has been tested under these conditions, the most effective being s+B+a, which achieves a 3.6 log reduction of B. atrophaeus spores with only 0.13% aldehyde (1/2 of the previous formula, used as DAN) after a contact of 30 minutes, that is, an efficacy similar to 4000 ppm hypochlorite, but without the toxicity and aggressiveness to metal of this one. If we use mycobacteria or bacteria of hospital origin on glass germ carriers (surface model), this synergistic combination completely destroys the inocula of all of them in 10 minutes.

The disinfectant and sporicidal composition of the present invention can be used for high-level cleaning and disinfection of materials used in medical or veterinary environments, including but not limited to, surgical instruments, medical devices, hospital equipment, veterinary equipment and laboratory equipment, since the composition is effective in killing a wide range of microorganisms, even those that are resistant to other disinfectants, including bacteria, viruses, fungi and spores.

The composition may also contain other ingredients, such as other surfactants, chelating agents and pH adjusters, to enhance its cleaning and disinfecting properties. The composition may be prepared in liquid, aerosol or foam form.

The composition can be obtained at a higher concentration, although by diluting it with water to the desired concentration, depending on the application. The diluted composition can be applied to the surface of the material as a medium-level disinfectant and left for 30 min to allow the elimination of any type of microorganisms. The material can be rinsed with water and dried.

The composition can also be used as a dipping solution (of surfaces or internal passages of instruments), where the material is soaked in the solution for a specific period of time before being removed and allowed to dry.

The composition of the present invention offers several advantages over existing disinfectants and sporicidal compositions. The low concentration of glutaraldehyde used in the composition reduces the risk of toxicity and skin or airway irritation to personnel handling it, making it safer for use by medical and veterinary professionals. But despite that dilution, the composition is also highly effective at killing a wide range of microorganisms, including those that are resistant to other disinfectants, making it an ideal choice for use in medical, veterinary and industrial facilities.

In addition, the surfactant used in the composition helps to improve the wetting and penetration of the solution into the material, thus increasing its effectiveness in killing microorganisms.

In conclusion, the disinfectant and sporicidal composition of the present invention provides an effective and safe means of cleaning and disinfecting materials used in medical or veterinary environments or even in the food industry. The low concentration of glutaraldehyde used in the composition, together with the presence of a surfactant, makes the composition less toxic and more effective than conventional disinfectants. The composition can be used as a dipping solution. The present invention is not limited to the specific embodiments described above, and can be modified and adapted in various ways by those skilled in the art without departing from the scope of the appended claims.

Claims

1. A disinfectant and sporicidal composition comprising: - water; - glutaraldehyde at a concentration, in use, between 0.1% w/v and 1% w/v; - at least one alcohol selected from the group consisting of n-propanol, isopropanol and ethanol, alone or in any combination between them, in a concentration, in use, of 6-20% v/v; - at least one alkaline or alkaline earth salt in a concentration, in use, between 0.05% w/v and 0.5% w/v, characterized in that the composition further comprises at least one non-chlorinated cationic quaternary ammonium surfactant selected from didecyl methyl polyoxy ethyl ammonium propionate in a concentration, in use, of 0.1-5% v/v, or tetradecyl trimethyl ammonium bromide in a concentration, in use, of 0.1-5% w/v. 2. A disinfectant and sporicidal composition according to claim 1, wherein the glutaraldehyde is in a concentration, in use, of between 0.1% w/v and 0.5% w/v. 3. A disinfectant and sporicidal composition according to claim 2, wherein the glutaraldehyde is in a concentration, in use, of about 0.25% w/v. 4. A disinfectant and sporicidal composition according to claim 2, wherein the glutaraldehyde is in a concentration, in use, of about 0.13% w/v. 5. A disinfectant and sporicidal composition according to any of the preceding claims 1 to 4, wherein the alcohol is in a concentration of about 6% v/v. 6. A disinfectant and sporicidal composition according to any of the preceding claims 1 to 5, wherein the alkaline or alkaline earth salt is sodium or potassium carbonate or bicarbonate, in any combination between them. 7. A disinfectant and sporicidal composition according to claim 6, wherein the alkaline or alkaline earth salt is in a concentration, in use, between 0.05% w/v and 0.5% w/v. 8. A disinfectant and sporicidal composition according to any one of the preceding claims, wherein the didecyl methyl polyoxy ethyl ammonium propionate is in a concentration of 1-3% v/v. 9. A disinfectant and sporicidal composition according to any one of the preceding claims, wherein the tetradecyl-trimethyl-ammonium bromide is in a concentration of 0.1-1% W/v. 10. A method for cleaning and disinfecting materials for medical, veterinary or industrial use using the composition of any one of claims 1 to 9, comprising diluting the composition with water to the desired concentration, applying the diluted composition to the surface of the material to be disinfected, leaving the composition on the surface for a predetermined time, rinsing the material with water, and drying the material. 11. The method of claim 10, characterized in that the material is a surgical instrument, endoscope, dental equipment, or other medical or veterinary material. 12. Use of the composition of any of the preceding claims 1-9 in high-level disinfection for medical or veterinary instruments or for medium/low-level disinfection of sanitary surfaces or medical or veterinary instruments. 13. Use of the composition of any of the preceding claims 1-9 in the medium/low level disinfection of surfaces used in the food industry. 14. Kit for the in situ reconstitution of a disinfectant and/or sporicidal composition according to any of the preceding claims 1 to 9, wherein the glutaraldehyde is in a first container, the alcohol and the surfactant in a second container, and the at least one salt in a third container. 15. Kit for the in situ reconstitution of a disinfectant and/or sporicidal composition according to any of the preceding claims 1 to 9, wherein the glutaraldehyde and the alcohol are in a first container and the at least one salt and the surfactant are in a second container. 16. Kit for the in situ reconstitution of a disinfectant and/or sporicidal composition according to any of the preceding claims 1 to 9, wherein the glutaraldehyde and the alcohol are present in a first container, the at least one salt in a second container, and the surfactant in the third container. 17. Procedure for the in situ reconstitution of a disinfectant and/or sporicidal composition according to any of the claims 1 to 9 above, which includes the step of providing the glutaraldehyde, alcohol and/or salt at a concentration higher than that necessary to generate the reconstituted composition, and then diluting them in situ to a concentration according to said claims.