WO2022238739A1

WO2022238739A1 - Disinfectant solution comprising alcohol and chitosan

Info

Publication number: WO2022238739A1
Application number: PCT/IB2021/054772
Authority: WO
Inventors: Diogo MANUEL PEREIRA ALVES; Lígia MARGARIDA JORGE DE FIGUEIREDO; Eduardo DA FONSECA PESTANA ASCENSO PIRES; Frederico CASTELO ALVES FERREIRA; Sandra ISABEL SILVA DAMAS CABO VERDE
Original assignee: Bioceramed. - Cerâmicos Para Aplicações Médicas Sa; Instituto Superior Técnico
Priority date: 2021-05-11
Filing date: 2021-05-31
Publication date: 2022-11-17
Also published as: PT117220A

Abstract

The present invention discloses a solution comprising alcohol and chitosan and/or chitosan derivative(s); wherein the chitosan is of molecular weight from 100 KDa to 500 KDa, preferably from 150 KDa and 350 KDa; wherein the degree of deacetylation of chitosan is at least 50%, preferably from 70 to 99%, even more preferably from 80 to 98%; wherein the ratio between chitosan and/or chitosan derivative:alcohol is from 50:50 to 10:90, preferably from 40:60 to 20:80; and wherein the concentration of chitosan to aqueous/acid phase is at least 0.01%. The present invention also discloses a process for obtaining the solution herein disclosed and its use for disinfecting surfaces and hands.

Description

DISINFECTANT SOLUTION COMPRISING ALCOHOL AND CHITOSAN

Technical Field

[0001] The present disclosure relates to the field of chemistry, more particularly to the field of alcohol based disinfectant solutions and its uses.

Background

[0002] Alcoholic based disinfectant products for the elimination of bacteria, viruses and fungi are well known for their quick efficiency and ease of use in the cleaning of surfaces.

[0003] Chitosan, which is a cationic polymer derived from crustacean shells, for example shrimps, by deacetylation of chitin (Tabea 2003), is well known to fight bacteria and virus, including low pathogenic human coronavi ruses as already demonstrated in in vitro and ex vivo experiments (Milewska 2013).

[0004] However, alcoholic based disinfectant does not offer protection for long periods of time. Alcohol is a volatile product, so it evaporates quickly, offering a protection only for a short period of time, leaving the surface unprotected for recontamination.

[0005] The art has developed a variety of surface cleaning compositions, including some which contains chitosan. For example, U.S. Pat. No. 6,849,586 discloses a hard surface cleaner having a pH below 7.0, comprising of a surfactant; a poly D-glucosamine (chitosan), an acid; a disinfectant; a glycol ether solvent; a cellulosic thickener; and water. Moreover, this invention specifies that the surfactant in in the 0.1-10% weight range and the water is at least 50% by weight of the cleaner.

[0006] In another example, the U.S. Pat. No. 7,244,700 discloses an aqueous cleaning composition for the removal of mould and mildew. The composition includes a water- soluble source of chlorine, a surfactant, chitosan and water and has improved anti- fungal activity. [0007] In another example, the U.S. Pat. No. 2005/0239657, discloses a mixture composition of a chitosan of Mw of 3,000 to 60,000 Da with another chitosan of Mw of 35,000 to 90,000 Da for improving the disease resistance and growth of plants.

[0008] In another example, the U.S. Pat. No. 2014/0314820, discloses a chitosan solution that can be mixed with a silver solution resulting in a cationic complex that results in an antimicrobial solution.

[0009] In another example, the WO2005074947 claims a composition for ameliorating viral infection, the composition comprising an ionic multivalent metal component, a cationic polymer, and a cationic surfactant, wherein the ionic multivalent metal component is zinc chloride, the cationic polymer is chitosan, and the cationic surfactant is benzalkonium chloride or benzethonium.

[0010] As already described, chitosan has been used in several cleaning products, however, none of the disclosures of the prior art previously included a specific combination of chitosan molecular weight and a specific degree of deacetylation to provide an extended disinfecting action on surfaces as the one described in this invention.

[0011] Herein, an alcoholic based disinfectant containing chitosan is provided to improve the effective time.

[0012] These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.

General Description

[0013] The present invention discloses an improved alcohol based disinfectant solution comprising chitosan, which extends the effective time and keeps the surface from recontamination after initial cleaning.

[0014] The present invention relates to a solution comprising alcohol and chitosan and/or chitosan derivatives.

[0015] In an embodiment, the invention relates to a process for obtaining the formulation of the present invention. This process comprises the steps of: dissolving the chitosan in a solution having a pH between 2.8 and 6, and mixing with alcohol in a ratio in which chitosan does not precipitate.

[0016] The pH of acetic acid solution is 2.9 and the pH of dissolved chitosan in acetic acid solution is 3.5. The pH in alcoholic solution is 5.5.

[0017] In an embodiment the alcohol is ethanol or isopropanol.

[0018] In an embodiment the chitosan is chitosan with different molecular weight and deacetylation degree.

[0019] In an embodiment, the initial concentration of chitosan and/or chitosan derivative in the acidic solution is in the range of 0.1 and 1.5%, most preferably between 0.3 and 0.8% for best film formation on different surfaces such as, but not limited to aluminium, plastic and stainless steel.

[0020] In a preferred embodiment the present invention discloses a disinfecting solution comprising alcohol and chitosan and/or chitosan derivative(s); wherein chitosan's molecular weight is from 100 KDa to 500 KDa, preferably 150 to 350 KDa; wherein chitosan and/or chitosan derivative(s) has a degree of deacetylation of above 50%, preferably from 70 to 99%, even more preferably from 80 to 98%; wherein the ratio between chitosan and/or chitosan derivative:alcohol is from 50:50 to 10:90, preferably from 40:60 to 20:80; and wherein the chitosan content is at least 0.01 %.

[0021] In yet another embodiment, the present invention discloses a solution wherein the alcohol is ethanol, isopropanol or mixtures thereof, wherein the content of alcohol is from 60% to 80% (v/v).

[0022] In yet another embodiment, the present invention discloses a solution, wherein the chitosan and/or chitosan derivative is diethylaminoethyl chitosan, trimethyl chitosan, glycol chitosan, chitosan dimer dihydrochloride, methylglycol chitosan, carboxymethyl chitosan, short and large chitosan oligomers, N-dodecylated chitosan or mixtures thereof. [0023] In yet another embodiment, the present invention discloses a solution, wherein the chitosan and/or chitosan derivative has a deacetylation degree from 70 to 99%, preferably from 80 to 98%.

[0024] In yet another embodiment, the present invention discloses a solution, wherein the chitosan content is from 0.01 to 2%, preferably from 0.1 to 1.5%, more preferably from 0.3 to 1% and even more preferably 0.5 to 0.8%.

[0025] In yet another embodiment, the present invention discloses a solution further comprising water in an amount from 20 to 40% (v/v).

[0026] In yet another embodiment, the present invention discloses a solution further comprising acetic acid in an amount from 0.1 to 2% (v/v), preferably 0.1 to 1.5% (v/v).

[0027] In yet another embodiment, the present invention discloses a solution further comprising a surfactant.

[0028] In yet another embodiment, the present invention discloses a solution wherein the concentration of chitosan is 0.5%, chitosan^'s molecular weight is from 190 to 350 KDa and the degree of deacetylation of chitosan is from 75-85%, preferably 83%.

[0029] In yet another embodiment, the present invention discloses a solution diluted with 20% to 50% of a solvent, preferably water.

[0030] The present invention also discloses a process for obtaining the solution of the present invention comprising the steps of: dissolving the chitosan and/or chitosan derivative in a solution with a pH from 2.8 to 6, preferably from 2.9 to 5.5, even more preferably 3.5, to obtain a mixture; mixing the mixture with alcohol in a ratio between chitosan and/or chitosan derivative :alcohol is from 50:50 to 10:90, preferably from 40:60 to 20:80.

[0031] In another embodiment the present invention discloses a process according to the present invention, wherein the initial concentration of chitosan and/or chitosan derivative in the acidic solution is in the range from 0.1 to 1.5%, most preferably from 0.3 to 1%, even more preferably 0.5 to 0.8%. [0032] In another embodiment the present invention discloses a process for applying the solution of the present invention comprising the step of spraying the solution at a surface to be disinfected.

[0033] In another embodiment the present invention discloses a process further comprising the application of ultrasounds to the solution before spraying.

[0034] In another embodiment the present invention discloses a process wherein the surface to be disinfected is aluminium, plastic or steel, particularly stainless steel.

[0035] The use of the solution of the present invention for disinfecting hands is also disclosed.

[0036] The use of the solution of the present invention for disinfecting surfaces is also disclosed.

[0037] The use of the solution of the present invention for disinfecting steel or stainless- steel surfaces is also disclosed.

[0038] The use of the solution of the present invention for disinfecting aluminum, glass or plastic surfaces is also disclosed.

Brief Description of the Drawings

[0039] The following figures provide preferred embodiments for illustrating the disclosure and should not be seen as limiting the scope of invention.

[0040] Figure 1 illustrates a chitosan layer formed by different formulations from low to high chitosan concentration, left to right, respectively. Figure 1 shows several aluminum discs where the layer was tested with a dye, varying the concentration of chitosan in each, from 0.1% to 1% from left to right. The plaque on which the concentration of 0.1% chitosan was used, there are areas where no layer was formed, highlighting the importance of having a chitosan concentration higher than 0.1%.

[0041] Figure 2 illustrates an optical microscopy image of a 1% Chitosan formulation, where there are darker zones represent a higher aggregation of Chitosan.

[0042] Figure 3 illustrates an optical microscopy image of a 0.5% chitosan formulation, where a more homogeneous layer is shown. [0043] Figure 4 illustrates an optical microscopy image of a 0.1% chitosan formulation.

[0044] Figure 5 illustrates a chitosan layer in an aluminium surface.

Detailed Description

[0045] In an embodiment, the formulation of the present invention is a solution comprising an alcohol, preferably ethanol, isopropanol or mixtures thereof. In a preferred embodiment, the content of alcohol is from 60% to 80% by volume.

[0046] In an embodiment the chitosan derivative is diethylaminoethyl chitosan, trimethyl chitosan, glycol chitosan, chitosan dimer dihydrochloride, methylglycol chitosan, carboxymethyl chitosan, short and large chitosan oligomers, N-dodecylated chitosan and mixtures thereof.

[0047] In an embodiment, the formulation of the present invention comprises water and acetic acid to help dissolve the chitosan. Preferably, the content of water is between 20 to 40% (v/v) and content of acetic acid is between 0.1 to 2% (v/v), preferably 0.1 to 1.5% (v/v).

[0048] In an embodiment, chitosan with different molecular weight and deacetylation degrees are used.

[0049] For the purposes of the present invention, the molecular weight range is Small (<190 KDa), Medium (190 to 350 KDa) or Large (>350 KDa), preferably Small and Medium, even more preferably Medium; and the deacetylation degree (DDA) is from 70 and 99%, preferably between 80 and 98%.

[0050] For the purposes of the present invention a degree of deacetylation low is from 75-85%.

[0051] In an embodiment, chitosan content is between 0.01 and 2%, preferably between 0.1 and 1.5%, most preferably between 0.3 and 1%.

[0052] In an embodiment, the solution is used to disinfect a surface. Due to the chitosan coating after the evaporation of alcohol, the surface remains free from contamination even after 24 hours. [0053] In an embodiment, the solution is used as a hand disinfectant. Due to the presence of 60-80% alcohol, it shows a good disinfectant application for hand hygiene.

[0054] In an embodiment, a formulation comprising 0.5 and 0.8 % of chitosan (v/v) coats the surface evenly.

[0055] In an embodiment, chitosan coats different surfaces of several materials including, but not limited to, aluminium, plastic, glass, and stainless steel.

Examples

Example 1

[0056] Different solutions according to the present invention were prepared by mixing the alcohol with chitosan dissolved in water and acetic acid. Chitosan at different concentrations, molecular weights and deacetylation degrees as indicated in Table 1 were used. Regarding experimental evidence obtained until now, small and medium molecular weight chitosan produce a spray with good dispersion.

Table 1

[0057] To test the coating effects of chitosan, the solutions were sprayed on a surface and alcohol was left to evaporate. A red dye was used to show the chitosan coating on said surface. 0.1%, 0.5% and 1% chitosan were used, and the coating effect is shown in Fig. 1. The microscope views of coating effect are shown in Fig.2, Fig. 3 and Fig. 4. 0.5% and 1% chitosan have an uniform coating on the surface while 0.1% is not. Moreover, 0.5% chitosan has a more homogenous film, without cluster formation in comparison to 1% chitosan coating.

[0058] The compositions that did not produce a spray were submitted to additional production steps to improve their spray formation. These steps included the addition of a surfactant to reduce the surface tension. The compositions that did not produce a spray were submitted to an ultrasound equipment, including the composition with surfactant. With the addition of energy to the system (ultrasound), the aggregation of some polymer chains was separated, reducing viscosity and surface tension and enhancing the spray formation. By doing so, compositions 1, 2 and 4 formed a spray with good dispersion.

Example 2

[0059] Furthertests were performed to determine which composition presents the best effect against virus and bacteria.

[0060] Table 2 shows the results regarding antiviral activity for a first set of tests:

A strain of human adenovirus type 5 was used to assess the antiviral activity. This virus is associated with several mild disorders, such as lower respiratory tract and gastrointestinal infections in the elderly and children. The test conditions are described below: Virus: [HAdv-5] = 3x10⁸TCID50/mL Control = Aluminium disk + virus; All tests were done in triplicates.

Table 2- First set of tests against HAdv-5 with 30 min exposure time

[0061] As can be seen from Table 2, small Mw alone combined with high concentration of chitosan (1%), namely Product 3 and 12 did not cause any log reduction on HAdV-5 virus titer, regardless of the degree of deacetylation (DDA). Product 3 had a low DDA, while Product 12 had a high one.

[0062] Product 13 (0.5%, Large Mw and high DDA) induced 1 log reduction on HAdV-5 titer, much better than Product 12 with the same DDA (high).

[0063] Product 14 (0.5%, Medium Mw and high DDA) showed much better virucidal results than the other compositions. A 2 log reduction on HAdV-5 titer was the same as 70% Isopropanol and bleach 15%, which are known as standard efficacious disinfectants. This is an indication that the intermediary concentration, 0.5%, associated with Medium Mw and high DDA showed the best results for a potential disinfectant.

[0064] Table 3 shows a second set of tests after 30 min exposure: Table 3- Second set of tests against HAdv-5 with 30 min exposure time.

[0065] In this second set of experiments (Table 3), it is possible to observe that Product 2 (1%, Medium Mw and low DDA) caused a very small log reduction on virus titer, only 0.5. Showing that Medium Mw associated with high concentration (1%) and low DDA is not as effective as the other combinations.

[0066] Product 5 (0.5%, Medium Mw, low DDA) and 11 (1%, Mw high DDA), both containing Medium Mw showed the best results concerning the log viral reduction. They have however different concentrations and DDA. When compared to composition 14 (0.5%, Medium Mw, high DDA), both 5 and 11 showed much better results.

[0067] When Product 14 and 2 are compared, it is possible to observe that the combination of high concentration (1%) and low DDA leads to lower efficacy.

[0068] Table 4 shows a third set of tests extending the time of exposure: Table 4- Third set of tests including an extended exposure time.

Example 3

[0069] At table 4 the studies have been conducted at 30 min and 24 h exposure time to give an indication of the virucidal efficacy at longer exposure time.

[0070] Both samples, 5 (0.5%, Medium Mw, low DDA) and 15 (0.5%, Small Mw, high DDA) showed better results than bleach after 24 h exposure, which is a clear indication of the long-lasting effect of presence of chitosan after alcohol is evaporated.

[0071] Tables 5, 6 and 7 show the results of tests with ethanol using product 5 and 15 in aluminum, steel, and plastic surfaces respectively using an exposure time of 30 min.

Table 5- Aluminium surface results using an exposure time of 30 min.

Table 6- Steel surface results using an exposure time of 30 min.

Table 7- Plastic surface results using an exposure time of 30 min.

[0072] Product 5 and 15 indicated to have higher efficacy against HAdV-5 (99% efficacy) on steel comparatively to the other surfaces, suggesting a synergistic effect between the samples and steel surface compositions (Example 4). On the other surfaces, aluminum and plastic, the samples also demonstrated virucidal activity with efficacies of 90% or 97%.

[0073] In what concerns antibacterial activity, as it was expected, the highly deacetylated chitosan showed a high efficacy against virus, since the higher the degree of deacetylation (DDA), the more amine groups in the chain, which can be translated in a more active surface. This highlights the surprising effect of the present invention.

[0074] As shown in the state of the art, higher molecular weight chitosan is expected to present more amino groups, while other experiments have also shown that very low molecular weight showed better results against fungi, since the small molecules would enter the structure of microorganisms and disturb its mechanisms (Kendra 1984). Also, chitosan antimicrobial activity is more immediate on fungi and algae than on bacteria (Savard 2002). This highlights the surprising effect of the present invention.

[0075] One would expect that either highly deacetylated chitosan of high molecular weight or highly deacetylated of low molecular weight would be the best candidates for antiviral activity, but the present results however have unexpectedly revealed that the combination of a medium molecular weight with a low DDA and an intermediary concentration of chitosan at least 0.01 % is the best candidate for a prolonged antiviral activity.

[0076] Example 4

[0077] Tables 8, 9 and 10 show the results of tests with ethanol using Compositions 5 and 15 in aluminium, steel, and plastic surfaces respectively using 8h exposure time to give an indication of the virucidal efficacy at longer exposure time in different surfaces.

Table 8- Aluminium surface at 8h exposure time.

Table 9- Steel surface at 8h exposure time.

Table 10- Plastic surface at 8h exposure time.

[0078] The results show that, with an 8h exposure time, the compositions have at least a log reduction of 1, which represent an efficacy of 90%. Comparing the results of Composition 5 and 15 with the 70% ethanol and 15% Bleach both 70% Ethanol and 15% Bleach show no Log reduction, which indicates that these products do not offer an extended protection, contrary to Composition 5 and 15.

[0079] Regarding the efficacy of the Compositions in different surfaces, there is no significant difference between aluminium surface and plastic surface. However, in steel surface, the efficacy of the products increases significantly.

[0080] Example 5

[0081] Tables 8, 9 and 10 show the results of tests with ethanol using Compositions 5 and 15 in aluminium, steel, and plastic surfaces respectively using 24h exposure time to give an indication of the virucidal efficacy at longer exposure time in different surfaces. Table 11- Aluminium surface at 24h exposure time.

Table 12- Steel surface at 24h exposure time.

Table 13- Plastic surface at 24h exposure time.

[0082] The results show that the efficacy of the composition changes according to the surface, like it was proven in the 8h exposure time results. [0083] The immediate effect and 24h results show that the medium molecular weight with a low DDA and an intermediary concentration of chitosan at least 0.01 % is surprisingly one of the best candidate for an immediate and prolonged antiviral activity.

[0084] Example 6

[0085] The composition that was most promising, Composition 5, was used in four sets of tests, according to norms:

[0086] Test 1: Bactericidal activity at 30 minutes in clean (0,3 g/L bovine albumin) and dirty (3 g/L bovine albumin) conditions according to PN-EN 1276:2019-12. The product was diluted to 80%, 50% and 0.01%.

Table 14- PN-EN 1276:2019-12 dirty method results.

Table 15- PN-EN 1276:2019-12 dirty method results

[0087] The results presented in table 14 and table 15 show that Composition 5 diluted to 80% and 50% shows bactericidal activity. The criteria for this method to prove that the product is effective against bacteria is Ig R ≥ 5. As it can be seen, the product diluted to 50% and 80% has lg≥ 5 against all test organisms.

[0088] Test 2: Fungicidal activity at 30 minutes in clean (0,3 g/L bovine albumin) and dirty (3 g/L bovine albumin) conditions according to PN-EN 1650:2019-12. The product was diluted to 80%, 50% and 0.01%

[0089] Table 16- PN-EN 1650:2019-12 dirty method results

[0090] Table 17- PN-EN 1650:2019-12 clean method results

[0091] The results presented in tables 16 and 17 show that the Composition 5 diluted to 80% and 50% shows fungicidal activity against all target organisms. The criteria for this method to prove that the product is effective against fungi is Ig R ≥ 4. As it can be seen, the product diluted to 50% and 80% has lg≥ 4 against all test organisms.

[0092] Test 3: Bactericidal and fungicidal activity at 30 minutes in dirty conditions (3 g/L bovine albumin) and in non-porous surface with Product 5 conditions without mechanical action according to PN-EN 13697+Al:2019-08. Table 18- PN-EN 13697+Al:2019-08 dirty method results

[0093] The results presented in table 18 show the activity of Composition 5 against all test organisms used in tests of tables 14 and 15, both bacteria and fungi. For the product to have activity against fungi, it must have a R ≥ 3 log and to have bactericidal activity it must have a R ≥ 4 log. As it is shown in the results, composition 5 in concentrations of 50% and 80% has a R≥ 4 log for all results except for Aspergillus brasiliensis ATCC 16404, where it has a R of 2.13. These results show that Composition 5 has a good activity against both bacteria and fungi in dirty conditions.

[0094] Test 4: Bactericidal effect against transient microorganisms used in the hygienic procedure of hand disinfection - a single rubbing of 3 mL of the preparation for 30 seconds according to PN-EN 1500:2013-07. Table 19- PN-EN 1500:2013-07 hygienic procedure of hand disinfection results.

[0095] This test was made to prove that Composition 5 can be used as a hand sanitizer.

[0096] Log x is the logarithm of the average value of the initial left and right hand. Log y is the logarithm of the average value of the final left and right hand. Log z is the logarithm reduction, calculated by doing log x - log y. If Log z(P)>3 it means that the product has a good efficacy. The efficacy of the Composition was compared against a reference hygienic handrub (60% 2-propanol).

[0097] The results show that Composition 5 has an efficacy as good as the reference, therefore this product can also be used as a hand sanitizer.

[0098] The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof.

[0099] The above-described embodiments are combinable.

[00100] The following claims further set out particular embodiments of the disclosure. References

[00101] Milewska, A.; Ciejka, J.; Kaminski, K.; Karewicz, A.; Bielska, D.; Zeglen, S.; Karolak, W.; Nowakowska, M.; Potempa, J.; Jan, B. B.; Pyre, K.; Szczubialka, K. Novel polymeric inhibitors of HCoV-NL63. Antiviral Research 97 (2013) 112-121

[00102] Papineau, A. M.; Hoover, D. G.; Knorr, D.; Farkas, D. F. Food Biotechnol. 1991, 5, 45.

[00103] Savard, T.; Beauliu, C.; Boucher, I.; Champagne, C. P. J. Food Prot. 2002, 65, 828.

[00104] Rabea, E. I., Badawy, M. E.-T.; Stevens, C. V.; Smagghe, G.; and Steurbaut W. Chitosan as Antimicrobial Agent: Applications and Mode of Action. Biomacromolecules, Vol. 4, No. 6, 2003.

[00105] Kendra, D. F.; Hadwiger, L. A. Exp. Mycol. 1984, 8, 276.

Claims

CLAIMS 1. Disinfecting solution comprising alcohol and chitosan and/or chitosan derivative(s); wherein chitosan's molecular weight is from 100 KDa to 500 KDa, preferably 150 to 350 KDa; wherein chitosan and/or chitosan derivative(s) has a degree of deacetylation of above 50%, preferably from 70 to 99%, even more preferably from 80 to 98%; wherein the ratio between chitosan and/or chitosan derivative:alcohol is from 50:50 to 10:90, preferably from 40:60 to 20:80; and wherein the chitosan content is at least 0.01 %.

2. Solution according to the previous claim wherein the alcohol is ethanol, isopropanol or mixtures thereof, wherein the content of alcohol is from 60% to 80% (v/v).

3. Solution according to any of the previous claims, wherein the chitosan and/or chitosan derivative is diethylaminoethyl chitosan, trimethyl chitosan, glycol chitosan, chitosan dimer dihydrochloride, methylglycol chitosan, carboxymethyl chitosan, short and large chitosan oligomers, N-dodecylated chitosan or mixtures thereof.

4. Solution according to any of the previous claims, wherein the chitosan and/or chitosan derivative has a deacetylation degree from 70 to 99%, preferably from 80 to 98%. 5. Solution according to any of the previous claims, wherein the chitosan content is from 0.01 to 2%, preferably from 0.1 to 1.5%, more preferably from 0.3 to 1% and even more preferably 0.

5 to 0.8%.

6. Solution according to any of the previous claims further comprising water in an amount from 20 to 40% (v/v).

7. Solution according to any of the previous claims further comprising acetic acid in an amount from 0.1 to 2% (v/v), preferably 0.1 to 1.5% (v/v).

8. Solution according to any of the previous claims further comprising a surfactant.

9. Solution according to claim 1, wherein the concentration of chitosan is 0.5%, chitosan's molecular weight is from 190 to 350 KDa and the degree of deacetylation of chitosan is from 75-85%, preferably 83%.

10. Solution according to the previous claim diluted with 20% to 50% of a solvent, preferably water.

11. Process for obtaining the solution of any one of claims 1-10 comprising the steps of: dissolving the chitosan and/or chitosan derivative in a solution with a pH from 2.8 to 6, preferably from 2.9 to 5.5, even more preferably 3.5, to obtain a mixture; mixing the mixture with alcohol in a ratio between chitosan and/or chitosan derivative :alcohol is from 50:50 to 10:90, preferably from 40:60 to 20:80.

12. Process according to the previous claim, wherein the initial concentration of chitosan and/or chitosan derivative in the acidic solution is in the range from 0.1 to 1.5%, most preferably from 0.3 to 1%, even more preferably 0.5 to 0.8%.

13. Process for applying the solution of any one of claims 1-10 comprising the step of spraying the solution at a surface to be disinfected.

14. Process according to the previous claim further comprising the application of ultrasounds to the solution before spraying.

15. Process according to any of claims 11-14 wherein the surface to be disinfected is aluminium, plastic or steel, particularly stainless steel.

16. Use of the solution of any one of claims 1-10 for disinfecting hands.

17. Use of the solution of any one of claims 1-10 for disinfecting surfaces,

18. Use of the solution of any one of claims 1-10 for disinfecting steel or stainless-steel surfaces.

19. Use of the solution of any one of claims 1-10 for disinfecting aluminum, glass or plastic surfaces.