BIOCIDAL FORMULATION

Abstract

A dry biocidal absorbent composition comprises an interspersed mixture of a dry absorbent silicate mineral material and a dry biocide. The absorbent silicate mineral material may comprise expanded perlite and/or exfoliated vermiculite. The biocide may comprise sodium dichloroisocyanurate or a hydrate thereof. The composition may be used for cleaning up a bodily spill from a floor or other surface.

Claims

1. A dry biocidal absorbent composition comprising an interspersed mixture of a dry absorbent silicate mineral material and a dry biocide.

2. A composition as claimed in claim 1, wherein the absorbent silicate mineral material comprises at least one of expanded perlite and exfoliated vermiculite.

3. A composition as claimed in claim 2, wherein the absorbent silicate mineral material is expanded perlite.

4. A composition as claimed in claim 1, wherein the biocide is an oxidising biocide.

5. A composition as claimed in claim 1, wherein the biocide is a halogenated biocide.

6. A composition as claimed in claim 5, wherein the halogenated biocide comprises an alkali metal halocyanurate.

7. A composition as claimed in claim 6 wherein the alkali metal halocyanurate comprises sodium dichloroisocyanurate or a hydrate thereof.

8. A composition as claimed in claim 1, wherein the biocide comprises bromochlorodimethylhydantoin.

9. A composition as claimed in claim 1, wherein the biocide comprises a mixture of sodium percarbonate and tetraacetylethylenediamine.

10-13. (canceled)

14. A method of using a dry biocidal absorbent composition comprising the following steps: applying a quantity of a composition comprising an interspersed mixture of a dry absorbent silicate mineral material and a dry biocide; leaving the formulation in place for a period of time to form a residue; and removing the residue for disposal.

15. A container containing a quantity of the composition according to claim 1.

16. A method of preparing a composition, comprising mixing a dry biocide with a dry absorbent silicate mineral.

17. The method of claim 14, wherein the applying step comprises applying the quantity of the composition onto a bodily spill on a floor or other surface.

18. The method of claim 14, wherein the applying step comprises applying the quantity of the composition on surfaces of a bin to sanitize the bin.

19. The method of claim 14, wherein the applying step comprises applying the quantity of the composition onto surfaces in areas where livestock are or have been kept or confined as a cleaning composition or disinfectant.

20. The method of claim 14, wherein the applying step comprises applying the quantity of the composition onto land or ground as a sanitizer.

21. The method of claim 16, wherein the absorbent silicate mineral comprises expanded perlite.

22. The method of claim 16, wherein the biocide comprises a halogenated biocide.

23. The method of claim 22, wherein the halogenated biocide comprises an alkali metal halocyanurate.

24. The method of claim 23, wherein the alkali metal halocyanurate comprises sodium dichloroisocyanurate or a hydrate thereof.

Description

EXAMPLES

[0047] The present invention will now be described in further, non-limiting, detail by summarising some of the experiments which have been carried out.

[0048] First Test Series

[0049] In a first test, 25 ml of organism (bacterial or mould) suspension was added to 25 ml of 3.0 g/l bovine albumin, simulating a bodily spill. This was left for 2 minutes. The chosen biocide (sodium dichloroisocyanurate; tetraacetylethylenediamine, known as TAED, +sodium percarbonate; or 1-Bromo-3-chloro-5,5-dimethylhydantoin, known as BDCMH) was added to the flask and shaken gently for approximately 5 seconds. The flask was left for the remainder of the 1 minute contact time, before a 1 ml portion of the test mixture was removed and neutralised. This was diluted in neutraliser and all dilutions were plated using the appropriate media in order to measure the remaining concentration of viable bacteria of fungal cells (colony forming units, or cfu).

[0050] The results of this test series are presented in the following Table 1. In this table Vc=viable count; N=number of cfu/ml in the bacterial test suspension; Q=quotient of control of weighted mean counts; Nv=number of cfu/ml in the bacterial validation suspension; A=number of cfu/ml in the experimental conditions validation; B=number of cfu/ml in the neutraliser toxicity validation; C=number of cfu/ml in the dilution-neutralisation validation; Na=number of cfu/ml in test mixture after contact time; R=reduction in viability (Log 10). Furthermore, as the upper limit for counting bacterial plates is 330 cfu; counts over this are entered as >330. The upper limit for counting fungal plates is 165 cfu, and counts above this are entered as >165.

[0051] The above Table 1 presents results of these tests on bacterial strains Staphylococcus aureus and Pseudomonas aeruginosa, as well as on mould strain Aspergillus brasiliensis. The biocidal effect of the biocide is shown in the number Na of colony forming units (cfu) per ml after contact time (see second last row in the table for each test organism), compared to the initial number N of cfu (see column entitled Bacterial Test Suspension (N)). A higher effect results in a lower value of Na. This can also be expressed in a logarithmic scale, represented by R, the reduction in viability (see last row in the table for each test organism). The data in the Table 1 clearly show that the effect of the biocide on bacterial organisms is significantly enhanced through the presence of perlite.

[0052] For example, for the two bacterial strains, Staphylococcus aureus and Pseudomonas aeruginosa, the reduction in viability figures (R expressed in a log scale) given in the table show that TAED+sodium percarbonate alone has effectively no effect (R=−0.08 for Staphylococcus aureus; R=−0.06 for Pseudomonas aeruginosa). The addition of perlite has a dramatic effect on the effect (R=5.40 for Staphylococcus aureus, R=4.74 for Pseudomonas aeruginosa). The effect of BDCMH on its own is better (R=1.92 for Staphylococcus aureus; R=1.00 for Pseudomonas aeruginosa) than TAED+percarbonate, but again improves dramatically with the addition of perlite (R=5.83 for Staphylococcus aureus; R=4.55 for Pseudomonas aeruginosa).

[0053] A clear improvement in the sterilizing effect of sodium dichlorisocyanurate on the mould strain Aspergillus brasiliensis is also demonstrated with the addition of perlite (R=2.84 without perlite; R=4.34 with perlite).

[0054] Second Test Series

[0055] In a second test, the antimicrobial action of a dry formulation was tested. A small amount of a quaternary ammonium compound, specifically in this case benzalkonium chloride (0.36 ml of a 50% solution onto 100 grams of perlite) was added to expanded perlite such that the quaternary ammonium compound was completely absorbed and the perlite was dry. The dry formulation was then prepared by mixing this dry perlite with dry sodium dichloroisocyanurate to produce the dry biocidal formulation. A dry biocidal formulation is produced in this manner with three different proportional compositions: Level 1, comprising 1% (w/w) sodium dichloroisocyanurate to 99% (w/w) treated perlite; Level 2, comprising 10% (w/w) sodium dichloroisocyanurate to 90% (w/w) treated perlite; and Level 3, comprising 20% (w/w) sodium dichloroisocyanurate to 20% (w/w) treated perlite.

[0056] The essential components of the formulation are the solid silicate mineral material (here, expanded perlite) and the solid biocide (here, sodium dichloroisocyanurate). The addition to the perlite of a further material, e.g. a quaternary ammonium compound, in a preceding step, is an optional feature; the invention is effective with or without this feature.

[0057] The biocidal effect of the above described dry formulations was tested on a variety of surfaces (viz. wood, ceramic, vinyl), each of which was cleaned and disinfected according to standardised procedures prior to testing.

[0058] Cultures of a variety of test organisms, as detailed below, were prepared. Each of these cultures was supplied to a surface by pipetting a 5 ml mixture of the organism and a suspension of a mixture of bovine albumin (3.0 g/l) and sheep erythrocytes (3.0 ml/L). The mixture of bovine albumin (3.0 g/l) and sheep erythrocytes simulates a bodily spill. For tests involving viruses, a medium/serum solution was also included in the mixture. In this manner the test surfaces were prepared. Tests were performed for three different contact times (1 min, 5 mins and 10 mins). For each of these contact times, each test surface was prepared in duplicate.

[0059] Tests were performed for each of the following organisms prepared in culture: [0060] Staphylococcus aureus (bacterial strain) [0061] Pseudomonas aeruginosa (bacterial strain) [0062] Candida albicans (yeast strain) [0063] Aspergillus brasiliensis (conidiospores) [0064] Bacillus subtilis ATCC 6633 (bacterial spore strain) [0065] Adenovirus 5 [0066] Poliovirus 1 [0067] Murine parvovirus

[0068] To test the sterilizing effect of the dry perlite formulation, a pre-weighed amount of the perlite formulation was added to each test surface and then left there for the contact time. At the end of the contact time, the surface was scraped to remove the residue. Organisms still surviving on the surface were then recovered using diluent and swabbing. A standard assay procedure was then used to determine the concentration of surviving organisms.

[0069] Second Test Series Results

[0070] A logarithmic scale is used in the presentation of the results. For example, when a disinfection reduces 10.sup.8 bacteria to 10.sup.2 bacteria, this is a logarithmic reduction of 6; when a disinfection reduces 5×10.sup.7 fungal spores to 8×10.sup.3 fungal spores this is a logarithmic reduction of 3.79.

[0071] The results of the second test series are shown in the following tables. Each table represents surface test results for strains at three concentrations (Level 1=1.0% W/W sodium dichloroisocyanurate; Level 2=10.0% W/W sodium dichloroisocyanurate; Level 3=20.0% W/W sodium dichloroisocyanurate) for 1 minute, 5 minutes and 10 minutes contact time at 20° C. on three representative surfaces. Results are expressed by the mean log reduction and standard deviation (s.d.) (N=2).

[0072] The first two sets of test results in this series relate to antibacterial activity.

[0073] Staphylococcus aureus, Perlite+Sodium Dichloroisocyanurate

TABLE-US-00001 TABLE 2 Contact Wood wood ceramic ceramic vinyl vinyl Level time Mean s.d mean s.d mean s.d Level 1 1 min 2.40 0.08 2.53 0.24 2.61 0.35 5 min 2.21 0.08 2.42 0.02 2.46 0.06 10 min  2.65 0.70 2.42 0.37 3.29 1.00 Level 2 1 min 2.11 0.69 2.61 0.13 3.05 0.05 5 min 2.69 0.39 3.58 0.57 3.42 0.58 10 min  2.98 0.04 3.74 0.28 4.12 1.03 Level 3 1 min 2.60 0.23 3.98 0.26 2.72 0.42 5 min 4.26 0.11 4.88 0.24 4.54 2.91 10 min  4.27 0.14 6.16 2.51 4.55 0.38

[0074] The above results show that a log reduction of 4 logs is achieved for the level 3 concentration of Staphylococcus aureus on all surfaces tested at both 5 minute and 10 minute contact times. This indicates a clearly effective activity against bacteria. Lower concentration levels (level 2 on the vinyl surface with 10 minutes contact time) and lower contact time (level 3 on ceramic surface with 1 minute contact time) experiments approached this performance. These results show that the formulation reduces the bacterial count of Staphylococcus aureus to an effective extent.

[0075] Pseudomonas aeruginosa, Perlite+Sodium Dichloroisocyanurate

TABLE-US-00002 TABLE 3 Contact Wood Wood ceramic ceramic Vinyl vinyl Level time Mean s.d mean s.d Mean s.d Level 1 1 min 2.54 0.07 3.54 0.02 2.41 0.08 5 min 2.60 0.07 3.80 0.86 2.67 0.02 10 min  2.54 0.20 3.54 0.26 2.58 0.03 Level 2 1 min 2.59 0.10 4.39 0.15 2.47 0.16 5 min 3.37 0.20 4.61 1.27 2.87 0.06 10 min  3.75 0.14 5.00 0.52 4.82 2.18 Level 3 1 min 5.07 1.22 5.97 0.35 4.20 1.79 5 min 6.52 1.43 7.11 0.83 5.75 0.65 10 min  5.98 2.20 6.20 0.14 6.81 0.08

[0076] The level 3 concentration provides a 4 log reduction in the activity of Pseudomonas aeruginosa on all three surfaces tested and within 1 minute contact time. The level 2 concentration matches this sterilisation performance on ceramic, again for all three tested contact times, and approaches or exceeds this performance for this bacteria for 10 minutes contact time on all surfaces. These results show that the formulation reduces the bacterial count of Pseudomonas aeruginosa to an effective extent.

[0077] The next two sets of test results relate to fungicidal activity.

[0078] Candida albicans, Perlite+Dichloroisocyanurate

TABLE-US-00003 TABLE 4 Contact wood wood ceramic ceramic vinyl vinyl Level time mean s.d mean s.d mean s.d Level 1 1 min 1.50 0.28 2.56 0.17 2.16 0.07 5 min 1.32 0.24 1.91 0.72 1.75 0.20 10 min  1.71 0.11 1.92 0.44 1.86 0.24 Level 2 1 min 1.81 0.10 2.76 0.14 3.10 0.71 5 min 2.79 1.73 2.67 0.27 3.25 1.01 10 min  1.91 0.71 3.09 1.50 2.46 0.01 Level 3 1 min 1.97 0.97 2.84 1.17 2.47 0.17 5 min 2.08 1.17 2.43 0.03 2.14 0.15 10 min  1.79 0.31 2.39 0.71 3.06 0.64

[0079] Aspergillus brasiliensis (Conidiospores), Perlite+Dichloroisocyanurate

TABLE-US-00004 TABLE 5 Contact wood wood ceramic ceramic vinyl vinyl Level time mean s.d mean s.d mean s.d Level 1 1 min 1.56 0.37 1.94 0.12 0.96 0.41 5 min 1.18 0.21 2.21 0.18 0.74 0.15 10 min  1.58 0.30 2.11 0.11 0.78 0.14 Level 2 1 min 1.48 0.49 2.12 0.28 1.06 0.34 5 min 1.52 0.29 2.29 0.57 1.33 0.01 10 min  1.92 0.10 2.40 0.06 1.12 0.26 Level 3 1 min 2.28 0.66 2.42 0.48 0.97 0.25 5 min 1.73 1.73 2.92 0.50 1.30 0.04 10 min  1.69 1.69 2.76 0.63 1.13 0.50

[0080] The disinfectant product showed a sterilization activity of >3 log reduction against C. albicans (yeast, vegetative cells) on vinyl surfaces at the 10.0% W/W and 20.0% W/W concentrations surfaces at 5 minutes at 20° C. This is an effective result for this yeast. Regarding A. brasiliensis (filamentous fungus, conidiospores) the data tabulated in Table 5 here show some activity on the surfaces tested. It should also be noted, that the standard contact time for defining disinfectant action against fungi is 15 minutes, and further experiments indicate favourable behaviour as a yeasticidal disinfectant with contact times of 15 minutes.

[0081] Results for endospores are now presented.

[0082] Bacillus subtilis (Endopores), Perlite+Dichloroisocyanurate

TABLE-US-00005 TABLE 6 Contact wood wood ceramic ceramic vinyl vinyl Level time mean s.d mean s.d mean s.d Level 1 1 min 2.80 0.52 3.17 0.03 2.88 0.13 5 min 2.78 0.47 3.20 0.06 2.99 0.22 10 min  2.51 0.17 3.10 0.07 2.95 0.05 Level 2 1 min 2.74 0.09 3.19 0.09 2.85 0.07 5 min 2.95 0.45 3.14 0.23 2.88 0.14 10 min  2.69 0.14 3.08 0.11 3.09 0.21 Level 3 1 min 2.66 0.42 3.13 0.10 2.80 0.39 5 min 2.79 0.15 3.27 0.10 3.12 0.30 10 min  2.78 0.38 2.99 0.21 2.80 0.22

[0083] The above results show sporicidal activity well above a log reduction of 2 logs for Bacillus subtilis on all three tested surfaces, at all three concentrations tested, and this from a contact time of 1 minute. This is a highly effective result for activity against spore strains.

[0084] The final three sets of results are for viruses. The three test viruses, Adenovirus-5, Poliovirus-1 and Murine parvovirus, are standard naked virus strains with established high chemical resistance to biocides. Efficacy against these standard viruses represents activity against all known human viruses and veterinary viruses. The results for these final three tests are discussed together.

[0085] Adenovirus-5, Perlite+Dichloroisocyanurate

TABLE-US-00006 TABLE 7 Contact wood wood ceramic ceramic vinyl vinyl Level time mean s.d mean s.d mean s.d Level 1 1 min 6.26 0.62 5.20 0.00 6.11 0.12 5 min 6.35 0.49 5.20 0.00 6.11 0.12 10 min  6.35 0.49 5.11 0.12 6.20 0.00 Level 2 1 min 6.35 0.49 5.11 0.12 5.95 0.35 5 min 6.35 0.49 5.20 0.00 6.20 0.00 10 min  6.18 0.73 5.03 0.23 6.11 0.12 Level 3 1 min 6.10 0.85 4.70 0.00 6.20 0.00 5 min 6.18 0.49 5.20 0.00 6.20 0.00 10 min  6.26 0.37 5.03 0.23 6.20 0.00

[0086] Poliovirus-1, Perlite+Dichloroisocyanurate

TABLE-US-00007 TABLE 8 Contact wood wood ceramic ceramic vinyl vinyl Level time mean s.d mean s.d mean s.d Level 1 1 min 3.11 0.12 3.36 0.00 4.54 0.00 5 min 3.03 0.23 3.44 0.59 4.70 0.00 10 min  2.95 0.59 3.69 0.23 5.37 0.24 Level 2 1 min 2.78 0.35 2.94 0.83 5.20 0.00 5 min 3.62 1.06 3.36 0.47 5.87 0.00 10 min  4.78 0.12 2.94 0.12 5.04 0.71 Level 3 1 min 3.70 0.24 3.28 1.06 4.95 1.06 5 min 4.20 1.41 5.03 0.00 4.95 0.83 10 min  4.53 0.71 4.03 1.17 5.03 0.47

[0087] Murine Parvovirus, Perlite+Dichloroisocyanurate

TABLE-US-00008 TABLE 9 Contact wood wood ceramic Ceramic vinyl vinyl Level time mean s.d mean s.d mean s.d Level 1 1 min 2.44 0.12 2.78 0.12 2.45 0.12 5 min 2.53 0.24 2.95 0.12 2.62 0.11 10 min  3.03 0.00 3.20 0.23 2.62 0.11 Level 2 1 min 3.44 0.12 3.87 0.00 3.70 0.23 5 min 3.53 0.47 4.53 0.23 4.70 0.00 10 min  5.03 0.00 4.78 0.12 4.87 0.00 Level 3 1 min 4.03 0.00 3.70 0.00 3.78 0.12 5 min 5.03 0.00 4.87 0.00 4.87 0.00 10 min  5.03 0.00 4.87 0.00 4.87 0.00

[0088] Overall, the data show that an antiviral activity corresponding to a reduction of ≥4 log for adenovirus and murine parvovirus, and an antiviral activity corresponding to a reduction of ≥3 log for poliovirus, was achieved between 1 minute and 5 minutes contact for the 20.0% W/W Perlite+dichloroisocyanurate based product. This corresponds to a high level of virucidal activity for each of these individual organisms.

[0089] Against adenovirus-5 the disinfectant product showed very high level virucidal activity (>6 log reduction) at 1.0%, 10.0% and 20.0% W/W dichloroisocyanurate (levels 1, 2 and 3) within one minute on wood and vinyl surfaces. The same formulation at all three tested concentrations also showed very effective action (>5 log reduction) against adenovirus-5 within one minute on ceramic surfaces.

[0090] Poliovirus −1 is a high chemical resistance virus with a log reduction acceptance criterium of ≥3 logs. On vinyl surfaces, this virus showed a >4.0 log reduction at 1.0%, in one minute and a 5.00 log reduction (ranging from 4.95 to 5.87) after 1 minute at 10.0% and 20.0% W/W. On wood surfaces, the activity was lower, but still virucidal, achieving >4.0 log reductions in 10 minutes at 10.0% W/W and within 5 minutes at 20.0% W/W. On ceramic surfaces, a >4.0 log reduction was achieved after 10 minutes at 20.0% W/W.

[0091] The 10% W/W, Level 2, formulation showed activity of respective log reductions on all three surfaces, wood, ceramic and vinyl, within 5 minutes, and complete kill after 10 minutes. The level 3 formulation achieved the same rate of complete kill on all surfaces within 5 minutes. Thus, this formulation was completely effective at 10.0% W/W within 10 minutes and at 20.0% W/W in 5 minutes against murine parvovirus on the surfaces tested. The efficacy at 1 minute was in the range 3-4 log reductions for both the 10.0% and 20.0% W/W formulations.