Deactivants for dust mite allergens

Abstract: A method for deactivating a Der-f and/or a Der-p allergen comprising contacting the allergen with a deactivating effective amount of a deactivant which is 6-isopropyl-m-cresol.

Description: It has been known for a long time that house dust can trigger allergenic reactions in humans, such as asthma and rhinitis. It was reported, as early as 1928, that it was the dust mites in the dust that were the primary source of the allergenic response but it was only in the 1960's that researchers appreciated its significance. It is believed that the faeces of two particular house dust mite species, Dermatophagoides farinae (known as Der-f) and Dermatophagoides pteronyssinus (known as Der-p) trigger the immune responses of the body, thereby giving rise to well known allergenic symptoms. A review of this is given in Experimental and Applied Acarology, 10 (1991) p. 167-186 in an article entitled "House dust-mite allergen" : A review by L. G. Arlian. Both the Der-f and Der-p species are found throughout the world. In some areas, Der-f will be the sole Dermatophagoides species. In other areas Der-p will be the sole species. In still other areas, the two species are both present through, generally, one or the other will predominate. One way to overcome these allergenic response has been to vacuum surfaces, such as carpets, that contain the dust mites and their faeces thoroughly and often, but that is both time consuming (i.e has to be regularly done if one wants to make an allergenic free environment) and is very dependant on the efficiency of vacuum cleaner and filter bag used e.g. micron filter bag or 2 layer vacuum bags. An alternative method of creating an allergen-free environment has been to denature the allergen, for example as described in US Patent No. 4,806,526. The only effective method however of which we are aware is to apply tannic acid to the allergen. However, tannic acid can cause staining, and this is a particularly acute problem for light coloured carpets (e.g. white and light beige carpets) and other textile surfaces as tannic acid leaves a deep brown stain. Therefore, we have been looking for allergenic denaturants which will not stain susceptible surfaces such as carpets and still deactivate the allergen. We have discovered a number of allergen deactivants which are effective against both the Der-f and the Der-p species. Quite surprisingly, we have discovered that some of these deactivants are specific to the type of dust mite allergen being treated. For example an effective Der-f allergen deactivants will not automatically work effectively as a Der-p allergen deactivant. According to the invention there is provided a method for deactivating a Der-f and/or a Der-p allergen comprising contacting the allergen with a deactivating effective amount of a deactivant, the method using a composition containing the deactivant in an amount from 0.01 to 7%, the deactivant being immobilised tannic acid. "Immobilised tannic acid" is tannic acid on polyvinyl pyrollidone beads. Immobilised tannic acid was prepared as follows: 100mg of tannic acid was dissolved in water; 50 mg of Polyclar 10 (ISP, Guildford Surrey) polyvinyl pyrollidone beads were added and stirred for one hour; the beads were filtered off the solution and washed with a few mls of iced water until no colour was seen in the washings; they were then dried in the oven at 50°C. The deactivant is preferably present in an amount of from 0.01% to 3%. In methods for treating rugs and carpets to deactivate allergens, the amount of deactivant present is from about 16g to about 170g per 10 square meters, preferably about 32g per 10 square meters. Further according to the invention there is provided an aerosol composition containing 0.01 to 7% of immobilised tannic acid as deactivant, a propellant, and, optionally, a solvent. Preferably the amount of deactivant present in such a composition of the invention is from 0.01% to 3%. Preferably the amount of propellant present in such a composition is from 4% to 50%, more preferably from 4% to 30%. Preferably the amount of solvent present in such a composition is 0% to 90%, and most preferably from 20% to 90%. Preferably the propellant is selected from those commercially available, for example C 1-4 alkanes, chlorofluorocarbons and compressed gases such as nitrogen, air and carbon dioxide. Preferably the solvent is selected from C 1-6 alcohols (e.g. ethanol) or water. In addition the compositions of this invention may also contain one or more of the following a fragrance, preferably in an amount of 0% to 5%, more preferably 0% to 2%; an antimicrobial compound e.g. alkyldimethylbenzyl ammonium saccharinate preferably in an amount of 0.01% to 1%; a surfactant e.g. Dow Corning 193 Surfactant, preferably in an amount of 0.01% to 1%; a corrosion inhibitor e.g. sodium nitrite, sodium benzoate, triethanolamine and ammonium hydroxide preferably in an amount of 0.01% to 10%; and a miticide such as benzyl benzoate, pyrethroid pemethrin, d-allethrin and optionally a synergist such as piperonyl butoxide, preferably in an amount of 0.1% to 10%. It has been found that deactivant of the invention has allergen deactivating properties as effective as tannic acid but without the drawback of staining. The invention will now be illustrated by the following Examples. Examples The test procedure in Examples 1 to 6 is as follows and is known as the ELISA protocol. The ELISA protocol for Der-f and Der-p has been developed as follows as a measure of denaturing property for denaturants. ELISA Protocol 1 1. Dust is collected from Hoover™ vacuum cleaner bags and passed through a series of sieves down to 63 microns. 2. Clean petri dishes are labelled with the chemical to be tested (on the base). Three replicates are used for each treatment. 3. Filter paper is used to line each dish and 0.2g of dust is added to each dish onto the filter paper. The lid (or base, as dishes are inverted) is replaced and the dish is shaken to disperse the dust evenly over the filter paper. 4. Immobilised tannic acid was used as a 1% dispersion. 5. The dust is sprayed with the corresponding treatment, 2 sprays are required for sufficient coverage (1 spray = 1.5 ml). 6. Leave uncovered at room temperature, in well aerated room, until filter paper is dry. This can take up to 4 hours. 7. Empty dust in epindorfs labelled according to treatment. 8. Add 1 ml of 5% Bovine Serum Albumen Phosphate Buffer Saline - Tween BSA-PBS-T to each epindorf (5 times the weight of dust) (20ml of BSA-PBS-T =1 g of BSA in 20ml of PBS-T). 9. Leave overnight in a refrigerator. 10. Centrifuge for 5 minutes at 13,000 rpm. 11. Decant the supernatant into a new epindorf labelled according to treatment. 12. Centrifuge again for 5 minutes at 13,000 rpm. 13. Make up dilutions of 1:10 and 1:100 by adding 100 µl of neat solution to 900 µl of 1% BSA-PBS-T (1:10). This is repeated using µl of 1:10 dilution and add to 900 µl of 1% BSA-PBS-T for 1:100 dilution. ELISA Protocol 2 for Der-f and Der-p: Indoor Biotechnologies 1. Prepare samples and dilutions as in protocol 2. Prepare 500 ml of 50 mM carbonate/bicarbonate buffer by dissolving 0.795g Na 2 CO 3 and 1.465g NaHCO 3 in 500 ml of distilled water. Check the pH is at 9.6. (This solution is kept in the refrigerator in a conical flask). 3. Monoclonal antibody (kept in the freezer) has to be added to the buffer using the following method, (1 µg per well ; 11ml is needed) applied to the ELISA plate 11ml of carbonate/bicarbonate buffer is added to the dispensing tray. 11µl of Der-f1 or Der-p1 monoclonal antibody (stored in freezer, epindorf in use is in the refrigerator) is added to the buffer. To ensure that all the antibody is removed from the tip, wash out the pipette tip by sucking up and down the buffer solution, gently stirring to mix thoroughly. 4. Pipette 100 µl of the antibody solution into each well of the microtiter plate, cover with a plate sealer and leave overnight at 4°C. 5. Empty the plate by quickly inverting it over the sink, then dry by banging on a stack of paper towels. 6. Add 200 µl of wash buffer to each well: PBS/0/05% Tween (PBS-T). 7. Repeat stages 5 and 6 once more (making a total of 2 washes). 8. Make sure all the wells are dry, then add 100 µl of 1% BSA-PBS-T. Replace the plate sealer and incubate for 1 hour at room temperature*. 9. Repeat steps 5 to 7 (2 washes). 10. During the hour incubation period, prepare the allergen standards at dilutions between 125 and 1 µg/ml Der f 1 or Der p1: Add 25 µl of allergen standard (kept in the fridge in polystyrene box) to 475µl of 1% BSA-PBS-T and mix thoroughly - labelled '125'. 250 µl of 1% BSA-PBS-T is added to 7 further epindorfs which are labelled 62.5, 31.25, 15.63, 7.61, 3.9, 1.95 and 0.98. 250 µl is taken from the 1st epindorf (labelled 125) and transferred to the next (labelled 62.5). This is mixed thoroughly. Using a new pipette tip, 250µl is removed from epindorf labelled 62.5 and transferred to 31.25, this procedure is continued down to the 0.98 concentration (125, 62.5, 31.25, 15.63, 7.61, 3.9, 1.95, 0.98) In total 475 + (250 x 7) = 2.3ml : 0.023g of BSA added to 2.3 ml of PBS-T. 11. Add 100µl aliquots of the allergen sample to the plate along with the standard allergen samples for the reference curve in duplicate. The standards usually go in the first two columns on the left hand side, with the least concentrated on top. Incubate for 1 hour. 12. Follow stages 5 to 6, completing a total of 5 washes. 13. Pour 11ml of 1% BSA-PBS-T(0.11g of BSA to 11ml of PBS-T) to the dispensing tray. Add 11 µl of the biotinylated monoclonal antibody (refrigerator) and mix thoroughly. 14. Pipette 100 µl into each well and incubate for 1 hour at room temperature. 15. Empty plate and wash as described in stage 12. (5 washes). 16. Add 11 µl of Streptavidin (freezer) to 11ml of 1%BSA-PBS-T. Pipette 100 µl into each well and incubate for 30 minutes. Reserve any remaining solution in a vial. 17. Empty plate and wash as described in stage 12 (5 washes). 18. Make a solution of OPD, by putting the two tablets (in silver and gold foil) into 20 ml of distilled water (in a glass vial). Shake quite vigorously in the dark until the tablets have dissolved (Wrap the vial up either in tin foil or paper towel). 19. Add a small amount to the remaining solution from stage 16. Wait for a colour change (positive reaction). Add 200 µl to each well and incubate for a minimum of 30 minutes in the dark. 20. Read the plate at 450nm/405nm if filter not available. Example 1 The deactivant set out in the following table was used against Der-f allergens according to the above procedure and the results are as given below. Tannic acid was used as a comparator. What was measured after treatment with deactivant and tannic acid was the amount of allergen remaining active after treatment. The ratio of amount of remaining active allergen after treatment with immobilised tannic acid compared with tannic acid is also given. Deactivant Amount of allergen remaining active after treatment with immobilised tannic acid Amount of allergen remaining active after treatment with tannic acid Immobilised tannic acid 1550 1175 Example 2 The deactivant mentioned below was used against Der-p allergens according to the above procedure and the results are as given below. What was measured were the amount of allergens remaining after treatment with deactivant and the amount of allergens remaining after vacuuming with no deactivant treatment. Deactivant Amount of allergen remaining active after treatment with immobilised tannic acid Amount of allergen remaining after no deactivant treatment Immobilised tannic acid 1125 5642 Example 3 - 6 The following formulations can be made up as carrier compositions for use in an aerosol for deactivating Der-f and Der-p allergens. Example 3 Raw Ingredient Description By Weight Item Classification % Anhydrous Ethanol (SD Alcohol 40) Solvent 79.646 Alkyl dimethyl benzyl ammonium saccharinate Cationic Surfactant 0.106 Corrosion Inhibitor (I) 0.192 Corrosion Inhibitor (II) 0.192 Corrosion Inhibitor (III) 0.096 Deionized Water Water/Solvent 15.768 Carbon Dioxide Propellant 4.000 TOTAL 100.000 Example 4 Raw Ingredient Description by Weight Item Classification % Anhydrous Ethanol (SD Alcohol 40) Solvent 57.000 Fragrance#17 Fragrance 0.0500 Dow Corning 193 Surfactant Surfactant 0.025 Corrosion Inhibitor (I) 0.100 Corrosion Inhibitor (II) 0.100 Deionized Water Water/solvent 14.725 NP-40/Butane 40 Hydrocarbon propellant 28.000 TOTAL 100.000 Example 5 Raw Ingredient Description by Weight Item Classification % Anhydrous Ethanol (SD Alcohol 40) Solvent 79.646 Benzyl Benzoate - an acaricide Active/ester 4.600 Alkyl dimethyl benzyl ammonium saccharinate Cationic Surfactant 0.106 Corrosion Inhibitor (I) 0.192 Corrosion Inhibitor (II) 0.192 Corrosion Inhibitor (III) 0.096 Deionized Water Water/solvent 11.168 Carbon Dioxide Propellant 4.000 TOTAL 100.000 Example 6 Raw Ingredient Description by weight Item Classification % Anhydrous Ethanol (SD Alcohol 40) Solvent 57.000 Benzyl Benzoate Active/ester 4.600 Fragrance#17 Fragrance 0.0500 Dow Corning 193 Surfactant Surfactant 0.025 Corrosion Inhibitor (I) 0.100 Corrosion Inhibitor (II) 0.100 Deionized Water Water/solvent 10.125 NP-40/Butane 40 Hydrocarbon propellant 28.000 TOTAL 100.000

Claims: A method for deactivating a Der-f and/or a Der-p allergen comprising contacting the allergen with a deactivating effective amount of a deactivant, the method using a composition containing the deactivant in an amount from 0.01 to 7%, the deactivant being immobilised tannic acid. A method as claimed in claim 1, wherein the allergen is a Der-f allergen. A method as claimed in claim 1, wherein the allergen is a Der-p allergen. A method as claimed in any preceding claim, wherein the immobilised tannic acid deactivant is applied to fabric materials selected from rugs, carpet and upholstered furniture, at an application rate of from 16 grams to 170 grams of deactivant per 10 square meters, thereby to combat allergens associated with faecal particles excreted by dust mites on the surfaces of the fabric materials. A method as claimed in any preceding claim, wherein the deactivant is comprised within an aerosol composition, also containing a propellant and optionally, a solvent. A method according to claim 5 in which the amount of deactivant present is from 0.01% to 3%, the amount of propellant present is from 4% to 50%, and the amount of solvent present is from 0% to 90%, all percentages being by weight. A method according to claim 5 or 6 in which the propellant is selected from a C 1-4 alkane and carbon dioxide. A method according to any one of claims 5 to 7, the solvent being selected from C 1-6 alcohols and water. A method according to claim 8 in which the solvent is ethanol. A method according to any one of claims 5 to 9 in which the composition contains one or more of the following: a fragrance, a surfactant, an antimicrobial agent, a corrosion inhibitor, a miticide.

Inventors: CORNELIUS GAY, MCKECHNIE MALCOLM TOM, SUH JANETTE, THOMPSON IAN ANDREW, CORNELIUS, GAY, MCKECHNIE, MALCOLM, TOM, SUH, JANETTE, THOMPSON, IAN, ANDREW
Applicants: RECKITT BENCKISER UK LTD, RECKITT BENCKISER (UK) LIMITED
Application year: 1998
Main classification: A62D3
IPC codes: A61L2, A01N65