AU2849797A - Disinfectant effervescent tablet formulation - Google Patents

Description

S F Ref: 385670

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Tri-Link Unlimited, d/bla Southland, Ltd.

1590 Roberts Road Suite 111 Kennesaw Georgia 30144 UNITED STATES OF AMERICA Richard A DeSenna Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Disinfectant Effervescent Tablet Formulation The following statement is a full description of this Invention, including the best method of performing it known to me/us:- 07 829 3 6 AUG97 -1- DISINFECTANT EFFERVESCENT TABLET FORMULATION This is a continuation-in-part of application serial no. 08/539,873, tiled October 6, 1995, presently pending.

j FIELD OF THE INVENTION The present invention relates generally to a method of cleaning dental and medical instruments, equipment, and the like. More specifically, the invention relates to an effervescent tablet formulation that can be used to prepare a disinfecting solution usefil for disinfecting inanimate surfaces.

BACKGROUND OF THE INVENTION In the medical and dental fields, walls, flours, examination chairs and tables other equipment, and instruments used in examination and treatment are contaminated by various organic materials which contain or support the grw.ih off.various micrioor :isIns Cleaning alone is not sufficient to kill or inhibit the i .tio;t ofthese oganisms andl use of disinfectants is necessary.

A disinfectant is a substance which destrcys o irreversibly inactivates infectious or other undesirable bacteria, pathogenic fungi, and 'ruses on surfaces or inanimate objects Disinfectants kill the growing forms but not necessarily the resistant spore forms of microorganisms. Sterilizers, on the other hand, destroy the growing and spore forms of viruses, bacteria, and fungi on inanimate surfaces. Sanitizers are used to reduce the number SO of living bacteria or viable virus particles on inanimate surfaces, in water, or in the air, and S.f tungicides and fungistats are used to inhibit the growth of or destroy fungi on inanimate surfaces- It has become common practice to use gutaraldehyde solutions as surface disinfectants or sterilants in dental and medical facilities. However, while glutaraldehyde i. S- solutions are an effective disinfectant, there are many drawbacks to the use of S glutaraldehyde, including safety concerns, problems with storing the large volumes of solutions required, and the limited shelf stability of solutions. In addition, if the glutaraldehyde solution is prepared by dilution of a concentrated solution there is the Sinconvenience of measuring and pouring the liquid concentrate.

The use of disinfectant or sterilant concentrates in a powdered form has been taught in the prior art; for example, in U.S. Patent No. 5,350,563 to Kralovic et al. The problem with the use of powders as disinfectant concentrates is that they also must be poured from -2one container to a.other. In addition, there are sometimes problems with forcing the powder into solution.

Another problem faced when using liquid or powdered concentrates is that many of the ingredients used for disinfectants can be harmful to humans and the handling of I concentrated amounts of these ingredients can be even more harnfiul. Care must be taken not to spill or come into contact with any concentrate and not to inhale any dust from powdered concentrates.

Other patents, for example, those of Hunt etal., U.S. Patent No. 4,265,847, and White et al., U.S. Patent No. 4,536,389, teach effervescent tablets useful for preparing I0 solutions for sterilizing or disinfecting. Such compositions are rapid vater soluble tablets typically comprising an active chemical compound, and alkali metal bicarbonate, e.g.

sodium or potassium bicarbonate, and a solid alipHatic carboxylic acid such as citric acid, tartaric acid, adipic acid, or an acid salt thereof. in use. such tablets are dissolved in water whereupon the interaction of the bicarbonate and acid components results in the release of it carbon dioxide, thus increasing the rate of solution of the other components and producing a solution in which the active (disinfecting) ingredient is homogeneously dissolved. Method for forming effervescent tablets are well known in the art. For example, see U.S. Patent No. 4,265,847 to Hunt et al. and U.S. Patent No. 5.114,647 to Levesque et al. which disclosures are incorporated herein in their entireties, by reference.

Halogen compounds are effective as disinfecting agents but their use as such agents is limited due to difficulties in storage, mixing, and handling of concentrated halogens and instability of dilute forms. The use of sodium dichloroisocyanurateloroisocyanurate as a disinfecting agent is known in the prior art. For example, see U.S. Patent No. 4,536,389, S* to White et al., and U.S. Patent No. 4,114,642, to Levesue et al. Sodium .S dichloroisocyanurate hydrolyses in water to produce hypochlorous acid (HOCI) and hypochlorite (OCl), which exist in solution at an equilibrium that is dependent upon the pH of the solution. For example, as shown in Fig. 1, at neutral pH a solution consists of about 75% hypochlorous acid and 25% hypochlorite. The prior art teaches the use of bromide as a disinfectant, the hypobromous acid and hypobromite species are produced in solution otypically by the use of bromo, chloro-5,5-dimethylhydantoin. They hypohalous acid specie is the antimicrobial form of the above compounds, with the hypohalite having some antimicrobial effect. However, the negative charge of the hypohalite inhibits its diffusion -3through the cell wall of microorganisms and thus lowers its anitimicrobal effect Chloride and bromide have different equilibriums in solution, as shown by the chart of Fig. 1. The dissociation characteristics of hypobromous acid are such that the hypobromous acid is the predominant species over hypobronite up to a pHl- of about S.3.

Swhich is the point when the concentrations of hypobronious acid and hypobromite area about equivalent. However, hypochlorous acid is predominant species over hpochlorite only up until a pH about 7.4. At a pH above about 6-0, as shown by Figs 1. a solution of hypobromous acid is a much more effective disinfectant because more of the hypohalite species is present. Furthermore, in addition to the greater percentage of hypobromous acid >o compared to hypobromite. hypobromous acid is a stronger antimicrobial agent tlhan hypochlorite acid. as shown by Fig. 2.

Accordingly, there is a need for an elTective disinfecting agent packaged and supplied in a convenient efervescenft fonr The etenrvescent tablet must lill dissolve in a rapid fashion to form a homogeneous disinfecting solution which is highly active and stable K for a useful length oftime.

SUMMARY OF TIE INVENTION It is an object of the present invention to provide an effervescent tablet formulation that can be used to prepare a disinfecting solution wherein the formulation avoids the S.disadvantages and problems of prior art disinfectant concentrates.

.t It is an object of the present invention to provide a product to be used for preparing a solution for disinfecting dental and medical instruments and equipment that dissolves fully and results in a solution which has disinfecting power for a useful period of time over a wide pH range.

The present invention comprises a water soluble effervescent tablet formulation that j- can be added directly to water to prepare a disinfecting solution. The preferred disinfecting S, agent is a combination of a bromide releasing agent and a hypochlorite releasing agent Further, the formulation includes a stabilizer for increasing the stability of the effective S" disinfecting species in solution. In particular, a two tablet system has been developed where in the bromide releasing agent is in one effervescent tablet and the hvoochlorite releasing agent is in a second effervescent tablet.

SodilUm bromide is useful sthre bromide resesino,- aorent Sodiull diloroisocyanurate is useful [3 pro-6de both hvpochlorie alld to act as a stabilizin,- agelem to mitain desired leesof th.- active inluredients Both tablets contain eilhvescent apent's such as are used in the art;. for e~:anple. sodiumn bicarbonate in comibination wth citric acid SOther ingredients ma% optiOna ii, be included such aS SUrtbant-11S, &deootuS, lubricants.

anld fillers ITe tableis prepared iteni thre activ-e ttt2fis and te Cieik[W Centl agtent1s are of SUClt at size and concentration to aihaW uIsing1 whole tablets or niuhilple tablets in a (-tte quart volume or other typically used v-olle. The use ol'tablets ellininaies havinig to dilute and Mix concetrates, andI store diit(edluds Ih Is oftilt iutrelniae aigt pour p)owd.er concerntrates Inhrav. producemdsrbe and lmarnihi doust 'Thei etlervescenice provides rapid stlt andmixit ofthle act:ive inleredieltcS Thte uISe Otfih two tablet svs-tetnl allows wir to:-nation ot't je- pretet red h\ p troiniotis acid spcies 0therI ulmjeCOS t~tulrt an1d :mriVanta'es oif the present inventiolt will becotum I apparent fiorn the rollowvine' 4::Tailed de,;en'yIoa In Con lnctloll -witlt thle accolmtrpnuvim! BRIEF I)ESCRIPTio.N OF-i DI VIRAWINGCS Fig. I is; a graph l\i rthe dissociation Of he1pobro11ouIs acid artd hvpochlorous acid~ i.2 is a giraph compoaring the biocidal actiities of hvpobronmoLS !ci and hvpocillorous acid.

D)ETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Tile present invention isz a two tablet effiervescent tablet formulation. The tablets are made of appropriate sizes so that, preferably, one of each of the two tablets car, be used .~for one quart of wvater. In this way a disirLfeecins! solution can be miade up as it is needed and does not need to be maie up in lar-ge quantities all at once. Therefobre, storage problems are avoided. The use of the effervescent tablets instead of a concentrated liquid or concentrated powder allows for easy handling and ming of thLeie uniyo disinfectintt solution- 3C One tablet. Tablet A- comprises a fLunctional amount of et~fervescing agent and a bromide releasing a gent. The prefenrred bromnide releasing agent is sodium bromide (-NaBr).

However, other bromide releasin- aguents mnay be used. such as-. for example, dibromodimiethyliydantoin, chioro, bromo-dimetivilhvdantoiri anid other bromide salts. The tablet further includes lubricating- agents, such as. for examiple. sodiuln laurel sulfate and PEG 8000, and a filler such as sodium carbonate (soda ash). Tablet B comprises an efrective amount of effiervescing a-ent and a hypochlorite releasing agenit such as sodium dichloroisuCVajiulratc. It is antiiatedl that other hv.pochlorite g-eneratingt ageCrits call be used such as, for example, ithuim hypochlorite. caliu hpohrie aesu lwpochloriate. and trichlorisocyanurate. Tablet B fuirther canl includle a tiller such as soda ashi and lubricating agents such assdium alaurel suilffte anid PEG S000.

0 The two tablet fornnulation avoids reaction between bromide anid hvpo\ lit e I' which wouild occuir if the two chemicals were packaged into one ctl hvescent tablet- Thle inventor has Found that if a brort.iie releasing agent and hvNpochlorite relcasi agent are combined in a sitwkl elrvRescen: :alet. the chemaicals will react lifthe tablet is exposed to a small amiount of moisture- *iTussc tablet-- are not stable.

When one each of Tablles A and B are dissolved InI water, sodiuml w -j dichluroisocvanurate hydrolyse ",to an equilibrium mix of hy pochilorous acid and hypochlorite- Tablet B dissolve and renders free bromide and NaBr. The hypochlorite undergo hialogen transfer wvith the Br and sodium bromide (Nalr) so that hypnibromite is forrmed. This Peecies in turn forms hiypobromnous acid so that anl Z~ equilibriumn, dependent upon the pI{ is achieved between hypobromite anld hypobromotis Saci'd.

Effiervescent tablet preparation is know.%n in the art. A technique which has wvorked 34for the present invention is as follows- Effervescent granules are prepared by mnixing 200 kilogram batches of 52 59/ sodim bicarbonate. 41.5% citric acid, and 5.5% maltodextrin.- QThis mixture of solids iscombined with 20 liters of isopropanol and 800 milliliters of distilled water to form a very dry agglomreration. The agglcomeration is dried and coarsely ground into effervescing r anules. he effervecng granules are mixed wt h te gredients of Tablet A and Tablet B as described above. In one particular- formulatioth following amounts of ingredients were used.

TABLETr A: Intyredient elbavescent granules sodium bromide rsodium laurVI SUh-IuC soda ash PEG 8000 XWeiiehrtPercent 66t 10.0 1.01 200 3 0 to TABLET 13: Ingredient effervescent anlukcs sodium dichloroizocvinurate s;oda ash x~sodium lauri sulfate PEG S000 Total \Veiuht I~LrCCn! 470 i~) ~s ~m lO(i 0 I-he ahove mhixtures of inLeredicrits were blended and then fornned into tablets onl an IS station tablet press. Each tablet contained about 3 granis.

One of each of the above tablets is added to abc ut one quart of water at rouml temperature and allowed to completely solubilize. The solution can be applied to completely solubilize- The solution can be applied to the area to be cleaned Nwith a spray bottle, cloth, sponge. miop. or other cleaning method.

Another technique for effexrvescent tablet preparation which is useful for the present invention Is as follows. The below fisted ingredients were blended and then formed into tablets on an IS station tablet press. Each tablet contained about 3 grams. Inr this formulation effervescent g-ranules do not need to be prepared but rather the -7etffrvescing acents are directly mixed with the other ingredients. This formula provides a tighter and firmer tablet and is also less expensive.

-l iF.

TABLET A: Ingredient sodium bicarbonate citric acid soda ash sodium bromide sorbitol 1o sodium lauryl sulfate carbowax 8000 sodium benzoate Total ij TABLET B: Ingredient sodium bicarbonate citric acid soda ash Ao sodium dichloroisocvanurate S sorbitol sodium lauryl sulfate carbowax 8000 sodium benzoate Total Weight Percent 31.5 23.3 22_8 10.0 74 100.0 Weight Percent 25.0 18.3 21.7 24_7 5.3 100.0 The weight percentages of the above ingredients can be altered and the tablet sizes can be altered as long as an effective pH and concentration of halogen are present in the prepared solution. An effective pH for a disinfecting solution is from about 7.5. The pH of the solution prepared as above is about 7.2. An effective concentration of halogen in the prepared solution is form about 300-500 ppm- A Preferred concentration1 is from about 375-440 ppmi A -Solution prepared as above has abo)Ut 400 ppm hlogzen.

It can be appreciated by those skilled in the art that a novel disinfecting~ product and modificat ions thereof have been shown and described in detail herein. Various additional changes and modifications may be made without departing from the scope of the present invention.

Claims (16)

1. An effervescent tablet formulation for preparing a disinfecting solution, comprising: a first tablet comprising an effervescing agent and a bromide releasing agent; and a second tablet comprising an effervescing agent and a hypochlorite releasing agent.

2. The effervescent tablet formulation of claim 1. wherein said first tablet further comprises a lubricating agent and a filler.

3. The effervescent tablet formulation of claim 1. wherein said second tablet further comprises a lubricating agent and a filler.

4. The effervescent tablet formulation of claim 1, wherein said bromide I releasing agent includes sodium bromide.

The effervescent tablet formulation of claim 1, wherein said hypochlorite releasing agent is selected from the group consisting of sodium dichloroisocyanurate, sodium trichloroisocyanurate, lithium hypochlorite, calcium hypochlorite, and magnesium hypochlorite.

6 The effervescent tablet formulation of claim 1 wherein said hypochlorite releasing agent includes sodium dichloroisocyanurate.

7. The effervescent tablet formulation of claim 1, wherein said effervescent agent includes a mixture of sodium bicarbonate and citric acid.

8. The effervescent tablet formulation of claim 1 wherein said effervescent agent includes granules formed from a mixture of about 52.5% sodium bicarbonate, about 44.5% citric acid. and about 5.5% maltodextrin. and in which wetting agents isopropanol and distilled water are used to agglomerate said mixture and the agglomerated mixture is formed into granules.

9. The effervescent tablet formulation of claim 2, wherein said lubricating agent comprises a combination of sodium lauryl sulfate and PEG 8000 and said filler comprises sodium carbonate.

10. A disinfectant effervescent tablet formulation comprising: a first tablet comprising about 66% effervescing agent, about 10% sodium bromide, about 1% sodium lauryl sulfate, about 20% sodium carbonate, and about 3% PEG 8000; and a second table comprising about 47% effervescing agent, about 24% sodium dichloroisocyanurate, about 25% sodium carbonate, about 1% sodium lauryl sulfate and about 3% PEG 8000.

11. The disinfectant effervescent tablet formulation of claim 10, wherein said effervescent agent comprises granules formed from a mixture of about 52.5% sodium bicarbonate, about 44.5% citric acid, and about 5.5% maltodextrin, and in which wetting ag-nts isopropanol and distilled water are used to agglomerate said mixture and said agglomerated mixture is formed into granules.

12. A method for forming a disinfecting solution, comprising: preparing a first effervescent tablet comprising an effervescing agent and a bromide releasing agent; preparing a second effervescent tablet comprising an effervescing agent and a hypochlorite releasing agent; and dissolving at least one of said first tablet and at least one of said second tablet in water to form a disinfecting solution.

13. A disinfectant effervescent tablet formulation, comprising: a first tablet comprising about 31.5% sodium bicarbonate, about 23.3% citric acid, about 22.8% sodium carbonate, about 10% sodium bromide, about 7.4% sorbitol, about 1% sodium lauryl sulfate, about 3% carbowax 8000, and about 1% sodium benzoate; and a second tablet comprising about 25% sodium bicarbonate, about 18.3% citric acid, about 21.7% sodium carbonate, about 24.7% sodium dichloroisocyanurate, about 5.3% sorbitol, about 1% sodium lauryl sulfate, about 3% carbowax 8000, and about 1% sodium benzoate.

14. A disinfectant effervescent tablet formulation, comprising: a first tablet comprising an effervescing agent comprising a mixture of sodium bicarbonate and citric acid, a filler, sodium bromide, and a lubricating agent; and a second tablet comprising an effervescing agent comprising a mixture of sodium bicarbonate and citric acid, a filler, a sodium dichloroisocyanurate, and 25 lubricating agents.

A table formulation for preparing a disinfecting solution, comprising: a first effervescing tablet comprising an agent that releases bromide upon dissolution of the table in aqueous solution; and a second effervescing tablet comprising an agent that releases hypochlorite upon dissolution of the table in aqueous solution.

16. An effervescent tablet formulation, substantially as hereinbefore described with reference to any one of the Examples. Dated 7 July, 1997 Tri-Link Unlimited, D/B/A Southland, Ltd. Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON