WO2000047178A1

WO2000047178A1 - Bath salt

Info

Publication number: WO2000047178A1
Application number: PCT/GB2000/000434
Authority: WO
Inventors: Ian Stanley Parsons
Original assignee: Ectopharma Limited
Priority date: 1999-02-13
Filing date: 2000-02-11
Publication date: 2000-08-17
Also published as: EP1150656A1; GB9903173D0; AU2678500A

Abstract

The present invention relates to the use of disodium octaborate tetrahydrate as the sole ingredient, or as component of a bath salt, rpimarily intended for use in a bath for one or a small number of individuals. The novel incorporation of DOT is said bath salt preparation allows the characterised beneficial properties such as an anti-microbial effect, which reduces the propagation of micro-organisms in the bathing medium and also promotes and exhibits wound healing properties. Thus, the incorporation of such a preparation into the bather's medium will offer many beneficial effects.

Description

"BATH SALT"

This invention relates to the use of disodium octaborate tetrahydrate (D.O.T.) as the sole ingredient, or as an active component of a bath salt primarily intended for use in a bath for one or a small number of individuals .

Borates are oxides of the element Boron. The borate to be used in the invention is refined from a naturally occurring ore found in the hot, dry climate of the Mojave Desert of Southern California. The natural origin of the material combined with its comprehensively defined toxicological characteristics gives a material which is safe in the intended use and which exhibits properties required of a functional bath salt.

General medical use of boric acid and borax is well documented prior art. In particular, the bacteriostatic and fungicidal properties of borates general benefit in wound healing. Boracic or boric lint has been in continuous use from 1875 to the present day. Borax and boric acid are used in cosmetics such as creams and with other ingredients such as powders .

The invention disclosed herein is quite distinct and provides advantages over such previous applications of other forms of borate.

It is further known in the field that several soluble mineral salts are used either alone or in combination with surfactants and perfumes as bath salts. The claims of these salts are invariably imprecise and non- functional, for example, claims that the salts produce a feeling of invigoration. Of the bath salts generally available no evidence is offered as to the specific or general effects of the salts, if any are claimed.

The present invention provides the use of disodium octaborate tetrahydrate as, either totally, or substantially, or in part, a bath salt, with such a bath salt exhibiting many advantages over existing bath salts and other forms of borate.

The invention thus provides a bath salt consisting of, or comprising disodium octaborate tetrahydrate as an active ingredient thereof. In various embodiments the bath salt of the present invention may further comprise any of the group comprising surfactants, oils and herbal extracts. These are believed to extend the bacteriostatic qualities of borates. Such formulations are been designed to create a pleasant smell, to enhance other qualities such as cleansing or to suit particular skin types. For example dry skin in particular is known to benefit from the emollient properties of some oils.

Bathing generally consists of an individual being immersed in preferably hot water for a reasonable period of time. Although this water is at a temperature that makes it comfortable to bathe in, it has the disadvantage of providing a suitable environment for the multiplication of many forms of bacteria and other microorganisms and fungi of medical importance. The occurrence and propagation of such microorganisms in said bathing medium constitutes a health risk. In such instances, the present invention has particular advantages for the bather by means of reducing the propagation of such microorganisms in the bathing medium. This is due to the bacteriostatic properties of disodium octaborate tetrahydrate. In bath salt formulations where additional ingredients are added to the DOT, these may also exhibit bacteriostatic properties, though these ingredients would not necessarily be selected for such properties.

As such the present invention provides the use of DOT to prevent the build-up of bacteria and fungi in bathing environments. The invention also provides the use of disodium octaborate tetrahydrate to provide water softening characteristics and or wound healing characteristics m a bath salt.

According to the present invention, there is provided a bath salt comprising or consisting of disodium octaborate tetrahydrate.

Preferably, this bath salt preparation would be dissolved into the bathing water prior to the commencement of bathing.

Preferably also, the bath salts are used m circumstances where the bathing will be done m water of a hot or warm temperature (typically between 5 and 40°C) .

It is a preferred characteristic of this invention that its properties offer several advantages over the state of the art m that it provides both benefit to the bather and maintains the cleanliness of the bathing medium through its bacteriostatic effects.

Further, it is equally preferable for the disodium octaborate tetrahydrate preparation to be formulated in combination with other adjuvants and surfactants.

Preferably, the bath salt preparation has suitable characteristics. It will dissolve into a solution with the bathing medium. Essentially, the bath salt shall exert no harmful effect on either the bather or the bath.

Preferably, the bath salt preparation containing disodium octaborate tetrahydrate is incorporated into the bather's medium for beneficial effects.

The invention is demonstrated with reference to the following non-limiting experiments. The figures accompanying the text are as follows:

Figure 1 illustrates the IC₅₀ values of three tested compounds in standard aqueous buffer solution (lOmM phosphate, pH 7.2) at 25°C.

Figure 2 illustrates a comparison of toxicities of the three compounds calculated on a weight basis.

Experimental Analysis

Boric acid and its salts have been shown to be toxic to bacteria using the Microtox^® assay. The Microtox assay utilises ViJbrio fischeri , a Gram-negative, luminescent marine bacterium, which belongs to the same family of organisms as Escherichia coli ( E. coli ) . The principle of assay is that bioluminescent light output, from the bacterium requires cellular respiration and accordingly the expenditure of metabolic activity. Thus healthy, metabolising cells give high levels of bioluminescent light output, while dead or otherwise metabolically inactive cells limit no light. On the basis, the light output from a culture in aqueous suspension, as measured using a luminometer, is a direct measure of the health of that culture.

The toxicity of a compound can be measured by this assay thus determining the toxic characteristics of the component and whether it will effect the cellular respiration of the bacteria which in turn will lead to a decline in the overall bio-luminescence emitted from the culture.

The rate of decay of light output from a bacterial culture following the addition of a putative toxic compound ('toxicant') can be straightforwardly translated into an IC₅₀ valve the IC₅₀ concentration of a toxicant required to reduce the bioluminescent light output of a v. fischeri culture by fifty percent. An LC₅₀ valve is determined in a 1 hour test; while for an IC₅₀ valve, the concentration required to reduce the numbers of bacteria by 50%, is determined in a 30 minute test.

Comparative toxicity tests were carried out between boric acid, sodium tetraborate (borax) and disodium octaborate tetrahydrate (DOT) . Suitable samples of the above-named were prepared for use in the Microtox^® assay, by dissolving each in a standard aqueous buffer solution (lOmM phosphate, pH 7.2) at a temperature of 25°C. Initial bioluminescence readings were taken for the v. fischeri cultures before the subsequent addition of each of the toxicants which were to be quantitated. From the results, IC₅₀ values were calculated for each of the three toxicants, these were as follows:

A boric acid - 8.2 mmol/1 B sodium tetraborate - 1.14 mmol/1 C disodium octaborate - 0.7 mmol/1

These results are represented graphically in Figure 1.

To evaluate further the effectiveness of the three compounds, their toxicity was compared with that of 2- hydroxybiphenyl (HBP) , an aromatic compound commonly used in household and commercial disinfectant preparations. HBP has been shown to have an IC₅₀ value of 0.026mmol/l.

The comparison of IC₅₀ values in mmol/1 concentrations, as detailed above permits direct comparison of toxicity on a molecule-for-molecule basis. Nevertheless, it is also useful to compare the toxicities of compounds on a weight basis. The toxicities of boric acid, borax and DOT are calculated in this format to be as follows:

A boric acid - 500mg/l B borax - 230mg/l C DOT - 292mg/l

The comparison of the compounds as a weight basis is further shown in Figure 2. The toxicity of HBP, when calculated on a weight basis is 44mg/l.

Thus, the above experimentation and results show that for germicidal applications, bath salts can be formulated which deliver borates to a final concentration in the range 100 - 1000 mg/1 (0.1 - lg/1) .

Although the above data pertain specifically to the toxicity of borates towards Vibrio fischeri , it is reasonable to assume that the toxicity towards other bacteria will be comparable.

The concentration given in the results at which toxicity against the bacteria is shown is perfectly workable. A lower concentration may have no, or a reduced effect.

It is known that Boron is present in bath water at around 5 parts per million. When added to a bath, the concentration of the borate can be raised to saturation level . Further the temperature of the bath water may be increased to allow increased solubility of borate up to the saturation point the specific water temperature. It should be especially noted that bath water temperature may be above 25°C.

It can be assumed that if the concentration of the borate in the bath water medium is increased, there will be a resultant enhancement in the speed of effect, or the extent of the antimicrobial effects.

It can be seen from the results that DOT is more effective than the other two borates tested. Further, DOT is far more soluble than the other borates tested, which will have an effect on the action of the borate. As such, these properties support the enhanced suitability of DOT for incorporation into a bath salt.

The following examples give further details of the invention, through defining further the specific characteristics of DOT. One of the most desirable properties of disodium octaborate tetrahydrate which makes it particularly suited to being incorporation into a bath salt is its high degree of solubility, especially at increased water temperatures. This high solubility in water, and in particular hot water, overcomes the problem of lower solubility associated with other borates such as sodium tetraborate (borax) and boric acid. Table 1 details the increase in solubility of disodium octaborate tetrahydrate, compared with the solubility of borax, when the temperature of an aqueous medium is increased.

Table 1: Solubility of DOT and borax at varying temperatures .

The alkalinity (or pH) is an important characteristic of a bath salt . A remarkable attribute of borates in general and disodium octaborate tetrahydrate in particular is the fairly constant pH for a wide range of concentrations at a given temperature. Aqueous solutions of disodium octaborate tetrahydrate range from mildly alkaline at low concentrations to practically neutral as the concentration increases at ordinary temperatures. This property is particularly relevant to the intended application as a bath salt. Table 2 exemplifies the above points by comparing the percentage of disodium octaborate tetrahydrate by weight of solution to its respective pH at 23°C. Table 2 : Comparison of the percentage of disodium octaborate tetrahydrate (DOT) by weight of solution to its respective pH at 23°C.

In further methods of application of the present invention, DOT may be formulated with many adjuvants, surfactants etc. It is envisaged that it would be preferable for all formulations to be placed in the bath, in the vicinity of the hot tap where they would be dissolved into the bathing water by means of the turbulent flow created by the hot water entering the bathing vessel, until a saturated solution is achieved.

Preferably, this bath salt preparation would be dissolved into the bathing water prior to the commencement of bathing. The invention is inclusive of all forms of disodium octaborate tetrahydrate which can be presented as a fine powder or as large granules or alternatively in liquid form in solution.

For private bathing, the invention would be placed under the hot water tap in sufficient quantity to approach saturation for any chosen temperature. Some individuals may prefer to use a lower quantity of said DOT than others. As an example of the many forms of packaging encompassed by the invention; disodium octaborate tetrahydrate in granular form, incorporating all herbal extracts and surfactants could be supplied in a one-use, one-bath sized "Tea Bag" style bag device . The bag could be suspended by means of string in the hot water stream entering the bath from the tap or placed directly in the bath. The bag may be made of linen or similar fabric or of man made fibres of slightly course texture, which could be used to rub and gently cleanse the skin. This would have the effect of removing dead skin cells, thus helping to remove bacteria and generally exfoliating and invigorating the skin. The cloth could also be used to clean the surface of the bath after use, before being disposed of.

The advantages of these "bath salts" are clearly linked to the functional claims of the innovative product which is used in it. The characteristics of disodium octaborate tetrahydrate are now clearly understood and the production of a bath salt consisting of disodium octaborate tetrahydrate has several properties which make it especially compatible and relevant for use in the presently described invention. These characteristics are detailed below;

- Softens hard water, relevant in hard water areas, makes the water feel better, extends the effect of soaps and detergents. Makes baths easier to clean.

- Cleanses the skin, natural cleaning removes oils, odour, dead skin and detoxifies the skin.

- Feeling, during and after immersion the skin has a unique wonderfully silky smooth feeling.

- Promotes healthy skin. Essentiality of boron for plant cell growth has been established and studied since the 1920 's. Borates are now known to be essential for cell growth in humans and can contribute to the care of common human dermatological conditions including those with the following known causative organisms.

- Bacteria. Borates have proven bacteriostatic properties and can help to control those bacteria responsible for skin conditions including Staphylococci and Streptococci. In functional terms herbal extracts and surfactants are selected to enhance bacteriostatic properties.

- Protozoa. In areas where inadequate treatment of the water supply is common, it has been reported that Protozoal diarrhoea can be contracted from showering and bathing. Examples are known in St Petersburg in the former Soviet Union. Residents in or visitors to such areas of risk could gain protection by the use of the invention. - Fungicidal . For some forms of fungi borates are the most effective form of control available. Disodium octaborate tetrahydrate has been shown to be effective where boric acid has no effect, due to its greatly increased solubility in aqueous solution. As an example of this effect, it has been shown that the hyphae of the parasitic fungal condition Saprol egnia parasi ti ca are substantially controlled by one hour's immersion in disodium octaborate tetrahydrate, at saturation in water at 20°C (boric acid was not effective) . No growth of zoospores occurred following immersion in disodium octaborate tetrahydrate in aqueous solution (100,000 PPM) at 20°C for 1 hour. Positive, (repeatable) effects were observed down to 100 PPM.

Fungi that the invention will help to control include Candida albi cans , a normal comensural of the human gut, which can colonise pre-existing dermatitis, all dermatophyte infections (forms of tinea such as dandruff and athletes foot) and the yeast causative organisms of Pityriasis versicor.

Specific recommendations and formulations can be prepared for the treatment of individuals suffering from any of the above skin conditions. Infestations:

Scabies. The mite Sarcoptes scabei burrows into the stratum corneum and dies after egg laying. The eggs hatch and the new generation matures after 14 days. Existing treatments are to paint the body for extended periods with Organophosphorus (OP) compounds, including Lindane . Sulphur is recommended for children due to the recognised dangers of OP's. Pediculosis capitis (Head Lice) and Pediculosis corporis (Body Lice) are also commonly treated with OP's and other compounds which have known risks and are becoming ineffective due to the development of resistance in the target organisms. It is a characteristic of human infestations that all members of a family, work or school group must be treated simultaneously. The need for safe forms of treatment is therefore of paramount importance. Specific recommendations and formulations will be prepared for the treatment, with this invention, of individuals suffering from the above infestations.

Safety case. This has been very well documented. Of particular relevance to the present invention are the subjects of eye irritation and absorption through intact skin.

Eye Irritation; many studies have been carried out on all forms of borate, mild irritation is the worst outcome. Borates have been used in eyewashes and ointments for a very long period and are used today in readily available, proprietary, eyewashes and contact lens cleansing applications.

Percutaneous absorption; studies published until 1970 must be questioned as the means of measuring very small quantities of borates were probably inaccurate.

An application to which the present invention may be of particular relevance is to women who have just given birth. Following childbirth, there is a need for the mother to have a sterile bath. This is especially required when surgery or damage has occurred as part of the childbirth process. In such instances, the present invention would be of particular benefit due to the provision of sterile conditions and the promotion of wound healing and regeneration of skin cells which is facilitated by the borate esters.

It should be noted that bathing in bath salts of disodium octaborate tetrahydrate is not universally acceptable. For example human infants can readily absorb many chemicals. As such infants should not bathe in bath salts. This is also the case for the elderly. This also applies to people with serious or extensive skin conditions. It would be recommended that before using any product produced by means of the present invention, individuals if concerned should seek the advice of a dermatologist, or similar medical advice.

This invention is not intended for use in public facilities where there is a risk of transmission of serious disease from one person to another. Where these risks have been overcome by use of an effective non-chemical treatment system (possibly ultra violet) then it may be safe to use the invention.

It is clear from the information herein that at normal bath temperature (that is, up to 35 °C) DOT can be in solution at saturation level for the given temperature and will increase the effects upon bacteria and amplify the effects of DOT over the other borate.

Claims

1. A bath salt comprising or consisting of disodium octaborate tetrahydrate as an active ingredient thereof .

2. A bath salt as claimed in claim 1 further comprising at least one ingredient chosen from the group comprising surfactants, oils and herbal extracts.

3. A bath salt as claimed in claim 1 or 2 wherein the salt is presented as a fine powder or as granules.

4. A bath salt as claimed in claim 1 or 2 wherein the bath salt is presented in a solution.

5. A bath salt as claimed in any of claims 1 to 3 wherein the salt is presented in a one use fabric bag.

6. Use of disodium octaborate tetrahydrate as an active ingredient in a bath salt.

7. Use of disodium octaborate tetrahydrate as claimed in claim 6 wherein the bath salt further comprises at least one ingredient chosen from the group comprising surfactants, oils and herbal extracts.

8. Use as claimed in claim 6 or 7 wherein the disodium octaborate tetrahydrate exhibits water softening properties.

9. Use as claimed in claim 6, 7 or 8 wherein the disodium octaborate tetrahydrate exhibits wound healing characteristics.

10. Use of disodium octaborate tetrahydrate as claimed in any of claims 6 to 9 in the preparation of a bath salt formulation for treatment of wounds on a human body .

11. Use of disodium octaborate tetrahydrate as claimed in any of claims 6 to 10 wherein the DOT prevents build up of bacteria and fungi in a bathing environment .

12. Use of disodium octaborate tetrahydrate as claimed in any of claims 6 to 11 wherein the disodium octaborate can be incorporated at up to 21.9 parts DOT per 100 parts weight in solution in bath at a temperature of up to 40 °C.

13. Use as claimed in claim 12 wherein the bath is at a temperature of up to 30 °C.