WO2007113513A2

WO2007113513A2 - Malodour compositions

Info

Publication number: WO2007113513A2
Application number: PCT/GB2007/001172
Authority: WO
Inventors: Keith Douglas Perring; Martin John Behan; Susan Griffin; Montserrat Vela
Original assignee: Quest International Services B.V.
Priority date: 2006-03-31
Filing date: 2007-03-30
Publication date: 2007-10-11
Also published as: GB0606519D0; GB2451966A; WO2007113513A3; GB0816787D0

Abstract

Synthetic urine malodour compositions comprising urea, ammonium chloride, sodium chloride, disodium hydrogen orthophosphate, ammonia, trimethylamine, acetic acid and water, together with a method of preparing the compositions and a method of evaluating a fragrance for its performance against the perception of urine malodour by combining the fragrance with the urine malodour composition are provided.

Description

Title: Malodour Compositions

Field of Invention

This invention relates to synthetic urine malodour compositions, methods of making them, and the use of such synthetic urine malodour compositions in processes for the evaluation of test urine malodour-reducing compositions for producing urine malodour-reducing compositions that are used in an array of products, including hygiene products such as diapers and incontinence pads.

The synthetic urine malodour compositions have an odour simulating the odour of natural urine, particularly human urine, and are made by combining materials in vitro. They are thus distinguished from urine produced by the human or animal body.

Background

Urine is a transparent fluid that normally has an amber colour. The average amount of urine excreted by a human in 24 hours is about 1,200 cubic centimeters. Chemically, urine is mainly an aqueous solution of sodium chloride and organic substances such as urea and uric acid. Typically, it contains about 960 parts of water to 40 parts of solid matter.

More than 1000 different mineral salts and compounds are estimated to be in urine. These can include, vitamins, amino acids, antibodies, enzymes, hormones, antigens, interleukins, proteins, immunoglobulins, gastric secretory depressants, tolergens, immunogens, uric acid, urea, proteoses, directin, and urokinase.

The pH of normal urine is between 4.5 and 7.8, but usually it ranges between 5.0 and 6.0, due to obligatory excretion of acid produced every day. Nitrogen-containing compounds in urine, such as ammonia, contribute to the malodour recognised by most people from either soiled diapers or other hygiene products such as adult incontinence products. This malodour is at least partly a consequence of growth of bacteria, such as Proteus spp. All strains of Proteus spp. form the enzyme urease during their metabolism. Urease has the ability to rapidly break down urea (constituting about 2% of human urine) into ammonia causing unpleasant odour.

Due to the large number of substances in urine, including chemical residues and contaminants, and its wide range in terms of pH variation (anywhere from 3 to 10), there is, in general, no continuity of odour between the smell of urine malodours arising from the same or from different sources. As a result, it is difficult to provide an evaluation method that is able to produce reliable and repeatable results in the evaluation of urine malodour- reducing compositions for use against a wide spectrum of urine malodours.

A number of urine odour controlling methods and compositions have been described in the literature. For instance, carbon is e.g. in the form of activated carbon well-known for its ability to adsorb odoriferous molecules.

U.S. Pat. No. 3,903,259 concerns a method of deodorising diapers and human excreta comprising applying to the diapers or the excreta a chemical composition which in its simplest form consists of an acidic material, an antibiotic material, and a solvent. The impregnating composition may also contain a chelating agent and a wetting agent.

U.S. Pat. No. 3,935,862 discloses a disposable diaper comprising means for inhibiting ammonia formation therein including an aminopolycarboxylic acid compound in an amount of at least 0.001 g per square inch.

U.S. Pat. No. 5,593,398 discloses protective underwear with malodorous flatus filter comprising activated carbon as the malodour controlling agent.

Evaluation methods to identify malodour-reducing compositions generally rely on olfactive assessments by experts. In order to accurately establish standards of comparison for such methods, reliable urine malodour samples are needed that have a stable, consistent urine malodour and are essentially free from any odoriferous contaminants. Thus, the development of suitable, synthetic urine malodour samples would improve evaluation methods by providing experts with an accurate standard baseline olfactive reading for urine malodours by which to determine malodour-reduction and/or counteraction.

A number of synthetic urine compositions are disclosed in the literature. These include U.S. Pat. No. 6,306,422 (Batich); U.S. Pat. No. 5,328,954 (Sarangapani); U.S. Pat. No. 5,489,281 (Watanabe); and U.S. Pat. No. 4,146,644 (Griffith). However, these references are all concerned with the use of synthetic urine compositions for medical purposes and are not concerned with the odour of the urine compositions.

There exists a need for stable synthetic urine malodour compositions that allow for the evaluation of malodour-reducing compositions suitable for malodour suppression over a broad spectrum of urine odours, such as the odours associated with urine in hygiene products.

Summary of the Invention

It is an object of this invention to provide synthetic urine malodour compositions and methods for their manufacture.

Accordingly, synthetic urine malodour compositions are claimed. These urine malodour compositions comprise urea, ammonium chloride, sodium chloride, disodium hydrogen orthophosphate, ammonia, trimethylamine, acetic acid and water and, optionally, 5α- Androst-16-en-3-one and/or isovaleric acid.

Thus, the synthetic urine malodour compositions of the present invention can provide a reproducible urine malodour simulating the natural odour of e.g. human urine across a wide age range, for use e.g. in a method of evaluating a fragrance composition for its performance against urine malodour in a reliable and repeatable manner. Additionally, because the urine malodour compositions are synthetic, they do not necessarily contain bacteria. Such compositions are therefore relatively stable.

Preferably, the synthetic urine malodour compositions of this invention have a pH between 8 and 10.

A method for manufacturing synthetic urine malodour compositions is also disclosed. The method involves mixing together the above ingredients typically at concentrations as detailed in table 1.

Detailed Description of the Invention

While urine may at varying times contain a wide range of chemical compounds, it has been discovered that an effective synthetic urine malodour composition may comprise: urea, ammonium chloride, sodium chloride, disodium hydrogen orthophosphate, ammonia, trimethylamine, acetic acid and water and, optionally, 5α-Androst-16-en-3-one and/or isovaleric acid.

This invention also includes a method of making synthetic urine malodour compositions that include mixing the components specified above to produce a base solution. The order of addition of components is in general not critical and may be decided for the convenience of the formulator and according to the feedstock available. For example the very volatile compound, ammonia, is best added to the composition under condition that minimizes evaporate loss. Also disclosed is a method of using synthetic urine solution to evaluate fragrance compositions for their performance against urine malodours.

It is a further object of this invention to provide synthetic urine malodour compositions that are capable of retaining their viability and utility for extended periods of time.

According to the invention there is provided a method of evaluating a fragrance composition for its performance against urine malodour comprising combining the fragrance with a urine malodour composition according to the invention, and assessing the combination for perception of urine malodour.

Typical sources of urine malodours, against which consumer products, comprising malodour-reducing compositions that have been identified through evaluation methods using synthetic urine malodour compositions according to this invention, may be used, include, but are not limited to, rest rooms, sewers, incontinence pads, nappies and cat litter.

Preferably, the consumer products are hygiene products, even more preferably sanitary articles, and especially diapers and/or incontinence pads. For use in the evaluation of fragrances in malodour counteraction compositions for use in sanitary products, the synthetic urine malodour compositions of this invention can reproduce a wide range of urine malodours, including malodours ranging from those associated with babies to those associated with incontinent adults.

Once the synthetic urine malodour composition is prepared it is best to stored in a sealed container under refrigeration to maintain a potent odour.

The term "hygiene product" covers any product suitable for adsorbing or collecting urine and the like. Examples of hygiene products contemplated include diapers and adult incontinence products.

Hygiene products typically comprise an absorbing material such as polyacrylate superabsorbers. These superabsorbers are capable of absorbing many times their own weight in liquid, such as urine, making it possible to provide thin and less bulky hygiene products capable of holding an increasing amount of liquid before leaking the fluid. These increased amounts of liquid in the hygiene product increase the malodour problem.

In the context of the present invention the term "malodour" means an unpleasant or pungent bad smell caused by any of a variety of compounds e.g. ammonia.

The term "absorbing material" covers all kinds of materials capable of holding back liquids.

The term "malodour-reducing" or "malodour-reduction" means that the malodour determined by a test panel is assessed to be less pronounced in comparison to a corresponding standard sample. Examples

1. Synthetic Urine Malodour

A base solution (based on constituents commonly found in urine) comprising 2.5g urea, 0.3 g NH₄Cl, 0.9g NaCl and 0.25g Disodium Hydrogen Orthophosphate was prepared in lOOg distilled water. See Table 2.

Three 1Og aliquots of the abovementioned base solution were taken and ammonia, trimethylamine, glacial acetic acid, isovaleric acid and optionally 5-α-Androst-16-en-3-one were added in the proportions given in table 3 to give urine malodour models A, B and C.

Table 2: Base Composition

Ingredients CAS Number % w/w % w/w % w/w

Urea 57-13-6 2.5 2.5 2.5

Ammonium chloride 12125-02-9 0.3 0.3 0.3

Sodium chloride 7647-14-5 0.9 0.9 0.9

Disodium Hydrogen

7558-79-4 0.25 0.25 0.25 Orthophosphate

Table 3: Additional Components

2. Evaluation of Urine Malodour Quality

2ml aliquots of each of Model Samples A, B and C were individually placed on separate incontinence pads. One minute thereafter, a three member panel of experts, skilled in urine malodour evaluation, performed an olfactory evaluation for detection of urine malodour and recorded their observations. AU tests were performed with no member of the panel being aware of the identity of the material being tested.

The results of the above evaluation are shown in Table 4.

3. Typical Malodour Counteraction Evaluation Protocol

To determine the performance of possible malodour-reducing compositions against urine malodours, the following protocols may be used incorporating synthetic urine malodour compositions of this invention:

(A) Performance is evaluated by placing a sample (e.g. 3ml) of synthetic urine malodour in a suitable (e.g. 15 ml) uncapped wide-mouth jar. This jar is then placed into a suitable larger wide-mouth jar (e.g. 500 ml) that also contains test malodour-reducing composition (e.g. 1 ml) in an uncapped wide-mouth jar (e.g. 15ml). The large jar is then capped and the system left to equilibrate prior to evaluation.

(B) Panellists then may rate the headspace for (1) total intensity, (2) malodour intensity, (3) overall like/dislike (hedonics). Panellists may then be provided with an identified sample of malodour as a reference. Each group of samples presented to the panel preferably contains an unidentified positive control (test malodour-reducing composition with no synthetic urine malodour), two unidentified negative controls (synthetic urine malodour with no test malodour-reducing composition) and up to twelve test samples (each test malodour- reducing composition is preferably presented in duplicate or triplicate).

At least 20 assessments are made of each sample, or sufficient to demonstrate a suitable test of discrimination where significant sensory differences occur. For example, sufficient panellists should be available and trained such that a change of 10% in the odour intensity of the malodour standard should be significantly discriminable at the 95% confidence level.

The results of the assessments are analysed using Analysis of Variance (ANOVA) and multiple comparison tests.

It is to be noted that evaluations are commonly carried out by 18-24 panellists who have been extensively screened for their olfactory acuity and trained in a quantitative method for rating sensory intensity. The preferred method is Magnitude Estimation.

Magnitude estimation of odour intensities provides normally distributed data that can be analysed by parametric statistical techniques. For information on Magnitude Estimation, see ASTM Document #E1697-95, Standard Test Method for Unipolar Magnitude Estimation of Sensory Attributes, available from ASTM, 100 Barr Harbor Drive, West Conshohocken, Pa. 19428-2959. Panellist performance is constantly monitored and reviewed.

The results of these evaluations maybe expressed in terms of malodour-reduction, change in overall intensity and improvement in hedonics.

Candidate malodour-reducing compositions that are identified as able to be used to reduce the perception of urine malodours may then be incorporated into consumer products as required. It is understood that the compositions and method of the present invention are not restricted to any particular physical mode or product form, and may be contained for example and not as the limitation to the present invention, in aqueous and non-aqueous products, foams, powders, granules, gels, aerosols, non-aerosols, waxes, microencapsulated vehicles, phase- change microencapsulated vehicles, and the like.

Compositions of the present invention may be used in a number of malodorous urine containing environments or products. For example, and not as a limitation to the present invention, environments such as cat litter, sewers and rest rooms, and for products for bathroom care, room freshening, adult incontinence, household and hard surface cleaning, and the like.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

1. A synthetic urine malodour composition comprising urea, ammonium chloride, sodium chloride, disodium hydrogen orthophosphate, ammonia, trimetliylamine, acetic acid and water.

2. A composition according to claim 1, which further comprises isovaleric acid.

3. A composition according to claim 1 or 2, which further comprises 5α-Androst-16-en- 3 -one.

4. A composition according to any one preceding claim, which has a pH of from 8 to 10.

5. A composition according to any one preceding claim, which comprises from 1 to 3 wt % urea.

6. A composition according to any one preceding claim, which comprises from 0.1 to 0.5 wt % ammonium chloride.

7. A composition according to any one preceding claim, which comprises from 0.5 to 1.5 wt % sodium chloride.

8. A composition according to any preceding claim, which comprises from 0.1 to 0.4 disodium hydrogen orthophosphate.

9. A composition according to any one preceding claim, which comprises from 0.05 to 0.15 wt % ammonia.

10. A composition according to any one preceding claim, which comprises from 0.001 to 0.02 wt % trimethylamine.

11. A composition according to any one preceding claim, which comprises from 0.01 to 0.07 wt % acetic acid.

12. A composition according to any one of claims 2 to 11, which comprises up to 0.002 wt % isovaleric acid.

13. A composition according to any one of claims 3 to 12, which comprises up to 2 x 10^'8 wt % 5α-Androst-16-en-3-one.

14. A method of preparing a synthetic urine malodour composition, comprising mixing together urea, ammonium chloride, sodium chloride, disodium hydrogen orthophosphate, ammonia, trimethylamine, acetic acid and water.

15. A method of evaluating a fragrance composition for its performance against urine malodour comprising combining the fragrance with a urine malodour composition according to any one of claims 1 to 13, and assessing the combination for perception of urine malodour.