DK170521B1 - Process for producing a stable coal tar shampoo, and the shampoo which is produced in the process - Google Patents

Description

DK 170521 B1 i

The present invention relates to a particular process for producing a unique novel coal tar shampoo and, more particularly, to a process which enables consistent replication of a coal tar shampoo at a given pH which is of a clear light color and is capable of maintaining its clarity and color, as well as the preselected viscosity over time, well beyond the durability that has heretofore been accepted as inevitable. Furthermore, the invention relates to the shampoo produced by the process.

Soil-containing shampoo systems have so far been available for therapeutic use to control specified dermatological conditions such as seborrhoea, psoriasis, and subacute and chronic eczematous conditions on the scalp. While such products have been well recognized as being capable of meeting the stated therapeutic purposes, such products have the inability to maintain a stable viscosity, color or clarity over time, i.e. an economically viable durability, caused heavy losses and made the product extremely expensive. Furthermore, the desired pH value for such preparations was extremely difficult to reproduce consistently, further increasing unit costs. Another major problem with these previous products was the lack of stability of their viscosity, which has decreased as much as 1,700 cps in aging, with the desired viscosity for such products ranging from 5,000 to 10,000 cps. Furthermore, aging and exposure to heat have so far caused a deterioration of both the color and the clarity of the previously known products to an appearance which was completely unacceptable to the ordinary consumer. All in all, these problems have caused such products to be subject to a disproportionate number of returns.

Successful resolution of the aforementioned problems with previously known coal tar shampoos is far more significant than economic ones. Due to the aesthetically unattractive nature of a dark and obscure low viscosity product, consumers often do not use the product as consistently as they should. In order for the consumer to recognize the improvement in his scalp condition, he or she must use the product continuously. A charcoal shampoo with better viscosity, color and clarity, on the other hand, will promote good regulatory use and is therefore therapeutically beneficial to the user. Thus, eliminating the problems that hitherto known cultured shampoos have suffered will produce a product whose properties make it comfortable to use and encourage the patient to better follow the prescription.

The healthcare industry has previously addressed such shelf-life problems in conventional shampoos with some degree of success. For example, the stability of the viscosity of such formulations has been resolved by the addition of rubbers and polymers, while the pH reproducibility has been realized using selected buffers. However, these traditional solutions have been found not to work by attempting to solve the stated problems in systems containing raw coal tar as an active ingredient. Also, no technique has been previously described that solves the problems that arise with the color and clarity of charcoal tar shampoo systems in aging.

The present invention is based on the discovery of a novel and unique method of producing a clear, light coal tar shampoo which is particularly stable in viscosity, color and clarity over time, thus achieving economically viable durability , and the huge waste that has hitherto been associated with such a product is eliminated. In addition, this new method results in a product with a more uniform pH. Furthermore, the product prepared by the novel method of the invention retains all the traditional therapeutic values that have hitherto been associated with coal tar shampoos, i.e. that it is effective in controlling symptoms of seborrhea, dandruff, psoriasis and subacute and chronic eczema of the scalp.

Specifically, the unique process rests on the observation that unique and unexpected benefits can be obtained when the ratio of fatty acid ethanol amide ("Fatty Acid DEA") to cocamidopropyl betaine ("CAPB") in the coal tar shampoo formulation is strictly limited to the range of 1, 3 to 2.6: 1, the preservative and fragrance are deliberately premixed in the Fatty Acid DEA phase without heat prior to introduction into the master portion, and the 30-year coal tar shampoo is neutralized at the beginning of the process cycle rather than at its end, as has hitherto been the usual practice.

Accordingly, the object of the invention is to provide a new and unique process for the preparation of an improved coal tar shampoo which results in a clear, light product capable of retaining its clarity, color and viscosity upon aging.

The present invention rests on the provision of a successful solution to serious product problems that have existed in known carbon dioxide shampoos, namely the inability of such products to maintain the attractive color and clarity after aging or exposure and maintain a freshly bottled. product viscosity standard grade and the ability to consistently achieve a preselected pH value during fabrication.

5 While trying to solve the problems of the prior art, it was learned that the order of addition of one or more of the several components included in the shampoo is critical and that a critical relationship exists as well as the ratio of fatty acid DEA and CAPB are concerned.

10 Fatty acid ethanol amides have so far been mainly proposed for use in shampoo formulations as foaming enhancers and viscosity builders. However, in the prior art there has been no suggestion that a critical relationship could exist between the fatty acid diethanolamide and CAPB which could improve shampoo stability. The amount of fatty acid DEA according to the invention will generally be in the range of approx. 3 to approx. 5% by weight based on the total weight of the composition. The CAPB will usually be used in concentrations ranging from approx. 1 to approx. 4% on the same basis. The specific amount of each compound should be selected such that the ratio of fatty acid DEA / CAPB 20 ranges from 1.3: 1 to 2.6: 1.

Fatty Acid DEAet can be selected from the commercially available products where the fatty acid derivative is a laurine, myristine, oil, palmitic, stearic, tall oil or coconut fatty acid derivative. In the preferred embodiment of the invention, optimum results are obtained by using the coconut fatty acid derivative or lauric acid derivative.

The method according to the invention is characterized by the method of claim 1.

A practical embodiment of the invention in which a coal tar shampoo having all of the above-mentioned desired properties while producing the costly and troublesome problems suffered by the prior art products will now be described. First, a homogeneous particle-free solution containing sodium lauryl ether sulfate ("SLES"), coal tar extract and purified water USP (hereinafter referred to as "Solution I") is prepared.

Next, prepared for use as later discussed separate solutions of anhydrous citric acid USP and sodium chloride (Solution II and III, respectively).

Then a mixture of fatty acid DEA, methyl paraben and propylparaben is mixed until the parabens are completely dissolved. Then, the desired fragrance substance is added to the fatty acid DEA-paraben mixture and thoroughly mixed therewith (Solution IV). This solution is covered and set aside until used as described later.

To complete the preparation of the new and improved coal tar shampoo, coal tar extract SLES solution (I) is placed in a batch mixing tank of appropriate dimensions in which the mixer runs at moderate speed. Then, the following ingredients are added one at a time under continuous mixing to ensure that the newly added ingredient is completely dissolved before the subsequent ingredient is added: Tetrasodium EDTA, imidazolidinylurea, citric acid solution (II), coca-midopropyl betaine ("CAPD") and fatty acid DEA paraben fragrance solution (IV). Note that the weight ratio of Fatty Acid DEA in Solution IV to CAPD must be between 1.3: 1 and 2.6: 1 if all the advantages of the invention are to be achieved.

After preparing the aforementioned mixture, the pH of the portion is measured using conventional techniques and additional citric acid solution (Solution II) is added as needed to bring the pH of the solution to 7.6. Finally, the viscosity in cps is measured using conventional techniques and sodium chloride solution 20 (Solution III) is added in sufficient quantity to give a reading of 8,000 cps. Both the citric and sodium chloride solution are added using conventional techniques, i.e. only a portion, for example 75% of the theoretically necessary reagent, is added and mixed. Then another reading is performed and the procedure is repeated until the desired value is reached. Following the procedure of adding only part of the stoichiometric adjustment required avoids exceeding the desired limit.

The portion is now ready for packaging in containers of any desired size using conventional, sterile filling equipment.

To further illustrate the practice of the invention, the following examples are given. '

Example 1 35 A portion of coal tar shampoo is prepared to produce 3,785 liters of finished product. A basic solution is prepared by introducing 1,495.5 kg of sodium lauryl ether sulfate into a stainless steel blend tank of appropriate size, after which 81.5 kg of coal tar extract is added under stirring and the mixture is mixed until homogeneous. Then 2,046.7 kg of purified water USP (United States Pharmacopoeia) is added and stirring is continued until the mixture is homogeneous. The homogeneous solution is then filtered to remove unwanted particulate material therefrom to produce 3,623.7 kg of coal tar extract SLES solution.

A citric acid solution is prepared in a separate stainless steel container of appropriate size by mixing 6.8 kg of anhydrous citric acid USP and 6.8 kg of purified water USP and solution with a propeller, among others. This solution is then stored until needed as set out below.

A sodium chloride solution is prepared in a separate stainless steel container of appropriate size by mixing approx. 25% by weight sodium chloride and approx. 75% by weight of purified water USP until all the sodium chloride it is dissolved and the resulting solution is stored until needed as indicated below.

A solution of coconut fatty acid diethanol amide ("Coconut fatty acid DEA") is prepared by introducing 148.8 kg of Coconut fatty acid DEA into a stainless steel container of appropriate size and provided with a mixer, after which 7.7 kg of methyl paraben USP and 2.0 kg of propylparaben USP ten 1-20 is added until the parabenes are completely dissolved. Then, 38.6 kg of a suitable fragrance compound is added and mixed until the compound is completely dissolved, then the container is covered and stored for addition to the main portion as set forth below.

The shampoo formulation is supplemented by applying the coal tar extract-SLES solution to the batch mixing tank. While the mixer is running at moderate speed, the following ingredients are added separately, dissolving or thoroughly mixing the added ingredient before the next ingredient is added. The first ingredient added to the 3,623.7 kg of coal tar extract SLES solution is 1.2 kg of Tetrasodium EDTA 30 (technical grade). Then add 19.3 kg of imidazolidinylurea and mix thoroughly. Then 7.0 kg of citric acid solution is added followed by 58.0 kg of cocamidopropyl betaine. After the betaine has been thoroughly mixed in the portion, 197.0 kg of the Coconut fatty acid DEA paraben fragrance solution is transferred to the portioning tank from the covered container and also thoroughly mixed with the portion.

After the portion pH has reached a reasonable equilibrium, the pH value is measured using conventional quality control techniques.

Then further citric acid solution is added to the extent necessary to bring the pH of the portion to 7.6. Then, sodium chloride solution is mixed, as needed, in an amount sufficient to provide the portion with a viscosity of 8,000 cps using standard measurement techniques. The portion is ready for packaging.

5

Example 2 *

Several samples of product prepared according to Example 1 were compared with prior art product to determine the stability of clarity upon exposure to storage at 40 ° C (see Table A) and 50 ° C (see Table B). The samples were checked periodically for obscurity. The age of the sample, when obscurity was first observed, was recorded. As can be seen from the data, samples prepared in accordance with the invention lasted substantially longer before showing any obscurity. Thus, at 40 ° C, it averaged 4.7 months before cloudiness occurred in the product of the invention, as opposed to the 1.5 months on average obtained with the prior art product. At 50 ° C, it lasted an average of 2.1 months before cloudiness occurred in the product of the invention, whereas for the prior art product it lasted an average of 1.4 months. The ability to maintain clarity is an essential feature of the maintenance of cosmetic for traction and marketable durability.

TABLE A

Clarity stability after storage at 40 ° C

Method according to Method according to

Lot No. of known technique_ invention_ 1001 2 months 1002 1 month 1003 1 month 30 1004 2 months 2001 5 months 2002 6 months * 2003 3 months 2004 5 months 35 2005 5 months 2006 4 months 2007 5 months

Average 1.5 months 4.7 months 7 DK 170521 B1

TABLE B

Clarity stability after storage at 5 ° C

Process according to Method according to 5 Lot No. of known technique_ invention_ 1001 1 month 1002 1 month 1003 1 month 1004 2 months 10 1005 2 months 2001 2 months 2002 3 months 2003 2 months 2004 2 months 15 2005 2 months 2006 2 months 2007 2 months

Average 1.4 months 2.1 months 20 The prior art shampoo formulation has a fatty acid DEA: CAPB ratio of 3.0: 1 and above, whereas the present shampoo has a fatty acid DEA: CAPB ratio of 1.3-2.6: first

According to the present invention, fragrance and preservative are premixed in fatty acid DEA, whereas the prior art adds fragrance and preservative separately and without first mixing it with fatty acid DEA.

Example 3

Several samples of product made according to the invention are obtained for comparative color stability testing against a similar number of samples of product of the prior art. One half of the samples were stored at 40 ° C (see Table C) and the other half of the samples stored at 50 ° C (see Table D). Each sample was measured at 2-week intervals to obtain absorbance readings at 700 nm, with the readings 35 representing spectrophotometric measurements of darkness using standard measurement techniques, with higher numbers indicating a darker color.

As can be seen from the data, the prior art product had on average 0.436 absorbance units darkened after 12 weeks at 40 ° C and on average 1.282 units darkened after 12 weeks at 50 ° C. IN

In contrast, the product of the invention had only become 0.132 units darker after 12 weeks at 40 ° C and only 0.267 units darker after 12 weeks at 50 ° C.

TABLE C

5 Stability of color measurement after storage at 408C

ir

Prior Art Tests Tests According to the Invention Period 1001 1002 1005 2001 2003 2005

Start 0.059 0.077 0.07 0.072 0.074 0.073 10 2 weeks 0.094 0.135 0.152 0.106 4 weeks 0.104 0.160 0.109 0.106 0.123 6 weeks 0.126 0.174 0.134 0.125 8 weeks 0.166 0.193 0.155 0.146 0.177 10 weeks 0.202 15 12 weeks 0.216 0.139 1.019 0.189 0.227 0.117 0.153 0.125

Through average 20 change 0.436 0.132

TABLE D

Stability of color measurement after storage at 50 ° C

25 Prior Art Samples Samples according to the invention

Period 1001 1002 1005 2001 2003 2005

Start 0.059 0.077 0.07 0.072 0.074 0.073 2 weeks 0.117 0.179 0.133 0.175 0.122 4 weeks 0.146 0.193 0.164 0.145 0.231 0.143 30 6 weeks 0.189 0.223 0.263 0.242 0.195 8 weeks 0.217 0.221 0.387 0.246 0.288 0.226 10 weeks 0.352 1.058 0.31 1,594 0.337 0.356 0.327 Change 0.722 1.602 1.524 0.265 0.282 0.254

Average! ig change 1.228 0.267 35 DK 170521 B1 g

Example 4

Samples of product prepared according to the invention were compared with a similar number of prior art samples (i.e. product prepared by previous methodology) to determine viscosity stability over an extended period of time. The product was stored at room temperature and viscosity measured in cps using standard viscosity measurement techniques. As shown in Table E, the viscosity drop for the prior art product ranged from 2,930 up to 5,129 cps over an 18 month period, while the product manufactured according to the invention not only maintained its viscosity but increased its viscosity slightly.

TABLE E

Viscosity stability after storage at room temperature (Viscosity measured at 25 ° C1 15

Samples of the Prior Art Samples of the Invention Period 1003 1001 1006 2004 2003 2001

Start 6250 4350 6533 9100 8767 9232 4 months 4165 3147 4900 9300 8200 11000 20 12 months 1547 1520 3500 10300 11067 12967 18 months 1130 1420 2500 9833 11200 13000 Amendment -5129 -2930 -4033 +733 +2433 +3767

Example 5 Several batches of coal tar extract shampoo were prepared using both prior art methodology and the process of the invention. After completion of the formulation and before packaging, the pH of each portion was measured using conventional methodology to determine its replication ease. As shown in Table F, the prior art method yielded a standard deviation of 0.23, while the method of the invention yielded a standard deviation of 0.10.

35 10 DK 170521 B1

TABLE F

The pH value immediately after manufacture

Process according to Method according to 5 Lot no. Of the prior art_ 1001 7.18 1007 6.67 1008 7.13 1003 7.05 10 1005 7.23 1009 6.96 1010 7.39 2008 7.66 2009 7.71 15 2010 7.50 2004 7.47 2005 7.67 2006 7.69 Standard deviation 0.23 0.10

Example 6

A coal tar extract shampoo was prepared using the method of Example 1 with apple solutions of the following composition:

Solution I

Sodium lauryl ether sulfate 41.12%

Coal tar extract 4.51% POE (20) sorbitan monolaurate 5.10% 30 Purified water, USP 49.27%

Solution II

Citric acid 50%

Purified water, USP 50%

Solution III

Sodium Chloride 25%

Purified water, USP 75%

Solution IV

Lauric Acid DEA 74.26% 11 DK 170521 B1

Methyl paraben, USP 3.96%

Propylparaben, USP 1.98%

Fragrance Compound 19.80%

Solution V

Solution I 88.27%

Solution II 0.15% EDTA 0.03%

0.5% imidazolidinylurea

Cocoamidopropyl betaine 2.85% Sodium lauryl ether sulfate (86%) 3.0%

Solution IV 5.05%

Solution III qs

The product thus produced was tested and found to have all the properties shown in Examples 2, 3, 4 and 5.

Example 7

A coal tar extract shampoo was prepared using the procedure of Example 1 with solutions of the following composition:

Solution I

Sodium lauryl ether sulfate 40.00%

Carrot extract 2,00%

Purified water, USP 58.00%

25 Solution II

Citric acid 50%

Purified water, USP 50%

Solution III

Sodium Chloride 25% 30 Purified Water, USP 75%

Solution IV

Coconut fatty acid DEA 80.25%

Methyl paraben, USP 4.93%

Propylparaben, USP 2.47% Scent Compound 12.35%

Solution V

Solution I 93.60%

Solution II 0.15% 12 DK 170521 B1 EDTA 0.03%

Imidazoli di nylurea 0.5%

Cocoamidopropyl betaine 2.0%

Solution IV 4.05% 5 Solution III qs

The product thus produced was tested and found to have all the properties shown in Examples 2, 3, 4 and 5.

Example 8 A coal tar extract shampoo was prepared using the procedure of Example 1 with solutions of the following composition:

Solution I

Sodium lauryl ether sulfate 41.0% Coal tar extract 2.25%

Purified water, USP 56.75%

Solution II

Citric acid 50%

Purified water, USP 50%

20 Solution III

Sodium Chloride 25%

Purified water, USP 75%

Solution IV

Coconut fatty acid DEA 86.20% Methyl paraben, USP 3.45%

Propylparaben, USP 1.72%

Fragrance Compound 8.62%

Solution V

Solution I 91.2% Solution II 0.15% EDTA 0.03%%

Imidazolidinylurea 0.3%

Cocoamidopropyl betaine 2.5%

Solution IV 5.8% 1 35 Solution III qs

The product thus produced was tested and found to have all the properties shown in Examples 2, 3, 4 and 5.

DK 170521 B1 13

Example 9

A coal tar extract shampoo was prepared using the procedure of Example 1 with solutions of the following composition:

5 Solution I

Sodium lauryl ether sulfate 41.2%

Coal tar extract 2.25%

Purified water, USP 56.55%

Solution II

Citric acid 50%

Purified water, USP 50%

Solution III

Sodium Chloride 25%

Purified water, USP 75%

Solution IV

Lauric Acid DEA 74.75%

Methyl paraben, USP 3.88%

Propylparaben, USP 1.95%

Fragrance Compound 19.42%

20 Solution V

Solution I 92.67%

Solution II 0.15% EDTA 0.03%

Imidazolidinylurea 0.5% Cocoamidopropyl betaine 1.5%

Solution IV 5.15%

Solution III qs

The product thus obtained was tested and found to have all the properties shown in Examples 2, 3, 4 and 5.

Example 10

A coal tar extract shampoo was prepared using the procedure of Example 1 with solutions of the following composition:

Solution I

48.0% sodium lauryl ether sulfate

Coal tar extract 2.25% 35 14 DK 170521 B1

Purified water, USP 49.75%

Solution II

Citric acid 50%

Purified water, USP 50%

5 Solution III

Sodium Chloride 25% *

Purified water, USP 75%

Solution IV

Lauric Acid DEA 69.76% Methyl paraben, USP 4.66%

Propylparaben, USP 2.33%

Fragrance Compound 23.25%

Solution V

Solution I 86.0% Solution II 0.15% EDTA 0.03%

0.5% imidazolidinylurea

Cocoamidopropyl betaine 1.25%

Solution IV 4.30% 20 Solution III qs

Purified water, USP 7.75%

The product thus produced was tested and found to have all the properties shown in Examples 2, 3, 4 and 5.

25

Example 11

A coal tar extract shampoo was prepared using the procedure of Example 1 with solutions of the following composition:

30 Solution I

Sodium lauryl ether sulfate 41.27%

Coal tar extract 2.25% -

Purified water, USP 49.75%

Solution II% 35 Citric acid 50%

Purified water, USP 50%

Solution III

Sodium Chloride 25%

Claims (9)

1. Process for Preparing a Coal Tar Hollow Shampoo with Stable Viscosity, Color and Clarity CHARACTERISTICS OF PRIORING A SUMMARY OF SEPARATE SOLUTIONS CONTAINING, BY WEIGHT% AND, respectively, a) from 40 to 48% Sodium Lauryl Ether Sulfate (SLES) which is free of particulate matter, from 2 to 5% carbon tar extract and from ca. 47 to approx. 58% purified water USP (here called "Solution I"), 30 b) 50% anhydrous citric acid USP and 50% purified water USP (here called "Solution ΙΓ), c) 25% sodium chloride and 75% purified water USP (here called "Solution III"), d) 69 to 81% fatty acid ethanol amide (Fatty Acid DEA), 4.9 to 7.4% 35 paraben in the form of methyl paraben, propylparaben or mixtures thereof, and from 8 to 24% fragrance (herein called "Solution IV"), in% by weight of the final formulation, introduces from about 88 to about 94% of Solution I into a stainless steel blend tank under moderate mixing, set DK 170521 B1 ter about 0.03% Tetrasodium EDTA for Solution Into and thoroughly blending therein to form a first mixture therewith, then adding from about 0.3 to about 0.5% imidazolidinylurea to the first mixture and mixing thoroughly to form a second mixture, from about 0, 1 to 5, about 0.2% of Solution II to the second mixture to form a third mixture, mixes from about 1.2 to about 2.9% of cocamidopro pylbetaine * ("CAPB") in the third mixture to form a fourth mixture with CAPB thoroughly mixed therewith and providing this mixture with a fatty acid DEA: CAPB ratio of at least 1.3: 1 and at most 2.6: 1, then blend -10 there from approx. 4.0 to approx. 5.8% of Solution IV with this fourth mixture to form a fifth mixture, measures the pH of the fifth mixture, sets the pH of the fifth mixture to 7.6, measures the viscosity, sets the viscosity of approx. 8000 cps and packaging the pH-adjusted fifth mix. 15 Process according to claim 1, characterized in that Solution II is mixed in the fifth mixture in an amount sufficient to give a pH value = 7.6. Process according to claim 1, characterized in that Solution III is mixed in the pH-adjusted fifth mixture in an amount sufficient to provide the portion with a viscosity of approx. 8,000 cps. 4. A process according to claim 1, 2 or 3 characterized in that the fatty acid DEA is in the form of lauric, myristine, oil, palmitic, stearic, tall oil or coconut fatty acid DEA. 5 Coal tar extract 1.75-4.7 Anhydrous citric acid 0.05-0.1 Fatty acid DEA 3-5 Methyl paraben, USP 0.8-3.2 Propylparaben, USP 0.2-0.8 10 EDTA 0.03 Imidazolidinylurea 0.3-0.5 Cocoamidopropyl Betaine (CAPB) 1-4 Purified Water, USP 36.67-57.65 Fragrance Compound 0.32-1.4 with the weight ratio of Fatty Acid DEA to CAPB being at least 1 , 3: 1 and a maximum of 2.6: 1. 5. A process according to claim 1, characterized in that the fatty acid DEA is cocodiethanolamide. 30 5 Propylparaben, USP 1.95% Fragrance Compound 19.42% Solution V Solution I 92.77% Solution II 0.15% EDTA 0.03% Imidazolidinylurea 0.5% Cocoamidopropyl betaine 1.5% Solution IV 5.15% Solution III qs The product thus obtained was tested and found to have all the properties shown in Examples 2, 3, 4 and 5. From the foregoing, it will be seen that 20 methods and compositions have been described herein which fulfill all of the foregoing purposes in a remarkably unexpected manner. Charcoal tar hole shampoo with stable viscosity, color and clarity upon standing characterized in that it is prepared by the process of any one of claims 1-5 and that it contains sodium amyl ether sulfate ("SLES"), coal tar extract, anhydrous citric acid 35 USP, sodium chloride, fatty acid DEA, methyl paraben, propylparaben, a fragrance, tetrasodium EDTA, imidazolidinylurea, cocamidopropyl betaine ("CAPB") and purified water, the ratio of fatty acid DEA to CAPB being at least 1.3: 1 and at most 2 , 6: 1. DK 170521 Bl 7. Cultured tar shampoo with stable viscosity, color and clarity upon standing according to claim 6, characterized in that it consists in weight% of: 8. Charcoal tar shampoo according to claim 7, characterized in that the 20 fatty acid DEA is in the form of lauric, myristine, oil, palm, n, stearic, tall oil or coconut fatty acid DEA. 9. Charcoal tar shampoo according to claim 8, characterized in that the fatty acid DEA is cocodiethanol amide fatty acid. 25 30