FIELD OF THE INVENTION
The present invention relates to depilatory compositions. More particularly, the present invention relates to a hair removal gel.
BACKGROUND OF THE INVENTION
Currently, the removal of hair from the human body has received considerable attention due to reasons of hygiene and aesthetic appeal. The hair and hair follicles can be removed by surgical methods, lasers or by electrolysis. Although traditionally hair has been removed by the use of tweezers, razors or other instruments; however, compared to surgical procedures such methods do not produce long lasting effects. Moreover, the use of hair removal instruments is generally confined to removal of hair from along the eyebrows, nostrils or arm pits. Creams or cold waxes have been formulated for the purpose of achieving more lasting hair removal over greater skin areas than is possible by plucking out individual hairs from a localized part of the body.
Depilatory formulation is a cosmetic preparation used to remove hair from the skin on the human body. The most common active ingredient in chemical depilatories is an alkali or alkaline earth metal thioglycolate, or thioglycolic acid which weakens the hair by breaking the disulfide bonds in the keratin of hair. When enough chemical bonds are broken, the hair can be rubbed or scraped off where it emerges from its follicle. The thioglycolate salt is formed by reacting an alkali or alkaline earth metal hydroxide with thioglycolic acid. An excess of alkali or alkaline earth metal hydroxide allows the thioglycolic acid to react with the cystine in keratin. The chemical reaction is as follows:
2SH-CH2-COOH (thioglycolic acid) + R-S-S-R (cystine) ? 2R-SH + COOH-CH2-SS-CH2-COOH (dithiodiglycolic acid).
A depilatory composition comprising the active components may be formulated in the form of a powder. Such a composition, prior to its application, is mixed with suitable quantity of water to form a paste. Thereafter, the paste is applied to the skin using a spatula or a hair dyeing brush. After that, the paste is left on the skin for 5 to 10 minutes. Finally, the depilatory is removed with a spoon or spatula and rinsed thoroughly.
However, a depilatory formulation in the form of a powder has numerous drawbacks. The formulation being in the form of a powder is prone to produce a dust cloud, which can be quite irritating on inhalation or contacting the eyes or mucous membrane. A powdered depilatory formulation requires careful mixing with a predetermined quantity of water, leading to longer usage durations for the product. Further, the paste formed from the depilatory powder may not be of optimum consistency, thereby affecting its depilatory efficacy.
Several depilatory compositions have been developed in the art for hair removal purposes; however, fast acting, efficient and safe depilatory compositions are still being sought. Currently, consumers prefer ready to use and fast acting formulations. Commonly used active ingredients in depilatories include thioglycolic acid and its salts, which break down the disulfide bonds in keratin and weaken the hair so that it is easily scraped off where it emerges from the hair follicle. Depilatory compositions which allow for reduced or similar amounts of the active ingredients compared to prior art, along with increased efficacy and safety, and lower incidence of allergic reactions are highly desirable. An increase in the concentration of the active depilatory component in the depilatory composition may improve the performance of said composition. However, increasing the concentration of an active in a depilatory composition may result in several side effects, such as skin irritation, burns, and skin damage, and may not necessarily provide effective and safe depilatory action in a short period of time.
The efficacy of the active component in a formulation may be increased by combining with components that may or may not have a mode of action similar to that of the active component. This phenomenon is termed as synergism and the additional components are termed as synergists. Hence, there remains a need in the art for a depilatory composition comprising thioglycolic acid and its salts and synergists to improve the depilatory efficacy. There is also a need for a depilatory formulation which can achieve effective depilatory action in a short period of time, without producing any side effects.
PCT publication WO2017122020 A1 discloses depilatory compositions comprising a depilatory active, alkali metal hydroxide and an aminoalkylpropanol, where alkali metal hydroxide preferably comprises potassium hydroxide and the aminoalkylpropanol preferably comprises aminomethylpropanol and composition is formulated in gel, mousse, foam, cream, lotion or peelable film.
US patent US4631064A discloses aqueous depilatory compositions containing biguanide and active thiol agent(s) which provide for faster hair removal due to the acceleration by biguanide, allowing the thiol active to more readily exert its depilatory effect.
US patent US6306380B1 discloses oil-in-water emulsion depilatory compositions comprising continuous aqueous phase, depilatory agent substantially free from tertiary amines degrading hair keratin.
US patent publication US20090004128A1 discloses non-irritant rapid-action depilatory composition, comprising at least one bisulphic and/or sulphite compound and an organic reducing agent in a cosmetically acceptable medium formulated in gel, foam, emulsion or cream.
The depilatories may be in the form of cream, gels, roll-ons, powders, aerosol or a mousse prior to use. Regardless of the form, they are expected to achieve and provide certain desirable attributes, such as desirable texture, stable formulations, ease and convenience of use and application, short application times and effective hair removal. Moreover, changing consumer requirements present an opportunity to produce depilatory compositions that are readily available and convenient for the consumer to use and store.
According to “A short communication on formulation and evaluation of depilatories”, in International Journal of Pharmacy Review & Research, Vol 3, Issue 2, 2013, 71-73, by A. Elumalai et al., the qualities of an ideal depilatory are as follows:
i. Non-toxic and non-irritant to the skin.
ii. Fast and efficient in action, preferably causing depilation within five minutes.
iii. Preferably odourless.
iv. Should be stable upon storage.
v. Non-staining/damaging to the clothing.
vi. Cosmetically elegant
Several depilatory compositions have been developed in the art for hair removal purposes; however, efficient and safe depilatory compositions are still being sought. Common active ingredients used in depilatories, include thioglycolic acid and its salts, which break down the disulfide bonds in keratin and sufficiently weaken the hair so that it is easily dislodged from where it emerges from the hair follicle. Depilatory compositions which allow for reduced amounts of the active ingredients, increased safety and lower the incidence of allergic reaction are highly desirable. An increase in the concentration of the active depilatory component in the depilatory composition may improve the performance of said composition. However, increasing the concentration of an active in a depilatory composition may result in several side-effects, such as skin irritation, skin burn and skin damage.
The efficacy of the active component in a formulation may be increased by combining with components that may or may not have a mode of action similar to that of the active component. This phenomenon is termed as synergism and the additional components are termed as synergists.
Hence, there remains a need in the art for a depilatory composition comprising thioglycolate and synergists to improve the depilatory efficacy of thioglycolate. There is also a need for a depilatory formulation which can achieve effective depilatory action in a short period of time. Further, there is also a need to develop an effective depilatory formulation in the form of gel providing several benefits, such as ease of formulation and ease of application, spreading on the skin and removal.
In order to overcome the drawbacks of the prior art, the inventors of the present invention have formulated a depilatory composition in the form of a gel,
OBJECTS OF THE INVENTION
The main object of the present invention is to provide a synergistic depilatory composition which is fast acting, efficient and having a high depilation rate.
It is an object of the present invention to provide a depilatory composition useful for the removal of body hair.
It is a further object of the invention to provide fast acting, efficient and safe depilatory composition for effective removal of unwanted body hair.
It is another object of the present invention to provide effective depilatory action in a short period of time, without producing any side effects.
Another object of the present invention is to provide a synergistic depilatory composition which effectively masks the unpleasant odour of thioglycolic acid or and its salt.
Another object of the invention is to provide a method for utilizing the said depilatory composition.
SUMMARY OF THE INVENTION
According to the present invention there is provided a synergistic depilatory composition comprising: (a) thioglycolic acid or and its salt; (b) sodium gluconate; (c) sodium lactate; (d) alcohol; (e) guanidine carbonate as active ingredients.
In an embodiment of the present invention, thioglycolic acid or and its salt is present in range of 0.5%-30%; sodium gluconate is present in range of 0.01%-10%; sodium lactate is present in range of 0.01%-10%; alcohol is present in range of 0.01%-20% and guanidine carbonate is present in range of 0.5%-20%.
In an embodiment of the present invention, the composition further comprises at least one adjunct ingredient for formulating topical composition
In an embodiment of the present invention, the composition further comprises adjunct ingredients are selected from group selected from aqua, base, thickening agent, moisturizing agent, solubilizer, fragrance and cooling agent.
In an embodiment of the present invention, the composition further comprises water as DM water that in range of 30.0%-90.0%
In an embodiment of the present invention, the composition further comprises at least one hydroxide base that in range of 0.1%-10.0%.
In an embodiment of the present invention, there is provided the composition further comprises a thickening agent that is selected from hydroxy ethyl cellulose.
In an embodiment of the present invention, hydroxy ethyl cellulose is a natrosol HEC 250 HHR (0.5-5.0%) and Aculyn-33 (0.1-4.0%).
In an embodiment of the present invention, the composition further comprises a moisturizing agent
In an embodiment of the present invention, moisturizing agent is selected from the group of urea in the range of about 0.2 to 20.0%.
In an embodiment of the present invention, the composition further comprises a solubilizer that includes tween 20 in the range of about 0.1 to 20.0%.
In an embodiment of the present invention, the composition further comprises fragrance perfume in range of 0.1%-2.0%.
In an embodiment of the present invention, the composition further comprises a cooling agent i.e. methanol in range of 0.001-1.0%
In an embodiment of the present invention, the composition is formulated in form of gel.
In an embodiment of the present invention, the composition depilates up to 98% within ten minutes.
DETAILED DESCRIPTION OF THE INVENTION
Discussed below are some representative embodiments of the current invention. The invention in its broader aspects is not limited to the specific details and representative methods. The illustrative examples are described in this section in connection with the embodiments and methods provided. The invention according to its various aspects is particularly pointed out and distinctly claimed in the attached claims read in view of this specification, and appropriate equivalents.
It is to be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a composition containing “a compound” includes a mixture of two or more compounds. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
The expression of quantity in terms of "% w/w" or “%” means the percentage by weight, relative to the weight of the total solution or composition, unless otherwise specified.
The present invention provides a synergistic depilatory composition comprising, a) one or two depilating agents; b) Chelating agent; c) Acidity regulator d) solvent and adjunct ingredients.
The “depilating agents” used are reducing agent (i.e. hair digesting or decomposing agents) which comprises Potassium thioglycolate, guanidine carbonate, thioglycolic acid or and its salt in the range of about 1.0 % to 20.0%.
The “chelating agent” includes sodium gluconate wherein it is present in the range of about 0.001-1.0%.
The “acidity regulator” includes sodium lactate wherein it is present in the range of about 0.01-10%.
The “solvent” comprises ethyl alcohol and isopropyl alcohol, but preferably isopropyl alcohol in the range of about 0.01-20%.
In accordance with an aspect of the invention, there is provided a synergistic depilatory composition, comprising: (a) Thioglycolate; (b) Sodium gluconate; (c) Sodium lactate; (d) Isopropyl alcohol; and Guanidine carbonate.
In accordance with another aspect of the invention, there is provided a depilatory composition is formulated in the form of a gel, comprising: (a) The synergistic depilatory composition; and (b) Ingredients selected from the group consisting of water, thickening agents, solubilizers, perfumes, solvents, alkali and alkaline earth metal hydroxides, moisturizing agents and combinations thereof.
In accordance with an embodiment of the present invention a synergistic depilatory composition comprising (a) thioglycolate, present in range of 0.5%-30%; (b) sodium gluconate, present in range of 0.01%-10%; (c) sodium lactate, present in range of 0.01%-10%; (d) Isopropyl alcohol, present in range of 0.01%-20%; (e) guanidine carbonate, present in range of 0.5%-20%.
In accordance with an embodiment of the present invention, a variety of conventional additives and adjunct ingredients are commonly used in the art of formulating topically applied compositions. These ingredients may include, but are not limited to, aqua, base, thickening agent, Moisturizing agent, solubilizer, fragrance, cooling agent etc.
The “aqua” includes DM water present in the range of about 30%-90%. The “base” includes sodium hydroxide present in the range of about 0.1-10.0%.
The “Thickening agent” includes Natrosol HEC 250 HHR and Aculyn-33, wherein Natrosol HEC 250 HHR is present in range of 0.5-5.0 and wherein Aculyn-33 present in range of 0.1-4.0.
The “Moisturizing agent” includes urea in the range of about 0.2 to 20.0%.
The “solubilizer” includes Tween 20 in the range of about 0.1 to 20.0%.
The “Fragrance” includes perfumes in a range of about 0.1-2.0%
The “cooling agent” includes methanol in range of 0.001-1.0%.
In accordance with another aspect of the invention, there is provided a depilatory composition is formulated in the form of a gel
Alkali and alkaline earth metal hydroxides result in softening and swelling of hair fibres, thereby facilitating their removal. Commonly used alkali and alkaline earth metal hydroxides include calcium hydroxide and sodium hydroxide.
A thickening agent enhances the consistency, volume and viscosity of cosmetic products, thereby providing more stability and better performance. Thickening agents that may be used in the present invention include hydroxyethylcellulose, xanthan gum, polyacrylic acid and its salts, hydroxypropylmethylcellulose or combinations thereof.
Perfumes play a vital role in cosmetic preparations. Since perfumes are generally oils, they are sparingly soluble in water. Hence, a mixture of water and oil affords a hazy system. It is therefore essential to add a solubilizer along with perfume to prepare a clear and transparent gel. The solubilizers that may be used in the present invention include polysorbate 20, PEG-40 hydrogenated castor oil or combinations thereof.
The hair removing composition of the present invention differs markedly from prior art chemical depilatory in that it is composed of inexpensive, readily available, safe, non-irritating materials and can be utilized at room temperature.
The hair removing compositions of the present invention are non-toxic and non-irritating to even the most sensitive skin area. Moreover they have no offensive odour and can easily be washed off with soap and water, nor does their use create an offensive odour.
The present invention is more particularly described in the following non-limiting examples that are intended as illustrations only since numerous modifications and variations within the scope of the present invention will be apparent to a skilled artisan. Unless otherwise noted, all parts, percentages, and ratios reported in the following examples are on a weight basis, and all reagents used in the examples were obtained or made available from the chemical suppliers.
EXAMPLES
Example 1: Depilatory Formulations
Five different depilatory formulations were produced using the ingredients set forth in table 1 above, each ingredient being present in the compositions in the percentage by weight specified in Table below.
Hair Removal Gel formulation

S.no Ingredients I II III IV V VI
1 DM Water 79 64.6 72.9 67.5 70.5 65.9
2 Natrosol HEC 250 HHR - 2.5 - 1.5 - 2.5
3 Carbopol 934 0.7 - - - - -
4 Xanthan gum - - 0.8 - - -
5 HPMC - - - - 1.2 -
6 Aculyn-22 1.0 1.0 1.0 1.5 0.8 1.0
7 Urea 3.0 5.0 5.0 5.0 3.0 5.0
8 Thioglycolate - 12.5 - 12.5 12.5 12.5
9 Thioglycolic acid 5.0 - 5.0 - - -
10 Sodium gluconate - 0.3 - 0.3 0.3 -
11 Disodium EDTA 0.1 - 0.1 - - -
12 Sodium lactate 1.0 1.0 2.0 1.0 1.0 -
13 Tween 20 - 3.0 3.0 - - 3.0
14 Cresmer RH 40 1.5 - - 1.5 1.5 -
15 Perfume 0.6 0.6 0.6 0.6 0.6 0.6
16 Ethyl alcohol 1.0 2.0 2.0 1.0 1.0 2.0
17 Menthol 0.1 0.1 0.1 0.1 0.1 0.1
18 Calcium hydroxide 2.0 - - 2.5 - -
19 Sodium hydroxide - 2.4 2.5 - 2.5 2.4
20 Calcium carbonate - - 5.0 2.5 5.0 -
21 Guanidine carbonate 5.0 5.0 - 2.5 - 5.0
Table 2: Hair removal gel formulations
Hair Removal Gel formulation

S.no Ingredients %
1 DM Water 64.5
2 Natrosol HEC 250 HHR 2.5
3 Aculyn-22 1.0
4 Urea 5.0
5 Thioglycolate 12.5
6 Sodium gluconate 0.3
7 Sodium lactate 1.0
8 Tween 20 3.0
9 Perfume 0.6
10 Ethyl alcohol 2.0
11 Menthol 0.1
12 Sodium hydroxide 2.4
13 Guanidine carbonate 5.0

Table 3: Hair Removal Gel – Concentration Range
Hair Removal Gel formulation

S.no Ingredients % Range
1 DM Water 30-90
2 Natrosol HEC 250 HHR 0.5-5.0
3 Aculyn-22 0.1-4.0
4 Urea 0.2-20
5 Thioglycolate 0.5-30
6 Sodium gluconate 0.01-10
7 Sodium lactate 0.01-10
8 Tween 20 0.1-20
9 Perfume 0.1-2.0
10 Ethyl alcohol 0.01-20
11 Menthol 0.001-1.0
12 Sodium hydroxide 0.1-10
13 Guanidine carbonate 0.5-20

Example: Method of Preparation
Specified amount of thickening agent (Natrosol HEC 250 HHR/ Carbopol 934/ Xanthan gum/ HPMC) was weighed accurately and dissolved in specified amount of DM water and allowed to stir for complete swelling of polymer. Separately, Aculyn-22 polymer was added to DM water under stirring. Polymer base prepared was added to aculyn solution and stirred. Specified amount of Urea (dissolved in water) was added to the mixture with continuous stirring.
Thioglycolate was weighed accurately; added to the mixing vessel and stirred well. Specified amount of Sodium gluconate (dissolved in water), Sodium lactate, ethyl alcohol were added to mixture under stirring. Menthol, Sodium hydroxide, Guanidine carbonate were dissolved separately in water and added to the mixing vessel. Finally, perfume was solubilized in tween 20/ or Cresmer RH 40 and added to mixing vessel and stirred well to ensure uniform mixing. pH of formulation lie between 12.0-12.5 (adjust the pH, if necessary).
Table 4: Synergistic Experimentation with different combination of components
Hair Removal Gel formulation

S.no Ingredients II VI VII VIII IX
1 DM Water 64.6 65.9 69.6 65.6 64.9
2 Natrosol HEC 250 HHR 2.5 2.5 2.5 2.5 2.5
3 Carbopol 934 - - - - -
4 Xanthan gum - - - - -
5 HPMC - - - - -
6 Aculyn-22 1.0 1.0 1.0 1.0 1.0
7 Urea 5.0 5.0 5.0 5.0 5.0
8 Thioglycolate 12.5 12.5 12.5 12.5 12.5
9 Thioglycolic acid - - - - -
10 Sodium gluconate 0.3 - 0.3 0.3 -
11 Disodium EDTA - - - - -
12 Sodium lactate 1.0 - 1.0 - 1.0
13 Tween 20 3.0 3.0 3.0 3.0 3.0
14 Cresmer RH 40 - - - - -
15 Perfume 0.6 0.6 0.6 0.6 0.6
16 Ethyl alcohol 2.0 2.0 2.0 2.0 2.0
17 Menthol 0.1 0.1 0.1 0.1 0.1
18 Calcium hydroxide - - - - -
19 Sodium hydroxide 2.4 2.4 2.4 2.4 2.4
20 Calcium carbonate - - - - -
21 Guanidine carbonate 5.0 5.0 - 5.0 5.0
Application Very Good Very Good Very Good Very Good Very Good
Adhesiveness Good Good Good Good Good
pH 12.0-12.5 12.0-12.5 12.0-12.5 12.0-12.5 12.0-12.5
Time of application 10 min 10 min 10 min 10 min 10 min
Rate of depilation 98% 65% 40% 70% 80%

We claim:
1. A synergistic depilatory composition comprising: (a) thioglycolic or and its salt; (b) sodium gluconate; (c) sodium lactate; (d) alcohol; (e) guanidine carbonate as active ingredients.
2. The synergistic depilatory composition as claimed in claim 1, wherein thioglycolic acid or and its salt is present in range of 0.5%-30%; sodium gluconate is present in range of 0.01%-10%; sodium lactate is present in range of 0.01%-10%; alcohol is present in range of 0.01%-20% and guanidine carbonate is present in range of 0.5%-20%.
3. The synergistic depilatory composition as claimed in claim 1, wherein the composition further comprises at least one adjunct ingredient for formulating topical composition.
4. The synergistic depilatory composition as claimed in claim 3, wherein adjunct ingredients are selected from group selected from aqua, base, thickening agent, moisturizing agent, solubilizer, fragrance and cooling agent.
5. The synergistic depilatory composition as claimed in claim 4, wherein the water as DM water in range of 30.0%-90.0%.
6. The synergistic depilatory composition as claimed in claim 4, wherein at least one hydroxide base in range of 0.1%-10.0%.
7. The synergistic depilatory composition as claimed in claim 4, wherein the thickening agent that is selected from the group of hydroxy ethyl cellulose.
8. The synergistic depilatory composition as claimed in claim 7, wherein hydroxy ethyl cellulose is a natrosol HEC 250 HHR (0.5-5.0%) and Aculyn-33 (0.1-4.0%).
9. The synergistic depilatory composition as claimed in claim 4, wherein the moisturizing agent is selected from the group of urea in the range of about 0.2 to 20.0%.
10. The synergistic depilatory composition as claimed in claim 4, wherein the solubilizer that includes tween 20 in the range of about 0.1 to 20.0%.
11. The synergistic depilatory composition as claimed in claim 4, wherein the fragrance perfume in range of 0.1%-2.0%.
12. The synergistic depilatory composition as claimed in claim 4, wherein the cooling agent i.e. methanol in range of 0.001-1.0%.
13. The synergistic depilatory composition as claimed in claim 1, wherein the composition is formulated in form of gel.
14. The synergistic depilatory composition as claimed in claim 1, wherein the composition depilates up to 98% within ten minutes.