FIELD OF INVENTION
The present invention relates to a thickening system for transparent topical application, preferably a cleansing composition that provides excellent viscosity, rheology and transparency. The invention also relates to transparent cleansing compositions comprising the thickening system that provides excellent viscosity, rheology and transparency.
BACKGROUND AND PRIOR ART
It is customary to use thickening agents for cosmetic, detergent-containing preparations, e.g., shampoos, so as to stabilize the dispersed systems and for better handling during use. In the past, cocodiethanolamide has been extensively used as a thickening agent in shampoo preparations as it is liquid at room temperature, renders desired viscosity at extreme conditions and is cost effective. However, studies have raised concerns over the use of cocodiethanolamide, as nitrosamines are often present as a by-product of the cocodiethanolamide production, that may be potentially carcinogenic. Thus, the use of cocodiethanolamide in personal hair care and skin products such as cosmetics, facial soaps and shampoos has been questioned from a health and safe-use standpoint.
The formulation of shampoos necessitates a tradeoff between two conflicting physical properties. On the one hand, consumer conception demands a higher viscosity product; while on the other hand, economics require a product low in solid content. Thus, it has been a challenge to provide shampoo compositions that give excellent transparency, a desired viscosity at extreme temperatures, and is cost effective.
The disclosed invention has addressed this problem by combining a low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic ethoxylated ester as thickening system for a transparent topical composition, including shampoo composition.

OBJECTS OF THE INVENTION
An object of the invention is to prepare a low cost thickening system for transparent topical preparation without compromising on the quality of the product.
Another object of the invention is to prepare a transparent cleansing preparation with optimum viscosity.
A further object of the invention is to prepare a transparent cleansing preparation, which is stable at extreme temperatures
Further objects, features and advantages will become apparent from the following description
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a thickening system for transparent topical composition, said thickening system comprising low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester.
According to another aspect of the present invention, there is provided a transparent cleansing composition, said composition comprising:
(i) at least one surfactant selected from the group anionic, amphoteric or
mixtures there of; and (ii) thickening system for cleansing composition comprising low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester.

According to a specific embodiment of the invention, there is provided a shampoo composition comprising:
at least one surfactant selected from the group anionic, amphoteric or
mixtures thereof;
low molecular weight lipophilic non ionic surfactant;
polymeric high molecular weight hydrophilic, high ethoxylated ester;
an electrolyte;
an aqueous carrier;
the balance being conventional optional components.
DESCRIPTION OF THE INVENTION
The invention relates to a thickening system for transparent topical composition comprising low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester. The topical composition includes cleansing compositions like shampoo, face wash, shower gel etc., other cosmetic compositions, gels, foam baths and the like.
Preferably, the invention relates to a thickening system comprising Laureth 3 and PEG 150 pentaerythritol tetrastearate, for cleansing composition such as shampoo, face wash, shower gel etc.
In one embodiment, the present invention provides a transparent cleansing composition shampoo composition with a novel thickening system comprising low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester.
More preferably the present invention provides a shampoo composition with a novel combination of Laureth 3 and PEG 150 pentaerythritol tetrasterate, as thickening system.

The cleansing composition comprising the thickening system, preferably a hair wash preparation, enhances viscosity of the product while maintaining transparency of the product at extreme temperatures thus increasing its durability.
Surfactants:
The composition of the invention comprises at least one surfactant, which is chosen from anionic, or amphoteric surfactants or mixtures thereof.
Suitable anionic surfactants include the alkyl sulfates, alkyl ether sulfates, alkaryl sulfonates, alkyl sulfosuccinates, n-alkyl sarcosinates, alkyl phosphates, alkyl ether phosphates, alkyl ether carboxylates and alpha-olefin sulfonates, especially their ammonium, sodium, magnesium and mono-, di- and triethanolamine salts. The alkyl groups generally contain from 8 to 18 carbon atoms and may be saturated or unsaturated. The alkyl ether sulfates, alkyl ether phosphates and alkyl ether carboxylates may contain from 1 to 10 ethylene oxide units per molecule. One particular group of anionic surfactants are members selected from the group consisting of sodium lauryl sulfate, . sodium laureth sulfate, ammonium lauryl sulfate, ammonium laureth sulfate, disodium laureth sulfosuccinate; disodium ricinoleamido monoethanolamide ("MEA") sulfosuccinate, sodium cocoyl isethionate, sodium methyl oleoyl taurate, sodium methyl cocoyl taurate, sodium laureth-13 carboxylate, sodium CI4-16 olefin sulfonate, sodium laureth-4 phosphate, laureth-3 phosphate, triethylanolamine lauryl sulfate, magnesium lauryl sulfate, sodium tridecyl sulfate, and alpha-olefin sulfate. Another specific group includes ammonium laureth sulfate, ammonium lauryl sulfosuccinate and triethanolamine lauryl sulfate. The most preferred anionic surfactants are ammonium lauryl sulfate and sodium lauryl ether sulfate. The most preferred anionic surfactants are sodium lauryl sulfate, triethanolamine lauryl sulfate, sodium lauryl ether sulfate 1 EO, 2EO and 3EO and ammonium lauryl ether sulfate 1EO, 2EO and 3EO. "

The amphoteric surfactants suitable for use in the composition of the invention may include alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulphobetaines, alkyl glycinates, alkyl carboxyglycinates, alkyl amphopropionates, alkyl amidopropyl hydroxysultaines, acyl taurates and acyl glutamates wherein the alkyl and acyl groups have from 8 to 18 carbon atoms. Examples include lauryl amine oxide, cocodimethyl sulphopropyl betaine and preferably lauryl betaine, cocamidopropyl betaine and sodium cocamphopropionate.
The surfactants are preferably present in the shampoo composition of the invention in an amount of from 5% to about 50% by weight.
Thickening System:
As mentioned above an essential component of the thickening system of the present invention is lipophilic nonionic thickening surfactants. The most preferred nonionic surfactant used in the invention is Laureth 3 in combination with other thickening agents.
The polymeric high molecular weight hydrophilic, high ethoxylated ester forming the other component of the thickening system according to the present invention include PEG 150 distearate, PEG 105 pentaerythritol dibehenate, PEG 105 pentaerythritol tetrabehenate, PEG 150 pentaerythritol tetrastearate, PEG 150 pentaerythritol tetralaurate, PEG 150 pentaerythritol tetraisostearate, PEG 130 pentaerythritol tetrastearate and PEG 75 pentaerythritol tetrastearate. Also contemplated as particularly useful thickening agents in accordance with the present invention are PEG 105 pentaerythritol monobehenate, PEG 05 pentaerythritol tribehenate, PEG 150 pentaerythritol monostearate, PEG 150 pentaerythritol distearate, PEG 50 pentaerythritol tristearate, PEG 150 pentaerythritol monolaurate, PEG 150 pentaerythritol dilaurate, PEG 150 trilaurate, PEG 150 monoisostearate, PEG 150 pentaerythritol diisostearate, PEG 150 pentaerythritol triisostearate, PEG 130 pentaerythritol monostearate, PEG 130 pentaerythritol distearate, PEG 130 pentaerythritol tristearate, PEG 75 pentaerythritol

monostearate, PEG 75 pentaerythritol distearate, and PEG 75 pentaerythritol tristearate & similar other PEG derivatives e.g PEG 120-Methyl glucose dioleate are covered under the scope the present invention.
In the said thickening system the low molecular weight lipophilic non-ionic surfactant is
present in the amount from about 0.01% to about 2.0% by weight_and the polymeric high
molecular weight hydrophilic, high ethoxylated ester is present in the_amount from about 0.001 % to about 2.0% by weight of the composition.
The thickening system of the present invention may be employed in the formulation of a number of topical preparations, for example, shampoos, shower gel formulations, gels, cosmetics in general, foam baths and the like. The thickening system of the present invention is applicable to the formulation of a variety of topical preparations as noted hereinabove as falling within the scope of the present invention.
The polymeric high molecular weight hydrophilic, high ethoxylated ester component of thickening system of the present invention are prepared from a pentaerythritol intermediate such as PEG 75 pentaerythritol, PEG 105 pentaerythritol, PEG 130 pentaerythritol, PEG 150 pentaerythritol and the like. PEG stands for polyethylene glycol, while the number thereafter stands for the number of moles of ethylene glycol attached to the molecule. These intermediates are formed as a reaction product of pentaerythritol and ethylene oxide. By controlling the reaction, the number of moles of ethylene glycol attached to the molecule may be determined as desired.
However, as pentaerythritol is a solid having a melting point of about 267°C, it is initially reacted with ethylene carbonate which functions as both a solvent and a reactant to provide a liquid intermediate, PEG 4 pentaerythritol. This intermediate is subsequently reacted with ethylene oxide to produce the desired PEG "X" pentaerythritol intermediate having the desired number of moles "X" of ethylene glycol adhering to the molecule. It is to be understood that the number of moles of ethylene glycol in the specific examples is by way of illustration only, and is not intended as a limitation upon the thickening agent and topical preparations formulated therefrom which constitute the present invention.

The thickening system of the present invention increases the viscosity of the cleansing composition in which it is incorporated while maintaining the transparency.
The following examples while not intended to be limiting, demonstrate several preferred embodiments of formulating a PEG "X" pentaerythritol intermediate in accordance with the present invention.
Though the cleansing system is specifically described as shampoo herein, the thickening system of the present invention may be incorporated in any other cleansing composition where the other conventional components are incorporated according to state of art.
Aqueous Carrier
Water is used as an aqueous carrier in this shampoo composition. The disclosed invention comprises from about 20% to about 94%, preferably from about 50% to about 94%, more preferably from about 60% to about 85%, by weight of water.
Conventional Optional Components
The shampoo compositions of the present invention may further comprise one or more of the conventional optional components known for use in shampoo or conditioning compositions, provided that the components used are compatible with the essential component of the shampoo composition both physically and chemically. These optional components should necessarily not impair the stability, aesthetics or performance of the product. Concentrations of such optional components typically range from about 0.001% to about 50%) by weight of the shampoo compositions.
Optional components may include anti static agents, dyes, organic solvents or diluents, pearlescent aids, foam boosters, additional surfactants or co-surfactants (nonionic, cationic, zwitterionic), pediculocides, pH adjusting agents, perfumes, preservatives, proteins, skin active agents, suspending agents, styling polymers, sunscreens, thickeners, vitamins, and viscosity adjusting agents. This list of optional components is not meant to be exclusive, and other optional components can be used.

Although the present invention has been described with particular reference to specific examples, variations and modifications of the present invention can be effected within the spirit and scope of the invention.
Examples:
Example 1
Sodium Laureth Sulfate 14 wt %, Sodium chloride QS; Water QS to 100. Very high amount of electrolyte is required to get desirable viscosity. Thinning effect is observed at elevated temperature. The Viscosity is 1750 cps at 27°C as measured by a Brookfield DV-II pro viscometer at 50 rpm with spindle No. 15.
Example 2
Sodium Laureth Sulfate 14 wt%; PEG 150 Pentaerythritol Tetrasterate 0.1 wt%, Sodium chloride QS; Water QS to 100.
When using only polymeric thickener, the flowability of the mixture below 5°C reduces where gelling is observed. It enhances viscosity of the product while maintaining transparency of the product even at low temperature. The Viscosity is 11750 cps at 27°C as measured by a Brookfield DV-II pro viscometer at 50 rpm with spindle No. 15.
Example 3
Sodium Laureth Sulfate 14 wt%; Sodium chloride QS; Laureth 3 2.0 wt%; Water QS to
100.
When using the nqn-polymeric thickener, the mixture loses its viscosity at high
temperature. The Viscosity is 10775 cps at 27°C as measured by a Brookfield DV-II pro
viscometer at 50 rpm with spindle No. 15.
Example 4
Sodium Laureth Sulfate 14 wt.%, Sodium chloride QS; CDEA 1.0 wt%; Water QS to 100.

The system thickened with cocodiethanolamide (or CDEA) exhibits ideal flow properties at low as well as high temperatures. The transparency of the product remains unaffected under extreme temperature conditions. Optimum amount of electrolyte is required to get desired viscosity. The Viscosity is 1450 cps at 27°C as measured by a Brookfield DV-II pro viscometer at 50 rpm with spindle No. 15.
Example 5
Sodium Laureth Sulfate 14 wt%, Sodium chloride QS; CMEA 3.0 wt%, Water QS to
100.
The system thickened with cocodiethanolamide (or CDEA) exhibits gelling at low
temperature. Some times it also loses its transparency at low temperature. The process
also requires heating, as CMEA is solid at room temperature. The Viscosity is 6280 cps
at 27°C as measured by a Brookfield DV-II pro viscometer at 50 rpm with spindle No.
15.
Example 6
Sodium Laureth Sulfate 14 wt%; Sodium chloride QS; Laureth- 3 1.0 wt%, PEG 150
Pentaerythritol Tetrasterate 0.2 wt%; Water QS to 100_,
This mixture exhibits flow properties similar to cocodiethanolamide (or CDEA) thickened system at low as well as high temperatures. The transparency of the product remains unaffected under extreme temperature conditions. Optimum amount of electrolyte is required to get desired viscosity. The Viscosity is 2510 cps at 27°C as measured by a Brookfield DV-II pro viscometer at 50 rpm with spindle No. 15.

We Claim
1. A thickening system for transparent topical composition, said thickening system • comprising low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester wherein the lipophilic non-ionic surfactant is present in the amount of about 0.01% to about 2.0% by weight and the polymeric high molecular weight hydrophilic, high ethoxylated ester is present in the amount of about 0.001% to about 2.0 % by weight.
2. The thickening system as claimed in claim 1 wherein the lipophilic non-ionic surfactant is a low molecular weight lipophilic surfactant, preferably Laureth 3.
3. The thickening system as claimed in claim 1 wherein the polymeric high molecular weight hydrophilic, high ethoxylated ester is selected from PEG 150 distearate, PEG 105 pentaerythritol dibehenate, PEG 105 pentaerythritol tetrabehenate, PEG 150 pentaerythritol tetrastearate, PEG 150 pentaerythritol tetralaurate, PEG 150 pentaerythritol tetraisostearate, PEG 130 pentaerythritol tetrastearate and PEG 75 pentaerythritol tetrastearate, PEG 105 pentaerythritol monobehenate, PEG 05 pentaerythritol tribehenate, PEG 150 pentaerythritol monostearate, PEG 150 pentaerythritol distearate, PEG 50 pentaerythritol tristearate, PEG 150 pentaerythritol monolaurate, PEG 150 pentaerythritol dilaurate, PEG 150 trilaurate, PEG 150 monoisostearate, PEG 150 pentaerythritol diisostearate, PEG 150 pentaerythritol triisostearate, PEG 130 pentaerythritol monostearate, PEG 130 pentaerythritol distearate, PEG 130 pentaerythritol tristearate, PEG 75 pentaerythritol monostearate, PEG 75 pentaerythritol distearate, and PEG. 75 pentaerythritol tristearate and similar other PEG derivatives e.g. PEG 120-Methyl glucose dioleate.

4. A transparent cleansing composition, said composition comprising:
(i) at least one surfactant selected from the group anionic, amphoteric or mixtures thereof; and
(ii) a thickening system for cleansing composition comprising low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester wherein the lipophilic non-ionic surfactant is present in the amount of about 0.01% to about 2.0% by weight and the polymeric high molecular weight hydrophilic, high ethoxylated ester is present In the amount of about 0.001% to about 2.0 % by weight.
5. The composition as claimed in claim 4 wherein the lipophilic non-ionic surfactant is a low molecular weight lipophilic surfactant, preferably Laureth 3.
6. The composition as claimed in claim 4 wherein the polymeric high molecular weight hydrophilic, high ethoxylated ester is selected from PEG 150 distearate, PEG 105 pentaerythritol dibehenate, PEG 105 pentaerythritol tetrabehenate, PEG 150 pentaerythritol tetrastearate, PEG 150 pentaerythritol tetralaurate, PEG 150 pentaerythritol tetraisostearate, PEG 130 pentaerythritol tetrastearate and PEG 75 pentaerythritol tetrastearate, PEG 105 pentaerythritol monobehenate, PEG 05 pentaerythritol tribehenate, PEG 150 pentaerythritol monostearate, PEG 150 pentaerythritol distearate, PEG 50 pentaerythritol tristearate, PEG 150 pentaerythritol monolaurate, PEG 150 pentaerythritol dilaurate, PEG 150 trilaurate, PEG 150 monoisostearate, PEG 150 pentaerythritol diisostearate, PEG 150 pentaerythritol triisostearate, PEG 130 pentaerythritol monostearate, PEG 130 pentaerythritol distearate, PEG 130 pentaerythritol tristearate, PEG 75 pentaerythritol monostearate, PEG 75 pentaerythritol distearate, and PEG 75 pentaerythritol tristearate and similar other PEG derivatives e.g. PEG 120-Methyl glucose dioleate.

7. The composition as claimed* in any of claim 4 to 6 wherein the surfactant is selected from anionic or amphoteric surfactants and mixtures thereof.
8. The composition as claimed in any of claim 4 to 7 further comprising aqueous carrier, electrolyte and optional components selected from anti static agents, dyes, organic solvents or diluents, pearlescent aids, foam boosters, additional surfactants or co-surfactants, pediculocides, pH adjusting agents, perfumes, preservatives, proteins, skin active agents, suspending agents, styling polymers, sunscreens, thickeners, vitamins, and viscosity adjusting agents and mixtures thereof.
9. The composition as claimed in any of claim 4 to 8 wherein the composition is
selected from shampoo, shower gel, face wash and the like, preferably shampoo.
10. A shampoo composition comprising:
(i) at least one surfactant selected from anionic or amphoteric surfactants and mixtures thereof;
(ii) a thickening system comprising low molecular weight lipophilic non ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester wherein the lipophilic non-ionic surfactant is present in the amount of about 0.0i% to about 2.Q% by weight and the polymeric high molecular weight hydrophilic, high ethoxylated ester is present in the amount of about 0.001% to about 2.0 % by weight;
(iii) an electrolyte;
(iv) an aqueous carrier;
(v) the balance being conventional optional components.

ABSTRACT

TITLE : TRANSPARENT CLEANSING COMPOSITION
A thickening system for transparent topical composition, said thickening system comprising low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester. A transparent cleansing composition, said composition comprising at least one surfactant selected from the group anionic, amphoteric or mixtures thereof; and a thickening system for cleansing composition comprising low molecular weight lipophilic non-ionic surfactant and polymeric high molecular weight hydrophilic, high ethoxylated ester.