Concentrated and self-preserving compositions of mild surfactants for transparent and skin-pH personal care formulations

Abstract

The invention relates to aqueous, high active, self-preserving composition of mild surfactants which are used to create transparent liquid formulations with pH similar to skin's pH. More specifically, the composition comprise of sodium/potassium acyl isethionate of Formula I and mono potassium acyl glutamate of Formula II with solids content of at least 45 w/w, for personal care formulation that are ultra-mild, with skin pH and transparent.

Claims

1. A mild surfactant composition comprising; (i) aqueous blend of O-acyl isethionates of Formula I and monopotassium N-acyl glutamate of Formula II; ##STR00005## wherein, R is selected from C.sub.5 to C.sub.21 alkyl group, saturated or unsaturated, R.sub.1 is selected from H or methyl, X is selected from Na.sup.+ or K.sup.+ and prepared by the process, comprising steps of A) reacting more than one equivalence of fatty acid chloride with alkali metal hydroxyalkyl sulphonates to prepare compounds of Formula I, B) reacting the reaction mass of step (A) (containing the remainder fatty acid chloride) with glutamic acid in the presence of a potassium hydroxide under typical aqueous Schotten Baumann reaction conditions to form compounds of Formula II; wherein, the molar ratio of O-acyl isethionates of Formula I to N-acyl glutamate of Formula II is in range of 1.0:1.0 to 1.0:10.0, and (ii) 0.5 to 2% by weight mixture of N-undecylenoyl glycine and N-capryloyl glycine; wherein, the total solids content of the composition is at least 45% w/w and the pH of the said aqueous composition is below 6.5.

2. The surfactant composition of claim 1 wherein glutamic acid is selected from L-glutamic acid or D-glutamic acid or mixture thereof.

3. The surfactant composition as claimed in claim 1, wherein the mixture of N-undecylenoyl glycine and N-capryloyl glycine is in the ratio of 1:1.

4. The surfactant composition as claimed in claim 1, which is self-preserving.

5. The personal care formulation using the aqueous surfactant composition of claim 1.

6. The transparent, skin-pH personal care formulation using the aqueous surfactant composition of claim 1.

7. The personal care formulation as claimed in claim 5 is selected from shampoo, hand wash, body wash, face wash, shower gel, and baby bubble bath.

8. The surfactant composition as claimed in claim 1 containing other cosmetic benefit agents.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to better understand various exemplary embodiments, reference is made to the accompanying drawings, wherein:

(2) FIG. 1 shows the foaming property at pH 6.0 and 150 ppm hard water at 25 C. of various surfactant compositions, including GLI;

(3) FIGS. 2A and 2B show the lather generated by GLI (initial foam in FIG. 2A; foam after 5 minutes in FIG. 2B);

(4) FIGS. 3A and 3B show the lather generated by GI (initial foam in FIG. 3A; foam after 5 minutes in FIG. 3B);

(5) FIG. 4 shows zein values for various surfactant compositions, including GLI and GI;

(6) FIG. 5 shows the red blood cell denaturation index for various surfactant compositions, including GI and GLI, relative to SLS;

(7) FIG. 6 shows the decrease in transepidural loss of water (TEWL) from application of various surfactants, including GI and GLI, to skin;

(8) FIG. 7 shows the change in skin hydration from application of various surfactants, including GI and GLI, to skin; and

(9) FIG. 8 shows the self-preservation efficacy of GLI compositions containing O-acyl isethionate and N-acyl glutamate in a 1:2 molar ratio.

DETAILED DESCRIPTION OF THE INVENTION

(10) The present invention relates to high active, self-preserving, surfactant composition of mild surfactants. The super-mild surfactant composition of this invention is suitable to make transparent, skin-pH personal care formulations.

(11) The present invention relates to, self-preserving, high-active, mild surfactant compositions comprising: (i) aqueous blend of O-acyl isethionates of Formula I and monopotassium N-acyl glutamate of Formula II;

(12) ##STR00003##
wherein, R is selected from C.sub.5 to C.sub.21 alkyl group, saturated or unsaturated, R.sub.1 is selected from H or methyl, X is selected from Na.sup.+ and K.sup.+ and prepared by the process, comprising steps of

(13) A) reacting more than one equivalence of fatty acid chloride with alkali metal hydroxyalkyl sulphonates to prepare compounds of Formula I,

(14) B) reacting the reaction mass of step (A) (containing the remainder fatty acid chloride) with glutamic acid in the presence of potassium hydroxide under typical aqueous Schotten Baumann reaction conditions to form compounds of Formula II; wherein, the molar ratio of O-acyl isethionates of Formula I to N-acyl glutamate of Formula II is in range of 1.0:1.0 to 1.0:10.0, and (ii) 0.5 to 2% by weight mixture of N-undecylenoyl glycine and N-capryloyl glycine;
wherein, the total solids content of the composition is minimum 45% w/w and the pH of the said aqueous composition is below 6.5.

(15) The high active, aqueous, flowable compositions of the present patent applications have been made from a common starting material, fatty acid chloride. Fatty acid chloride can be single fatty acid chloride or it can be mixture of several alkanoyl chlorides as shown in the examples (Example 1 to 5). The synthesis has been carried out wherein excess fatty acid chloride (the amount above stoichiometric excess) is reacted with dry sodium or potassium hydroxyl ethyl sulphonate to yield O-acyl isethionate of Formula-I. Gaseous hydrochloric acid generated during this reaction is then scrubbed off by absorbing it in aqueous alkali. The unreacted excess fatty acid chloride in the reaction mass is then converted into N-acyl glutamate of Formula-II in aqueous medium in the presence of potassium hydroxide under typical Schotten Baumann conditions. The amount of water used in this N-acylation is controlled to yield the desired levels of solids content (active content) of the reaction mass.

(16) Prior to adjusting solids content of the compositions, 0.5 to 2% w/w of lipoglycines (mixture of N-capryloyl glycine and N-undecylenoyl glycine) are added (added externally or synthesized in situ) and pH adjusted to 6 to 6.5.

(17) Ratio of N-Acyl Glutamate to N-Acyl Isethionate in GLI

(18) The high active compositions of the present invention comprise of higher percentage of N-acyl glutamate and O-acyl isethionate. The molar ratio of O-acyl isethionates of Formula I to N-acyl glutamate of Formula II is in range of 1.0:1.0 to 1.0:10.0

(19) ##STR00004##

(20) In view of in-vitro studies of property of being mild (Zein protein solubilization or protein denaturation of live blood cells) and foaming and lathering performance, it has been discovered that for the optimal performance at skin pH can be achieved with compositions wherein the isethionate to glutamate ratio varies from 1:1 to 1:10. The zein value of a blend of potassium cocoyl glutamate and sodium cocoyl isethionate is lower than that of a blend of sodium cocoyl glutamate and sodium cocoyl isethionate and hence in our invention, potassium acyl glutamate (Formula II) is preferred over its sodium salt.

(21) Lipoglycines: N-Capryloyl Glycine and N-Undecylenoyl Glycine

(22) The surfactant composition of the present invention contains two types of mild surfactants, namely, N-acyl amino acid surfactants and O-acyl isethionates. In addition to these two classes of mild surfactants, the compositions of the present invention also contain 0.5 to 2% w/w skin care lipoglycines, namely, N-undecylenoyl glycine (CAS No 54301-26-7) and N-capryloyl glycine (CAS No. 14246-53-8).

(23) N-undecylenoyl glycine is known for its anti-acne and anti-dandruff properties (JP 49093521 (1974)) and commercially it is available as Lipacide UG. N-capryloyl glycine is a known derma purifier and commercially available as Lipacide C8G (Cosmetics & Toiletries, 17(3), 11-13, 16-19, (1996)). It restores skin's acidic mantle and has 5- reductase inhibitory activity that is said to control the secretion of sebum.

(24) In an embodiment, the lipoglycines added are 1:1 w/w mixture of N-capryloyl glycine and N-undecylenoyl glycine. These lipoglycines, N-capryloyl glycine and N-undecylenoyl glycine can be added externally after the synthesis of acyl isethionate and acyl glutamate as shown in Example 1 or they can be generated in-situ in the required amount during synthesis as demonstrated by Example 5.

(25) Foaming and Lather Potential of Compositions of Present Invention: Synergy Between N-Acyl Glutamate and N-Acyl Isethionate

(26) Both amino acids, glycine and glutamic acid are significant part of human skin collagen (34% and 7% respectively) and human hair (6% and 11% respectively). The surfactants based on glycine and glutamic acid, N-acyl glycinate and N-acyl glutamate, have established themselves as mild to the skin. Commercially, N-acyl glycinates are available as Galsoft SCG, Hostapon SG, Gerapon CG 3S, and Amilite GCS 12K. Trade names for N-acyl glutamates are Protelan AGL 95, and Hostapon KCG.

(27) It is reported in literature that at pH 6.5, N-acyl glutamate surfactants foam more than N-Acyl glycinate surfactants (K. Sakamoto, Yukagaku 44:256 (1995), Yukagaku Journal of Japan Oil Chemists' Society) and hence a physical blend of glutamate-isethionate is expected to foam more than a physical blend of glycinate-isethionate. The synthetic blends, GLI and GI, have been created by the process described in Example 1 and 3 respectively. GLI has been found to be significantly superior in foaming as compared to GI. The foam of GI solution at pH 6.5 collapses immediately as shown in Table I.

(28) Synergy between N-acyl isethionate and N-acyl glycinate has been well documented by Tsaur et al., in U.S. Pat. Nos. 8,105,994 and 8,268,767. However, hitherto synergy between isethionate and glutamate has not been reported. In our study, it has been found that the foam volume of individual surfactants, potassium cocoyl glutamate and sodium cocoyl isethionate is 600 ml and 380 ml respectively, whereas for the physical mixture of glutamate and isethionate (2:1) it is 580 mL. The exceptional synergy is seen between the surfactants of the present invention (Table 1) as is evident from the superlative foaming and lathering behavior of GLI (Example 1) (foam volume 900 mL) in comparison to the physical blend of glutamate and isethionate (Example 6).

(29) TABLE-US-00001 TABLE 1 Comparison of Foam volume and Lather Potential Surfactant (1%) at Foam volume Lather Potential 25 C. and at pH 6.5 (mL) (Drainage Time) Potassium Cocoyl glutamate 600 Above 5 minutes Sodium Cocoyl glycinate 200 Foam collapses immediately Sodium Cocoyl isethionate 380 Foam collapses immediately Sodium Cocoyl glycinate 320 Foam collapses and Sodium Cocoyl immediately isethionate (2:1) GI of Example 3 Potassium Cocoyl glutamate 580 Above 5 minutes and Sodium Cocoyl isethionate (2:1): physical mixing Potassium Cocoyl glutamate 900 Above 5 minutes and Sodium Cocoyl isethionate (2:1) (GLI of

(30) Physical blend is prepared by mixing the two separate surfactants, N-acyl amino acid and O-acyl isethionate (which is in solid form) and gently stirring the mixture at 70-75 C. till it becomes homogeneous. From foam height measurement, it can be easily seen that synthetically made Glutamate-Isethionate blend (GLI) is far superior to the blend of same surfactants that have been physically mixed (Example 6) (FIG. 1). Physically mixed composition of potassium cocoyl glutamate and sodium cocoyl isethionate of Example 6 develops haziness and part of it separates out on standing at room temperature. The surprisingly significant difference between GLI compositions of Example 1 and physically blended composition of Example 6 (Foam 900 cc vs Foam of 580 cc, FIG. 1 and Table 1) gets reflected in the formulation made from these surfactant systems. The compositions of Example 1 and 6 are blended with zwitterionic mild surfactant, cocoamidopropyl betaine (CAPB) and a rheology modifier Polyethylene glycol 150 distearate to get surfactant content of 12% to simulate a typical body cleansing formulations. The foam and lather drainage estimated by Hart-DeGeorge method have been found to be significantly superior for Formulation A of Example 7 than Formulation B of Example 7.

(31) Examination of foam (1% solution at pH 6.5) under microscope also reveals that the creamy lather generated by GLI remains thick and creamy FIGS. 2A and 2B) for a long time whereas the lather of GI becomes coarser and loses its creaminess very fast (FIGS. 3A and 3B). FIGS. 2A and 2B show the initial lather generated by GLI and the lather from GLI after 5 minutes, respectively. FIGS. 3A and 3B show the initial lather generated by GI and the lather from GI after 5 minutes, respectively.

(32) Relative Mildness of Surfactant Composition of the Present Invention

(33) Critical Micelle Concentration (CMC) and Mildness:

(34) It is well established that in case of surfactants, lower the CMC value, milder the surfactants. Ionic surfactant molecules interact with proteins through charge-charge interaction since the charge density on the head group is high. Whenever aggregates are formed the charge density of micelle is much lesser as the charge gets spread over the large micelle. In a solution, a surfactant that prefers to exists as micelles and not as free molecules; shows less irritancy toward skin. It can be seen from Table 2 that CMC of anionic sodium lauryl sulphate (SLS) is the highest and zwitterionic (electrically neutral) cocoamidopropyl (CAPB) is the lowest. Glutamate-Isethionate (GLI) of the present invention has the critical micelle concentration of 0.30 mM/liter exhibiting significant potential to be milder than other anionic surfactants (K. P. Ananthapadmanabhan et al., Cosmetic Dermatology, 307-316, 22(6) (2009)).

(35) TABLE-US-00002 TABLE 2 Molecular CMC Sr. No. Name Weight mM/liter 1 CAPB 360 0.06 2 SCI 330 0.14 3 GI 298 0.30 4 GLI 359 0.31 5 SCG 279 1.01 6 KCGL 405 1.01 7 SLS 288 5.90

(36) Zein Protein Solubilization Assay

(37) Mild surfactants are regarded as mild because when compared with harsh surfactants, the damage done to stratum corneum by them is significantly less. The constituents of stratum corneum that get affected by surfactants are proteins (keratin of corneocytes), enzymes and lipids. Zein (corn derived protein) solubility assay is a commonly used method to predict the protein damage (proteins get denautured by surfactants) potential of surfactants [E. Gotte Hautvertraglichkeit von Tensiden, genessen am Losevermogen fur Zein, 4.sup.th International Congress on Surfactants 3, 83 (1064), Kastner and Forsch, Fette, Seifen, Anshrichmittel, 83 33-46 (1981), Lang and Spengler, Surfactants in cosmetic formulations: skin irritancy and physical properties, Preprints of the XIVTH IFCC Congress, Barcelona, 1, 25-37 (1986)]. Surfactant induced denaturation and solubilization of zein are associated with surfactant's skin irritation potential. For Zein protein solubilization assay, 1% solution of surfactant at pH 7.0 is used.

(38) Employing standard protocol for zein number determination it has been surprisingly discovered that GLI is milder than GI (FIG. 4). Zein numbers of zwitterionic cocoamidopropyl betaine (CAPB) and anionic, sodium lauryl sulphate (SLS) is mentioned to give an idea of relative mildness measurement by this in-vitro methodology.

(39) Red Blood Cell Denaturation Index

(40) For mildness measurement surfactant's action on human red blood cells is quantified as per the literature [W. J. W. Pape and U. Hoppe, Standardization on in-vitro red blood cell for evaluating the acute cytoxic potential of tensides, Arzneimittel-Forschung, Publikationsorgen der Paul-Ehrlich-Gesellschaft fur Chemotherapie, 40, 498-502 (1990), W, J. W. Pape et al., Validation of red blood cell test as an in-vitro assay for the rapid screening of irritation potential of surfactants, Molecular Toxicology, 1, 525-536 (1987)]. Surfactants solutions at 50 to 500 ppm are prepared in phosphate buffered saline and degree of haemolysis is measured on heparinized human RBCs. After the contact time of 10 minutes, the solution is centrifuged to separate RBC from the supernatant that contains oxyhaemogoblin. The absorbance is measured at 570 nm. The plot of concentration against percentage haemolysis gives the H.sub.50.

(41) Taking SLS as control irritant (3.47 mmol/liter), Denaturation Index (DI) is calculated by measuring the absorbance of the supernatant that contains oxyhemoglobin after the lysis. Relative mildness of GLI and GI in comparison with standard irritant SLS is given in terms of % denaturation of proteins as given in FIG. 5. GLI has % denaturation number of 15 when SLS is considered as 100 (FIG. 5).

(42) The ratio of H.sub.50/DI gives the irritation potential. If the ratio is less than 1 then the surfactant is an irritant. Higher the number of L/D, lesser the potential for irritation H.sub.50/DI ratio for GLI is found to be 5.6 and for GI it is 4.0, hence GLI is found to be milder when compared with GI.

(43) Moisturization Efficacy of Compositions of the Present Invention

(44) GLI of Example 1 is compared with GI of Example 3. Three body-wash formulations are prepared with 12% active matter (GI, GLI and SLES (2EO) and 2% of PEG-150 distearate as viscosity builder (rheology modifier) and applied to subject's volar arm twice a day for fifteen days in a controlled relative humidity of 50% at 20 C. with acclimatization period of 30 minutes. From FIG. 6 it can be seen that on continuous application of surfactants, GLI seems to remove less amount of lipids and thus significantly less damage to stratum corneum, without altering/impacting rate of water loss. GI seems to be solubilizing lipids of SC significantly resulting in increase in TEWL. Corneometry analysis (FIG. 7) also suggests that GLI does not disturb the moisture level of skin whereas GI and sodium lauryl ether sulphate (2 EO) seem to dry the stratum corneum. Removal of Natural Moisturizing Factor (NMF) from stratum corneum during cleansing leads to a lower capacitance reading since there is less secondary bound water in the skin's corneocytes. GLI seems to remove less of NMF from stratum corneum hence does not disturb skin's hydration level. The corneometer findings are consistent with the TEWL findings.

(45) Self-Preserving Nature of Compositions of Present Invention

(46) Compositions of the present invention are tested for their self-preservation efficacy. The compositions contain O-acyl isethionate and N-acyl glutamate in 1:2 molar ratio. The final pH of these compositions is 6.5 and the total solids content is around 45%. The compositions have been challenge tested against Gram positive bacteria (Staphylococcus aureus ATCC 6538), Gram negative bacteria (Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 15442), yeast (Candida albicans ATCC 10231) and mold (Aspergillus niger ATCC 16404) by the usual protocol of CTFA (PCPC, Personal Care Products Council). The compositions of the present invention meet the criteria for passing the challenge test (FIG. 8).

(47) The GLI composition of the present invention also survived when challenged with acne causing Gram positive Propionibacterium acnes MTCC 1951 and dandruff causing Malassezia furfur MTCC 1374 (FIG. 8).

(48) Clear and Transparent Formulations with pH Similar to Skin's pH Made from Mild Surfactant Compositions of the Present Invention

(49) The compositions of the patent application allow formulators to create end-formulations that are of skin-pH and mild on skin while being transparent. The formulations detailed are 1) Body wash 2) Anti-acne face wash 3) Anti-dandruff shampoo and 4) Baby shampoo.

(50) Using GLI of Example 1 several formulations have been prepared. A few formulations are described in the experimental section (Examples 8, 9 and 10). The characteristic common features of these formulations are transparency and pH similar to skin's pH. The transparency of the formulations has been measured with nephelometer and found to be <10 NTU, nephelometric transmittance unit (Turbidometer 2100P from HACH Company). Example 1 illustrates the making of concentrated surfactant composition of sodium cocoyl isethionate and potassium cocoyl glutamate in the molar ratio of 1:2 whereas Example 2 illustrates the synthesis of sodium lauroyl isethionate and potassium lauroyl glutamate in the same molar ratio (1:2). Example 3 illustrates synthesis of blend of sodium cocoyl isethionate and sodium cocoyl glycinate in the molar ratio of 1:2. Example 4 illustrates composition of potassium cocoyl glutamate and potassium cocoyl isethionate while Example 5 shows the in-situ synthesis of undecylenoyl glycine and capryloyl glycine in the composition of N-acyl glutamate and O-acyl isethionate.

(51) Composition by physical blending of two surfactants, glutamate and isethionate is exemplified by Example 6. The composition made with physically blended sodium cocoyl isethionate and potassium cocoyl glutamate (45% solids, Example 6) is hazy and the turbidity is reflected in NTU unit of 30.

(52) The surfactant composition of the present invention can optionally contain cosmetic benefit agents. Cosmetic benefit agents may be selected from polymers, humectants, rheology modifiers, anti oxidants, fragrances, emollient, conditioning agents, moisturizers, pearlisers etc.

The Advantages of Present Invention

(53) 1. The present invention teaches the synergy of the two of the well established mild surfactants, namely, mono potassium acyl glutamate and sodium or potassium acyl isethionate when they are synthesized in a particular way. The synergy between these two mild surfactants is seen on three counts, a) foaming property b) lather potential and 3) mildness toward skin. Foam and lather of synthetic GLI is far superior to physically blended mixture of acyl glutamate and acyl isethionate (Table 1) Mildness as well as foaming/lathering properties of acyl glutamate and acyl isethionate composition of the present invention is superior to recently reported acyl glycinate-acyl isethionate combinations at skin pH 5.5 to 6.5. Zein number, RBC test, CMC data and moisturization data together show that the composition of Glutamate-Isethionate (GLI) to be milder towards skin than Glycinate-Isethionate (GI) at skin pH. 2. The present invention discloses a concentrated, yet flowable aqueous compositions of mild surfactants (45 to 50% solids content), mono potassium cocoyl glutamate and sodium or potassium cocoyl isethionate. Concentrated form of the compositions of the present invention make them more eco-friendly than the other current commercial surfactants. Thousands of metric tonnes of surfactant solutions are transported across the continent every day. Saving of transportation cost and reducing carbon footprint is extremely essential and relevant for the overall sustainability. 3. The compositions of the present invention are high active, flowable, low viscous liquids providing extreme ease for creating personal care cleansing formulations (8 to 16% active mild surfactants) with pH that is similar to pH of skin. 4. Creating personal care formulations without preservatives is extremely important since all the work-horse antimicrobial preservatives are implicated in serious toxicity towards either human or to the environment. Personal care industry is trying to go away from the controversial preservatives such as parabens, methyl and chloromethyl isothiazolinone (Kathon CG), Trichlosan, formaldehyde releasers like DMDM hydantoin, Imidazolidine urea, and Iodopropynyl butyl carbamate. The compositions of the present invention allow formulators to prepare end formulations without any toxic preservatives (Examples 8 to 10). The compositions with mild surfactants and without any toxic preservatives are suitable for baby products and sensitive skin with skin conditions such as psoriasis or eczema.

EXAMPLES

(54) The invention will now be illustrated with the help of examples. Examples illustrate the performance and the benefits through the formulations. The examples are by way of illustrations only and in no way restrict the scope of invention. Many changes and modifications can be made within the scope of the present invention without departing from the spirit thereof and the invention concluded all such modifications. A few formulations of skin and hair care preparations incorporating the compositions of the present invention are given in Examples 8 to 10.

(55) The foam height and lather potential study was carried out by method reported in J. Soc. Cosmet. Chem. 223-236, 31, (1980).

(56) Fatty acids chlorides were prepared as per the procedure reported in the Patent Application (WO2014181342) by Koshti et al. (Method to produce blends of O-acyl isethionates and N-acyl amino acid surfactants).

Example 1

(57) Synthesis of Surfactant Composition of Sodium Cocoyl Isethionate and Mono Potassium Cocoyl Glutamate in Molar Ratio of 1:2 and 1% w/w of Lipoglycines, Undecylenoyl Glycine and Capryloyl Glycine (1:1 w/w).

(58) The cocoyl chloride used in this experiment had the following alkyl chain distribution C.sub.8: 5.0%, C.sub.10: 6.0%, C.sub.12: 62.6%, C.sub.14: 20.0%, C.sub.16: 6.0%, C.sub.18: 0.4% To a stirred cocoyl chloride (328 g, 1.5 gmol) under slow purging of nitrogen at room temperature, sodium isethionate (74 g, 0.5 gmol) was added and the slurry was stirred at 55-60 C. for 4 h. The HCl gas generated was absorbed in alkali solution and the progress of reaction was monitored by IR spectrum analysis. The FTIR spectrum of the intermediate showed the presence of unreacted cocoyl chloride (carbonyl stretch at 1800 cm.sup.1), sodium cocoyl isethionate (carbonyl of ester at 1734 cm.sup.1) and disappearance of hydroxyl stretch (3323 cm.sup.1) of sodium isethionate.

(59) This fluid viscous reaction mass (380 g) was cooled to room temperature and then added slowly to a stirred aqueous solution of L-glutamic acid (155 g, 1.05 gmol) in water (545 g) along with potassium hydroxide solution (50%, 350 g, 3.1 gmol) simultaneously while maintaining the pH of the reaction mass between 10.0 to 10.5 and the temperature between 20 to 30 C. The addition was completed in two hours and the reaction mass was stirred for another 4 h at rt. To this mixture N-capryloyl glycine (7 g) and N-undecylenoyl glycine (7 g) were added and stirred until homogeneous. The pH was adjusted to 6.0 with HCl. The solids content of the reaction mass was adjusted to 45% solids content to yield 1430 g of aqueous solution as final product.

(60) The analysis of the above aqueous surfactant blend was as follows:

(61) TABLE-US-00003 Test Results Appearance Light yellow clear liquid Viscosity at 25 C. 400 cps pH as such 6.2 KCl, % w/w 6.25 Total solids, % w/w 45.00 Free glutamic acid % w/w 2.30 Free fatty acid % w/w 3.55

Example 2

(62) Synthesis of a Composition of Sodium Lauroyl Isethionate and Mono Potassium Lauroyl Glutamate in Molar Ratio of 1:2 and 1% w/w of Lipoglycines, Undecylenoyl Glycine and Capryloyl Glycine (1:1 w/w).

(63) To a stirred lauroyl chloride (218.5 g, 1.0 gmol) under slow purging of nitrogen at room temperature, sodium isethionate (49.5 g, 0.333 gmol) was added and the slurry was stirred at 65-70 C. for 4 h. The HCl gas generated was absorbed in alkali solution and the progress of reaction was monitored by IR spectrum analysis. The FTIR spectrum of the intermediate showed the presence of unreacted lauroyl chloride (carbonyl stretch at 1800 cm.sup.1), sodium lauroyl isethionate (carbonyl of ester at 1734 cm.sup.1) and disappearance of hydroxyl stretch (3323 cm.sup.1) of sodium isethionate.

(64) This fluid viscous reaction mass (255 g) was cooled to room temperature and then added slowly to a stirred aqueous solution of L-glutamic acid (103 g, 0.7 gmol) in water (296 g) along with potassium hydroxide solution (50%, 232 g, 2.066 gmol) simultaneously while maintaining the pH of the reaction mass between 10.0 to 10.5 and the temperature between 20 to 30 C. The addition was completed in two hours and the reaction mass was stirred for another 4 h at rt. To this mixture N-capryloyl glycine (4.5 g) and N-undecylenoyl glycine (4.5 g) were added and stirred until homogeneous. The pH was adjusted to 6.0 with HCl. The solids content of the reaction mass was adjusted to 50% to yield 886 g of aqueous thin paste as the final product.

(65) The analysis of the above aqueous surfactant blend was as follows:

(66) TABLE-US-00004 Test Results Appearance White flowable paste Viscosity at 25 C. 1600 cps pH as such 6.45 KCl, % w/w 6.90 Total solids, % w/w 50.00 Free glutamic acid % w/w 2.30 Free fatty acid % w/w 3.0

Example 3

(67) Synthesis of a Composition of Sodium Cocoyl Isethionate and Sodium Cocoyl Glycinate in Molar Ratio of 1:2 and 1% w/w of Lipoglycines, Undecylenoyl Glycine and Capryloyl Glycine (1:1 w/w).

(68) The cocoyl chloride used in this experiment had the following alkyl chain distribution C.sub.8: 5.0%, C.sub.m: 6.0% C.sub.12: 62.6% C.sub.14: 20.0% C.sub.16: 6.0% C.sub.18: 0.4% To a stirred cocoyl chloride (234 g, 1.05 gmol) under slow purging of nitrogen at room temperature, sodium isethionate (52 g, 0.35 gmol) was added and the slurry was stirred at 55-60 C. for 4 h. The HCl gas generated was absorbed in alkali solution and the progress of reaction was monitored by IR spectrum analysis. The FTIR spectrum of the intermediate showed the presence of unreacted cocoyl chloride (carbonyl stretch at 1800 cm.sup.1), sodium cocoyl isethionate (carbonyl of ester at 1734 cm.sup.1) and disappearance of hydroxyl stretch (3323 cm.sup.1) of sodium isethionate.

(69) This fluid viscous reaction mass (270 g) was cooled to room temperature and then added slowly to a stirred aqueous solution of glycine (53.55 g, 0.71 gmol) in water (730 g) along with sodium hydroxide solution (48.8%, 116 g, 1.41 gmol) simultaneously while maintaining the pH of the reaction mass between 10.2 to 10.5 and the temperature between 20 to 30 C. The addition was completed in two hours and the reaction mass was stirred for another 4 h at 25 C. To this mixture N-capryloyl glycine (6.0 g) and N-undecylenoyl glycine (6.0 g) were added and stirred until homogeneous. The pH was adjusted to 7.5 with HCl. The solids content of the reaction mass was adjusted to 30% to yield 1169 g of aqueous solution as final product.

(70) The analysis of the above aqueous surfactant blend was as follows:

(71) TABLE-US-00005 Test Results Appearance Light yellow clear liquid Viscosity at 25 C. 400 cps pH as such 7.5 NaCl, % w/w 3.7 Free glycine 0.75 Free fatty acid 2.4 Total solids, % w/w 31.00

Example 4

(72) Synthesis of a Composition of Potassium Cocoyl Isethionate and Mono Potassium Cocoyl Glutamate in Molar Ratio of 1:2 and 1% w/w of Lipoglycines, Undecylenoyl Glycine and Capryloyl Glycine (1:1 w/w).

(73) The cocoyl chloride used in this experiment had the following alkyl chain distribution C.sub.8: 5.0%, C.sub.m: 6.0%, C.sub.12: 62.6%, C.sub.14: 20.0%, C.sub.16: 6.0%, C.sub.18: 0.4% To a stirred cocoyl chloride (328 g, 1.5 gmol) under slow purging of nitrogen at room temperature, potassium isethionate (82 g, 0.5 gmol) was added and the slurry was stirred at 5560 C. for 4 h. The HCl gas generated was absorbed in alkali solution and the progress of reaction was monitored by IR spectrum analysis. The FTIR spectrum of the intermediate showed the presence of unreacted cocoyl chloride (carbonyl stretch at 1800 cm.sup.1), potassium cocoyl isethionate (carbonyl of ester at 1734 cm.sup.1) and disappearance of hydroxyl stretch (3323 cm.sup.1) of potassium isethionate.

(74) This fluid viscous reaction mass (388 g) was cooled to room temperature and then added slowly to a stirred aqueous solution of L-glutamic acid (155 g, 1.05 gmol) in water (600 g) along with potassium hydroxide solution (50%, 350 g, 3.1 gmol) simultaneously while maintaining the pH of the reaction mass between 10.0 to 10.5 and the temperature between 20 to 30 C. The addition was completed in two hours and the reaction mass was stirred for another 4 h at rt. To this mixture N-capryloyl glycine (7 g) and N-undecylenoyl glycine (7 g) were added and stirred until homogeneous. The pH was adjusted to 6.0 with HCl. The solids content of the reaction mass was adjusted to 45% solids content to yield 1505 g of aqueous solution as final product.

(75) The analysis of the above aqueous surfactant blend was as follows:

(76) TABLE-US-00006 Test Results Appearance Light yellow clear liquid Viscosity at 25 C. 400 cps pH as such 6.2 KCl, % w/w 6.4 Total solids, % w/w 45.00 Free glutamic acid % w/w 2.40 Free fatty acid % w/w 3.60

Example 5

(77) Synthesis of a Composition of Sodium Cocoyl Isethionate and Mono Potassium Cocoyl Glutamate in Molar Ratio of 1:2 and 2% w/w of Lipoglycines, Undecylenoyl Glycine and Capryloyl Glycine (1:1 w/w). (In-Situ Generation of UG/CG)

(78) The cocoyl chloride used in this experiment had the following alkyl chain distribution C.sub.8: 5.0%, 5.0%, C.sub.12: 62.0%, C.sub.14: 18.0%, C.sub.16: 6.0%, C.sub.18 (oleic): 4.0% To a stirred cocoyl chloride (331 g, 1.5 gmol) under slow purging of nitrogen at room temperature, sodium isethionate (74 g, 0.5 gmol) was added and the slurry was stirred at 55-60 C. for 4 h. The HCl gas generated was absorbed in alkali solution and the progress of reaction was monitored by IR spectrum analysis. The FTIR spectrum of the intermediate showed the presence of unreacted cocoyl chloride (carbonyl stretch at 1800 cm.sup.1), sodium cocoyl isethionate (carbonyl of ester at 1734 cm.sup.1) and disappearance of hydroxyl stretch (3323 cm.sup.1) of sodium isethionate.

(79) This fluid viscous reaction mass (385 g) was cooled to room temperature and then added slowly to a stirred aqueous solution of L-glutamic acid (155 g, 1.05 gmol) in water (600 g) along with potassium hydroxide solution (350%, g, 3.1 gmol) simultaneously while maintaining the pH of the reaction mass between 10.0 to 10.5 and the temperature between 20 to 30 C. To this mixture glycine (10.3 g, 0.137 gmol) was added and stirring continued. To this stirred mass mixture of undecylenoyl chloride and capryloyl chloride (25 g, 0.137 gmol) were added and the pH was maintained between 10.0 to 10.5. The reaction mass was then stirred for additional 4 hours and the pH was adjusted to 6.0 with HCl. The solids content of the reaction mass was adjusted to 45% solids content to yield 1600 g of aqueous solution as final product.

(80) The analysis of the above aqueous surfactant blend was as follows:

(81) TABLE-US-00007 Test Results Appearance Light yellow clear liquid Viscosity at 25 C. 400 cps pH as such 6.0 KCl, % w/w 6.7 Total solids, % w/w 45.00 Free glutamic acid % w/w 2.30 Free fatty acid % w/w 3.55

Example 6

Comparative Example

(82) Composition of Sodium Cocoyl Isethionate and Potassium Cocoyl Glutamate, Made by Physical Blending of the Same in Molar Ratio of 1:2 and 1% w/w of Lipoglycines, Undecylenoyl Glycine and Capryloyl Glycine (1:1 w/w).

(83) To a stirred mixture of monopotassium cocoyl glutamate (825 g, 48% solids solution) and water (250 ml) at 70 C., sodium cocoyl isethionate (155 g) is added and stirring is continued till a homogeneous solution is formed. The solid content is adjusted to 44.5%. The solution appears uniform but is hazy to naked eye. Turbidity on nephelometer is found to be 30 NTU. However, on standing sodium cocoyl isethionate precipitate out/crystallize out and settles at the bottom of the container.

(84) TABLE-US-00008 Test Results Appearance Light yellow hazy liquid Viscosity at 25 C. 350 cps pH as such 6.1 KCl, % w/w 7.2 Total solids, % w/w 44.50

Example 7: Formulations Prepared from Composition of Example 1 and Example 6

(85) TABLE-US-00009 Analysis of Formulation A: Viscosity 4000 cps at 25 C., pH as it is 6.0 Formulation A Ingredient % w/w GLI of Example 1 26.5 Cocoamidopropyl betaine 10 PEG 150 distearate 3 Water q.s. to 100 Analysis of Formulation B: Viscosity 4000 cps at 25 C., pH as it is 6.0. Formulation B Ingredient % w/w Physical blend of Example 6 26.5 Cocoamidopropyl betaine 10 PEG 150 distearate 3 Water q.s. to 100

(86) Comparison of Foam Volume and Lather Potential

(87) TABLE-US-00010 Lather Foam Potential volume (Drainage (ml) Time) (seconds) Formulation A 510 240 Formulation B 360 30

Example 8: Preparation of Transparent, Skin-pH Bodywash Using Composition of Example 1

(88) TABLE-US-00011 Phase Ingredient % w/w Function A GLI (Example 1) 20.6 Mild surfactant Cocoamidopropyl betaine 16.7 Mild surfactant PEG 150 distearate 2 Rheology modifier Water q.s. to 100 B Undecylenoyl glycine 0.5 Scalp care Capryloyl glycine 0.5 Sebum controller EDTA disodium 1.0 Chelating agent Fragrance 1.0 Fragrance Analysis: Viscosity = 6000 cps, pH = 5.6 and Transparency <10 NTU

Example 9: Preparation of Transparent Anti-Acne Face-Wash Using Composition of Example 1

(89) TABLE-US-00012 Phase Ingredient % w/w Function A GLI (Example 1) 14.7 Mild surfactant Cocoamidopropyl betaine 10 Mild surfactant PEG 150 distearate 2 Rheology modifier Water q.s. to 100 Salicylic acid 2.0 Anti-acne B EDTA disodium 0.1 Chelating agent Fragrance 0.5 Unecylenoyl glycine 0.5 Skin care agent Capryloyl glycine 0.5 Skin care agent Analysis: Viscosity = 1500 cps, pH = 4 and Transparency <10 NTU

Example 10: Preparation of Transparent, Sulphate-Free Anti-Dandruff Shampoo Using Composition of Example 1

(90) TABLE-US-00013 Phase Ingredient % w/w Function A GLI (Example 1) 24 Mild surfactant Cocoamidopropyl betaine 20 Mild surfactant PEG 150 distearate 2 Rheology modifier Water q.s. to 100 B Ketoconazole 1.0 Anti-dandruff agent EDTA disodium 0.1 Chelating agent Fragrance 0.5 Unecylenoyl glycine 0.5 Skin care agent Capryloyl glycine 0.5 Skin care agent Analysis: Viscosity = 1000 cps, pH = 7 and Transparency <10 NTU

Example 11: Preparation of Transparent, Baby Shampoo Using Composition of Example 1

(91) TABLE-US-00014 Phase Ingredient % w/w Function A GLI (Example 1) 11.8 Mild surfactant Cocoamidopropyl betaine 13.4 Mild surfactant Lauryl Glucoside 8 Rheology modifier Water q.s. to 100 Polyquatemium 10 0.4 Conditioning agent B Undecylenoyl glycine 0.5 Skin care agent Capryloyl glycine 0.5 Skin care agent EDTA disodium 0.1 Chelating agent Analysis: Viscosity = 9000 cps, pH = 5.2 and Transparency <10 NTU