Hydrolyzed Jojoba Esters to Potentiate Glycerin Moisturization Tiffany N. Oliphant and Douglas W. Gilmore Floratech, Chandler, AZ, USA Robert A. Harper, PhD Harper and Associates, La Jolla, CA USA of human skin sebum, making jojoba oil KEY WORDS: hydrolyzed jojoba esters, potentiation of moisturization, well-suited to augment skin moisturization mechanism of action and barrier repair. Similarly, hydrolyzed jojoba esters (HJEs) ABSTRACT: Hydrolyzed jojoba esters were incorporated into formulas also exhibit unique moisturization and sub- including a lotion, hand sanitizer and nonwoven wipes. stantive properties in cosmetic and personal Small, well-controlled clinical studies were then conducted care formulations, as will be shown. HJEs are to compare the formulas with or without glycerin. Results the partial saponification product of jojoba oil, whereby the ester bond linking the con- show the esters can potentiate the skin moisturizing effect stituent fatty acids and alcohols is severed, thus of glycerin under varying formula conditions. A mechanism liberating the hydrophobic fatty alcohol and of action also is discussed. creating a hydrophilic salt of the jojoba fatty acid (see Figure 1). Two patented forms of HJEs currently ydrolyzed jojoba esters are derived species. Jojoba oil primarily consists of exist, which will be referred to herein as H1a from jojoba oil, a unique natural oil straight chain monoesters of C and C and H2b. H1 includes approximately 20% H 20 22 expressed from the seed of the jojoba plant. alcohols and fatty acids with one point HJEs and 80% water, whereas H2 contains Jojoba oil (INCI: Simmondsia Chinensis of unsaturation on each side of the ester approximately 80% HJEs with 10% jojoba (Jojoba) Seed Oil) is unlike other “fixed,” i.e. linkage.1 It is the only known botanical wax esters and 10% water. The H1 form was botanically derived, oils in that it is a true ester that remains liquid at room tempera- developed from the H2 form since it was wax ester, in contrast to the triglyceride oils ture. In addition, its chemical structure is found to form a gel that was easier to use and often found in the seeds of other botanical similar to the large wax ester component less petrolatum-like in feel. H1 has previously been shown to potentiate the moisturizing effect of glycerin in astringent and lotion formulations when used at levels ≥ 5%, com- pared with control formulations without H1.2 The present article is meant to explore the potential of H1 and H2 when used at low levels, i.e. ≤ 1%, to assess the capability of HJEs in potentiating the skin moisturization a Floraesters K-20W Jojoba (INCI: Hydrolyzed Jojoba Esters (and) Water (aqua)) is a product of Floratech, Chandler, AZ, USA. b Floraesters K-100 Jojoba (INCI: Hydrolyzed Jojoba Esters (and) Jojoba Esters (and) Water (aqua)) is a Figure 1. Formation of hydrolyzed jojoba esters (saponified jojoba oil) product of Floratech, Chandler, AZ, USA. Formula 1. Test lotion used in Formula 2. Hand sanitizer used in effect of glycerin in three distinct product clinical evaluations clinical evaluations categories: hand and body lotions, hand sanitizers, and nonwoven wipes. Glycerin is Water (aqua) qs to 100.00% w/w Water (aqua) qs to 100.00% w/w considered an industry standard to increase Glycerin 4.00 Alcohol denat. 62.00 skin moisturization but generally is not aes- Steareth-2 3.00 PEG-6 Caprylic/ thetically pleasing. As will be shown here, Steareth-21 1.00 Capric Glycerides 1.00 using hydrolyzed jojoba esters in conjunc- Methylparaben 0.20 Glycerin 1.00 tion with glycerin can reduce the amount of Carbomer 0.15 Acrylates/C10-30 Alkyl glycerin required within a formula without Propylparaben 0.10 Acrylate Crosspolymer 0.25 reducing skin moisturization. Triethanolamine 0.05 Xanthan Gum 0.05 H1 0.00–1.00 H1 0.00 or 1.00 Methods The clinical studies described here were conducted in a controlled environment, at approximately 20–22°C with a relative humid- 100% Vehicle + 0.4% H1 ity of less than 50%. Each study included a Currently marketed product (+ control) wash-out period of two to three days prior Vehicle (0% H1) to initiation of the study during which the participants used a specified soapc for cleans- 80% ing their lower legs and no additional skin care products. The studies also included a 30-min equilibration period before application of the test formulas. Corneometer measurementsd 60% were carried out in triplicate. All clinical studies were approved by an independent institutional review board and each partici- pant signed an informed consent form before Increased Moisturization Increased 40% participating in the study. (percent change from baseline) change from (percent Hand and Body Lotions 20% 8 hr7 hr6 hr5 hr4 hr3 hr2 hr1 hr hr1 hr2 hr3 hr4 hr5 hr6 8 hr7 One of the largest skin care product cat- egories is the hand and body lotion category. Figure 2. Percent increase in skin hydration resulting from the application of lotion There are hundreds of finished products formulations with or without 0.4% H1, relative to untreated skin on the market containing ingredients pur- ported to provide skin moisture. Traditional ingredients include glycerin, petrolatum and silicones. However, formulators as well as con- 45% sumers are seeking new approaches to deliver 40% such benefits; in response, H1 is proposed as a natural alternative or supplement to synthetic 35% ingredients currently used in moisturizers. 30% A clinical study was conducted involving 10 healthy female participants with dry 25% skin on their lower legs. The objective was Vehicle + 1% H1 20% to determine the optimal ratio of H1a to Vehicle (0% H1) glycerin to provide maximum skin moistur- 15% Currently marketed product ization, compared with the control (without 10% H1) over time. One application of each test Increased Moisturization Increased formula (see Formula 1) was applied to the 5% (percent change from baseline) change from (percent appropriate test site on the lower legs of each 0% participant and corneometer measurements were taken every hour for eight hours. -5% Results: Results showed that when H1a 10 min 40 min was used between a ratio of 1:7 and 1:10 with 1 hr 10 min1 hr 40 min2 hr 10 min2 hr 40 min3 hr 10 min3 hr 40 min4 hr 10 min c Ivory Soap is a product of Procter and Gamble, Cincinnati, USA. Figure 3. Percent increase in skin hydration resulting from the application of hand sanitizer d The CM 825 Corneometer is a product of Courage formulations with or without 1% H1, relative to untreated skin and Khazaka, Köln, Germany. Formula 3. Hydro-alcoholic nonwoven wipe formula used 40% in clinical evaluations Vehicle + 1% H1 Water (aqua) qs to 100.00% w/w 30% Vehicle + 0.2% H2 Alcohol Denatured 65.00 Glycerin 1.00 Vehicle (0% H1/H2) H1 0.00 or 1.00 20% H2 0.00 or 0.20 10% glycerin, maximum skin moisturization was achieved, over the control. In all cases, the Moisturization Increased (percent change from baseline) change from (percent 0% test formula significantly outperformed (p < 0.05) the test vehicle, demonstrating that H1a can increase and extend skin moisturization -10% within a lotion containing glycerin, reducing 30 min 60 min 90 min 120 min the amount glycerin, with its inherent tacki- ness, required. Figure 2 shows the percent Figure 4. Percent increase in skin hydration resulting from the application of a hydro- increase in moisturization over eight hours. alcoholic formulation via nonwoven wipe with or without 1% H1 or 0.2% H2, relative to untreated skin Alcoholic Hand Sanitizers Another important finished product also suggests the ingredient could be incor- of alcohol, as prescribed by the FDA category is hand sanitizers. The World porated into formulas where only a small monograph, or an antibacterial agent such Health Organization recommends the use amount of glycerin is required to increase as benzethonium chloride. Both of these of hydro-alcoholic hand sanitizers to help the moisturizing benefits of the product. materials dry the skin, thus wipe formulas prevent the spread of infectious diseases;3 often incorporate glycerin as well to help however, chronic use of hand sanitizers can Nonwoven Wipes moisturize the skin. dry out the skin. To overcome this drying A clinical study was performed with 12 effect, conventional hand sanitizers often The wipe category is relatively new and healthy female participants having dry skin include ingredients such as glycerin or aloe has grown substantially in the last few years. on their lower legs. The object of the study was vera to reduce dryness, and since H1 was Both hydro-alcoholic and non-alcohol- to determine the moisturization potential of a shown to potentiate the effect of glycerin in based wipes often are used to sanitize the hydro-alcoholic nonwoven wipe containing a lotion formulation, the authors evaluated hands and body. The solutions used to make HJEs compared with the same formula not how the ingredient worked in a hydro- these wipes contain either largeVehicle amounts containing HJEs. In this study, either 1% H1 alcoholic environment. Vehicle + 1% glycerinVehicle A clinical study was performed with Vehicle + 1% glycerinVehicle + 0.5% + H1 1% glycerin nine healthy female participants hav- Vehicle Vehicle + 1% glycerinVehicle + 0.1% + H2 1% glycerin + 0.5% H1 ing dry skin on their lower legs. Two Vehicle + 1% glycerin Currently marketed productVehicle + 1% glycerin + 0.1% H2 formulas containing 1.0% glycerin with Vehicle + 1% glycerin + 0.5% H1 Currently marketed product and without 1.0% H1 (see Formula 2) 50% Vehicle + 1%50% glycerin + 0.1% H2 were tested and compared with a cur- Currently marketed product rently marketed product. Each participant 40% 50% received five applications of each test 40% formula in 25 min.