WO2006078245A1

WO2006078245A1 - Simulated vernix compositions for skin cleansing and other applications

Info

Publication number: WO2006078245A1
Application number: PCT/US2005/001839
Authority: WO
Inventors: Steven B. Hoath; William L. Pickens; Martha O. Visscher; Anyarporn Tansirikongkol; Richard Randall Wickett
Original assignee: Children's Hospital Medical Center; University Of Cincinnati
Priority date: 2005-01-19
Filing date: 2005-01-19
Publication date: 2006-07-27
Also published as: EP1838274A1; CA2595023A1; JP2008527036A

Abstract

A composition and a method of producing a composition which simulates hydration, cleansing and other properties of native vernix. The composition contains hydratable water-in-oil emulsified particles providing water vapor transport and evaporative water loss properties, rheologic, tactile, cleansing, and other properties simulating native vernix. The inventive composition simulates hydrophobic properties of native vernix by a matrix of one or more lipids that are present in native vernix, in which the simulated cells are dispersed. In one embodiment, the lipids are substantially physiologic. Any or all the following lipids may be used, each of which is found in native vernix, and each of which is available commercially : cholesterol esters, ceramides, triglycerides, cholesterol, free fatty acids, phospholipids, wax esters, squalene, wax diesters, and cholesterol sulfate. Other physiologically acceptable lipids, such Petrolatum and/or mineral oil, may be included in some formulations.

Description

SIMULATED VERNIX COMPOSITIONS FOR SKIN CLEANSING AND OTHER APPLICATIONS

Background of the Invention

A composition simulating natural vernix and uses for the composition. Summary of the Invention

One embodiment is a synthetic vernix composition having a continuous lipid phase where the lipids are substantially physiologic lipids, and a water phase of simulated cells dispersed in the lipid phase, the water phase capable of retaining greater than about 65%^w/w water of the total composition, with water vapor transport through the composition that ranges between about 85% of water vapor transport through a substantially highly permeable composition and about 5% of water vapor transport through a substantially highly occlusive composition, and a rate of evaporative water loss from the composition from about -38% water in composition/hr to 0% water in composition/hr from 0 h to 0.5 hr, that is, up to about 38% water loss within the first half-hour, and from about -8% water in composition/hr to 0% water in composition/hr from 0.5 hr to 3 hr, that is, up to about 8% water loss after the first half-hour and for the next two and one-half hours.

Another embodiment is a synthetic vernix composition having a lipid phase and a water phase, with the lipid phase having at least one emulsifying agent to form hydratable water-in-oil emulsified particles. The emulsifying agent has a hydrophile-lipophile balance (HLB) value such that the emulsifying agent does not substantially dissolve in the water phase. For example, the HLB value may range between about 3 to about 6.

In one embodiment, the synthetic vernix composition comprises hydratable water-in-oil emulsified particles having a lipid phase comprising lanolin, squalene, linoleic acid, cholesterol, ceramide III, wax, capric/caprilic triglyceride, cholesterol sulfate; PEG30 dipolyhydroxystearate and sorbitan sesquioleate emulsifying agents; and a water phase containing methylparaben and/or propylparaben, magnesium sulfate, glycerin, and water in concentrations sufficient to provide water vapor transport, evaporative water loss, tactile and rheological properties simulating native vernix. In another embodiment, the synthetic vernix composition comprises hydratable water-in-oil emulsified particles having a lipid phase comprising lanolin, stearyl alcohol, wax, mineral oil, and petrolatum; cetyl dimethicone copolyol and Abil WE09 (polyglyceryl-4-isostearate and cetyl dimethicone copolyol and hexyl laurate) emulsifying agents, and water. Another embodiment is a method of using synthetic vernix to remove soil from a skin surface. The composition is applied to the soiled surface, then is removed along with the soiling material. The method may be used on a premature or full term infant, a child, an adult, a geriatric patient, and the composition may be used on an intact or compromised surface, such as a wound or ulcer. The method may be used with a synthetic vernix composition that also contains a soap and/or surfactant.

Another embodiment is a method for fully or partially cleansing a baby (full term or premature) immediately after birth with a composition containing synthetic vernix to remove amniotic fluid, endogenous vernix, meconium, blood and other fluids, upon removing the composition.

Another embodiment is a method of cleaning a soiled skin surface by applying a composition consisting essentially of synthetic vernix under conditions to emulsify the soiling material in the vernix, and then removing the vernix and emulsified soiling material. The amount of synthetic vernix may be up to about 16 mg/cm².

Another embodiment is a method of cleansing skin by applying a nontoxic film having a thickness up to about 16 mg/cm² and consisting essentially of synthetic vernix to a layer of epithelial cells to provide a skin cleansing effect. The film may be applied either directly or indirectly to the surface; for example, it may be applied to a wash cloth, a wipe, a bandage, a pad, etc. Another embodiment is a method of cleansing an epithelial layer by applying a non-toxic film having a thickness of up to about 16 mg/cm² and consisting essentially of synthetic vernix to the epithelial layer, and then removing the film from the cleansed tissue. Another embodiment is a method to protect a skin surface of an individual who is, or may be, susceptible to commercially available cleansing products (e.g., one allergic to some commercial soaps or cleansers). In the method, a composition consisting essentially of synthetic vernix is applied to a skin surface of this individual in an amount up to 16 mg/cm² before exposing the skin surface to the product.

Another embodiment is a method to remove a soiling material from a skin surface by providing synthetic vernix and at least one soap or surfactant to the soiled surface under conditions resulting in flocculation and detachment of the soil from the surface.

The invention will be further appreciated with respect to the following detailed description, figures, and examples. Brief Description of the Figures

FIG. 1 schematically illustrates simulated cells dispersed in a lipid matrix.

FIGS. 2A, 2B, and 2C show evaporative water loss profiles of embodiments of synthetic vernix.

FIGS. 3A, 3B, and 3C are digital images of volar forearm skin, either unsoiled (FIGS. 3A1 and 3A2, after application of a soiling material (FIGS. 3B1 and 3B2), or after application of a synthetic vernix (FIGS. 3C1 and 3C2).

FIGS. 4A, 4B, 4C, 4D, 4E, and 4F are histograms quantitating the amount of soiling material on the skin surface of unsoiled (baseline), soiled, and cleansed skin treated with water (FIG. 4A), Aquaphor (FIG. 4B), commercial cleansers (FIGS. 4C, 4D), synthetic vernix (FlG. 4E), and native vernix (FIG. 4F). FIG. 5 is a plot of differences in L-scale scores before and after cleansing with various treatments.

FIGS. 6A1-6A6, 6B1-6B6, and 6C are representative digital images converted to black and white counterpart images and graphical results of skin treated with synthetic vernix and other cleansing agents. Detailed Description

A nontoxic simulated vernix composition, also referred to herein as synthetic vernix, contains a component of simulated cells and a component of at least one lipid. The inventive composition simulates the hydration, barrier, rheological, tactile, and other properties of native vernix. With respect to its hydration properties, native vernix provides both hydrophilic properties from the water associated with its cellular component, and hydrophobic properties from its lipid component. The inventive composition simulates hydrophilic properties of native vernix by hydrated emulsified water droplets, referred to herein as emulsified particles, that have the capability to retain, in a hydrated state, at least 65%^ water in the composition in their internal (water) phase. The inventive composition simulates hydrophobic properties of native vernix by a matrix of one or more lipids that are present in native vernix, in which the simulated cells are dispersed. In one embodiment, the lipids are substantially physiologic. The inventive composition thus retains or is capable of retaining water at a concentration that simulates native vernix, and transports water vapor at a rate that simulates native vernix.

Native vernix, as used herein, encompasses vernix as it is obtained from a newborn, as well as vernix obtained from a newborn that has been rendered tractable, as described in U.S. Patent Nos. 5,989,577; 6,113,932; 6,333,041; and U.S. Patent application Serial Nos. 09/850,844 (now U.S. Patent No. 6,562,358); 10/241 ,184; 60/377,430 and 60/439,966; and PCT application Serial No. PCT/US03/13612, now U.S. Patent application Serial No. 10/512,933, each of which is expressly incorporated by reference herein in its entirety.

In the inventive composition, the cell component of native vernix , is replaced by hydratable emulsified particles that perform the hydration functions of cells; these structures may be termed "simulated cells" or "synthetic cells". The "cellular" component, also referred to herein as simulated cells, hydrates a surface to which the inventive composition is applied. It does this by slowly releasing water and by transporting water vapor, as cells do in native vernix. The simulated cells in small particle form are mixed into a lipid matrix. The lipid matrix contains at least one commercially available lipid that is present in native vernix. Any or all of the following lipids may be used, each of which is found in native vernix, and each of which is available commercially (for > example, Sigma, St. Louis MO): cholesterol esters, ceramides, triglycerides, cholesterol, free fatty acids, phospholipids, wax esters, squalene, wax diesters, and cholesterol sulfate. The composition of the lipid phase may be varied to provide the desired spreading characteristics and viscosity for the final composition. For example, a relatively higher wax content will produce a less spreadable, more viscous composition than a relatively lower wax content; a relatively higher free fatty acid and/or triglyceride content will produce a more easily spreadable, less viscous composition than a relatively lower free fatty acid and/or triglyceride content.

Phase stable water-in-oil emulsions in small particle form in a lipid matrix provided compositions that simulated native vernix. This is shown schematically in FIG. 1 where water droplets 10 exist in a lipid matrix 20, the water droplets 10 packaged in particles 30 as emulsions. The synthetic vernix compositions substantially duplicated properties of native vernix. The emulsified particles performed the function of the biological cells in native vernix with respect to regulating water transport, permeability, barrier, water- loss, and other properties relating to water behavior. The emulsions effectively allowed the water to exist in droplets, i.e., packaged as droplets.

Emulsifying agents or emulsifiers are generally considered to be surface active agents or surfactants. While the term surfactant may refer to cleaning ability, in the case of the inventive compositions hydrophile-lipophile balance (HLB) is used to describe the nature of the emulsifier. The HLB of the emulsifier is selected so as to keep the water retained within the particular matrix of the formulation. If the HLB is too high, the emulsifier will dissolve in the water and therefore not keep the water as droplets within the lipid matrix. HLB is a property represented on an arbitrary scale of 0-20 for non- ionic surfactants, withhigher numbers indicating the most hydrophilic surface active agents, and lower numbers indicating the most hydrophobic surface active agents. The HLB of a nonionic surfactant is the approximate weight of ethylene oxide in the surfactant divided by 5. For example, polyoxyethylene derivatives of Spans (Tweens) have relatively higher HLB values in the range of about 9.6 to about 16.7, while sorbitan esters (Spans) have relatively lower HLB values in the range of about 1.8 to about 8.6. As other examples, the HLB of oleic acid is 1 ; the HLB of glyceryl monostearate (Span 80) is 3.8; the HLB of sorbitan monooleate (Span 20) is 4.3; the HLB of triethanolamine oleate is 12.0; the HLB of polyoxyethylene sorbitan is 15; the HLB of monooleate (Tween 80) polyoxyethylene sorbitan is 16.7; the HLB of monolaurate (Tween 20) sodium oleate is 18.0; the HLB of sodium lauryl sulfate is 40.

In the inventive composition, the HLB values of the emulsifying agents ranged from lower than 4 to about 6. In one embodiment, the HLB ranged from 3.8 to 6.0. In one embodiment, the HLB was about 3.8. These emulsifying agents provided a high internal phase (i.e., water phase) system, containing water as greater than about 65%^w/w of its total volume, and yielded a water loss profile simulating native vernix.

In one embodiment the emulsifying agents were polyhydroxy hydrocarbons. In another embodiment the emulsifying agents were the non-

ionic PEG-7 hydrogenated castor oil (Cremophore WO7®) (4%^w/w), or polyglyceryl-4 isostearate and cetyl dimethicone copolyol and hexyl laurate (Abil WE09) (5%^w/w). In another embodiment the emulsifying agents were cremophore WO7 (0.8%^w/w) and cetyl dimethicone copolyol (2%^w/w). In another embodiment the emulsifying agents were cetyl dimethicone copolyol (1 %^w/w) and Abil WE 09 (2%^w/w). In another embodiment, the emulsifying agent was Abil WE 09 (2%^w/w). In another embodiment the emulsifying agents were PEG-30 dipolyhydroxystearate (Arlacel P 135®, Uniqema, USA) (about 1.5%^w/w) and sorbitan sesquioleate (Uniqema) (about 0.5%^w/w). In another embodiment, the emulsifying agent is polyglyceryl-3-diisostearate (Unichema, Gouda, NL) and cetyl dimethicone copolyol. In another embodiment, the emulsifying agent is polyglyceryl-3-oleate (Danisco AJS, Copenhagen DK). In another embodiment, the emulsifying agent is polyglyceryl-4-isostearate (about 2.5%^w/w to about 4%^w/w) (ISOLAN Gl 34, Goldschmidt, Mannheim, DE). In another embodiment, emulsifying agent(s) is/are used with methyl glucose isostearate (about 2%^w/w to about 5%^w/w) (ISOLAN IS, Goldschmidt) as a co-emulsifier.

In one embodiment, the emulsifying agents were selected to minimize irritancy when the inventive composition was applied to a skin surface. As known to one skilled in the art, "low irritancy" materials cause little or no irritation in skin irritancy testing and among individuals with irritated skin, reactive skin conditions, or with susceptibility to skin irritation. Therefore, skin care product ingredients can be classified according to their effects on skin in standard testing. One irritancy test is the Human Patch Test. The materials to be evaluated are applied under an occlusive patch and left on the skin for up to 24 hours. Following application, the skin condition is evaluated by standard methods, such as dryness and erythema scoring using visual grading scales or instrumental measurement of skin barrier integrity and function. Low irritancy materials have relatively low Patch Test scores, e.g., 0.2-0.5 on a 0-4 scale, and/or cause substantially no irritation in a large population of healthy subjects. In one embodiment of the inventive composition, emulsifiers with low irritancy were selected over emulsifiers that yielded a stable product but that had the potential to cause low levels of irritation in irritated skin populations.

Physiologic lipids that are found in native vernix were incorporated in the formulation to constitute the lipid matrix. These included cholesterol and squalene (both from Sigma Aldrich, St. Louis, MO), ceramide III (Cosmoferm, NL), cholesterol sulfate (Acros Organics, Leicestershire, UK), linoleic acid (Henkel Corporation-Emery Group, Cincinnati OH), lanolin (Amerchol, Midland Ml), triglyceride (e.g., capric caprilic triglyceride) (Henkel), and wax (e.g. beeswax USP). Other physiologically acceptable lipids, such as Petrolatum® (CVS, Woonsocket, Rl) and/or mineral oil, may be included in some formulations.

The inventive simulated vernix composition retained, or was capable of retaining, greater than about 65% water of the total composition by weight in its internal (water) phase. Additional components may assist in maintaining the emulsion, providing hydration, etc. For example, the water phase may contain electrolytes. In one embodiment, the water phase contained magnesium sulfate (The PQ Corp, Berwyn, PA) which binds water, assists in water release properties of the synthetic cell, and stabilizes the water-in-oil emulsion. In another embodiment, the water phase contained glycerin (Cognis, Cincinnati, OH). Glycerin has a high affinity for water and therefore assists with slow release of the water; it also binds water to the skin surface. In another embodiment, the water phase contained a preservative such as methylparaben and/or propylparaben (Chatham ISP Sutton Laboratories, Wayne NJ). In one embodiment, the inventive composition is applied to a physiologically acceptable support structure in a liquid state to form a film. It is presented as .droplets which coalesce to form a film upon encountering the support. A film is defined herein as an interfacial surface covering, in either a liquid or a solid state, with temperature-dependant properties. Film-forming techniques include but are not limited to spraying, extruding, blowing, pouring, evaporating, coating and painting.

In an alternate embodiment, a preformed film of the inventive composition is applied to a physiologically acceptable support. The physiologically acceptable support is one that can withstand sterilization, preferably by standard sterilization techniques known to one skilled in the art such as exposing to gamma radiation, autoclaving, and so on. The support is not limited to a particular composition or configuration and, depending upon its use, may or may not be sterilized and may take various forms. In one embodiment, the film is used to enhance skin cell maturation and may be applied to structures such as filters, membranes, beads, particles, and so on. Similarly, the support structure is not limited to a particular state of matter and may be a solid, a semi-solid, a gel and so on. In one embodiment, the support consists of a nylon monofilament interpositional surfacing material such as N-terface® pads (Winfield Laboratories, Inc., Richardson TX), Biobrane II® (Sterling Drug Inc., New York NY) or circular nylon filters of suitable porosity (Micron Separations Inc., Westboro MA). Other support materials, however, may also be used to practice the invention.

In another embodiment, the film of the inventive composition is used to promote wound healing and/or tissue repair. It may be applied to various materials for placement either in direct contact or indirect contact with an intact or compromised skin site requiring treatment, such as a wound, an abrasion, an ulcer, a burned area, a site of infection or irritation, a wart, etc. The support may be permeable to physical and/or chemical agents, and may take a variety of forms, depending upon its purpose and the extent of the area requiring dressing or treatment. The film may be applied to various synthetics such as thermoplastic films, blown films and breathable films, and various natural and synthetic fabric compositions such as woven, non-woven, spun, and stitched fabrics. The invention may be used in a variety of products, examples of which include wound dressings and coverings such as bandages, tapes, gauze, adhesive products applied for a short or long term to the skin, ostomy care products, hospital pads such as incontinent pads, absorbent pads, and examination pads, disposable and cloth diapers, and feminine hygiene products such as intralabial devices. The inventive composition may be used therapeutically to promote skin growth, skin maturation, skin barrier formation, wound healing, skin flexibility, and tissue repair. It may also be used as a skin protectant to promote skin barrier formation, skin moisture retention, and skin flexibility. In one embodiment, the following general synthetic vernix composition A was used, with each component given in % weight (total of 100%):

Composition A

Lipid phase lanolin 1.5 - 2 squalene 3.2 - 5.8 linoleic acid 0.8 - 1.5 mineral oil 0 - 5 cholesterol 4 - 6 ceramide III 0.7 - 1.5 beeswax 3 - 4.2 capric/caprilic triglyceride 1 - 2 cholesterol sulfate 0-3

PEG30 dipolyhydroxystearate (Arlacel P135®) 1.5 sorbitan sesquioleate 0.5 Water phase methylparaben qs. magnesium sulfate 0.5 glycerin 2.5 - 5 water (deionized) 70.5 - 75

In another embodiment, the following synthetic vernix composition B was used, with each component given in % weight (total of 100%):

Composition B Lipid phase lanolin 2 squalene 3.5 linoleic acid 0.8 cholesterol 6 ceramide III 1.5 beeswax 4.2 capric caprilic triglyceride 1 cholesterol sulfate 1

PEG30 dipolyhydroxystearate (Arlacel P135®) 1.5 sorbitan sesquioleate 0.5

Water phase methylparaben, propylparaben qs. magnesium sulfate 0.5 glycerin 2.5 water (deionized) 75

In another embodiment, the following synthetic vernix composition C was used, with each component given in % weight (total of 100%):

Composition C Lipid phase lanolin 2 squalene 4 linoleic acid 1 mineral oil 5 cholesterol 4 ceramide III 1 beeswax 3 capric caprilic triglyceride 2 ^! PEG30 dipolyhydroxystearatθ (Arlacel P135®) 1.5 sorbitan sesquioleate 0.5

Water phase methylparaben, propylparaben qs. magnesium sulfate 0.5 glycerin 5 water (deionized) 70.5

In another embodiment, the following synthetic vernix composition D was used, with each component given in % weight (total of 100%):

Composition D Lipid phase lanolin 2 squalene 4 linoleic acid 1 mineral oil 3.5 cholesterol 5.5 ceramide III 1 beeswax 3 capric caprilic triglyceride 2

PEG30 dipolyhydroxystearate (Arlacel P135®) 1.5 sorbitan sesquioleate 0.5

In another embodiment, the following synthetic vernix composition E was used, with each component given in % weight (total of 100%):

Composition E Lipid phase lanolin 2 squalene 4 linoleic acid 1 mineral oil 3 cholesterol 5.5 ceramide IN 1 beeswax 4.2 capric caprilic triglyceride 1.5 PEG30 dipolyhydroxystearate (Arlacel P135®) 1.5 sorbitan sesquioleate 0.5

In another embodiment, the following synthetic vernix composition F was used, with each component given in % weight (total of 100%):

Composition F Lipid phase lanolin 2-3 stearyl alcohol 3-4 beeswax 1-2 mineral oil 6-7 petrolatum 4-6 polyglyceryl-4-isostearate and cetyldimethicone 2 copolyol and hexyl laurate (Abil WE09) cetyl dimethicone copolyol 1 Water phase propylparaben qs. sodium chloride 0.7 glycerin 7 water (deionized) 70

In one embodiment of composition F, specific concentrations are 2.7%^ lanolin, 3.5%^wt stearyl alcohol, 1.7%^ beeswax, 6.4%^ mineral oil, and 5%^ petrolatum.

Lanolin is classified chemically as a wax, being a complex mixture of naturally occurring esters and polyesters of thirty-three high molecular weight alcohols (principally sterols) and thirty-six fatty acids. It is 98% ester minimum, of which the fatty alcohols and fatty acids comprise an approximately 50/50 ratio. A typical composition of lanolin contains esters of sterols and triterpene alcohols (35.4%), esters of aliphatic alcohols (23.7%), monohydroxyesters of sterols and of triterpene and aliphatic alcohols (20.0%), di- and polyhydroxyesters and free diols (7.9%), free aliphatic alcohols (5.6%), free sterols (4.1 %), free hydrocarbons (0.6%), free fatty acids (0.5%), and unknown components (2.2%).

In formulating the inventive compositions, the components of the lipid phase except squalene, Arlacel P135® and sorbitan sesquioleate in compositions A-E, and except Abil WE09 and cetyl dimethicone copolyol in composition F, were mixed. The mixture was heated on a water bath until it softened and became flowable. The temperature of the mixture ranged from about 70⁰C to about 75⁰C. The remaining components of the lipid phase were added with continued heating on the water bath until the mixture was completely melted. The temperature of the mixture ranged from about 7O⁰C to about 75°C.

The components of the water phase were mixed. The resulting mixture was heated on a water bath until the temperature of the mixture ranged from about 70°C to about 75⁰C.

The water phase was then slowly added over about three to about five minutes to the melted lipid phase with vigorous stirring. After the water phase had been added and the mixture became homogeneous, the mixture was homogenized using a BioSpec Products homogenizer (Bartlesville OK) at about 15,000 rpm (set at 1 to 1.5 speed; the setting range is 1 to 5 to yield 5,000 rpm to 30,000 rpm) for about 4-5 minutes sufficient to form a viscous emulsion. The mixture was allowed to cool, then it was stored in a closed container under ambient conditions (i.e., about 20⁰C to about 22⁰C).

This procedure was used to prepare 10 grams of the inventive composition; hence, parameters such as the time of mixing may be varied for other amounts, as known to one skilled in the art.

The invention will be further appreciated with reference to the following examples.

EXAMPLE 1

Evaporative water loss from the composition over time, which may alternatively be expressed as percent water retained in the composition over time, was evaluated. This was done by measuring the water in the composition at intervals over thirty minutes (FIG. 2A) and up to three hours (180 min) (FIGS. 2B and 2C) and calculating the percent of water for embodiments of the inventive composition (compositions B, C, D, E, F), native vernix, and the commercially available agents Eucerin® (Beiersdorf AG, Hamburg Germany) (a water-in-oil emulsion; the ingredients are listed as follows: water, petrolatum, mineral oil, ceresin, lanolin alcohol, methylchloroisothiazolinone, methylisothiazolinone), and Curel™ (Andrew Jergens Co., Cincinnati, OH) (an oil-in-water emulsion; the ingredients are listed as follows: water, glycerin, distearyldimonium chloride, petrolatum, isopropyl palmitate, cetyl alcohol, dimethicone, fragrance, sodium chloride, methylparaben, propylparaben).

To assess evaporative water loss from each of the compositions, the compositions were spread as a thin film (3.28 mg/cm²) on an aluminum pan (14 mm diameter) weighing dish and immediately weighed on a Cahn C-31 microbalance® (Cahn Instruments, Inc., Cerritos CA). This initial weight was designated Wj_nt. Gravimetric measurements were made every two minutes for the first thirty minutes, and every thirty minutes thereafter for three hours (180 min). The weighing dish and composition were then placed in a vacuum desiccator to remove all water in the composition. For samples in which the water content is unknown, the sample was weighed every day for up to seven to ten days or until a constant weight was obtained. This final weight was designated W_end- Temperature and relative humidity of the room during the period of study were noted. If the relative humidity deviated from about 41 % to about 45%, the experiments were performed in a controlled humidity chamber. A control material was used in all experiments to account for differences in environmental humidity (room conditions) from one experiment to another to allow data comparison. The difference between W_int and W_end was referred to as the total water content in the composition. These data were used to calculate the initial percent water content in the composition and to obtain the percent water content at each time point. These data were plotted in terms of percent water content remaining in the composition over the period of time.

Native vernix provided the best water retention, both in its high water content and low rate of water loss. Native vernix contained about

81 %^w/w water at zero time. At 30 min, native vernix contained about 78%^w/w water (about a 3%^w/w loss in water). At 180 min, native vernix contained about 75%^w/w water (about a 6%^w/w loss in water).

Curel™ contained about 70%^w/w water at zero time. At 180 min, Curel™ contained about 14%^w/w water (about a 56%^w/w loss in water). Eucerin® contained about 39%^w/w water at zero time. At 180 min, Eucerin® contained about 36%^w/w water (about a 3%^w/w loss in water).

Composition B contained about 73%^w/w water at zero time. At 30 min, composition B contained about 67%^w/w water (about a 6%^w/w loss in water, calculation based on initial percent water). At 180 min, composition B contained about 59%^w/w (about a 14% loss in water, calculation based on initial percent water).

Composition C contained about 70%^w/w water at zero time. At 30 min, composition C contained about 50%^w/w water (about a 20%^w/w loss in water, calculation based on initial percent water). At 180 min, composition C contained about 33%^w/w water (about a 37% loss in water, calculation based on initial percent water).

Composition D contained about 68%^w/w water at zero time. At 30 min, composition D contained about 55%^w/w water (about a 13%^w/w loss in water, calculation based on initial percent water). At 180 min, composition D contained about 37%^w/w water (about a 31% loss in water).

Composition E contained about 70%^w/w water at zero time. At 30 min, composition E contained about 61 %^w/w water (about a 9%^w/w loss in water, calculation based on initial percent water). At 180 min, composition E contained about 48%^w/w water (about a 22% loss in water, calculation based on initial percent water).

Composition F contained about 70%^w/w water at zero time. At 30 min, composition F contained about 57%^w/w water (about a 13%^w/w loss in water, calculation based on initial percent water). At 180 min, composition F contained about 39%^w/w water (about a 31% loss in water, calculation based on initial percent water).

The rates of evaporative water loss from the composition over the first thirty minutes (from 0 to 0.5 hour), and then over the next two and one-half hours (from 0.5 to 3 hours), for each of the above compositions are summarized in the following table:

Rate of Evaporative Water Loss

The rates were calculated from the data collected at intervals over 180 minutes (3 hours). This calculation was performed to quantify the shape of the curve of evaporative water loss, as shown in FIGS. 2A-C.

The data were obtained by performing regression analyses, one for the time from 0-0.5 hr (0-30 minutes), and the other for the time from 0.5-3 hrs (30-180 minutes). The rates were taken as the slopes of the regression lines expressed as change in % water in the composition/change in time. The first rate was the change over the first 0.5 hr, and the second rate was the change from 0.5-3 hrs. Therefore, the rate was change in % water/time in hrs. The rates were negative in sign because they represented a loss in water. A composition that lost no water would have a value of 0 (the numerator would be 0 and the denominator would be 0.5 or 2.5 hr).

For native vernix, the first and second rates were, respectively, -5.2% water in composition/hr and -1.5% water in composition/hr. For Eucerin®, the first and second rates were, respectively, -2% water in composition/hr and -0.5% water in composition/hr. Eucerin® had a very slow evaporative water loss, similar to vernix, but it had a much lower starting water level, as is subsequently described.

The inventive compositions had a rate of evaporative water loss during 0-0.5 h from about -38% water in composition/hr up to 0% water in composition/hr, and a rate of evaporative water loss during 0.5-3 hr from about -8% water in composition/hr up to 0% water in composition/hr. In one embodiment, the upper limit for rate of evaporative water loss during 0-0.5 h was about -1% water in composition/hr, and the upper limit for rate of evaporative water loss during 0.5-3 hr was about -0.2% water in composition/hr.

Water vapor transport (WVT) through the compositions was also evaluated for the inventive compositions, as well as native vernix, Curel™, and Eucerin®. A modification of ASTM E96E, procedure B subsequently described, was used where a cream form of the composition was prepared in a film form and applied to a highly porous and permeable synthetic substrate at 37-38% relative humidity. The permeable substrate allowed the permeability characteristics of the composition to be determined without interference from the substrate. Water vapor transport through these films was determined as follows. Specifically, four grams of distilled water was added to a hexagonal polystyrene disposable weighing dish (20 mm length x 20 mm width x 10 mm height). The dish was completely covered by a substantially highly permeable substrate of which N-terface® (Winfield Laboratories, Inc., Richardson TX) (50 mm x 50 mm) is an example, which was glued with cyanoacrylate applied to the rim of the dish to form a watertight seal. The composition to be evaluated was uniformly applied to the outer surface of the substrate by spatula at a concentration of 25 mg/cm². The apparatus was maintained at the stated relative humidity. Testing under steady state conditions was performed after two hours of equilibration. Weight loss was measured at zero time, two hours, and four hours. The rate of weight loss, that is, the water vapor transport (WVT), was calculated for each composition

in terms of weight per unit area per time (g/m²/h). Temperature and relative humidity of the room during the period of study were recorded. The results of WVT at two hours are shown in the following table.

Composition (25 mα/cm²) WVT (q/m²/h) native vernix 19.2 ± 4.9

Eucerin® 2.6 ± 0.2

Curel™ 72.0 ± 3.0 composition B 21.6 ± 3.0 composition C 20.0 ± 0.4 composition D 13.4 ± 0.4 composition E 13.2 ± 0.8 composition F 18.9+ 1.3

For comparison, the water vapor transport for the dish alone (no substrate) was 150 + 4 g/m²/hr, and for the substrate alone was 132 + 9 g/m²/hr. The water vapor transport through vernix was about 19.2 + 4.9 g/m²/h. The water vapor transport through a water-in-oil emulsion (Eucerin®) was 2.6 + 0.2 g/m²/h. The water vapor transmission through an oil-in-water emulsion (Curel™) was 72.0 + 3.0 g/m²/h. Water vapor transport through composition B was 21.6 + 3.0 g/m²/h. Water vapor transport through composition C was 20.0 + 0.4 g/m²/h. Water vapor transport through composition D was 13.4 + 0.4 g/m²/h. Water vapor transport through composition E was 13.2 + 0.8 g/m²/h. Water vapor transport through composition F was 18.9 + 1.3 g/m²/h. Water vapor transport or transmission through the inventive synthetic vernix composition ranged between the percent water vapor transmission through a substantially highly permeable film, such as N-terface ®, and the percent water vapor transmission through a substantially highly occlusive film, such as polytetrafluoroethylene (TEFLON ®) or Saran Wrap ®. In one embodiment, water vapor transmission of the inventive synthetic vernix composition was between about 85% of the water vapor transmission through a substantially highly permeable film, and about 5% of transmission through a substantially highly occlusive film. That is, water vapor transmission through the synthetic vernix film was in the range that is at least 15% lower than water vapor transmission through a highly permeable film, and at least 5% higher than water vapor transmission through a highly occlusive film. All compositions were stable at room temperature (about 20⁰C) for at least two months without phase separation (i.e., they were phase stable), and without syneresis of the water (beading of water onto the sample surface). There was no change in color. The compositions thinned over time with slow evaporation of the internal phase water. Evaporation was accelerated if the compositions were not covered. Freeze thaw data were obtained as a technical measure of composition stability. The compositions were stressed by freezing at -20±5°C and thawing at +20±5°C over three cycles. The freeze/thaw cycle testing was performed to demonstrate phase stability during temperature stresses, e.g., during shipment, storage, etc. Compositions were placed at a cold temperature (-20±5°C), then placed at a warm temperature (+20±5°C), then returned to a cold temperature. The cycle of cold to warm was repeated three times. The compositions did not separate or change viscosity, and were considered stable for storage, shipment, etc. under various weather conditions.

The inventive compositions had tactile properties similar to native vernix. Tactile properties were evaluated by individuals experienced in assessing tactile characteristics and using methods known to one skilled in the art, such as when the composition is rubbed between the fingers, and skin feel to which the compositions had been applied. To further characterize the feel of the compositions, the tactile properties were compared with tactile properties of standard oil-in-water and water-in-oil emulsions (data not shown). The inventive compositions were thick and viscous with characteristics of a cream, spreadable using a slight force such as that used to apply lotion or cream to the surface of skin to spread on skin, and did not leave a sticky feeling to the skin.

The compositions had rheological properties similar to native vernix. They did not flow under normal gravity. Characteristics observed during handling, spreading, etc were used to evaluate viscosity. The viscosity increased with increasing internal phase (water) because increasing the internal phase and reducing each droplet of internal phase resulted in packing of the composition. Increasing the internal phase (water phase) from about 70%^w/w water to about 75%^w/w water, for example, does not likely change the viscosity, because the compositions are already viscous. Increasing the internal phase (water phase) from about 30%^w/w water to about 70%^w/w water, however, resulted in a visually observable increase in viscosity. The viscosity of the inventive compositions was based on the amount of internal phase (water phase), and the type and amount of external phase (lipid).

The inventive compositions had an overall neutral pH. The compositions had a high and uniform water content (e.g., from greater than about 65%^w/w to about 82%^w/w water). They were highly viscous at room temperature (about 20⁰C to about 22°C). They were highly permeable to water, and only very slowly released water. The inventive compositions had a viscosity profile, a rheology profile, penetrability, tactile properties, permeability, and water vapor transport properties that were substantially similar to native vernix.

Exogenously applied synthetic vernix removes soil from the skin with an effectiveness that was quantitatively at least equivalent to, and may be better than, commercial skin cleansers. Synthetic vernix on the skin surface interacts with exogenous cleansing agents such as soaps and/or surfactants, with subsequent flocculation and detachment, consistent with a function of vernix as an endogenous skin cleanser at birth. A soap, as used herein, is a mixture of sodium salts of long chain fatty acids, typically Ci₂ to Ci₈ fatty acids. A surfactant, as used herein, is a surface-active substance. Both soaps and surfactants are cleansing agents. The cleansing aspects of synthetic vemix Composition B was evaluated in cleansing assays. Synthetic vemix was stored at room temperature until use. Ten mg of soiling material in the form of uniform black carbon particles (toner from a photocopier) were applied to normal adult volar skin (area=16 cm²). In some embodiments, a photographic image of the pre- soiled skin was recorded. This was followed by manual application and removal (gently wiping the area with a dry 4 in x 4 in gauze pad) of about 12.5 mg/cm² of synthetic vernix, or selected skin cleansers (Pond's Cold Cream™ and Johnson & Johnson Baby Wash™). Removal of soil was quantified as a change in light intensity, using L-scale analysis of digital images of the cleansed skin.

Digital images of adult volar forearm were recorded at 3Ox magnification using a Skin Surface Analyzer (Moritex USA, Inc.), which captures digital images between 10x through 70Ox magnification and can be operated using two different modes of illumination. One mode supplies light en faces, rendering precise surface detail. The second mode illuminates the skin via back-scattered light, resulting in polarization of the light source; this is useful when specular reflectance from the skin surface interferes with image analysis. For the cleansing assay, 10 mg of the previously described soiling material was uniformly applied to pre-cleaned normal adult volar forearm skin (area=16 cm²). This was followed by manual application and removal of 12.5 mg/cm² of synthetic vernix, 12.5 mg/cm² of irradiated isolated native vernix, Pond's Cold Cream™, Johnson & Johnson Baby Wash™, water, or Aquaphor. All applications and removals used manual pressure under routine conditions. High resolution digital photographs were obtained with a Kodak DCS 420C digital camera before and after applying the soiling material, and after cleansing.

Digital images obtained during cleansing were analyzed to assess efficacy of vernix and the two commercially available topical cleansing preparations. Soil removal was quantified by processing the images in two ways. In one way, the change in light intensity was quantitated using Adobe Photoshop L-scale analysis. In the other way, a program was written using Matlab technical computing software (The Math Works, Natick MA), whereby the original digital image was first segmented into 16 equally sized regions and then converted to Gray scale. A threshold algorithm was performed on each region to distinguish between soiling material and background features of the skin. This process generated a black and white image that was used to calculate the percent of the region that was covered with the soiling material. FIG. 3 demonstrates the cleansing capacity of synthetic vernix.

FIGS. 3A, 3B, and 3C show the unsoiled, carbon-soiled, and synthetic vernix- cleansed skin, respectively, in photographs using a light source that illuminates from above.

To quantitate the amount of soiling material on the skin surface, L-score values of volar forearm skin were obtained. Adult volar forearm was assessed using Adobe Photoshop L-scale analysis of digital images. With reference to FIG. 3, data were collected before soiling (baseline), after soiling material was manually rubbed into the skin (soiled), and after cleansing (cleaned). The cleansing treatments were either Aquaphor, Johnson & Johnson Baby Wash™, Pond's Cold Cream™, or vernix. The results are shown in FIGS. 4A, 4B, 4C, 4D₁ 4E, and 4F for tests with synthetic vernix compared to native vernix. The data demonstrate that all of the tested cleansing agents returned the skin to near baseline L-scale levels.

FIG. 5 quantitates the results from FIG. 3 as differences in L-scale scores before and after cleansing. The data in FIGS. 5 and 5A are (L value after cleansing -L value before soiling). A negative value indicated that skin retained some soiling material, with higher negative values indicating more soiling material retained. A positive value indicated that the skin was cleaner after the cleansing procedure. As shown in FIG. 5, approximate values for each treatment in tests using synthetic vernix in comparison to native vernix (FIGS. 4A-4F), were as follows: Aquaphor -2; synthetic vernix -5.8; Johnson & Johnson Baby Wash™ +2.1 ; Pond's Cold Cream™ -0.9; native vernix -4; water -1.1.

FIGS. 6A1-6A6 show representative images of soiled skin and its black and white counterpart images before treatment with the indicated cleansing agent. FIGS. 6B1-6B6 show the respective images after treatment with the cleansing agent. The Matlab technical computing software was used to segment the original image into 16 equally sized regions. The resultant images are first converted to Gray scale, then a threshold algorithm is performed on the Gray scale images to distinguish between the soiling material and endogenous topographical features of the skin. This process generates the black and white image. The comparative cleansing abilities are shown graphically in FIG. 6C.

The data for synthetic vernix demonstrated that all the cleansing agents performed well and demonstrated the cleansing capacity for synthetic vernix. It was noted that there was inter-subject variability in the amount and depth of dermatogyphics, that spreading of soiling material and the skin's affinity for soil retention were affected by pore size and skin surface oiliness, and that hair and areas of hyperpigmentation may affect Matlab and L score results.

Among the clinical implications of the invention are the in vitro use of synthetic vernix as a skin cleansing material. Prenatally, vernix detaches into the amniotic fluid under the influence of pulmonary surfactant. This biological process is similar to self-cleaning (desquamation) of the stratum corneum. Vernix as an endogenous cleanser utilizes this cleansing function for optimal delivery room management during transition of the neonate, either full term or pre-term, to a nonsterile environment. The hydrophilic component of vernix aids in removing hydrophilic soils. The hydrophobic component of vernix aids in removing hydrophobic soils. The choice of an exogenous cleanser for the first bath may be tailored to detach soil and endogenous vernix, with vernix detachment either partial or complete as desired. Other variations or embodiments of the invention will also be apparent to one of ordinary skill in the art from the above description. For example, a simulated cell component may be used as a vehicle to deliver agents to the skin surface to provide an anti-infective benefit, and also as a vehicle to deliver anti-oxidants such as Vitamin E to the skin. As another example, actives can be loaded by direct addition to melted lipid or water (i.e., before hydration), or by diffusion into the structure after it is formed. The composition may include other skin cleaning agents, and or other components such as emollients, humectants, etc. Thus, the forgoing embodiments are not to be construed as limiting the scope of this invention. What is claimed is:

Claims

1. A simulated vernix composition comprising a continuous lipid phase consisting essentially of physiologic lipids, and a hydratable water phase of simulated cells dispersed in the lipid phase, the hydratable water phase capable of retaining greater than about 65%^w/w water of the total composition, said composition in a hydrated film form having a water vapor transmission rate that is between about 85% of the transmission rate through a substantially highly permeable film and about 5% of the transmission rate through a substantially highly occlusive film by a modified ASTM E96E procedure B, and having up to about 38% evaporative water loss from 0 h to 0.5 hr, and up to about 8% evaporative water loss from 0.5 hr to 3 hr.

2. The composition of claim 1 wherein the simulated cells are emulsified particles.

3. The composition of claim 1 wherein the simulated cells are water-in-oil emulsified particles.

4. The composition of claim 3 further comprising an emulsifying agent having a hydrophile-lipophile balance (HLB) to provide water-in-oil emulsified particles.

5. The composition of claim 4 wherein the HLB ranges between about 3 to about 6.

6. The composition of claim 4 wherein the HLB ranges between about 3.5 to about 6.0.

7. The composition of claim 4 wherein the HLB ranges between 3.8 to about 6.0.

8. The composition of claim 4 wherein the emulsifying agent is selected from the group consisting of polyhydroxy hydrocarbons, non-ionic PEG-7

hydrogenated castor oil (Cremophore WO7®), polyglyceryl-4 isostearate and cetyl dimethicone copolyol and hexyl laurate (Abil WE09), PEG-30 dipolyhydroxystearate (Arlacel P 135®), sorbitan sesquioleate, polyglyceryl-3- diisostearate, polyclyceryl-3-oleate, and polyglyceryl-4-isostearate.

9. The composition of claim 4 further comprising a co-emulsifier.

10. The composition of claim 9 wherein the co-emulsifer is methyl glucose isostearate.

11. The composition of claim 1 wherein the lipids comprise at least one of cholesterol esters, ceramide, triglycerides, cholesterol, free fatty acids, phospholipids, wax esters, squalene, wax diesters, or cholesterol sulfate.

12. The composition of claim 4 wherein the emulsifying agent is at least one of PEG-30 dipolyhydroxystearate (Arlacel P 135®) or sorbitan sesquioleate.

13. The composition of claim 1 wherein the water phase retains greater than about 65%^w/w water of the total composition.

14. A synthetic vernix composition comprising hydratable emulsified particles dispersed in a continuous lipid phase wherein the lipid is selected from at least one of lanolin, squalene, linoleic acid, cholesterol, ceramide, wax, triglyceride, at least one emulsifying agent selected from sorbitan sesquioleate or PEG30 dipolyhydroxystearate, the hydratable emulsified particles capable of retaining at least 65%^ water .

15. The composition of claim 14 comprising about 1.5%** to about 2%^ lanolin, about 3.2%™* to about 5.8%^ squalene, about 0.8%^ to about 1.5%^ linoleic acid, about 4%^wt to about 6%^ cholesterol, about 0.7%^ to about

1.5%^wt ceramide III, about 3%^ to about 4.2%* beeswax, about 1 %^w to about 2%^wt capric/caprilic triglyceride, about 1.5%^ PEG30 dipolyhydroxystearate, and about 0.5%^ sorbitan sesquioleate.

16. The composition of claim 14 comprising about 2% ^ lanolin, about 3.5% ** squalene, about 0.8% ^wt linoleic acid, about 6% ** cholesterol, about 1.5% ^ ceramide III, about 4.2% ^ beeswax, about 1 % ^ capric caprilic triglyceride, about 1.5% ^ PEG30 dipolyhydroxystearate, about 0.5% ^wt sorbitan sesquioleate, and about 1 % ^ cholesterol sulfate.

17. The composition of claim 15 further comprising about 0% to about 3% cholesterol sulfate.

18. The composition of claim 15 further comprising about 0%^ to about 5%^ mineral oil.

19. The composition of claim 14 comprising about 2% ^ lanolin, about 4% ^ squalene, about 1 % ^ linoleic acid, about 5% ^ mineral oil, about 4% ^ cholesterol, about 1 % ** ceramide III, about 3% "* beeswax, about 2% "* capric caprilic triglyceride, about 1.5%^ PEG30 dipolyhydroxystearate, and about 0.5% ^ sorbitan sesquioleate.

20. The composition of claim 14 comprising about 2% ^wt lanolin, about 4% ^ squalene, about 1% ^ linoleic acid, about 3.5% ** mineral oil, about 5.5% "* cholesterol, about 1 % ^ ceramide III, about 3% "" beeswax, about 2% ^ capric caprilic triglyceride, about 1.5% ^ PEG30 dipolyhydroxystearate, and about 0.5% ^ sorbitan sesquioleate.

21. The composition of claim 14 comprising about 2% ^ lanolin, about 4% ^ squalene, about 1% ^ linoleic acid, about 3% ^ mineral oil, about 5.5% *" cholesterol, about 1% "" ceramide III, about 4.2% ^ beeswax, about

1.5% ^ capric caprilic triglyceride, about 1.5% ^ PEG30 dipolyhydroxystearate, and about 0.5%^ sorbitan sesquioleate.

22. The composition of claim 14 wherein the water phase further comprises magnesium sulfate, glycerin, and at least one of methylparaben or propylparaben.

23. The composition of claim 22 comprising about 0.5%^wt magnesium sulfate and about 2.5%^ to about 5%^ glycerin.

24. A synthetic vernix composition comprising hydratable emulsified particles dispersed in a continuous lipid phase wherein the lipid is selected from at least one of lanolin, stearyl alcohol, wax, mineral oil, or petrolatum; at least one emulsifying agent selected from cetyl dimethicone copolyol or polyglyceryl-4-isostearate and cetyl dimethicone copolyol and hexyl laurate (Abil WE 09), the hydratable emulsified particles capable of retaining at least 65%^ water.

25. The composition of claim 24 comprising about 2%^ to about 3%^ lanolin, about 3%^ to about 4%^ stearyl alcohol, about 1 %"" to about 2%^ wax, about 6%^ to about 7%^ mineral oil, about 4%^ to about 6%^ petrolatum, about

cetyl dimethicone copolyol.

26. The composition of claim 24 comprising about 2.7%^ lanolin, about 3.5%^wt stearyl alcohol, about 1.7%^ wax, about 6.4%^ mineral oil, about 5%^ petrolatum, about 2⁰Z₀^ AbH WE 09, and about 1 %* cetyl dimethicone copolyol.

27. The composition of claim 24 wherein the water phase further comprises glycerin, sodium chloride, and methylparaben.

28. A method of treating a skin surface of an individual to remove a soiling material from the soiled skin surface, the method comprising applying a synthetic vernix composition to the soiled skin surface in an effective amount for removal of the soiling material, and thereafter removing the composition and soiling material from the skin surface, the synthetic vernix composition comprising a continuous lipid phase consisting essentially of physiologic lipids, and a hydratable water phase of simulated cells dispersed in the lipid phase, the hydratable water phase capable of retaining greater than about 65%^w/w water of the total composition, said composition in a hydrated film form having a water vapor transmission rate that is between about 85% of the transmission rate through a substantially highly permeable film and about 5% of the transmission rate through a substantially highly occlusive film by a modified ASTM E96E procedure B, and having up to about 38% evaporative water loss from 0 h to 0.5 hr, and up to about 8% evaporative water loss from 0.5 hr to 3 hr.

29. The method of claim 28 wherein the simulated cells are water- in-oil emulsified particles.

30. A method of cleansing a soiled skin surface, the method comprising providing to the soiled skin surface a synthetic vernix composition simulating native vernix, the synthetic vernix composition comprising hydratable emulsified particles dispersed in a continuous lipid phase wherein the lipid is selected from at least one of lanolin, squalene, linoleic acid, cholesterol, ceramide III, wax, or triglyceride; and at least one emulsifying agent selected from sorbitan sesquioleate or PEG30 dipolyhydroxystearate, the hydratable emulsified particles capable of retaining at least 65%^ water.

31. The method of claim 30 wherein the composition comprises about 1.5%** to about 2%^ lanolin, about 3.2%** to about 5.8%^ squalene, about 0.8%^ to about 1.5%^wt linoleic acid, about 4%^ to about 6%^ cholesterol, about 0.7%^ to about 1.5%*" ceramide III, about 3%^ to about 4.2%^wt beeswax, about 1⁰Zo^ to about 2%^ capric/caprilic triglyceride, about 1.5%^wt PEG30 dipolyhydroxystearate, and about 0.5%*" sorbitan sesquioleate.