Methods and a predictive in vitro preclinical model for clinical irritation and skin barrier impairment potential of mild surfactant-based skin cleansing compositions

Abstract

Provided are in vitro methods for predicting an in vivo clinical irritation marker of skin cleansing compositions and for predicting a skin barrier impairment potential property of skin cleansing compositions.

Description

[0001] METHODS AND A PREDICTIVE IN VITRO PRECLINICAL MODEL FOR CLINICAL IRRITATION AND SKIN BARRIER IMPAIRMENT POTENTIAL OF MILD SURFACTANT-BASED SKIN CLEANSING COMPOSITIONS

[0002] 1. FIELD

[0003] Aspects of the present disclosure generally relate to methods for predicting clinical mildness of cleansing compositions, and in particular, predictive methods involving utilization of an in vitro model’s cytokine interleukin la (IL- la) secretion and barrier trans epidermal electrical resistance (TEER) measurements to accurately predict clinical exaggerated arm wash (EAW) study’s (EAWS) erythema scores and trans epidermal water loss (TEWL) values.

[0004] 2. BACKGROUND

[0005] Skin cleansing compositions have been used for many years to cleanse skin and maintain personal hygiene. The plethora and characteristics of ingredients determine the cleansing efficacy and mildness of skin cleansing compositions and are two key factors attributed to consumer reception of a cleansing product. Synthetic surfactants, such as cationic, anionic, amphoteric, and non-ionic surfactants, typically used in skin cleansing compositions can compromise the integrity of the skin barrier to the penetration of external aggressors, resulting in skin irritation. As concentrations of such surfactants increase in skin cleansing compositions to impart increased cleansing efficacy, the skin irritation associated with such compositions also tends to increase. For example, a consumer may feel that a skin cleansing composition cleans the skin very well, but if the level of cleansing is too intense, leaving the skin feeling dry and irritated, such skin cleansing composition would be deemed more toward the harsh end of the scale and undesirable for use on or near the skin and / or eyes.

[0006] As such, skin cleansing compositions designed for topical application to skin need to be safe and non-irritating. Within the consumer products industry, safety testing is often taken a step further with the goal of demonstrating enhanced or improved product mildness and there is an unmet need for efficient and accurate methods of determining whether a skin cleansing composition would be considered mild. Traditionally, human clinical testing, in conjunction with animal testing, has been used to test product safety and demonstrate enhanced mildness. Ethical concerns over unnecessary animal use and the need for efficient, cost-effective preclinical screens for prototype exploration have prompted the development of alternative methods for determining skin irritation and predicting adverse skin reactions. Assessing mildness of skin cleansing compositions on skin is typically performed by clinical evaluation and measurement of alterations in trans epidermal water loss (TEWL) following exaggerated patch test or exaggerated arm wash test protocols. However, clinical evaluation methods exhibit a few defects and concerns. First, the tests typically require large panel sizes to differentiate between varying levels of mildness, which can be expensive and time-consuming. Second, clinical observation is evaluated subjectively, which can introduce variabilities. Lastly, clinical test results are subject to test environment and locations. For instance, the surfactants in patch tests can respond differently under occluded versus normal use conditions; the results of arm immersion tests can be weather-dependent; and the tested skin site in flex wash tests may not be representative of other areas of the body.

[0007] There is therefore an unresolved need for methods of evaluating and predicting the clinical impact of skin cleansing compositions on skin barrier by objectively assessing the concentration profile of a biomarker associated with skin cleansing composition-induced skin irritation and by directly measuring the functionality of the skin barrier. The presently disclosed subject matter through evaluating and predicting the impact of skin cleansing compositions with a biomarker and mathematical models address these and other needs.

[0008] 3. SUMMARY

[0009] The presently disclosed subject matter relates to predictive methods for assessing the mildness of skin cleansing compositions. Further, the presently disclosed subject matter provides methods to measure and / or predict the effect of barrier enhancement of skin cleansing compositions.

[0010] The presently disclosed subject matter provides an in vitro method of predicting an in vivo clinical irritation marker of a skin cleansing composition. The in vitro method comprises the steps of: providing a skin cleansing composition; measuring an in vitro cytokine interleukin la secretion value of the skin cleansing composition to provide a measured cytokine interleukin la secretion value (Xi); calculating an erythema score (Ye) following a mathematical formula (I): Ye =Xi a - b (I); predicting the in vivo erythema score of the skin cleansing composition in an exaggerated arm wash (EAW) study. The value of a is from about 0.010 to about 0.012, b is from about -0.5 to about -0.7. The predicted exaggerated arm wash (EAW) study’s erythema score is a clinical irritation marker of the skin cleansing composition.

[0011] In certain embodiments, the in vitro method to measure and / or predict the effect of barrier enhancement of skin cleansing compositions further comprises a step of validating predictive capacity and accuracy of said mathematical formula (I).

[0012] In certain embodiments, the predictive capacity and accuracy of said mathematical formula (I) is greater than 90%.

[0013] In certain embodiments, the predictive capacity and accuracy of said mathematical formula

[0014] (I) is greater than 95%.

[0015] In certain embodiments, the skin cleansing composition comprises at least one surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants, nonionic surfactants, and combinations of two or more thereof.

[0016] In certain embodiments, the skin cleansing composition is in the form of a shampoo, wash, bath, gel, lotion, cream, or fluid impregnated on a wipe.

[0017] The presently disclosed subject matter further provides an in vitro method of predicting a skin barrier impairment potential property of a skin cleansing composition. The in vitro method comprises the steps of: providing a skin cleansing composition; measuring an in vitro barrier transepidermal electrical resistance value (TEER) of the skin cleansing composition to provide the measured barrier transepidermal electrical resistance value TEER value (Xt); calculating a transepidermal water loss (TEWL) value (Yt), following a mathematical formula (II): Yt=Xt c + d (II); predicting the in vivo transepidermal water loss (TEWL) value of the skin cleansing composition. The value of c is from about -0.14 to about -0.21, d is from about 19.00 to about 23.00. The TEWL value is characteristic of skin barrier impairment potential properties of the skin cleansing composition.

[0018] In certain embodiments, the in vitro method of predicting a skin barrier impairment potential property of a skin cleansing composition, further comprising validating the predictive capacity and accuracy of said mathematical formula (II).

[0019] In certain embodiments, the predictive capacity and accuracy of said mathematical formula

[0020] (II) is greater than 60%.

[0021] In certain embodiments, the predictive capacity and accuracy of said mathematical formula (II) is greater than 70%. In certain embodiments, the skin cleansing composition comprises at least one surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants, nonionic surfactants, and combinations of two or more thereof.

[0022] In certain embodiments, the skin cleansing composition is in the form of a shampoo, wash, bath, gel, lotion, cream, or fluid impregnated on a wipe.

[0023] The presently disclosed subject matter further provides an in vitro method of predicting an in vivo clinical irritation marker of a skin cleansing composition. The in vitro method comprises the steps of: providing a skin cleansing composition; measuring an in vitro cytokine interleukin la secretion value of the skin cleansing composition to provide a measured cytokine interleukin la secretion value (Xi); calculating an erythema score (Ye); and predicting the in vivo erythema score of the skin cleansing composition in an exaggerated arm wash (EAW) study. The predicted exaggerated arm wash (EAW) study’s erythema score is a clinical irritation marker of the skin cleansing composition.

[0024] In certain embodiments of the in vivo clinical irritation marker of a skin cleansing composition, the erythema score (Ye) is calculated by the mathematical formula: Ye=Xi a - b (I). The value of a is from about 0.010 to about 0.012, b is from about -0.5 to about -0.7.

[0025] The presently disclosed subject matter further provides an in vitro method of predicting a skin barrier impairment potential property of a skin cleansing composition. The in vitro method comprises the steps of: providing a skin cleansing composition; measuring an in vitro barrier transepidermal electrical resistance value (TEER) of the skin cleansing composition to provide the measured barrier transepidermal electrical resistance value TEER value (Xt); calculating a transepidermal water loss (TEWL) value (Yt); and predicting the in vivo transepidermal water loss (TEWL) value of the skin cleansing composition. The TEWL value is characteristic of skin barrier impairment potential properties of the skin cleansing composition.

[0026] In certain embodiments of the in vitro method of predicting a skin barrier impairment potential property of a skin cleansing composition, the transepidermal water loss (TEWL) value (Yt) is calculated by the mathematical formula (II): Yt = Xt c -i-d (II). The value of c is from about -0.14 to about -0.21, d is from about 19.00 to about 23.00. 4. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1A depicts a graph of the normalized in vitro trans epidermal electrical resistance (TEER) values of the skin cleansing composition plotted against its observed skin barrier marker, i.e., in vivo clinical exaggerated arm wash study (EAWS) trans-epidermal water loss (TEWL) values.

[0028] FIG. IB depicts a graph of the normalized in vitro cytokine interleukin la (IL- la) values of the skin cleansing composition plotted against its observed skin barrier marker, i.e., in vivo clinical exaggerated arm wash study (EAWS) erythema scores.

[0029] 5. DETAILED DESCRIPTION

[0030] The presently disclosed subject matter relates to efficient and accurate predictive methods for assessing the mildness and / or the effect of barrier enhancement of skin cleansing compositions. These and other aspects of the disclosed subject matter are discussed in more detail below and in the Examples. For clarity, and not by way of limitation, this detailed description is divided into the following sub-portions:

[0031] 5.1 Definitions;

[0032] 5.2 Methods and Predictive In Vitro Preclinical Models; and

[0033] 5.3 Skin Cleansing Compositions.

[0034] 5.1. Definitions

[0035] The terms used in this specification generally have their ordinary meanings in the art within the context of this disclosure and in specific context where each term is used. Certain terms are discussed below, or elsewhere in the specification, to provide additional guidance in describing the compositions and methods of the disclosure and how to make and use them.

[0036] As used herein, “skin cleansing composition” means a composition suitable for administration to the skin that provides effective cleansing efficacy without causing detrimental irritation to the skin barrier. As used herein, effective cleansing includes applying both chemical and physical mechanisms to remove contaminants from the skin surface. The clinical mildness of such skin cleansing compositions can be predicted with in vitro preclinical models of the present disclosure. As used herein, “benefit agent” is an element, an ion, a compound (e.g., a synthetic compound or a compound isolated from a natural source) or other chemical moiety in liquid, or gaseous state and compound that has a cosmetic or therapeutic effect on the skin. As used herein, the term “benefit agent” includes any active ingredient that is to be delivered into and / or onto the skin at a desired location, such as a cosmetic or a pharmaceutical.

[0037] 5.2. Methods and Predictive In Vitro Preclinical Models

[0038] The present disclosure relates to predictive methods for assessing the mildness of skin cleansing compositions and, in particular, methods utilizing of an in vitro model to measure cytokine interleukin la (IL- la) secretion and barrier trans epidermal electrical resistance (TEER) to determine clinical exaggerated arm wash (EAW) study’s erythema scores and trans epidermal water loss (TEWL) values.

[0039] Predictive Methods: Clinical Mildness of Skin Cleansing Compositions

[0040] In certain embodiments, methods of the present disclosure provide methods to predict clinical (in vivo) mildness of skin cleansing compositions. The method includes providing a skin cleansing composition, measuring an in vitro cytokine interleukin la (IL- la) secretion release in human epidermal equivalents (HEEs) of the skin cleansing composition, performing a regression curve analysis to establish a mathematical formula (I), transferring the measured IL- la value to the mathematical formula (I), extracting parameters of erythema score of the skin cleansing composition from the mathematical formula to calculate the erythema score, predicting the mildness of the skin cleansing composition, and formulating conclusions about the effects of the skin cleansing composition on the skin.

[0041] Methods of the present disclose utilize in vitro methods to predict clinical mildness of skin cleansing compositions. In certain aspects, methods of the present disclosure utilize in vitro interleukin- la (IL- la) to predict clinical mildness of skin cleansing compositions. Loss of viability as well as IL- la and interleukin- 1 receptor antagonist (IL- Ira) secretion in human epidermal equivalents can be correlated with human irritation data. (Bernhofer, et al., 1999). IL- la can correlate with clinical redness on Day 4 (Bernhofer, et al., 1999). Cleanser-induced skin irritation can be associated with cytokine interleukin la (IL- la) release in human epidermal equivalents (HEEs). The local inflammatory reaction (erythema and oedema) upon exposure to an irritant can be associated with the release of primary cytokines such as interleukin- la (IL- la) and tumor necrosis factor (TNFa) from keratinocytes. Primary cytokines can stimulate the synthesis and release of multifunctional secondary cytokines, such as interleukins, colony stimulatory factors, growth factors, and chemotactic cytokines that can either escalate and drive the inflammatory cascade or can serve to repress the reaction through negative feedback. The release of pro- inflammatory mediators in response to an irritant from skin equivalents has been shown to be useful for the prediction of skin irritation potential when in vitro data were compared to the human clinical response.

[0042] Measurement of cytokines from skin equivalents can be used for predicting the skin irritation potential of topically applied skin cleansing compositions and have shown that the measurement of viability in conjunction with release of the keratinocyte derived primary cytokine, IL- 1 a, from epidermal skin equivalents aka human epidermal equivalents (HEEs) can be indicative to the degree of skin irritation. Essentially, skin cleansing compositions that cause greater than 20% toxicity are typically considered as one broad class of irritant, while those with toxicity are less than 20% are typically considered less irritating and ranked by the amount of IL- 1 a and IL- Ira they induce.

[0043] In vitro cytokine interleukin la (IL- la) measurement can be performed, for example, by applying skin cleansing compositions topically to human epidermal equivalents (HEEs), followed by subsequent removal by repeated rinsing with phosphate buffered saline and the equivalents placed in fresh medium. Medium is then collected twenty-four (24) and forty-eight (48) hours post-treatment and stored at -20 °C and cell viability is determined forty-eight (48) hours posttreatment with AlamarBlue™ cell viability reagents following manufacturers’ protocols and a Molecular Device Fluorescent Plate Reader. Cytokine content can be measured using human colorimetric enzyme-linked immunosorbent assay (ELISA) kits for IL- la. Cleansers that cause greater than 20% toxicity are typically broadly classified as severe irritants, while those for which toxicity is less than 20% are typically considered less irritating and ranked by the amount of IL- la. The erythema score can be calculated by mathematical formula (I) as described below.

[0044] Predictive Methods: Barrier Enhancement of Skin Cleansing Compositions

[0045] In certain embodiments, methods of the present disclosure provide methods to predict the effect of barrier enhancement of skin cleansing compositions. The method includes providing a skin cleansing composition, measuring an in vitro barrier trans epidermal electrical resistance (TEER) of the skin cleansing composition, performing a regression curve analysis to establish a mathematical formula (II), transferring the measured TEER value to the mathematical formula (II), extracting parameters of trans epidermal water loss (TEWL) of the skin cleansing composition from the mathematical formula to calculate the TEWL value and predict the effect of barrier enhancement, and formulating conclusions about the effects of the skin cleansing composition on the skin.

[0046] Methods of the present disclosure can further utilize in vitro methods to measure and predict the effect of barrier enhancement of skin cleansing compositions. In certain aspects, methods of the present disclosure utilize an in vitro transepithelial electrical resistance (TEER) method to measure and predict the effect of barrier enhancement of the skin cleansing compositions. In some embodiments, trans epidermal water loss (TEWL) values can be used. Transepithelial / trans endothelial electrical resistance (TEER) is the measurement of electrical resistance across a cellular monolayer, a sensitive and reliable method to confirm the integrity and permeability of the monolayer. The trans-epidermal electrical resistance (TEER) value of reconstructed human skin can be measured to assess the tightness of cell layers. TEER is a direct measure of functionality of the skin barrier; it reflects the global resistance of the tissue which is given by its own thickness as well as by its own structure. It reflects the integrality of intercellular contacts at the level of tight junctions, of the bilaminar lipidic structure that oppose penetration of outside compounds. TEER is inversely proportional to TEWL measured in vivo which is the measurement of the trans-epidermal water loss; the higher the TEWL, the higher the damage to the barrier function, whereas the higher the TEER, the lower the damage to the barrier function. For TEER measurement, the examined reconstructed skin is in a cell insert and topically -400 ul of the phosphate buffer saline (PBS) is applied to the top surface of the tissue. A chopstick electrode will be used with the long-end inserting into the medium and the short-end inserting into the PBS. The TEER values (typically of treated and non-treated tissues) are determined using Millipore-ERS Volt / ohm-meter. TEER is typically presented as in ohms and will normalized by the baseline value before treatment. TEWL value can be calculated by the mathematical formula (II) as described below.

[0047] Regression Curve Analysis and Mathematical Formulas Methods of the present disclosure can include a regression curve analysis rendered on a mild cleanser control HTT, a generic liquid cleanser containing either salicylic acid or sodium laureth sulfate as a harsh cleanser control, and a selection of skin cleansing compositions. Specifically, according to the present invention, the independent predictive variables are transepithelial electrical resistance (TEER) and IL- la values and the dependent predicated variables are TEWL and erythema scores, respectively, and the regression curve analysis is used for prediction of TEWL and erythema scores of cleansers with their TEER and IL- la values by a linear regression analysis. The mild cleanser control, the harsh cleanser control, and the selection of skin cleansing compositions can each be tested in human epidermal equivalents (HEEs) tissues in order to determine its transepithelial electrical resistance (TEER) and inflammatory cytokine secretion interleukin la (IL- la) values, respectively. The in vitro TEER value (normalized by the TEER value of the mild cleanser control expressed as %HTT) and IL- la secretion value (normalized by the IL- la value of the mild cleanser control expressed as %HTT) of each skin cleansing composition can be determined and plotted accordingly on the X and Y axes, with the IL-1 a and TEER values are set as 100% HTT for the mild control cleanser as reference.

[0048] As shown in FIGS. 1A and IB, the normalized in vitro TEER and IL- la values of the skin cleansing composition can be plotted against their respective observed skin barrier markers, namely, in vivo trans-epidermal water loss (TEWL) values and in vivo clinical EAWS scores, respectively.

[0049] Based on the plotted data, a regression curve analysis can be performed with statistically significant correlations established between normalized in vitro IL- la with in vivo erythema scores, and between normalized in vitro TEER with in vivo TEWL values, respectively. The following mathematical formula, including the coefficients, can be established from statistical analyses of the correlations between in vivo trans-epidermal water loss (TEWL) values and in vitro TEER values and in vivo clinical EAWS scores and in vitro IL- la values. Upon regression curve analysis, the following mathematical formula can be established from statistical analyses of the correlations:

[0050] Ye*=Xi* a-b (I)

[0051] Wherein a is from about 0.010 to about 0.012, b is from about -0.5 to about -0.7. Preferably Ye*=Xi* (0.011)-0.562 (I)

[0052] Ye*: normalized erythema values

[0053] Xi*: values of normalized IL- la

[0054] Yt*=Xt* c +d (II)

[0055] Wherein c is from about -0.14 to about -0.21, d is from about 19.00 to about 23.00.

[0056] Preferably, c is from about -0.15 to about -0.20, d is from about 20.00 to about 22.00.

[0057] Preferably Yt* = Xt* (-0.17) + 21.09 (II)

[0058] Yt*: normalized TEWL value

[0059] Xt*: normalized TEER values

[0060] The predictive power and accuracy of the above mathematical formulae can be validated by testing with in vitro TEER and IL- 1 a values with known in vivo erythema scores and TEWL values of the mild cleanser control. For instance, the predictive capacity and accuracy of the mathematical formula (I) can be validated by comparison of the predicted erythema scores with a clinically determined erythema score of a control skin cleansing composition. In certain embodiments, the predictive capacity and accuracy of mathematical formula (I) was validated by dividing a predicted erythema score of the control skin cleansing composition by the clinically determined erythema score of a control skin cleansing composition as determined by mathematical formula (I) in order to yield a percentage result. According to the present disclosure, the predictive capacity and accuracy of mathematical formula (I) can be greater than 90%. In certain embodiments, the predictive capacity and accuracy of mathematical formula (I) can greater than 95%. In particular embodiments, the predictive capacity and accuracy of mathematical formula (I) can be 90%, 95%, 97% or 99%. In certain embodiments, the predictive capacity and accuracy of mathematical formula (I) can be from 90% to 99% or from 95% to 99%. Similarly, the predictive capacity and accuracy of the mathematical formula (II) can be validated by comparison of the in vivo predicted trans epidermal water loss (TEWL) value of a control skin cleansing composition with a clinically determined trans epidermal water loss (TEWL) value of a control skin cleansing composition. In certain embodiments, the predictive capacity and accuracy of mathematical formula (II) was validated by dividing a predicted in vivo trans epidermal water loss (TEWL) value of the control skin cleansing composition by the clinically determined trans epidermal water loss (TEWL) value of a control skin cleansing composition as determined by mathematical formula (II) in order to yield a percentage result. According to the present disclosure, the predictive capacity and accuracy of mathematical formula (II) can be greater than 60%. In some embodiments the predictive capacity and accuracy of mathematical formula (II) can be greater than 70%. In particular embodiments, the predictive capacity and accuracy of mathematical formula (II) can be 60%, 65%, 70%, 73%, 75%, 80%, or 90%. In certain embodiments, the predictive capacity and accuracy of mathematical formula (II) can be from 60% to 99%, from 65% to 95%, or from 70% to 80%.

[0061] The presently disclosed subject matter utilizes mathematical formulas to evaluate the mildness of skin cleansing compositions and predict the effect of barrier enhancement of the skin cleansing compositions. In certain embodiments, mathematical formula (I) can be used to calculate and predict an erythema score (Ye) of a skin cleansing composition with a measured cytokine interleukin la secretion value (Xi) of the skin cleansing composition in an exaggerated arm wash (EAW) study.

[0062] Ye=Xi a-b (I)

[0063] Wherein a is from about 0.010 to about 0.012, b is from about -0.5 to about -0.7.

[0064] Preferably Ye=Xi (0.011)-0.562 (I)

[0065] Wherein, Ye is the predicted / calculated erythema score of the skin cleansing composition and Xi is the measured cytokine interleukin 1 a secretion value of the skin cleansing composition.

[0066] In certain embodiments, mathematical formula (II) can be used to predict a trans epidermal water loss (TEWL) value (Yt) of a skin cleansing composition with the measured barrier transepidermal electrical resistance TEER value (Xt) of the skin cleansing composition.

[0067] Yt=Xt c +d (II)

[0068] Wherein c is from about -0.14 to about -0.21, d is from about 19.00 to about 23.00. Preferably, c is from about -0.15 to about -0.20, d is from about 20.00 to about 22.00.

[0069] Preferably Yt=Xt (-0.17) + 21.09 (II)

[0070] Wherein, Yt is the predicted transepidermal water loss (TEWL) value of the skin cleansing composition; Xt is the measured barrier transepidermal electrical resistance TEER value of the skin cleansing composition; and the TEWL value is characteristic of skin barrier impairment potential properties of the skin cleansing composition.

[0071] 4.3. Skin Cleansing Compositions

[0072] The present disclosure includes one or more skin cleansing compositions to be evaluated. The skin cleansing compositions are cleansing materials that can be applied on the skin to remove contaminants from the skin and the mechanism of cleansing action can be chemical. In certain embodiments, the skin cleansing composition can be a surfactant-based cleansing material. For example, the skin cleansing composition can be a harsh substance(s) that can decrease the skin barrier properties and increase the interleukin- la (IL- la) value. The present disclosure can predict the erythema score of the skin cleansing composition in an exaggerated arm wash (EAW) study thus the mildness classification of the skin cleansing composition without an in vivo or in vitro testing. In yet other aspects, the skin cleansing composition can include a super absorbent polymer material which can physically remove the undesirable contaminants. In other aspects, the skin cleansing composition can include a barrier substance(s), that can be designed to help protect the skin and increase its barrier property. As noted above, the present disclosure can advantageously predict the effect of barrier enhancement by measuring transepithelial electrical resistance (TEER) value without having to perform an in vitro or in vivo testing on skin.

[0073] The skin cleansing composition can include one or more surfactants. In certain embodiments, the skin cleansing composition can include at least two surfactants, for example, in which the first surfactant and the second surfactant are different from each other. Surfactants suitable for use with the present disclosure include anionic surfactants, such as sulfonates (olefin sulfonates, isethionates, taurates, sulfoacetates, sulfosuccinates, sulfolaurates), aminoacid-type surfactants (glycinates, glutamates and sarcosinates), crypto anionic surfactant (phosphates, carboxylates, citrates), polymeric surfactants (Sodium Hydrolyzed Potato Starch Dodecenylsuccinate, Potassium Acrylates Copolymer) and combinations thereof. Further surfactants suitable for use with the present disclosure include cationic surfactants, such as quaternary ammonium salts, amine oxides, and ester quats; amphoteric surfactants, such as betaines, amidobetaines, ester betaines, amphoacetates, ampho diacetates, sultaines; and nonionic surfactants, such as alkyl polyglucosides, poloxamers, polysorbates, ethoxylated fatty alcohols, ethoxylated fatty acids, ethoxylated sorbitan esters, ethoxylated glyceryl esters, polyglyceryl esters. Additional examples of surfactants can be found in U.S. Patent Nos. 8,258,250; 8,343,902; and 8,399,590, each of which is incorporated herein by reference in its entirety.

[0074] In certain embodiments, the skin cleansing composition can include at least two or more surfactants. The two or more surfactants can both be anionic surfactants, nonionic surfactants, cationic surfactants, or amphoteric surfactants. In certain embodiments, the first surfactant and the second surfactant can be the same in ionic nature. For example, and not by way of limitation, in certain embodiments, the cleansing composition can include a first surfactant and a second surfactant.

[0075] The skin cleansing composition of the present disclosure can further include one or more benefit agents or pharmaceutically acceptable salts and / or esters thereof, the benefit agents generally capable of interacting with the skin to provide a benefit thereto. The benefit agents useful herein can be categorized by their therapeutic benefit or their postulated mode of action. However, it is to be understood that the benefit agents useful herein may, in some circumstances, provide more than one therapeutic benefit or operate via greater than one mode of action. Therefore, the classifications provided herein are made for the sake of convenience and are not intended to limit the benefit agents to the application(s) listed. Examples of suitable benefit agents include those that provide benefits to the skin, such as, but not limited to, depigmentation agents; reflectants; amino acids and their derivatives; antimicrobial agents; allergy inhibitors; anti-acne agents; antiaging agents; anti-wrinkling agents, antiseptics; analgesics; shine-control agents; antipruritics; local anesthetics; anti-hair loss agents; hair growth promoting agents; hair growth inhibitor agents, antihistamines; anti-infectives; anti-inflammatory agents; anticholinergics; vasoconstrictors; vasodilators; wound healing promoters; peptides, polypeptides and proteins; deodorants and antiperspirants; medicament agents; skin firming agents, vitamins; skin lightening agents; skin darkening agents; antifungals; depilating agents; counterirritants; hemorrhoidals; insecticides; enzymes for exfoliation or other functional benefits; enzyme inhibitors; poison ivy products; poison oak products; burn products; anti-diaper rash agents; prickly heat agents; vitamins; herbal extracts; vitamin A and its derivatives; flavonoids; sensates; anti-oxidants; hair lighteners; sunscreens; anti-edema agents, neo-collagen enhancers, film-forming polymers, chelating agents; anti-dandruff / sebhorreic dermatitis / psoriasis agents; keratolytics; and mixtures thereof.

[0076] The skin cleansing compositions of the present disclosure can be in the form of a shampoo, wash, bath, gel, lotion, cream, or fluid impregnated on a wipe.

[0077] 6. EXAMPLES

[0078] The following Examples are intended to illustrate, but not to limit, the disclosed subject matter in any manner, shape, or form, either explicitly or implicitly.

[0079] EXAMPLE 1: Predictive Methods for Clinical Irritation and Skin Barrier Impairment of Skin Cleansing Compositions

[0080] Test Cleansers

[0081] Several skin cleansing compositions were prepared and evaluated as shown below. Seven (7) surfactant-based skin cleansing composition with varying degrees of irritation potential were evaluated for their effects on skin barrier and irritation in clinical exaggerated arm wash study (EAWS) and in human epidermal equivalents (HEE) tissues in vitro. A mild cleanser (Johnson's® Head-to-Toe® Baby Wash & Shampoo, HTT) was used for in vitro testing as the mild control skin cleansing composition. Two generic liquid cleansers containing either salicylic acid (SA) or sodium laureth sulfate (SLES) were used for in vitro testing as the harsh control skin cleansing compositions.

[0082] Epidermal Model

[0083] EpiDermTM Epi-200, a human epidermal model, was obtained from MatTek Corporation (Ashland, MA, USA) and maintained according to the manufacturers’ instructions.

[0084] In vitro Interleukin- 1 a (IL- la) Measurement

[0085] Tested cleansers were exposed in triplicate to 100 pl topically applied test material, for 1 hr. Following exposure, the cleansers were removed by repeated rinsing with phosphate buffered saline (Gibco-BRL, Gaithersburg, MD, USA) and the equivalents placed in fresh medium. Medium was collected twenty-four (24) hour and forty-eight (48) hour post-treatment and stored at -20 °C. Viability was determined at forty-eight (48) hours post-treatment with alamarBlue™ (Alamar Biosciences, Sacramento, CA, USA), using manufacturers’ protocols and a Molecular Device SpectraMax Fluorescent Plate Reader (San Jose, CAUSA). Cytokine content was measured using human colorimetric ELISA kits for IL-1 a (R&D Systems, Minneapolis, MN, USA). Media samples from each equivalent were measured for the amount of IL- la induced by cleansers. Clinical Erythema score can be calculated based on the equation below.

[0086] In vitro Transepithelial Electrical Resistance (TEER) Measurement

[0087] Tested cleansers were exposed in triplicate to 100 pl topically applied test material, for 1 hr. Following exposure, the cleansers were removed by repeated rinsing with phosphate buffered saline (Gibco-BRL, Gaithersburg, MD, USA) and the equivalents placed in fresh medium. TEER measurement was collected twenty-four (24) hour and fourty-eight hour post-treatment. For TEER measurement, the examined reconstructed skin is in a cell insert and topically -400 pl of the phosphate buffer saline (PBS) is applied to the top surface of the tissue. A chopstick electrode will be used with the long-end inserting into the medium and the short-end inserting into the PBS. The TEER values are determined as ohms using Millipore-ERS Volt / ohmmeter (MilliporeSigma, Burlington, MA, USA).

[0088] Clinical Exaggerated Arm Wash (EAW) Study (EAWS)

[0089] A double -blind evaluation of personal product mildness was performed for the tested cleansers. Tested cleansers were assigned to multiple test sites on the forearm in a random order. Sites were treated by gently rubbing lather on the premoistened test site for a total of two (2) minutes. The site was rinsed with warm tap water for thirty (30) seconds and dried. Treatments were preformed two (2) times daily for four (4) days and once (1) on Day 5. Skin evaluations for visual erythema were made prior to the first treatment and prior to the second treatment during the first four (4) days, prior to the first treatment on Day 5, and then following the Day 5 treatment. Visual assessments of erythema using a five-point scale were made. Trans-epidermal Water Loss (TEWL) measurements were made prior to the first treatment, prior to the treatment on Days 3 and 5, using an open-chambered evaporimeter (RG1 Evaporimeter; cyberDERM, Broomall, PA).

[0090] Regression Curve Analysis A Johnson's® Head-to-Toe® Baby Wash & Shampoo cleanser (HTT) was used for in vitro testing as a mild cleanser control.

[0091] Test cleansers were tested in human epidermal equivalents (HEEs) tissues, to determine their in vitro values of trans epithelial electrical resistance (TEER) and IL- la, respectively, as shown above. Then, the in vitro values of the test cleanser, were normalized against the in vitro values obtained for the Johnson's® Head-to-Toe® Baby Wash & Shampoo cleanser (as mild cleanser control and set as 100% HTT).

[0092] The normalized in vitro TEER values for the above test cleansers were plotted against their respective observed skin barrier marker, namely, in vivo trans-epidermal water loss (TEWL) values. Similarly, the normalized in vitro IL- la values for the above test cleanser were plotted against their respective observed in vivo clinical EAWS scores. Based on the plotted data, a regression curve analysis was performed with statistically significant correlations established between normalized in vitro IL- 1 a with in vivo erythema score, and between normalized in vitro TEER with in vivo TEWL values, respectively. The following mathematical formula, including the coefficients, were established from statistical analyses of the correlations between in vivo trans- epidermal water loss (TEWL) values and in vitro TEER values and in vivo clinical EAWS scores and in vitro IL- la values.

[0093] A regression curve analysis was performed, and the following mathematical formula was established from statistical analyses of the correlations:

[0094] Ye = Xi*(0.011)-0.562 (I)

[0095] Ye: predicted values of erythema

[0096] Xi: values of normalized IL- la

[0097] Yt = Xt*(-0.17) + 21.09 (II)

[0098] Yt: predicted values of TEWL

[0099] Xt: values of normalized TEER

[0100] The predictive power of the above mathematical formulae was validated by testing with Johnson's® Gentle Baby Moisture Wash cleanser in vitro for TEER and IL-la values to predict clinical erythema scores and TEWL values to compared with its known in vivo erythema scores and TEWL values. The theoretical predicted clinical values were compared to their respective actual observed clinical values in EAWS in vivo to validate the mathematical formulae’s predictivity in EAWS clinical outcomes.

[0101] As shown in Table 1 below, the normalized in vitro TEER and IL- la values of Johnson's® Gentle Baby Moisture Wash cleanser were 96.14 and 101.92, respectively. Using the mathematical formulas (I) and (II), the predicted TEWL value and erythema score was calculated to be 4.75 and 0.56, respectively. The calculated parameters were compared with the actual observed TEWL value (6.478) and erythema score (0.578), concluding the predictivity for TEWL value and erythema score exhibit an accuracy of 73% and 97%, respectively.

[0102] Table 1.

[0103] * * *

[0104] While systems and methods have been described in connection with the various embodiments of the description, it will be appreciated by those skilled in the art that changes could be made to the embodiments without departing from the broad inventive concept thereof. It is understood, therefore, that this disclosure is not limited to the particular embodiments disclosed, and it is intended to cover modifications within the spirit and scope of the present disclosure as defined by the claims.

[0105] It is to be appreciated that certain features of the invention which are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. That is, unless obviously incompatible or specifically excluded, each individual embodiment is deemed to be combinable with any other embodiment(s) and such a combination is considered to be another embodiment. Conversely, various features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub-combination. Finally, while an embodiment may be described as part of a series of steps or part of a more general structure, each said step may also be considered an independent embodiment in itself, combinable with others. It should be understood that the steps of the exemplary methods set forth herein are not necessarily required to be performed in the order described, and the order of the steps of such methods should be understood to be merely exemplary. Likewise, additional steps may be included in such methods, and certain steps may be omitted or combined, in methods consistent with various embodiments of the present invention. Although the elements in the following method claims, if any, are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

[0106] All publications and patent applications cited in this specification are herein incorporated by reference, and for all purposes, as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. The present disclosure controls if there an inconsistency between the present disclosure and any incorporated publications or patents.

Claims

CLAIMS1. An in vitro method of predicting an in vivo clinical irritation marker of a skin cleansing composition, comprising the steps of: i) providing a skin cleansing composition; ii) measuring an in vitro cytokine interleukin la secretion value of the skin cleansing composition to provide a measured cytokine interleukin la secretion value (Xi); iii) calculating an erythema score (Ye) following a mathematical formula:Ye =Xi a - b wherein a is from about 0.010 to about 0.012, b is from about -0.5 to about -0.7; and iv) predicting the in vivo erythema score of the skin cleansing composition in an exaggerated arm wash (EAW) study; wherein the predicted exaggerated arm wash (EAW) study’s erythema score is a clinical irritation marker of the skin cleansing composition.

2. The in vitro method of claim 1, further comprising validating predictive capacity and accuracy of said mathematical formula.

3. The in vitro method of claim 1, wherein the predictive capacity and accuracy of said mathematical formula is greater than 90%.

4. The in vitro method of claim 1, wherein the predictive capacity and accuracy of said mathematical formula is greater than 95%.

5. The in vitro method of claim 1, wherein the skin cleansing composition comprises at least one surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants, nonionic surfactants, and combinations of two or more thereof.

6. The in vitro method of claim 1, wherein the skin cleansing composition is in the form of a shampoo, wash, bath, gel, lotion, cream, or fluid impregnated on a wipe.

7. An in vitro method of predicting a skin barrier impairment potential property of a skin cleansing composition, comprising the steps of: i) providing a skin cleansing composition; ii) measuring an in vitro barrier transepidermal electrical resistance value (TEER) of the skin cleansing composition to provide the measured barrier transepidermal electrical resistance value TEER value (Xt); iii) calculating a transepidermal water loss (TEWL) value (Yt), following a mathematical formula:Yt=Xt c + d wherein c is from about -0.14 to about -0.21, d is from about 19.00 to about 23.00; and iv) predicting the in vivo transepidermal water loss (TEWL) value of the skin cleansing composition, wherein the TEWL value is characteristic of skin barrier impairment potential properties of the skin cleansing composition.

8. The in vitro method of claim 7, further comprising validating the predictive capacity and accuracy of said mathematical formula.

9. The in vitro method of claim 7, wherein the predictive capacity and accuracy of said mathematical formula is greater than 60%.

10. The in vitro method of claim 7, wherein the predictive capacity and accuracy of said mathematical formula is greater than 70%.

11. The in vitro method of claim 7, wherein the skin cleansing composition comprises at least one surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants, nonionic surfactants, and combinations of two or more thereof.

12. The in vitro method of claim 7, wherein the skin cleansing composition is in the form of a shampoo, wash, bath, gel, lotion, cream, or fluid impregnated on a wipe.

13. An in vitro method of predicting an in vivo clinical irritation marker of a skin cleansing composition, comprising the steps of: i) providing a skin cleansing composition; ii) measuring an in vitro cytokine interleukin la secretion value of the skin cleansing composition to provide a measured cytokine interleukin la secretion value (Xi); iii) calculating an erythema score (Ye); and iv) predicting the in vivo erythema score of the skin cleansing composition in an exaggerated arm wash (EAW) study; wherein the predicted exaggerated arm wash (EAW) study’s erythema score is a clinical irritation marker of the skin cleansing composition.

14. The in vitro method as claimed in claim 13, wherein the erythema score (Ye) is calculated by the mathematical formula: Ye=Xi a - b wherein a is from about 0.010 to about 0.012, b is from about -0.5 to about -0.7.

15. An in vitro method of predicting a skin barrier impairment potential property of a skin cleansing composition, comprising the steps of: i) providing a skin cleansing composition; ii) measuring an in vitro barrier transepidermal electrical resistance value (TEER) of the skin cleansing composition to provide the measured barrier transepidermal electrical resistance value TEER value (Xt); iii) calculating a transepidermal water loss (TEWL) value (Yt); and iv) predicting the in vivo transepidermal water loss (TEWL) value of the skin cleansing composition, wherein the TEWL value is characteristic of skin barrier impairment potential properties of the skin cleansing composition.

16. The in vitro method of claim 15, wherein the transepidermal water loss (TEWL) value (Yt) is calculated by the mathematical formula: Yt = Xt c +d wherein c is from about -0.14 to about -0.21, d is from about 19.00 to about 23.00.

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