Sunscreen compositions containing visible light protectants and methods of use

Abstract

Provided herein is a method of reducing or preventing sunburn in a subject due to visible and ultraviolet radiation, the method comprising topically applying to the subject a sunscreen composition comprising at least one inorganic ultraviolet filter selected from zinc oxide or titanium dioxide; at least one inorganic pigment selected from iron oxide; the visible light protective agents comprise barium sulfate and mica; wherein the at least two visible light protective agents are present in an amount effective to reduce or prevent sunburn caused by visible light. Also provided herein are sunscreen compositions and methods of increasing the visible light protection coefficient of sunscreen compositions.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of and relies on U.S. Provisional Patent Application No. 63 / 396,769, filed on August 10, 2022, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention discloses a composition for topical sun protection, which comprises a combination of at least one inorganic ultraviolet filter, at least one inorganic pigment, and at least two visible light protectants. The compositions disclosed herein can be used to prevent both erythema caused by visible light and erythema caused by ultraviolet radiation. Background Art

[0004] The electromagnetic spectrum is a spectrum that includes the frequency range of electromagnetic radiation and its associated wavelengths, ranging from the radio waves with the lowest wavelengths to the gamma ionizing radiation waves with the highest wavelengths. The electromagnetic spectrum is divided into the following bands starting from the waves with the lowest frequencies: radio waves, microwaves, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays. Initially, only visible light with a corresponding wavelength range of approximately 400 nm to approximately 700 nm was known to exist. However, in 1801, Johann Ritter discovered that the UV part of the electromagnetic spectrum has photochemical and photobiological activity, with a corresponding wavelength range of approximately 10 nm to approximately 400 nm. The most common source of ultraviolet rays is the sun, and what is commonly referred to as "sunburn" or "erythema" is exactly caused by ultraviolet radiation. The ultraviolet band of the electromagnetic spectrum itself contains three sub-spectra of bands: UVA (approximately 320 nm to 400 nm), UVB (approximately 280 nm to 320 nm), and UVC (approximately 100 nm to 280 nm).

[0005] Sunburn is the reddening of the skin caused by prolonged exposure to sunlight. The severity of sunburn varies from mild to severe, depending on various factors, including the duration of exposure, the intensity of exposure, and an individual's skin type, with fair skin being at greater risk. Sunburn is a recognized risk factor for skin cancer.

[0006] The Fitzpatrick skin typing system is a commonly used system that predicts a person's tendency to sunburn or tan when their skin is exposed to sunlight. Fitzpatrick et al., The Validity and Practicality of sun-reactive skin types I through VI, ARCHIVES OF DERM., 1988, 124(6): 869-871. According to the Fitzpatrick skin typing system, skin can be classified into six types, where type I skin is pale, usually sunburns but does not tan, while type II skin usually sunburns and tans less than average or is difficult to sunburn and tan. Type III skin tans moderately and only has mild sunburn; and type IV skin tans lightly and is not easily sunburned. Types V and VI refer to brown and black skin, respectively, which rarely or never sunburn. Fitzpatrick skin types can be used to help predict a person's risk of developing skin cancer due to sun exposure, where people with the fairest skin (i.e., type I or II skin) have the highest risk of developing skin cancer. People with type III-VI skin may also need to protect themselves from visible light to prevent the worsening of pigment abnormalities such as skin darkening and melasma.

[0007] Until recently, it was thought that sunburn was caused entirely by light within the ultraviolet wavelength range (i.e., 10 to 400 nm), and that visible light wavelengths (i.e., above 400 nm) had no effect on sunburn. The erythema caused by ultraviolet light is commonly referred to as sunburn, and its causative agent is thought to be the direct absorption damage to specific chromophores (mainly DNA) and other proteins in the epidermis and dermis due to exposure to UVB radiation, as well as the indirect damage caused by the photooxidation process induced by UVB and UVA radiation. For the photooxidative damage caused by UVA, when the absorbed radiation energy is present in a sufficient amount, it raises oxygen to the triplet or singlet excited energy level, enabling it to interact with other surrounding cellular structures and damage them, and ultimately resulting in skin erythema.

[0008] The action spectrum is used to describe the exact amount of radiation required to cause erythema at each specific wavelength, and it is reported that its wavelength range is approximately 250 to 400 nm. All published action spectra for erythema end precisely at 400 nm, meaning that wavelengths above 400 nm have no effect or role in the erythema response. See, for example, Schmalwieser, A. et al., A library of action spectra for erythema and pigmentation, PHOTOCHEM. PHOTOBIOL. SCI. 2012;11(2):252 - 268 (Schmalwieser, A. et al., A library of action spectra for erythema and pigmentation, PHOTOCHEM. PHOTOBIOL. SCI. 2012;11(2):252 - 268).

[0009] Recently, it has been found that this assumption is not correct, and that the visible light part of the electromagnetic spectrum, particularly the violet and / or blue light region of approximately 400 to 500 nm, can and does have an impact on the induction of erythema, especially when considering outdoor sunlight exposure, where the sun produces a large amount of visible light (e.g., 50%), compared to a relatively small amount of ultraviolet light at ground level (e.g., 5%). For example, Zastrow and his colleagues demonstrated that wavelengths in the ultraviolet and the entire visible spectrum can generate free radicals (excited oxygen molecules) in skin tissue. It is estimated that up to 50% of the free radicals produced by sunlight are caused by the visible light part of the solar spectrum when the action spectrum is combined with the ground solar spectrum, while the other 50% come from the ultraviolet part. Zastrow, L. et al., The missing link: light (280 to 1600 nm) induced free radical formation in human skin, SKIN PHARMACOL. PHYSIOL. 2009;22:31 - 34 (Zastrow, L. et al., The missing link, light (280 - 1600 nm) induced free radical formation in human skin, SKIN PHARMACOL. PHYSIOL. 2009;22:31 - 34.).

[0010] Nonetheless, the active ingredients in traditional sunscreen products are typically only designed to filter ultraviolet light (primarily UVA and UVB), without paying attention to the effects of visible light. Typical UV absorbers in sunscreen products can be organic (such as avobenzone, oxybenzone, octyl methoxycinnamate, etc.) or inorganic (i.e., titanium dioxide, zinc oxide, etc.). Since many consumers do not want sunscreen to be visible on their skin, manufacturers of these products have been striving to produce invisible sunscreen products. Although zinc oxide and titanium dioxide have been widely used in sunscreen products since around 1987, very small particles, such as nanoparticles, are usually used and incorporated into sunscreen products. Nanoparticles can minimize the visibility of zinc oxide and titanium dioxide, making the sunscreen product almost invisible on the skin after application, but still able to absorb the harmful effects of solar UV radiation. See Cole C. et al., Metal oxide sunscreens protect skin by absorption, not by reflection or scattering, PHOTOMED. PHOTOIMMUNOL. PHOTODERMATOL. 2016, 32:1, 5-10 (Cole C.et al., Metal oxide sunscreens protect skin by absorption, not by reflection or scattering, PHOTOMED. PHOTOIMMUNOL. PHOTODERMATOL. 2016, 32:1, 5-10).

[0011] Zinc oxide and titanium dioxide of nanoparticle size can still act as UV filters because, according to their bandgap energy, these zinc oxide and titanium dioxide can still be used as semiconductor absorbers for UV radiation below about 370 to 380 nm. Nonetheless, zinc oxide and titanium dioxide of nanoparticle size, due to their micronized / nanoparticle size, and to a large extent do not scatter and reflect radiation above these wavelengths. Therefore, even these inorganic-based sunscreen products provide little protection against radiation in the visible light part of the electromagnetic spectrum, and the protection against wavelengths in the higher end of the UVA spectrum (such as 375 to 400 nm) may be diminished.

[0012] Iron oxide is a known visible light absorber that can be added to sunscreen products to provide broad protection against ultraviolet and visible light. However, iron oxide is yellow, red, and brown, and these colors increase as the amount of iron oxide added to the sunscreen composition increases. Therefore, for people with type I or type II skin, i.e., those who most need visible light protection to reduce their risk of skin cancer erythema and skin aging, a sunscreen composition containing a high concentration of iron oxide or a concentration effective in protecting against visible light may not be ideal.

[0013] Accordingly, there is a need for a sunscreen composition that can protect against both ultraviolet radiation in sunlight and the visible light portion of the solar spectrum, and the color of the sunscreen is acceptable for people with fair to light skin tones. Ideally, the appearance of such a sunscreen composition should be acceptable to consumers and provide stronger protection against erythema to the skin than traditional pure ultraviolet protection sunscreen products. Summary of the Invention

[0014] Disclosed herein are sunscreen compositions and methods of using the sunscreen compositions to reduce or prevent sunburn caused by visible light and ultraviolet (UV) radiation, as well as methods of increasing the sun protection factor (SPF) and / or visible light protection factor of the sunscreen compositions.

[0015] In certain embodiments, the present invention discloses a sunscreen composition comprising (a) at least one inorganic ultraviolet filter selected from zinc oxide or titanium dioxide; (b) at least one inorganic pigment selected from iron oxides; and (c) at least one visible light protectant, such as barium sulfate, wherein the at least one visible light protectant is present in an amount effective to reduce or prevent sunburn caused by visible light. In certain embodiments, the present invention discloses a sunscreen composition comprising (a) at least one inorganic ultraviolet filter selected from zinc oxide or titanium dioxide; (b) at least one inorganic pigment selected from iron oxides; and (c) at least two visible light protectants, including barium sulfate and mica, wherein the at least two visible light protectants are present in an amount effective to reduce or prevent sunburn caused by visible light.

[0016] In certain embodiments, the sunscreen composition disclosed in the present invention is anhydrous. In certain embodiments, based on the total weight of the composition, barium sulfate is present in the sunscreen composition in an amount of about 0.1% to about 10%, such as about 1% to about 5%, about 2% to about 3%, about 5% or about 2.5% by weight. In certain embodiments, based on the total weight of the composition, mica is present in the sunscreen composition in an amount of about 0.1% to about 10%, such as about 1% to about 5%, about 2% to about 3%, about 5% or about 2.5% by weight. In certain embodiments, relative to the total weight of the composition, barium sulfate and mica are present in an amount of about 1% to about 5%, such as about 2% to about 3%, about 5% or about 2.5% by weight. In a further embodiment of the present disclosure, the sunscreen composition does not contain organic ultraviolet filters.

[0017] In certain embodiments of the present disclosure, the sunscreen composition comprises zinc oxide and titanium dioxide, and in certain embodiments, iron oxide is selected from the group consisting of black iron oxide, brown iron oxide, red iron oxide, yellow iron oxide, and mixtures thereof. In certain embodiments, at least one of the at least two visible light protectants further comprises a coating, such as a silica coating, and in certain embodiments, both mica and barium sulfate comprise a coating, such as a silica coating.

[0018] In certain embodiments of the sunscreen composition disclosed in the present invention, iron oxide is present in the sunscreen composition in an amount of from about 0.1% to about 10%, such as from about 1% to about 5%, from about 1% to about 3%, or from about 2% to about 3%. In certain embodiments, at least one inorganic UV filter is titanium dioxide, and in certain embodiments, the average particle size of titanium dioxide is from about 5 nm to about 20 nm. In certain embodiments, at least one UV filter is zinc oxide, and in certain embodiments, the average particle size of zinc oxide is from about 10 nm to about 100 nm.

[0019] In certain embodiments, the sunscreen composition disclosed herein further comprises at least one antioxidant, such as at least one antioxidant selected from the group consisting of vitamin E or its derivatives and vitamin C or its derivatives. In certain embodiments, relative to the total weight of the sunscreen composition, at least one antioxidant is present in the sunscreen composition in a total amount of from about 0.1% to about 5% by weight.

[0020] Also disclosed herein is a method of reducing or preventing sunburn in a subject due to visible light and ultraviolet (UV) radiation, comprising topically applying to the subject the sunscreen composition disclosed herein, such as the sunscreen composition comprising: (a) at least one inorganic UV filter selected from zinc oxide or titanium dioxide; (b) at least one inorganic pigment selected from iron oxide; and (c) at least one visible light protectant, such as barium sulfate, wherein the at least one visible light protectant is present in an amount effective to reduce or prevent sunburn caused by visible light. In certain embodiments, disclosed herein is a method of reducing or preventing sunburn in a subject due to visible light and ultraviolet (UV) radiation, which comprises topically applying to the subject the sunscreen composition as disclosed herein, such as the sunscreen composition comprising: (a) at least one inorganic UV filter selected from zinc oxide or titanium dioxide; (b) at least one inorganic pigment selected from iron oxide; and (c) at least two visible light protectants, which comprise barium sulfate and mica, wherein the at least two visible light protectants are present in an amount effective to reduce or prevent sunburn caused by visible light.

[0021] The present disclosure further provides methods for increasing the visible light protection factor of the sunscreen compositions disclosed herein. For example, the sunscreen composition comprises: (a) at least one inorganic ultraviolet filter selected from zinc oxide or titanium dioxide; (b) at least one inorganic pigment selected from iron oxide; and (c) at least one visible light protectant, such as barium sulfate, wherein the at least one visible light protectant is present in the sunscreen composition in an amount effective to increase visible light protection in the electromagnetic wavelength spectrum of from about 400 nm to about 800 nm, such as from about 400 nm to about 500 nm. In certain embodiments of the methods disclosed herein, the visible light protection factor is increased by at least about 0.5, such as at least about 0.7, at least about 0.8, or at least about 0.9, i.e., the visible light protection factor can be increased, for example, from about 2.7 to about 3.2, which represents an increase of about 0.5. In certain embodiments, the present disclosure provides methods for increasing the visible light protection factor of the sunscreen compositions disclosed herein. For example, the sunscreen composition comprises: (a) at least one inorganic ultraviolet filter selected from zinc oxide or titanium dioxide; (b) at least one inorganic pigment selected from iron oxide; and (c) at least two visible light protectants, including barium sulfate and mica, wherein the at least two visible light protectants are present in the sunscreen composition in an amount effective to increase visible light protection in the electromagnetic wavelength spectrum of from about 400 nm to about 800 nm, such as from about 400 nm to about 500 nm. In certain embodiments of the methods disclosed herein, the visible light protection factor is increased by at least about 0.5, such as at least about 0.7, at least about 0.8, or at least about 0.9.

[0022] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and do not limit the teachings of the claimed invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a graph showing the absorbance of the six sunscreen formulations described in Example 1 in the ultraviolet and visible spectra (300 nm to 800 nm) of the electromagnetic spectrum.

[0024] Figure 2 is a graph showing the absorbance of the four sunscreen formulations #1, #2, #3, and #4 described in Example 2 in the ultraviolet and visible spectra (300 nm to 800 nm) of the electromagnetic spectrum.

[0025] Figure 3 is a graph showing the absorbance of the four sunscreen formulations #5, #7, #8, and #9 described in Example 2 in the ultraviolet and visible spectra (300 nm to 800 nm) of the electromagnetic spectrum.

[0026] Figure 4It is a graph showing the absorbance of the seven sunscreen formulations #7, #8, #9, #9a, #9b, #10, and #11 described in Example 2 within the ultraviolet and visible spectra (300 nm to 800 nm) of the electromagnetic spectrum.

[0027] Figure 5 It is a graph showing the dose response of blue light (about 400 nm to 500 nm) protection, which is related to the iron oxide concentration of the sunscreen formulations described in Example 2.

[0028] Figure 6 It is a bar graph showing the blue light protection factors of the sunscreen formulations #2, #3, #4, #5, #6, and #7 described in Example 2. Error bars represent CI = 95%, and the brackets above the bars indicate statistical significance, where p < 0.01 for formulation #2 compared to #3, and p < 0.1 for formulation #3 compared to #4. Similarly, p < 0.011 for formulation #5 compared to formulation #6, and p < 0.01 for formulation #7 compared to formulation #5 or #6.

[0029] Figure 7 It is a graph showing the critical wavelength and iron oxide concentration dependence of sunscreen formulations #9b, #9a, #9, #8, #7, and #10 (in increasing order of iron oxide concentration), as described in Example 2.

[0030] Figure 8 It is a graph showing the absorbance of four sunscreen formulations #1213A, #1213B, #1122B, and #1212B, as well as the absorbance graph generated by mica alone, where 4.4% TiO 2 spectrum, as described in Example 3, covers the ultraviolet and visible spectra (300 nm to 700 nm) of the electromagnetic spectrum. Detailed Description

[0031] Now, the embodiments of the teachings of the present invention will be described in detail. In the following description, exemplary embodiments in which the teachings of the present invention can be practiced are presented. Therefore, the following description is merely exemplary.

[0032] Disclosed herein is a sunscreen composition that provides protection for the skin against the visible and ultraviolet portions of sunlight. Also disclosed are methods of using the sunscreen composition to reduce or prevent sunburn caused by the visible and ultraviolet portions of sunlight, and methods of increasing the SPF and / or visible light protection factor of the sunscreen composition. The sunscreen composition disclosed herein comprises a combination of inorganic reagents that absorb the visible rays of the sun, mainly in the blue region, thereby reducing or preventing erythema.

[0033] In certain embodiments, a sunscreen composition is disclosed herein that comprises at least one visible light protectant. Also disclosed herein is a sunscreen composition that comprises at least two visible light protectants, such as barium sulfate and mica.

[0034] In certain embodiments, the sunscreen composition may further comprise iron oxide as an inorganic pigment, which also serves to absorb visible light, and in certain embodiments, the sunscreen composition may further comprise iron oxide and at least one inorganic ultraviolet filter, such as titanium dioxide and / or zinc oxide.

[0035] In certain embodiments, the sunscreen composition disclosed herein is anhydrous, and in certain embodiments, the sunscreen composition is in the form of an emulsion, such as an oil-in-water emulsion or a water-in-oil emulsion. Compared to water-based sunscreen compositions, the anhydrous sunscreen compositions disclosed herein provide excellent water resistance when topically applied to the skin of a user, and in certain embodiments, the anhydrous sunscreen compositions can be waterproof. Additionally, compared to water-based sunscreen compositions, the anhydrous sunscreen compositions can improve the resistance to microbial contamination. In certain embodiments, the anhydrous sunscreen compositions disclosed herein are substantially free of preservatives.

[0036] Compared to conventional sunscreen products, including, for example, conventional sunscreens that do not provide a combination of visible light blockers, the sunscreen compositions disclosed herein provide excellent protection against sunlight-induced erythema. The visible light protection provided by at least two visible light protectants, such as barium sulfate and mica, is synergistic and is superior not only to iron oxide alone but also to individual visible light protectants, thereby allowing the sunscreen composition to provide equivalent or better visible light protection while containing a reduced amount of iron oxide, which may be undesirable as a pigment in colored sunscreens for individuals with fair skin. Thus, the sunscreen compositions disclosed herein provide visible light protection in a cosmetically acceptable manner and can be adjusted by concentration (e.g., the concentration of iron oxide) and color grade to match the skin tone of the user.

[0037] The sunscreen compositions disclosed herein can be formulated to provide a physical feel and tactile properties that are comfortable to the user. In certain embodiments, the sunscreen is formulated to provide an acceptable color match to an individual (such as an individual with Fitzpatrick type I or II skin). In certain embodiments, the sunscreen is formulated to provide an acceptable color match to an individual with Fitzpatrick type III, IV, V, or VI skin.

[0038] Definitions

[0039] As used throughout this specification, ranges are used as a shorthand notation for describing each and every value within the range. Any value within the range can be selected as the boundary of the range. Additionally, all references cited herein are incorporated by reference in their entirety. If there is a conflict between the definitions in this invention and those in the cited references, the definitions in this invention shall prevail. Unless the context clearly indicates otherwise, the following terms and their cognates shall have the following meanings.

[0040] The term "at least one" is used to refer to one or more of the listed items that can be selected. For example, if the list of items is A and B, then at least one of A and B means A alone, B alone, or A and B.

[0041] The term "about" should be understood to cover the normal range of variation accepted in the art, such as including 10%, 1%, 0.1%, or 0.01% of the stated value. Unless otherwise specified, all numerical values provided herein should be understood to be modified by the term "about".

[0042] As used herein, the term "erythema" is used interchangeably with the term "sunburn" and refers to redness of the skin surface caused by excessive exposure to waves from the electromagnetic spectrum, including visible light and UV radiation. As used herein, erythema and sunburn are distinct from increased skin pigmentation (such as tanning).

[0043] As used herein, the term "ultraviolet radiation" or "UV radiation" refers to electromagnetic radiation in the range of about 290 nm to about 400 nm. Within the UV radiation spectrum, UVB radiation is electromagnetic radiation in the range of about 290 nm to about 320 nm, while UVA radiation is electromagnetic radiation in the range of about 320 nm to about 400 nm.

[0044] As used herein, the term "visible light" refers to electromagnetic radiation in the range of about 400 nm to about 700 nm. Within the visible light spectrum, the violet region ranges from about 380 to 450 nm, the blue region ranges from about 450 to 495 nm, the green region ranges from about 495 to 570 nm, the yellow region ranges from about 570 to 590 nm, the orange region ranges from about 590 to 625 nm, and the red region ranges from about 625 to 700 nm. In certain embodiments, the blue region can be combined with the violet region to describe a blue region spanning from about 400 nm to about 500 nm.

[0045] As used herein, the terms "sun protection factor" and "SPF" represent a measure of the amount of solar energy required to produce erythema or sunburn on the skin after application of a sunscreen composition relative to the amount of solar energy required to produce erythema on the skin without application of any sunscreen composition. The amount of solar energy can be affected by the duration of exposure (time) and the intensity of the solar energy. The intensity of the solar energy can be related to the time of day, geographical location (wherein the solar energy intensity may be greater at higher latitudes), and weather (e.g., cloud cover).

[0046] As used herein, the term "visible light protection factor" or "VL-PF" represents a measure of the effectiveness of a sunscreen composition in preventing erythema or sunburn caused by solar visible light after application of the sunscreen composition relative to the amount of solar energy required to produce erythema on the skin without application of any sunscreen composition. In certain embodiments, the VL-PF corresponds to the reciprocal of the average transmittance value in a given wavelength range, such as from about 400 nm to about 800 nm, from about 400 nm to about 600 nm, or from about 400 nm to about 500 nm.

[0047] As used herein, the term "effective amount" refers to an amount of a sunscreen composition that is sufficient to prevent, reduce, or mitigate damage caused by exposure to ultraviolet and visible light, including sunburn, when administered or dosed in an appropriate quantity and frequency.

[0048] Additional definitions are set forth throughout the detailed description.

[0049] Sunscreen composition

[0050] Disclosed herein are sunscreen compositions that, when topically applied to the skin of a user, can be used to reduce or prevent damage caused by visible and ultraviolet radiation, including sunburn.

[0051] In certain embodiments, a sunscreen composition is disclosed that comprises (a) at least one inorganic ultraviolet filter, such as titanium dioxide and / or zinc oxide; (b) at least one inorganic pigment selected from iron oxides; and (c) at least one visible light protecting agent, wherein the at least one visible light protecting agent is present in an amount effective to reduce or prevent sunburn caused by visible light. In certain embodiments, a sunscreen composition is disclosed that comprises (a) at least one inorganic ultraviolet filter, such as titanium dioxide and / or zinc oxide; (b) at least one inorganic pigment selected from iron oxides; and (c) at least two visible light protecting agents, including barium sulfate and mica, or consisting of barium sulfate and mica, wherein the at least two visible light protecting agents are present in an amount effective to reduce or prevent sunburn caused by visible light.

[0052] Ultraviolet filter

[0053] In certain embodiments, the sunscreen composition comprises at least one inorganic ultraviolet filter selected from the group consisting of titanium dioxide, zinc oxide, cerium oxide, zirconium oxide, and mixtures thereof. The inorganic ultraviolet filter can be used to filter or absorb ultraviolet radiation in the ultraviolet band of the electromagnetic spectrum, such as including UVA and UVB radiation having wavelengths of about 320 nm to 400 nm and 280 nm to 320 nm, respectively.

[0054] In certain embodiments, the sunscreen composition disclosed herein may further comprise titanium dioxide as an inorganic ultraviolet filter. Titanium dioxide can be present as micronized or nano-sized solid particles, such as solid particles having an average particle size range of about 10 nm to about 100 μm, such as about 10 nm to about 25 μm, about 10 nm to about 10 μm, or about 15 nm to about 5 μm. In certain embodiments where titanium dioxide is present as an ultraviolet filter, titanium dioxide may comprise nanoparticles having an average particle size range of about 5 nm to about 1000 nm, such as about 5 nm to about 500 nm, about 10 nm to about 50 nm, or about 15 nm to about 40 nm, or about 15 nm. The titanium dioxide nanoparticles may also form aggregates having a larger average particle size, such as an average aggregate particle size range of about 100 nm to about 1000 nm, such as about 200 nm to about 500 nm, or about 250 nm to about 400 nm. In certain embodiments, titanium dioxide can be larger than the nanoparticle size, having an average particle size range of about 1 μm to about 25 μm, such as about 5 μm to about 20 μm, or about 10 μm to about 15 μm. In certain embodiments, titanium dioxide comprises a mixture of nanoparticles (e.g., for ultraviolet filtering protection) and larger micronized-sized particles (e.g., for visible light scattering protection).

[0055] Titanium dioxide can be present in the sunscreen composition in any effective amount to filter ultraviolet light, thereby preventing or reducing the sunburn effect when topically applied to a user, and it can be present alone or together with other components of the sunscreen. In an embodiment, based on the total weight of the sunscreen composition, by weight, titanium dioxide can be present in the sunscreen composition in an amount of about 1% to about 25%, such as about 5% to about 20%, or about 5% to about 15%, such as about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 12.5%, about 13%, about 14% or about 15%.

[0056] In various embodiments of the present disclosure, in addition to titanium dioxide or in place of titanium dioxide, the sunscreen composition comprises zinc oxide as an inorganic ultraviolet filter. As discussed above with respect to titanium dioxide, zinc oxide can be present as micronized or nano-sized solid particles, for example having an average particle size in the range of about 10 nm to about 400 μm, such as about 10 nm to about 25 μm, about 10 nm to about 10 μm, or about 15 nm to about 5 μm. As used herein, "nano-sized" or "nanoparticle" means a particle size less than about 1000 nm, such as about 1 nm to about 1000 nm or about 1 nm to about 100 nm, while "micronized" or "micron-sized" means a particle size range of about 1 μm (i.e., about 1000 nm) to about 1000 μm. In embodiments where zinc oxide is present as an ultraviolet filter, the zinc oxide can comprise nanoparticles having an average particle size range of about 5 nm to about 1000 nm, such as about 10 nm to about 1000 nm, about 30 nm to about 200 nm, about 40 nm to about 100 nm, about 60 nm to about 80 nm, about 10 nm to 50 nm, or about 25 nm to about 40 nm, or about 80 nm. However, as described below, zinc oxide can also be present in the sunscreen compositions disclosed herein as at least one inorganic pigment at the pigment grade, which indicates that the zinc oxide can be larger than the nanoparticle size, having an average particle size range of about 100 nm to about 1000 nm, such as about 200 nm to about 500 nm, or about 1 μm to about 400 μm, such as about 10 μm to about 100 μm, about 2 μm to about 25 μm, about 5 μm to about 20 μm, or about 10 μm to about 15 μm. In certain embodiments, the zinc oxide comprises a mixture of nanoparticles (e.g., for ultraviolet filtering protection) and larger micronized-sized particles (e.g., for visible light scattering protection).

[0057] Titanium dioxide can be present in the sunscreen composition in any effective amount to filter ultraviolet light, thereby preventing or reducing the sunburn effect when topically applied to a user, and it can be present alone or together with other components of the sunscreen. In certain embodiments, based on the total weight of the sunscreen composition, by weight, zinc oxide can be present in the sunscreen composition in an amount of about 1% to about 25%, such as about 5% to about 20%, or about 5% to about 15%, such as about 5%, about 6%, about 7%, about 7.5%, about 8%, about 9%, 10%, about 11%, about 12%, about 13% or about 15%.

[0058] Generally, inorganic ultraviolet filters, including zinc oxide and titanium dioxide, based on the total weight of the sunscreen composition, by weight, the inorganic ultraviolet filters can be present in the sunscreen composition in an amount of about 2% to about 50%, such as about 5% to about 40%, about 10% to about 30%, or about 20% to about 25%, such as about 20%, about 21%, about 22%, about 23%, about 23.5%, about 24% or about 25%.

[0059] In certain embodiments, the sunscreen composition may be formulated for fair - skinned users, such as users having Fitzpatrick skin type I or II. In such embodiments, the amount of titanium dioxide in the composition may be greater than the amount of zinc oxide in the composition. Without wishing to be bound by theory, it is believed that titanium dioxide may contribute more to the SPF protection compared to zinc oxide.

[0060] In certain embodiments, at least one inorganic UV filter may be a surface - treated inorganic UV filter. Surface - treating at least one inorganic UV filter may reduce or prevent the photoreactivity of the agent and / or facilitate mixing with other components in the sunscreen composition. A surface - treated inorganic UV filter means that the UV filter has been surface - treated by any means, including chemically, electrically, and / or mechanically. In certain embodiments, surface - treating at least one inorganic UV filter may enhance the water - resistant properties of the UV filter and the sunscreen composition. In certain embodiments, all of the UV filters present in the sunscreen composition are surface - treated, which may reduce the potential photoreactivity of the UV filters.

[0061] The inorganic UV filter may be surface - treated by any surface - treating method or agent known in the art. In certain embodiments, at least one inorganic UV filter may comprise coated particles. For example, the coating may comprise a hydrophobic material such as an alkylsiloxane (e.g., triethoxysilane octane), an organotitanate, a halogenated phosphate (e.g., perfluoroalkyl phosphonate), an organohalosilane, a modified amino acid (e.g., disodium stearoyl glutamate), an organosilicon, or a metal salt of a fatty acid.

[0062] For example, exemplary embodiments of surface - treated coated UV filters may include coated zinc oxide, such as triethoxysilane octane zinc oxide (e.g., HP1), and / or coated titanium dioxide, such as triethoxysilane octane titanium dioxide (e.g., CM3K40T4 and UV Cut TiO 2 -41 from Kobo Products).

[0063] Inorganic pigment

[0064] In various embodiments, the sunscreen compositions disclosed herein may also include at least one inorganic pigment, such as iron oxide. Without wishing to be bound by theory, it is believed that the role of the inorganic pigment is to absorb visible light from the sun, such as visible light in the blue region of the visible light spectrum (e.g., from about 450 nm to about 495 nm) and the violet region of the visible light spectrum (e.g., from about 380 nm to about 450 nm), which may overlap with UVA radiation in the upper range of the UVA spectrum (e.g., from about 375 nm to about 400 nm). Exemplary inorganic pigments may include titanium dioxide, zinc oxide, iron oxides including black iron oxide, brown iron oxide, red iron oxide, and yellow iron oxide, manganese violet, ultramarine blue, chromium oxide, hydrated chromium, iron blue, and mixtures thereof. In certain embodiments, the at least one inorganic pigment comprises a mixture of iron oxides, such as a mixture of red iron oxide, yellow iron oxide, and black iron oxide. Notably, the bandgap energy of titanium dioxide and zinc oxide is approximately 3.3 eV and absorption stops at about 375 nm to 380 nm, and instead scatters light at wavelengths above this range. The bandgap energy of iron oxides and other oxides is only about 2.1 eV to 2.2 eV, which can absorb light from about 500 nm to 590 nm and scatter light at wavelengths above this range.

[0065] In one embodiment, the at least one inorganic pigment includes iron oxide, and in one embodiment, the at least one inorganic pigment includes iron oxide and at least one of zinc oxide and titanium dioxide. While traditional nanoparticles of inorganic UV filters such as titanium dioxide and zinc oxide can be used to provide UVB protection against radiation in the range of about 280 nm to about 320 nm, these filters generally do not provide sufficient protection against the higher radiation wavelengths that make up UVA radiation, such as in the range of about 315 nm to about 400 nm, including from about 375 nm to about 400 nm, for erythema. However, as disclosed herein, adding at least one inorganic pigment, such as iron oxide, titanium dioxide, and / or zinc oxide, can enhance protection against erythema caused by UVA radiation and / or visible light, including, for example, protection against UVA radiation in the range of about 375 nm to about 400 nm and visible light in the range of about 400 nm to about 750 nm.

[0066] In embodiments where at least one inorganic pigment comprises titanium dioxide and / or zinc oxide, the particle size of the titanium dioxide and / or zinc oxide can be greater than that of the titanium dioxide and / or zinc oxide comprising the ultraviolet filter. It is known that smaller nanoparticles of titanium dioxide and / or zinc oxide have broad-spectrum ultraviolet filtering and absorption properties, but are less capable of scattering and reflecting visible light, and thus have a higher transparency when applied to the skin in the form of a sunscreen composition. For example, see Yin, H. et al., A comparative study of the physical and chemical properties of nano-sized ZnO particles from multiple batches of three commercial products, Journal of Nanoparticle Research, 2015; 17: 1-19 (Yin, H. et al., A comparative study of the physical and chemical properties of nano-sized ZnO particles from multiple batches of three commercial products, J. NANOPART. R ES . 2015; 17:1-19).

[0067] Accordingly, in certain embodiments of the sunscreen compositions disclosed herein that comprise a UV filter of zinc oxide nanoparticles and / or titanium dioxide nanoparticles, the sunscreen composition can further comprise at least one inorganic pigment selected from the group consisting of pigment-sized zinc oxide and pigment-sized titanium dioxide. "Pigmentary" or "pigment-sized" means that the average particle size of the titanium dioxide and / or zinc oxide is greater than that of the above-described nanoparticles, and the particle size is a cosmetically acceptable size and can be used as a pigment in the sunscreen composition. In certain embodiments, the average particle size range of the pigment-sized zinc oxide particles can be at least about 100 nm to about 25 μm, such as about 200 nm to about 10 μm, about 200 nm to about 500 nm, or about 5 μm to about 15 μm. In certain embodiments, the average particle size range of the pigment-sized titanium dioxide particles can be at least about 100 nm to about 25 μm, such as about 200 nm to about 10 μm, about 200 nm to about 500 nm, about 5 μm to about 15 μm, or about 8 μm to about 10 μm.

[0068] At least one inorganic pigment can effectively absorb visible light, such as visible light in the blue and / or violet regions of the visible light spectrum, and is present in the sunscreen composition in any amount, which can be present alone or together with other components of the sunscreen composition. In certain embodiments, based on the total weight of the sunscreen composition, by weight, at least one inorganic pigment, such as iron oxide, can be present in an amount of about 0.01% to about 10%, such as about 1% to about 5%, about 1% to about 4.5%, or about 1% to about 3%, for example about 0.5%, about 1%, about 1.5%, about 2%, about 2.5% or about 2.75%. In certain embodiments, based on the total weight of the sunscreen composition, by weight, the content of iron oxide in the sunscreen composition is less than 5%, such as less than about 4.5%, less than about 3%, less than about 2.75%, less than about 2.5%, less than about 2%, less than about 1.5%, less than about 1% or less than about 0.5%. In some embodiments, the composition is substantially free of iron oxide. Accordingly, a sunscreen composition is also disclosed herein, which comprises at least one inorganic UV filter selected from zinc oxide or titanium dioxide; and at least two visible light protectants, which include barium sulfate and mica, wherein the at least two visible light protectants are present in an amount effective to reduce or prevent sunburn caused by visible light.

[0069] In certain embodiments, at least one inorganic pigment can be a surface-treated inorganic pigment. Surface-treating at least one inorganic pigment can reduce or prevent the photoreactivity of the pigment and / or facilitate mixing with other ingredients in the sunscreen composition. A surface-treated inorganic pigment indicates that the inorganic pigment has been surface-treated by any means, including chemically, electrically, and / or mechanically. In certain embodiments, surface-treating at least one inorganic pigment can enhance the water resistance of the inorganic pigment and the sunscreen composition. In certain embodiments, all inorganic pigments present in the sunscreen composition are surface-treated.

[0070] The inorganic pigment can be surface-treated by any surface treatment method or agent known in the art. In certain embodiments, at least one inorganic pigment can comprise coated particles. For example, the coating can comprise a hydrophobic material such as an alkylsiloxane (such as triethoxysilane), an organotitanate, a halogenated phosphate (such as a perfluoroalkylphosphonate), an organohalosilane, a modified amino acid (such as disodium stearoyl glutamate), an organosilicon, or a metal salt of a fatty acid.

[0071] Exemplary embodiments of organic pigments can include surface-treated coated inorganic pigments, such as coated iron oxide, which includes triethoxysilane iron oxide (such as ), and coated and uncoated titanium dioxide (such as White LC 987 and White LC 987AS-EM, triethoxysilane titanium dioxide).

[0072] Additional visible light protectant

[0073] In certain embodiments, the sunscreen compositions disclosed herein, in addition to comprising at least one inorganic pigment, further comprise at least one visible light protectant, such as barium sulfate. In certain embodiments, the sunscreen composition further comprises at least two additional visible light protectants, such as barium sulfate and mica. Visible light protectants can include any compound, such as an inorganic pigment, that blocks or absorbs light in the visible light portion of the electromagnetic spectrum, such as electromagnetic wavelengths in the range of about 400 nm to about 700 nm. In certain embodiments, the visible light protectant blocks or absorbs light from the violet and / or blue light regions, such as about 380 nm to about 500 nm, about 400 nm to about 495 nm, or about 400 nm to about 500 nm. In certain embodiments, the visible light protectant blocks or absorbs light from the violet light region, such as about 380 nm to about 450 nm, and in certain embodiments, the light absorber blocks or absorbs light from the blue light region, such as about 450 nm to about 495 nm. In certain embodiments, the visible light protectant blocks or absorbs light from the green light region, such as, about 495 nm to about 570 nm; yellow light region, such as, about 570 nm to about 590 nm; orange light region, such as, about 590 nm to about 625 nm; and / or red light region, such as, about 625 nm to about 700 nm.

[0074] Visible light protectants can include, but are not limited to, at least one or at least two of transition metal oxides, iron oxides, barium sulfate, mica, silica, bismuth oxychloride, corn starch, calcium powder, or any visible colored pigment known in the art. In certain embodiments, at least one visible light protectant is barium sulfate. In certain embodiments, at least one visible light protectant is mica. In certain embodiments, at least two visible light protectants are barium sulfate and mica. In certain embodiments, the sunscreen composition is substantially free of bismuth oxychloride. In certain embodiments, the sunscreen composition is substantially free of visible light protectants other than barium sulfate and mica.

[0075] At least one or at least two visible light protectants can be present in the sunscreen composition in any amount effective to absorb visible light, such as visible light in the blue and / or violet regions of the visible light spectrum, and can be present alone or in combination with other components of the sunscreen composition, such as iron oxides, titanium dioxide, and / or zinc oxide.

[0076] In the embodiments disclosed herein, at least two visible light protectants can be present together in synergistic amounts such that the presence of the at least two visible light protectants can block a greater amount of visible light than any one of the visible light protectants acting alone. For example, barium sulfate and mica can be present in the sunscreen composition in synergistic amounts. In certain embodiments, at least one or at least two visible light protectants can be present in the sunscreen composition in amounts that synergize with another component of the sunscreen composition, such as at least one antioxidant.

[0077] As used herein, the terms "synergistic," "synergistically," and derivatives thereof refer to a combination, such as a combination of at least two visible light protectants, having an activity greater than the total activity when the visible light protectants are used alone. In some embodiments, each individual visible light protectant may have a minimal visible light protection effect when used alone; however, when the same amounts of visible light protectants are combined and used together in a sunscreen composition, they may have a high visible light protection ability, resulting in a higher SPF and / or visible light protection factor. This synergistic effect of at least two visible light protectants is surprising and unexpected.

[0078] In certain embodiments, based on the total weight of the sunscreen composition, by weight, at least one visible light protectant, such as barium sulfate, can be present in the sunscreen composition in an amount of from about 0.01% to about 10%, such as from about 1% to about 7%, from about 1% to about 5%, or about 5%.

[0079] In certain embodiments, based on the total weight of the sunscreen composition, by weight, at least two visible light protectants, such as barium sulfate and mica, can be present together in the sunscreen composition in an amount of from about 0.01% to about 10%, such as from about 1% to about 7%, from about 1% to about 5%, or about 5%. In certain embodiments, based on the total weight of the sunscreen composition, by weight, at least two visible light protectants, such as barium sulfate and mica, can be present together in the sunscreen composition in an amount of from about 0.01% to less than about 7%, such as from about 3.5% to less than about 7%, from about 4% to less than about 7%, from about 4.5% to less than about 7%, or from about 5% to less than about 7%. The amounts of barium sulfate and mica in the composition can be the same or different.

[0080] In certain embodiments of the sunscreen compositions disclosed herein, based on the total weight of the sunscreen composition, barium sulfate is present in the sunscreen composition in an amount of from about 0.01% to about 5%, such as from about 1% to about 3.5%, from about 1% to about 3%, from about 1.5% to about 2.5%, from about 2% to about 2.5%, or about 2.5% by weight. In certain embodiments of the sunscreen compositions disclosed herein, based on the total weight of the sunscreen composition, mica is present in the sunscreen composition in an amount of from about 0.01% to about 5%, such as from about 1% to about 3.5%, from about 1% to about 3%, from about 1.5% to about 2.5%, from about 2% to about 2.5%, or about 2.5% by weight. In certain embodiments disclosed herein, based on the total weight of the sunscreen composition, barium sulfate and mica are each present in the sunscreen composition in equal amounts, such as each being from about 1% to about 3%, from about 1.5% to about 2.5%, from about 2% to about 2.5%, or about 2.5%. In one embodiment of the present disclosure, the sunscreen composition comprises at least two visible light protectants, the visible light protectants including barium sulfate and mica, wherein, based on the total weight of the sunscreen composition, the content of barium sulfate is about 2.5% by weight, and the content of mica is about 2.5% by weight.

[0081] In certain embodiments disclosed herein, at least one of the at least two visible light protectants may be a surface-treated visible light protectant. Surface-treating at least one visible light protectant can reduce or prevent the photoreactivity of the agent and / or facilitate mixing with other components in the sunscreen composition. A surface-treated visible light protectant means that the visible light protectant has been surface-treated by any means, including chemically, electrically, and / or mechanically. In certain embodiments, surface-treating at least one visible light protectant can enhance the water resistance of the visible light protectant and the sunscreen composition. In certain embodiments, both of the at least two visible light protectants (e.g., barium sulfate and mica) present in the sunscreen composition are surface-treated, while in certain embodiments, only one of the at least two visible light protectants (e.g., barium sulfate or mica) present in the sunscreen composition is surface-treated.

[0082] The visible light protectant can be surface-treated by any surface treatment method or agent known in the art. In certain embodiments, at least one visible light protectant may comprise coated particles. For example, the coating may comprise a hydrophobic material such as an alkylsiloxane (e.g., triethoxysilane), an organotitanate, a halogenated phosphate (e.g., perfluoroalkylphosphonate), an organohalosilane, a modified amino acid (e.g., sodium stearoyl glutamate), an organosilicon, or a metal salt of a fatty acid.

[0083] Exemplary embodiments of the surface-treated visible light-protecting agent may include, for example, coating barium sulfate, such as barium sulfate triethoxyoctylsilane, and / or coating mica, such as mica triethoxyoctylsilane.

[0084] Additional ingredients

[0085] The sunscreen compositions of the present invention may contain any other additional ingredients known in the art and acceptable in cosmetics for topical sunscreen products. For example, in certain embodiments, the sunscreen compositions disclosed herein may further contain at least one of antioxidants, emollients / oils, emulsifiers, SPF boosters, organic pigments, organic UV filters, skin conditioners, film formers, fillers, preservatives, fragrances, silica, sodium chloride, citric acid, neutralizing agents or pH regulators (such as triethanolamine and sodium hydroxide), essential oils, and cosmetically acceptable carriers (including water). In certain embodiments, the sunscreen compositions disclosed herein are substantially free of water and are anhydrous sunscreen compositions.

[0086] In certain embodiments disclosed herein, the sunscreen composition further contains at least one antioxidant. Without wishing to be bound by theory, it is believed that at least one antioxidant helps to quench free radicals induced by solar visible light radiation, and thus can effectively prevent or reduce sunburn when topically applied to a user in an amount effective to quench free radicals. In certain embodiments, the at least one antioxidant may be selected from vitamin A, vitamin C, vitamin E, selenium, carotenoids (such as β-carotene), and thiols and their derivatives and mixtures. In certain embodiments, the at least one antioxidant is vitamin E (such as tocopherol) or its derivative, such as tocopheryl acetate. In certain embodiments, the at least one antioxidant is vitamin C (such as ascorbic acid) or its derivative, such as tetrahexyldecyl ascorbate. In certain aspects of the present invention, the at least one antioxidant comprises vitamin E or its derivative and vitamin C or its derivative.

[0087] At least one antioxidant can be effectively present in any amount in the sunscreen compositions disclosed herein to prevent or reduce sunburn caused by the visible region of the electromagnetic spectrum (e.g., from about 400 to 750 nm), and it can be present alone or in combination with other components of the sunscreen composition. In certain embodiments, vitamin C or its derivatives, such as tetrahexyldecyl ascorbate, are present in the sunscreen composition in an amount of from about 0.01% to about 5%, such as from about 0.1% to about 3%, from about 0.2% to about 2%, or from about 0.2% to about 1% by weight, based on the total weight of the sunscreen composition. In certain embodiments, vitamin E or its derivatives, such as tocopheryl acetate, are present in the sunscreen composition in an amount of from about 0.01% to about 5%, such as from about 0.1% to about 3%, from about 0.2% to about 2%, or from about 0.2% to about 1% by weight, based on the total weight of the sunscreen composition. In certain embodiments, at least one antioxidant is a combination of vitamin C or its derivatives and vitamin E or its derivatives, and at least one antioxidant is present in the sunscreen composition in an amount of from about 0.1% to about 10%, such as from about 0.2% to about 5%, from about 0.5% to about 4%, or from about 0.4% to about 2% by weight, based on the total weight of the sunscreen composition.

[0088] In certain embodiments, the sunscreen composition further comprises at least one organic UV filter, while in certain embodiments, the sunscreen composition does not comprise an organic UV filter such that the only UV filters in the sunscreen composition are inorganic UV filters. Traditional organic UV filters are small aromatic molecules, although any organic UV filter known in the art can be considered to be encompassed within the scope of the embodiments disclosed herein. For example, at least one organic UV filter disclosed herein can be selected from benzophenones (such as benzophenone-3, benzophenone-5, and benzophenone-8), 3-benzylidene camphor, bis-ethylhexyloxyphenol methoxyphenyl triazine, butyl methoxydibenzoylmethane, camphor benzalkonium methyl sulfate, diethylamino hydroxybenzoyl benzoic acid hexyl ester, diethylhexyl butamido triazone, cresol triazole trisiloxane, ethylhexyl methoxycinnamate, ethylhexyl dimethylaminobenzoate, ethylhexyl methoxycinnamate, ethylhexyl salicylate, ethylhexyl triazone, homosalate, isoamyl p-methoxycinnamate, methyl anthranilate, 4-methylbenzylidene camphor, methylene bis-benzotriazolyl tetramethylbutylphenol, octocrylene, para-aminobenzoic acid (PABA), polyacrylamidomethyl benzylidene camphor, polysiloxane-15, triethanolamine salicylate, and terephthalylidene dicamphor sulfonic acid.

[0089] In certain embodiments, the sunscreen composition further comprises at least one humectant, such as butylene glycol or glycerin.

[0090] In certain embodiments, the sunscreen composition may comprise at least one emollient. Suitable emollients may be selected from any emollient known in the art, including, for example, mineral oil, petroleum, vegetable / oil such as triglycerides (e.g., caprylic / capric triglyceride), waxes (e.g., beeswax), isopropyl palmitate, isopropyl myristate, diisopropyl adipate, dibutyl adipate, butyl octyl salicylate, C12-C15 alkyl benzoate, silicone oils (e.g., polydimethylsiloxane and stearyl dimethicone), animal oils, hydrocarbon oils, and fatty acids. By way of example, the at least one emollient may be selected from alkane oils (e.g., isododecane and isocetane), ester oils, ether oils (e.g., dioctyl ether), and synthetic triglycerides (e.g., decyloctyl glycerate, trimyristin, tripalmitin, trilinolein, trilaurin, tridecanoin, trioctanoin, tri(capric / caprylic) glyceride, tri(capric / caprylic / linolenic) glyceride, and mixtures thereof).

[0091] Exemplary ester oils may include, for example, ethyl palmitate; ethylhexyl palmitate; isopropyl palmitate; dicaprylyl carbonate; alkyl myristates, such as isopropyl myristate and ethyl myristate; isocetyl stearate; 2-ethylhexyl isononanoate; isononyl isononanoate; isodecyl neopentanoate; isostearyl neopentanoate; diethyl sebacate; isopropyl lauroyl sarcosinate; diisopropyl sebacate; bis(2-ethylhexyl) sebacate; diisopropyl adipate; dipropyl adipate; dioctyl adipate; bis(2-ethylhexyl) adipate; diisostearyl adipate; bis(2-ethylhexyl) maleate; triisopropyl citrate; triisocetyl citrate; triisostearyl citrate; trilactin; trioctanoin; tri(octyldodecyl) citrate; trioleyl citrate; neopentyl glycol diheptanoate; diethylene glycol diisononanoate; diisopropyl adipate; dioctyl adipate; 2-ethylhexyl hexanoate; ethyl laurate; cetyl octanoate; octyldodecyl octanoate; myristyl propionate; 2-ethylhexyl 2-ethylhexanoate; 2-ethylhexyl octanoate; 2-ethylhexyl octanoate / caprate; methyl palmitate; isononyl isononanoate; isohexyl laurate; hexyl laurate; isopropyl isostearate; isodecyl oleate; tri(2-ethylhexyl) glyceride; pentaerythrityl tetra(2-ethylhexanoate); 2-ethylhexyl succinate; C10-30 cholesterol / lanosterol esters; and mixtures thereof.

[0092] In certain embodiments, the sunscreen composition may further comprise at least one SPF booster. An SPF booster is a compound that, when two compounds are present together, refracts ultraviolet radiation, thereby increasing the path length of light within the medium and creating more ultraviolet absorption interactions with the ultraviolet filter. For example, in certain embodiments, styrene copolymer "spheres" can also be used to scatter ultraviolet and visible light radiation by this mechanism. The at least one SPF booster can be selected from any SPF booster known in the art, including, for example, diethylhexyl syringylidenemalonate; glass microspheres such as calcium aluminoborosilicate, sodium borosilicate, and calcium / sodium borosilicate; and copolymers of styrene and (meth)acrylic acid.

[0093] In certain embodiments, the sunscreen composition may further comprise at least one preservative. Suitable preservatives can include, but are not limited to, chlorphenesin, sorbic acid, disodium edetate, ethylhexylglycerin, phenoxyethanol, methylparaben, ethylparaben, propylparaben, phytic acid, imidazolidinyl urea, sodium dehydroacetate, benzyl alcohol, sodium benzoate, methylchloroisothiazolinone, methylisothiazolinone, and mixtures thereof.

[0094] In certain embodiments, the sunscreen composition may further comprise at least one skin conditioner, which may also act as a film former and / or emulsifier in certain embodiments. Suitable skin conditioners can include, but are not limited to, glycerols such as ethoxylated glycerol and propoxylated glycerol; sugar alcohols such as propylene glycol, dipropylene glycol, butylene glycol, hexylene glycol, pentylene glycol, polypropylene glycol, polyethylene glycol, octylene glycol, sorbitol, hydroxypropyl sorbitol, erythritol, threitol, pentaerythritol, xylitol, glucitol, and mannitol; hexanetriol (e.g., 1,2,6 - hexanetriol); glyceryl stearate; polydimethylsiloxane; cyclomethicone; phenyltrimethicone; phenyl dimethicone; cetyl dimethicone; stearyl dimethicone; octyl polymethylsiloxane; amino - terminated polydimethylsiloxane; C30 - 45 alkyl dimethicone and polymethylsiloxane; cetearyl polymethylsiloxane; dimethicone copolyol; cyclopentasiloxane (e.g., Bentone );Polydimethylsiloxane cross-linked polymer; Polydimethylsiloxane / vinyl polydimethylsiloxane cross-linked polymer; C30-45 alkyl cetearyl polydimethylsiloxane cross-linked polymer; Cetearyl polydimethylsiloxane cross-linked polymer; Polydimethylsiloxane / phenyl vinyl polydimethylsiloxane cross-linked polymer; Vinyl polydimethylsiloxane / lauryl polydimethylsiloxane cross-linked polymer; Trifluoropropyl polydimethylsiloxane / trifluoropropyl divinyl polydimethylsiloxane cross-linked polymer; Trimethylsiloxysilicate; Trisiloxane; Neopentyl glycol diheptanoate; Neopentyl glycol diethylhexanoate; Neopentyl glycol dicaprylate / dicaprate; Neopentyl glycol diglycidyl ether; Neopentyl glycol dicaprate; Neopentyl glycol diisostearate; Butyl octyl salicylate; Ethylhexyl stearate; Diethylhexyl 2,6-naphthalate; Petrolatum; Beeswax; Shea butter; Shea oil; Cocoa butter; Jojoba butter; Aloe butter; Olive butter; Coconut oil; Jojoba oil; Olive oil; Sunflower seed oil; and mixtures thereof.

[0095] In certain embodiments, the sunscreen composition may further comprise at least one film-forming agent. Suitable film-forming agents may include, but are not limited to, polyurethanes, acrylate / polydimethylsiloxane cross-linked polymers, waxes, silicone acrylates, and mixtures thereof.

[0096] The sunscreen compositions disclosed herein can be prepared by any means known in the art, such as by mixing and blending the ingredients of the composition in any art-acceptable manner. In certain embodiments, the sunscreen composition can be prepared by combining the various ingredients into a commercially available topical carrier, which can contain other ingredients dissolved or dispersed therein, such as film-forming agents, surfactants, emulsifiers, thickeners, emollients, preservatives, pH regulators, colorants, and fragrances.

[0097] Methods of using the sunscreen composition

[0098] Also disclosed herein are methods of reducing or preventing sunburn. The methods disclosed herein can include topically applying an effective amount of the sunscreen composition disclosed herein to the body surface of a user, such as hair, skin, nails, or lips. As used herein, an effective amount can be any amount that reduces or prevents sunburn due to exposure to ultraviolet radiation and visible light. In certain embodiments, the effective amount can range, for example, from about 0.5 mg / cm 2 to about 5 mg / cm 2 , such as from about 1 mg / cm 2 to about 3 mg / cm 2 , or about 2 mg / cm 2 . In certain embodiments, the methods disclosed herein further include allowing the sunscreen composition to dry after application. In certain embodiments, the sunscreen can be allowed to dry for about 5 minutes to about 30 minutes, such as about 10 minutes, about 15 minutes, about 20 minutes, or about 25 minutes.

[0099] Topical application of a sunscreen composition is to be understood to mean that the sunscreen composition can be applied to any surface of a user, including, for example, skin, hair, nails, and / or lips. The sunscreen composition can be topically applied in any manner known in the art, including spraying, wiping, laying, applying, or rubbing by hand or an applicator, such as a spray bottle, wipe, roller, etc.

[0100] The effectiveness of the ability of a sunscreen to block ultraviolet and / or visible light can be evaluated by any method known in the art. In certain embodiments, spectrophotometric measurements such as thin-film spectrophotometry can be used. For example, see Cole, C. et al., Evaluating sunscreen ultraviolet protection using a polychromatic diffuse reflectance device, Photodermatology, Photoimmunology & Photomedicine HOTODERMATOLOGY ,P HOTOIMMUNOLOGY ,&P HOTOMEDICINE ), 2019, 25(6):436 - 441. In certain embodiments, sun protection can be evaluated by the critical wavelength test specified in the FDA Sunscreen Monograph of the U.S. Food and Drug Administration (FDA): Labeling and effectiveness testing: Over-the-counter sunscreen drug products for human use, U.S. Federal Register 2011, 76:117, 35661 - 35665), and in certain embodiments, the ISO 24442 in vitro sunscreen UVA protection determination specified in ISO 24442: In vitro UVA protection standard for sunscreens, 2021 can be used. In certain embodiments, a spectroradiometer can be used to perform a spectral scan of the sunscreen using an illumination source (such as a solar simulator). Then, the irradiance of the solar simulator can be measured through the electromagnetic radiation spectrum (e.g., from 290 nm to 800 nm) for spectrophotometric measurement.

[0101] In certain embodiments, hybrid diffuse reflectance spectroscopy (HDRS) can be used to calculate the absorbance of a sunscreen formulation. HDRS can be used to measure the protective effect of the UVA portion of the electromagnetic radiation spectrum on human skin. For example, the in vitro data can be scaled to an appropriate magnitude using the HDRS measurement results of the formulation on human skin by matching the calculated UVA protection factor (UVA - PF) of the in vitro spectrum with the UVA - PF value measured by HDRS. In certain embodiments, the visible light blocking protection factor (similar to the SPF value but without biological weighting) can be calculated by determining the reciprocal of the average transmittance value within a given wavelength range.

[0102] The present disclosure relates to methods for increasing the visible light protection factor (VL-PF) of a sunscreen composition, the sunscreen composition comprising at least one inorganic ultraviolet filter and at least one inorganic pigment selected from iron oxides, the method comprising adding to the sunscreen composition at least one or at least two additional visible light protectants, such as at least two visible light protectants, which comprise barium sulfate and mica, wherein the presence amount of the at least one or at least two additional visible light protectants effectively increases the visible light protection factor of the sunscreen composition. The VL-PF is similar to the SPF value described herein, but without a biological weight. The VL-PF can be calculated by any method known in the art. For example, in certain embodiments, the VL-PF can be calculated by determining the reciprocal of the average transmission value within a given wavelength range, such as using the following formula:

[0103]

[0104] In various aspects of the present disclosure, the VL-PF of the sunscreen compositions disclosed herein can be increased by at least about 0.1, such as at least about 0.2, at least about 0.3, at least about 0.4, at least about 0.5, at least about 0.6, at least about 0.7, at least about 0.8, at least about 0.9, or at least about 1.0, within a wavelength range spanning from about 400 nm to 800 nm (such as from about 400 nm to 600 nm or from about 400 nm to 500 nm). In certain embodiments, the VL-PF range of the sunscreen compositions disclosed herein can be from about 1 to about 5, such as about 1, about 1.5, about 2, about 2.5, about 3, about 3.5, about 4, about 4.5, or about 5.

[0105] The present invention also discloses a method for increasing the SPF value of a sunscreen composition, the method comprising adding to the sunscreen composition at least one inorganic UV filter; at least one inorganic pigment selected from iron oxides, and at least one or at least two visible light protectants such as barium sulfate and mica. The SPF or sun protection factor can be measured by any method known in the art and as described herein. In one embodiment, the SPF can be measured according to the standard specified in International Organization for Standardization (ISO) 24444:2019, which measures the SPF as the ratio of [the amount of UV radiation required to produce erythema on sunscreen-protected skin] to [the amount of UV radiation required to produce erythema on unprotected skin]. Since the standard specified in ISO 24444:2019 defines the SPF based on UV radiation (i.e., below 400 nm), it does not consider, and in fact excludes, the effects of sunlight exposure in real life, including the effects of visible light. In fact, laboratory-based SPF tests typically use a solar stimulator that emits UV radiation only in the 290 to 400 nm region of the spectrum, while adding filters to eliminate radiation below 290 nm and above 400 nm and significantly reduce the content between 380 and 400 nm. Thus, many SPF determinations, including those based on laboratory-based SPF determinations for many commercially available sunscreen products, do not consider the effects of long-wave UVA and visible light on the skin.

[0106] In various aspects of the method disclosed herein, the SPF is determined based on actual outdoor sunlight exposure and can be defined as the ratio of [the minimum amount of sunlight exposure required to produce erythema on sunscreen-protected skin] to [the amount of sunlight exposure required to produce erythema on unprotected skin]. Thus, the SPF used herein takes into account all the effects of actual outdoor sunlight exposure (including UV radiation and visible light) and represents the performance of the product under actual use conditions.

[0107] In various aspects of the present disclosure, when tested under outdoor sunlight exposure conditions, the SPF of the sunscreen disclosed herein can be increased by at least about 3, such as at least about 4, at least about 5, or at least about 6, compared to a sunscreen that does not contain an effective amount of at least one or at least two visible light protectants. In some aspects, when tested under outdoor sunlight exposure conditions, the SPF of the sunscreen disclosed herein can be increased by about 2 to about 10, such as about 3 to about 5, or about 3 to about 4. Although this increase may seem small relative to the SPF obtained using an indoor solar simulator testing method, its impact is actually much greater compared to products tested under outdoor conditions, where the maximum SPF values observed for SPF 60 to 100 sunscreens are in the range of 8 to 10. For example, see Hughes SNG, Lowe NJ, Gross K, Mark L, Goffe B, Hughes H, and Cole C., Evaluating the natural sunlight protection provided by 10 high-SPF broad-spectrum sunscreens and sun-protective fabrics, Curr Probl Dermatol, 2021; 55, DOI: 10.1159 / 000517666. Thus, an increase of 2 to 6 SPF units above the maximum value of 8 to 10 observed under outdoor use conditions represents a significant improvement in actual protection.

[0108] Although the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein.

[0109] Although the present teachings have been illustrated with respect to one or more embodiments, changes and / or modifications may be made to the illustrated embodiments without departing from the spirit and scope of the appended claims. Additionally, although a particular feature of the present teachings may be disclosed with respect to only one of several embodiments, the feature may be combined with one or more other features of the other embodiments, which may be desirable and advantageous for any given or particular function. Further, with respect to the terms "including", "includes", "having", "with", or variants thereof used in the detailed description and claims, these terms are intended to be inclusive in a manner similar to the term "comprising". Additionally, in the discussion and claims herein, the term "about" means that the listed values may vary slightly, provided that such variation does not cause the method or structure to be inconsistent with the illustrated embodiments. Finally, "exemplary" means that the description is used as an example and does not imply that it is ideal.

[0110] It should be understood that the above-disclosed variations and other features and functions, or their alternatives, can be combined into many other different systems or applications. Those skilled in the art can subsequently make various substitutions, modifications, variations, or improvements that are currently unforeseen or unexpected, and these should also be included in the following claims.

[0111] Example

[0112] Example 1

[0113] Five anhydrous sunscreen stick compositions (0322A, 0211A, 0211B, 0211D, and 0314A) and one cream formulation (137-1216A) were prepared for evaluation, and their formulations are shown in Table 1 below.

[0114] Table 1 - Sunscreen Formulations

[0115]

[0116] All formulations listed in Table 1 above also contain C12-15 alkyl benzoate, beeswax, butyl octyl salicylate, carnauba wax, aluminum hydroxide or alumina, tocopheryl acetate, and triethoxysilyloctane. Control formulation #0322 and formulations 0211A, 0211B, 0211D, and 0314A are all anhydrous stick matrix compositions and also contain isocetane, caprylic / capric triglyceride, shea butter, trityl PVP, and stearic acid. Formulation 137-1216A is a cream matrix formulation and additionally contains cyclopentasiloxane, ethylhexyl methoxycinnamate, trimethylsiloxysilicate, PEG-10 dimethicone, silica cetyldimethicone, dimethicone lithium magnesium silicate, tetrahexyldecyl ascorbate, C10-30 cholesterol / lanosterol esters, propylene carbonate, hydrogenated poly(dimethylsiloxane), phenoxyethanol, and fragrance.

[0117] Sunscreen stick and sunscreen formulations containing inorganic sunscreen filters and visible light blocking additives were evaluated to understand their ability to protect against ultraviolet and visible light radiation.

[0118] In vitro ultraviolet and visible spectrophotometric evaluation in the range of 290 nm to 800 nm: The UV and visible light absorption spectra of the sunscreen formulations in Table 1 were evaluated in vitro using conventional thin film spectrophotometry, similar to the critical wavelength test of the US Food and Drug Administration (FDA) (FDA Sunscreen Monograph: Labeling and Effectiveness Testing: Over-the-Counter Sunscreen Drug Products for Human Use, US Federal Register 2011, 76:117, 35661-35665), and the ISO 24442 in vitro UVA protection standard (ISO 24442 In Vitro Determination of UVA Protection of Sunscreens, 2021).

[0119] The Helioscreen HD6 polymethyl methacrylate (PMMA) plate was weighed alone and tared, coated with the test sunscreen composition, and wiped with a finger to form a uniform film with a total weight per unit area of 0.7 mg / cm 1 . Two sunscreen-treated plates were prepared. Three blank PMMA plates were prepared and coated with glycerol as controls.

[0120] Using a 756 spectroradiometer with a 6-inch integrating sphere inlet, spectral scans were performed on the blank PMMA control plates and each sunscreen-treated plate. The illumination source was a Light LS1000 solar simulator with a 9-inch diameter beam. The irradiance of the solar simulator was measured in the range of 290 nm to 800 nm. First, the glycerol-treated control PMMA plate was placed on the input port of the spectroradiometer sphere integrator inlet for measurement. Next, each sunscreen-treated plate was measured in the same manner and position.

[0121] The absorbance of the sunscreen composition was calculated using the following formula: A = -log(I SS处理 / I 空白 ), where A is the absorbance, I SS处理 is the irradiance of the solar simulator with the sunscreen-treated plate at the inlet, and I 空白 is the irradiance of the solar simulator with the glycerol-treated control plate at the inlet.

[0122] Hybrid diffuse reflectance spectroscopy (HDRS): Although the above spectrophotometric measurements are suitable for determining the relative spectral shape or quality, the absolute amplitude of the absorbance curve may be affected by the uniformity of the formulation's spread on the PMMA plate and the ability of the sunscreen to form a uniform and continuous film on the plate surface. Therefore, these measurement results may not accurately estimate the absolute amplitude of the recorded absorbance curve. This is also why in vitro film spectroscopy is generally not approved for evaluating sunscreen efficacy, and relative shape measurements, such as critical wavelength, can be used instead for labeling.

[0123] HDRS fills this gap and provides a measurement of the absolute protection effect of the UVA part of the spectrum on human skin. By matching the UVA protection factor (UVA-PF) calculated from the in vitro spectrum with the UVA-PF value measured by HDRS, the in vitro data can be scaled to an appropriate amplitude using the HDRS measurement results of the same formulation on human skin.

[0124] In this example, a sunlight multi-color HDRS device was used to perform HDRS measurements on the UVA-PF values of the test formulations described in Table 1. The device emits UVA light onto the skin, which then scatters within the epidermis and dermis. A portion of the light is re-emitted from the skin and captured by the bundled optical fibers on the device and measured using a photomultiplier tube. In the example described herein, this was first done without any sunscreen on the skin and then again after applying the sunscreen and allowing it to dry for 15 minutes. The UVA-PF of the sunscreen formulation was calculated according to Equation 1 below:

[0125]

[0126] where I 无防晒 is the intensity of the reflected light without any sunscreen applied to the skin, and I 防晒 is the intensity of the reflected light when the sunscreen is applied to the skin. The square root function is used because the measured light intensity passes through the sunscreen film twice.

[0127] The UVA-PF of each formulation measured by HDRS was calculated, as well as the UVA-PF of the in vitro spectrum as described above. The in vitro spectrum absorbance (290 nm to 800 nm) was multiplied by a single numerical factor “s” to scale the in vitro spectrum to obtain the same UVA-PF value as the UVA-PF value determined by HDRS. The results are shown in Figure 1 where control sunscreen 0332A (containing titanium dioxide and 2.75% iron oxide, but no barium sulfate, silica, bismuth oxychloride, or mica) had the lowest absorbance spectrum in the ultraviolet and visible light wavelength ranges. The rod formulation containing mica had the highest visible light blocking absorbance, comparable to that of a visible sunscreen containing 4.5% iron oxide. The rod formulation containing mica had the highest blocking absorbance for visible light with wavelengths above 525 nm, and its absorbance was even higher than that of the visible sunscreen.

[0128] The visible light protection factor (VL-PF) was calculated by determining the reciprocal of the average transmittance value within a given wavelength range. The following equation was used:

[0129]

[0130] Table 2 below shows the VL-PF calculated for six test formulations within the visible light spectra in the ranges of 400 - 500 nm, 400 - 600 nm, and 400 - 800 nm.

[0131] Table 2 - Visible Light Protection Coefficient

[0132]

[0133] This value can also be calculated as the percentage of visible light blocked by the sunscreen, using the following equation: The results are shown in Table 3 below.

[0134] Table 3 - Visible Light Blocking Percentage

[0135]

[0136] As shown in Tables 2 and 3 above, compared with the other inorganic pigments tested (i.e., barium sulfate, silica, and bismuth oxychloride), the mica additive in the iron oxide-containing formulations provided the highest visible light blocking ability, and the mica-containing formulations were nearly as high and comparable to visible sunscreens, while the iron oxide content in visible sunscreens was almost twice that of theirs. When considering the entire visible light range of 400 - 800 nm, the mica-containing formulations had the highest protection factor and visible light blocking percentage among all the tested formulations, and barium sulfate ranked second. The bismuth oxychloride formulation containing 4.4% mica and 3.9% bismuth oxychloride had worse performance than any of the tested formulations and was similar to the control formulation without visible light blocking additives. Therefore, without being bound by theory, there may be some incompatibility between the mixture of mica and bismuth oxychloride.

[0137] HDRS SPF, UVA-PF, CW, and UVA1 / UV calculations: To understand the spectral shape of the sunscreen composition across the entire ultraviolet spectrum, combined with the HDRS measurement of UVA-PF, similar mixing calculations can be performed to estimate the SPF, UVA-PF, critical wavelength, and UVA1 / UV ratio of the composition. Using the calculation method described in the European Cosmetics Association HDRS test method (European Cosmetics Association Recommendation No. 26 on the use of ISO14444 alternative method: According to the Annex II HDRS method protocol, March 23, 2022), the following SPF, UVA-PF, critical wavelength, and UVA1 / UV ratio were calculated for each formulation and are shown in Table 4 below.

[0138] Table 4 - SPF, UVA-PF, Critical Wavelength, and UVA1 / UV Ratio

[0139]

[0140] The values are statistically greater than the 0322A control formulation (p < 0.05).

[0141] ** Compared with the 0322A control formulation, the p-value > 0.05 but < 0.1.

[0142] As shown in Table 4 above, compared with the 0322A control formulation, the barium sulfate additive produced significantly higher SPF and UVA-PF values, while the silica additive had a trend value of p > 0.05 but < 0.1. Mica had the highest SPF value but the lowest UVA-PF value, and relatively low medium UVA absorbance. The mica additive did exhibit longer UVA wavelength absorbance (380 - 390 nm), producing a critical wavelength value similar to all other tested formulations, as well as excellent visible light protection.

[0143] Compared with the 0322A control, both the barium sulfate and silica additives increased the SPF and UVA-PF values, while the bismuth oxychloride / mica formulation had a similar SPF and statistically higher UVA-PF. The visible sunscreen had the highest UVA-PF value, which may be due to the presence of 10% zinc oxide. The SPF measured by HDRS was consistent with the actual static SPF of the visible sunscreen, which had an SPF of 60 in in vivo testing.

[0144] From these experiments, it can be concluded that adding mica to the titanium dioxide and iron oxide formulations maximizes the SPF and visible light protection, but not the UVA-PF. Barium sulfate and silica also significantly enhanced the SPF, UVA-PF, and visible light protection. However, the combination of mica and bismuth oxychloride did not have an additive effect and only slightly improved the UVA protection without a significant increase in visible light protection.

[0145] Example 2

[0146] An anhydrous sunscreen stick formulation containing inorganic sunscreen filters and visible light protectants was evaluated for its ability to protect against UV and visible light radiation. This experiment also aimed to evaluate the ability of barium sulfate and mica, alone and in combination, to increase visible light protection.

[0147] The test materials included 12 inorganic stick formulations and one organic sunscreen formulation. The 13 formulations are shown in Table 5 below.

[0148] Table 5 - Test Sunscreen Formulations

[0149]

[0150]

[0151] All formulations listed in Table 5, except #11 (0923A), were anhydrous stick compositions and also contained C12-15 alkyl benzoate, beeswax, butyl octyl salicylate, carnauba wax, aluminum hydroxide, tocopheryl acetate, triethoxysilane octane, isocetane, caprylic / capric triglyceride, shea butter, tricontanyl PVP, and stearic acid.

[0152] In vitro ultraviolet and visible spectrophotometric evaluation and HDRS in the range of 290 nm to 800 nm: According to the method proposed in Example 1 above, the ultraviolet and visible light absorption spectra of the sunscreen formulations listed in Table 5 above were evaluated in vitro using conventional thin-film spectrophotometry. According to the method in Example 1 above, the UVA-PF of the sunscreen formulations was measured by HDRS using a sunlight multi-color HDRS device, and the UVA-PF of each formulation measured by HDRS and the UVA-PF of the in vitro spectrum were calculated. The in vitro spectral absorbance values (290 nm to 800 nm) were multiplied by a single numerical factor "s" to scale the in vitro spectrum to obtain the same UVA-PF as determined by HDRS, and the results are as Figures 2 - 4 shown.

[0153] Figure 2 shows the complete absorption spectra of Formulations #1-4 described in Table 5. Control Formulation #1 has a higher titanium dioxide content and does not contain zinc oxide or other additives; Formulations #2-4 contain a lower amount of titanium dioxide but contain 11% zinc oxide, where #2 contains 7.5% barium sulfate and no mica, #3 contains 7% mica and no barium sulfate, and #4 contains 3.5% barium sulfate and 3.5% mica. As Figure 2 shown, Formulations #2 and #4 have a higher visible light blocking level in the 400-500 nm visible light range than Formulation #1. Although the formulation with mica alone (#3) does not significantly increase the visible light protection effect, when combined with 3.5% barium sulfate (Formulation #4), its protection effect is similar to that provided by Formulation #2 containing 7.5% barium sulfate.

[0154] Figure 3 shows the complete absorption spectra of Formulations #5-7 described in Table 5. As shown, a synergistic effect was observed when barium sulfate and mica were added as visible light blocking additives in Formulation #7. In addition, an improvement in ultraviolet absorption can be seen in the visible light range, for example, between 400-550 nm for this formulation. It can be seen that the combination of barium sulfate and mica has a synergistic protective effect, where 5% of each additive alone has a similar visible light protection effect, while the combination of 2.5% barium sulfate and mica has a greater protective effect than either one alone.

[0155] Figure 4 shows the complete absorption spectra of Formulations #7-11, illustrating the dose-response of the protection provided by iron oxide in decreasing amounts of 4.75% (#10), 2.75% (#7), 2.0% (#8), 1% (#9), 0.5% (#9a), and 0% (#9b). The visible light protection was enhanced by increasing the iron oxide content, compared to a sunscreen formulation (#11) containing only organic ultraviolet filters that lacked visible light protection. Figure 4It shows that one factor for visible light protection is the iron oxide concentration.

[0156] The percentage of visible light blocked by VL-PFS and the sunscreen formulations was calculated using the formula described in Example 1 and is shown in Tables 6 and 7 below, respectively.

[0157] Table 6 - Visible Light Protection Factor

[0158]

[0159] Table 7 - Percentage of Visible Light Blocked

[0160]

[0161] Figure 5 It is a graph of the dependence of VL-PF [blue light protection factor (400 - 500 nm)] on the iron oxide concentration in the formulation. Among Figure 5 them, the first five data points (from left to right) represent Formulations #9b, 9a, 9, 8, and 7, all of which contain 2.5% barium sulfate and 2.5% mica, but the iron oxide content decreases continuously. As the iron oxide content in the formulation increases, the blue light protection effect also increases. The rightmost / top data point represents the regression based on the first 5 data points and the predicted protection factor of the formulation containing 4.75% iron oxide, 2.5% barium sulfate, and 2.5% mica. The data point below the predicted protection factor data point is the data point of Formulation #10, which contains 4.75% iron oxide but no barium sulfate or mica. The difference between the predicted data point and Formulation #10 is the estimated additional protection provided by the barium sulfate / mica combination, equivalent to an additional protection factor of approximately 0.4 protection factor units. The evaluation of visible light protection shows that the main protection element in the formulation is iron oxide, where when the iron oxide concentration changes from 4.75% to 0%, the blue light protection factor drops from 77% to 35%.

[0162] Figure 6Further illustrates that the synergistic combination of barium sulfate and mica provides better blue light protection in sunscreen formulations. Formulations #2, 3, and 4 show that when using barium sulfate and mica simultaneously (#4, 3.17 at 400 - 500 nm), the blue light protection effect is slightly enhanced compared to using barium sulfate alone (#2, 3.15 at 400 - 500 nm), and is also slightly enhanced compared to using mica alone (#3, 2.36 at 400 - 500 nm). Notably, Formulations #5, #6, and #7 show that when using barium sulfate and mica simultaneously (#7, 3.65 at 400 - 500 nm), the blue light protection effect is synergistically enhanced compared to using barium sulfate alone (#5, 2.35 at 400 - 500 nm) or mica alone (#6, 2.46 at 400 - 500 nm). This synergistically enhanced protection effect was observed across the entire visible spectrum from 400 - 800 nm.

[0163] Mixed calculations were performed as described in Example 1 above to estimate the SPF, UVA - PF, critical wavelength, and UVA1 / UV ratio for each of the tested formulations. Using the calculation methods described in the Cosmetics Europe HDRS test method, the results shown in Table 8 below were calculated:

[0164] Table 8 - Estimated SPF, UVA - PF, CW, UVA1 / UV, and VL - PF values for formulations

[0165]

[0166] Notably, the calculated SPF and UVA - PF values for Formulation #11 may be overstated as they do not include the impact of photo - stability on the expected SPF results. As shown in Table 8 and Figure 7 shown, in addition to the other calculated protection factor values, the critical wavelength depends on the iron oxide content, where an increase in the iron oxide content leads to an increase in the critical wavelength.

[0167] Example 3

[0168] The ultraviolet and visible light blocking properties of the individual ingredients used in stick and cream sunscreen formulations were evaluated. As shown in Table 9 below, 12 formulations containing individual ingredient sunscreen actives were prepared.

[0169] Table 9 – Formulations of individual sunscreen active ingredients

[0170]

[0171] In vitro ultraviolet and visible spectrophotometric evaluation - 290 - 800 nm:

[0172] The ultraviolet and visible light absorption spectra of 12 test sunscreen preparations were evaluated in vitro using traditional thin-film spectrophotometry, similar to the FDA critical wavelength test (FDA Sunscreen Monograph: Labeling and Effectiveness Testing: Over-the-Counter Sunscreen Drug Products for Human Use, Federal Register 2011, 76:117, 35661 - 35665), and the ISO 24443 in vitro UVA protection standard (ISO 24442 Determination of UVA Protection of Sunscreens in Vitro, 2021). Helioscreen HD6 polymethyl methacrylate (PMMA) plates were weighed individually and tared, coated with the test product, and wiped with a finger to form a uniform film with a total weight per unit area of 1.2 mg / cm 1 . Three blank control PMMA plates were prepared and coated with glycerol. Using a 756 spectral radiometer with a 6” integrating sphere inlet, spectral scans were performed on the control PMMA plates and each sunscreen-treated plate. Absorbance values from 290 - 450 nm were scanned using a Labsphere spectrophotometer. First, the baseline was measured from 290 - 800 nm for the glycerol-treated control PMMA plate using the Labsphere spectrophotometer, and then each PMMA plate coated with sunscreen was scanned at 9 positions. Absorbance over the entire upper ultraviolet and visible spectra was also measured using the OL756 spectral radiometer. First, the tungsten lamp output passing through the glycerol-treated plate (baseline) was measured, and then the tungsten lamp output passing through the sunscreen-treated plate was measured. Absorbance was calculated using the following equation: A = -log(I SS处理 / I 空白) , where I SS处理 is the irradiance of the tungsten lamp with the sunscreen-treated PMMA plate at the inlet, and I 空白 is the irradiance of the solar simulator with the glycerol-treated PMMA plate at the inlet. The spectra of the two absorbance devices were overlapped and standardized within the common wavelength region to provide continuous absorbance values in the range of 290 - 700 nm. The noise “ripples” in the scans were eliminated using an exponential smoothing function.

[0173] Hybrid Diffuse Reflectance Spectroscopy (HDRS) – HDRS measurements of the UVA-PF of the test product were performed using a sunlight multi-color HDRS device, and the UVA-PF was calculated using Formula 1 presented in Example 1 above. The in vitro spectral absorbance values (from 290 nm to 800 nm) were multiplied by a single numerical factor “s” to scale the in vitro spectrum, resulting in the same UVA-PF as determined by HDRS, thus providing an absolute absorbance spectrum. Figure 8 The absorbance performance of mica and barium sulfate additives is shown. Notably, in Figure 8 , when subtracting the 4.4% TiO 2 spectrum from the mica + 4.4% TiO 2When measuring absorbance, the absorbance of the mica itself obtained is almost zero throughout the spectrum. 5% barium sulfate has a very low absorbance value, and the average absorbance of the entire spectrum is approximately 0.1 AU. These data indicate that the highest contribution of BaS is 0.1 AU, while the contribution of mica is zero throughout the spectrum. However, when used in combination in the complete formulation (e.g., formulation #7 in Example 1 above), at a 5% concentration, the visible light protection effect is better than that of any one of them used alone. Although not wishing to be bound by theory, the explanation may lie in the physical interaction of BaS and Mica+TiO 2 with nano-TiO 2 and ZnO, thus better separating the aggregates and more completely covering the particles on the skin.

[0174] Example 4 - Natural sunlight SPF testing of 4 sunscreens in Arequipa, Peru

[0175] Under natural sunlight at tropical noon, the sun protection factor of four different sunscreen formulations was tested. The method used in the test was similar to the FDA sunscreen final rule, except that natural sunlight was used instead of a solar simulator.

[0176] Subjects: 10 subjects with Fitzpatrick skin types I (2 subjects), II (6 subjects), and III (2 subjects) participated in this study; none of the subjects were pregnant, had a history of skin cancer, or were disqualified for other reasons.

[0177] Sunlight exposure and conditions: On a cloudless day in Arequipa, Peru (16° south latitude, 7800 feet above sea level), the subjects were exposed to 3942 + / - 5 J / m 2 erythema effective energy (17.8 times the minimum erythema dose (MED) or 37.6 SED for type II individuals) and 60.3 + / - 1 J / cm 2 of UVA under outdoor natural sunlight, centered on solar noon, with a full sky exposure of 170 minutes. The temperature and humidity during the test were in the range of 70° to 71°, and the dew point was 17° - 37° (low humidity), close to clinical laboratory conditions. The solar altitude angle during the exposure ranged from 75° to 87.6°.

[0178] Test products: The formulations of four stick products contained 12.5% titanium dioxide and 10.8% zinc oxide as the main sunscreen active ingredients respectively. The formulations also contained different concentrations of iron oxide, ranging from 0 (control) to 4% (dark color), as shown in Table 10 below.

[0179] Table 10 - Concentrations of ingredients in the test reagents (% w / w)

[0180]

[0181] Heat the stick to a liquid form and aspirate a volume with a pipette to achieve the application density of the product on the skin, and let it dry for at least 15 minutes. Paste the aluminum laminated template onto the back of each subject, and paste the control and test sunscreens onto the determined circular exposed positions. Cover the rest of the back, legs, arms, and head with sun-protective clothing and hats. Each group of subjects is exposed to sunlight simultaneously. 2 Subjects are exposed to midday sunlight for up to 170 minutes centered around noon. They are asked to lie as still as possible with their backs to the sun. According to the pre-arranged sun exposure dose (erythema-weighted UVB dose), cover the test sites with aluminum foil tape. Measure the sun's sunburn UV intensity and UVA intensity every minute, and calculate the integrated dose during the exposure using a sunlight model PMA2100 radiometer equipped with a PMA2101 erythema sensor and a PMA2110 UVA sensor. Within the first 45 minutes, cover the control unprotected sub-sites at a preset interval of 25% to determine the minimum erythema and minimum pigment darkening doses for the unprotected areas. Also cover the exposed sub-sites of the sunscreen-treated areas at a predetermined dose to estimate the minimum erythema and minimum pigment darkening doses for the protected areas.

[0182] Subjects are exposed to midday sunlight for up to 170 minutes centered around noon. They are asked to lie as still as possible with their backs to the sun. According to the pre-arranged sun exposure dose (erythema-weighted UVB dose), cover the test sites with aluminum foil tape. Measure the sun's sunburn UV intensity and UVA intensity every minute, and calculate the integrated dose during the exposure using a sunlight model PMA2100 radiometer equipped with a PMA2101 erythema sensor and a PMA2110 UVA sensor. Within the first 45 minutes, cover the control unprotected sub-sites at a preset interval of 25% to determine the minimum erythema and minimum pigment darkening doses for the unprotected areas. Also cover the exposed sub-sites of the sunscreen-treated areas at a predetermined dose to estimate the minimum erythema and minimum pigment darkening doses for the protected areas.

[0183] Grading: Trained and impartial graders perform a blind test on the treatment locations (except for the unprotected MED). On the morning of the next day, 16 - 24 hours after sun exposure, the unprotected and protected skin sites are evaluated for erythema and PPD sun reactions. The erythema reaction and the persistent pigmentation reaction are graded separately. To distinguish between the two reactions, if both reactions are present, apply a slight pressure to the test sub-site. If no difference is seen in the sub-site, then the reaction is only a persistent pigment reaction. If blanching is also observed, score the erythema. If only erythema is seen, the persistent pigmentation score is 0.

[0184] The erythema grading criteria are as follows:

[0185] 0 = No obvious erythema or PPD

[0186] 0.5 = Erythema or PPD with ill-defined borders

[0187] 1 = Definite erythema or PPD with clear borders (MEDu or PPD - Pfu)

[0188] 2 = Severe and obvious erythema or PPD

[0189] 3 = Severe erythema or PPD with edema

[0190] Grade and photograph the protected and unprotected skin areas between 16 and 24 hours of sunlight exposure. Eight unprotected skin areas can be seen on a vertical line on the left side of each subject's back. Four sunscreen test areas (30 cm 2 ) are located to the right or directly below the unprotected areas. When the predetermined cumulative erythema-weighted UV dose is reached using a calibrated radiometer, six sunscreen sub-areas are gradually covered from the lower left to the lower right and then from the upper left to the upper right as per the instructions of the principal investigator. The erythema response of each sunscreen area develops in the order of redness (erythema) according to the cumulative amount of sunlight exposure. The grading results are shown in Table 11 below.

[0191] Table 11 - Erythema grades recorded for 10 test subjects using 4 sunscreen test products

[0192]

[0193] Although all formulations were not statistically different, the light, medium, and dark formulations were statistically different from the control (p < 0.05). Surprisingly, the median of the medium shade, which also contains mica and barium sulfate as well as 2.75% iron oxide, was higher than that of the dark product with a higher iron oxide content of 4.00%.

[0194] The SPF value is calculated by dividing the MED of each subject without sunscreen protection by the MED with sunscreen protection. For subjects who did not show an erythema response at the highest dose, the lowest SPF value was calculated using the highest protective MED value. Due to the lack of available area on the subjects' backs, the SPF of the control formulation was not determined; as mentioned above, only the highest exposure dose was evaluated. The results are shown in Table 12 below.

[0195] Table 12 - Minimum derived SPF values and minimum derived PPD - PF values for 10 subjects

[0196]

[0197] Although the SPF values may seem low compared to products currently on the market, this difference may be attributed to the light source used to test commercial products. Commercial products are tested using a simulated solar source that does not contain long - wave UVA1 and is completely free of visible light. Previous tests have shown that the FDA and ISO reference standard P2 sunscreen (SPF of 16.3 in a simulated sunlight clinical test) has an SPF of only 4.5 in natural sunlight.

[0198] Similarly, the ISO reference standard for sun protection P8.5 (SPF 63 in simulated sunlight clinical tests) was only SPF 8 in natural sunlight under conditions similar to those reported in this example. Therefore, it is unusual and remarkable to achieve a sun protection factor of above SPF 10 in natural sunlight. This difference is due to the contribution of erythema to the erythema response from long-wave UVA and the visible light part of natural sunlight, and these parts are not protected by filters that only block UV.

[0199] Similar to the erythema protection of SPF, the pigment darkening protection factor (PPD-PF) can provide a similar protection value against skin pigment darkening (tanning). PPD-PF is the ratio of the minimum dose required to cause an obvious pigment darkening reaction in unprotected skin after 24 hours of exposure to the minimum dose that causes an obvious pigment darkening reaction in sun-protected skin at the same time point. This is similar to the UVA-PF that is clinically tested only using UVA radiation, but in this case, the entire solar spectrum is utilized, including UVB, UVA, and visible light (and infrared) radiation.

[0200] The PPD-PF of the test subjects was calculated, and the results are shown in Table 12 above. Statistical analysis using the Student's T-test showed that there was no significant difference between the dark and medium formulations (p = 0.17); however, there were statistical differences between the medium and light formulations and between the dark and light formulations (p < 0.015 and p < 0.01, respectively).

[0201] Demonstrate the visible light protection effect of the test formulations: To demonstrate that the difference in protection effect can be attributed to the visible part of natural sunlight, additional subjects were tested, in which a CGA 400 long-pass filter was placed on the sun-protected area to block all ultraviolet radiation below 400 nm, allowing only visible light and infrared light to illuminate the sun-protected skin. Therefore, any distinguishable difference in protection of the test formulations can be attributed to the difference in visible light protection. The medium formulation and the control formulation were selected to prove this.

[0202] The medium formulation and the control formulation were applied to two independent but adjacent areas (diagonally) of the skin. In each subject, the results showed that the area treated with the control formulation had a stronger and more obvious reaction than the area treated with the medium formulation.

[0203] Example 5 - Evaluate the visibility of sun protection on the skin

[0204] The purpose of the evaluation was to assess the skin visibility of sunscreens using instrumental evaluation. The results showed that sunscreens containing a combination of mica and barium sulfate had lower skin visibility at an iron oxide content of 2.75% compared to sunscreens containing only 4.5% iron oxide without mica and barium sulfate; nonetheless, both compositions provided similar visible light protection.

[0205] The test sites on human skin included the dorsal side of the forearm (darkest), the volar side of the forearm, and the upper thigh (lightest). Using a Chromameter CR-400A skin reflectance spectrometer, measurements were taken in the L a*b color space for three different background color sites before and after applying the sunscreen. The sunscreen was applied to the test skin sites at a control application density of 2 mg / cm 2 and the change in visibility was calculated using the ΔE formula, where

[0206]

[0207] where ΔE is the CIE definition of the difference between two color measurements (i.e., the color difference before and after applying the sunscreen). ΔL is the difference in the L color space coordinate (black-white axis); Δa is the difference in the a* space coordinate (red-green axis); and Δb is the difference in the b* space coordinate (blue-yellow axis).

[0208] The following five formulations were evaluated as shown in Table 13 below.

[0209] Table 13 - Formulations for Skin Visibility Test

[0210]

[0211] Photos of the test sites clearly showed that formulation #2 was closest to the background skin of the test subjects and had the lowest calculated visibility after applying the sunscreen. The ΔE values were calculated for each of the five formulations. The lower the calculated ΔE value compared to untreated skin, the smaller the change in visibility after applying the sunscreen. At the three test sites, each formulation was statistically different from the other formulations (p < 0.05). Table 14 below shows the respective ΔE values for the three test sites.

[0212] Table 14 - Mean Values for Skin Visibility Test (n = 3)

[0213] Formulation #1 #2 #3 #4 #5 Dorsum of the forearm 13.645 3.5334 2.5872 5.2080 7.6801 Volar aspect of the forearm 7.4858 2.6528 6.6611 9.7941 11.5335 Upper thigh 12.0237 5.1198 9.6516 13.6768 14.3893 Average 11.0518 3.7684 6.3000 9.5600 11.2010

[0214] The results showed that the addition of mica and barium sulfate to 2.75% iron oxide (Formulation #4) did increase visibility compared to a formulation with the same iron oxide content but without mica and barium sulfate (Formulation #3). Nevertheless, Formulation #4 had lower visibility compared to Formulation #5 but still provided sun protection equivalent to Formulation #5, as demonstrated in the above examples, including in outdoor sun protection tests.

Claims

1. A method of reducing or preventing sunburn in a subject due to visible light and ultraviolet (UV) radiation, which comprises topically applying to the subject a sunscreen composition comprising: (a) at least one inorganic UV filter selected from zinc oxide or titanium dioxide; (b) at least one inorganic pigment selected from iron oxides; and (c) at least two visible light protectants comprising barium sulfate and mica; wherein the at least two visible light protectants are present in an amount effective to reduce or prevent sunburn caused by visible light.

2. The method according to claim 1, wherein the sunscreen composition comprises zinc oxide and titanium dioxide.

3. The method according to claim 1, wherein the sunscreen composition is anhydrous.

4. The method according to claim 1, wherein at least one of the at least two visible light protectants further comprises a silica coating.

5. The method according to claim 1, wherein the iron oxide is selected from the group consisting of black iron oxide, brown iron oxide, red iron oxide, yellow iron oxide, and mixtures thereof.

6. The method according to claim 1, wherein, based on the total weight of the sunscreen composition, the iron oxide is present in the sunscreen composition in a total amount of about 0.1% to about 10% by weight.

7. The method according to claim 1, wherein, based on the total weight of the sunscreen composition, the iron oxide is present in the sunscreen composition in a total amount of about 1% to about 3% by weight.

8. The method according to claim 1, wherein, based on the total weight of the composition, barium sulfate is present in an amount of about 0.1% to about 5%.

9. The method according to claim 1, wherein, based on the total weight of the composition, barium sulfate is present in an amount of about 0.1% to about 3% by weight.

10. The method according to claim 1, wherein, based on the total weight of the composition, barium sulfate is present in an amount of about 5%.

11. The method according to claim 1, wherein, based on the total weight of the composition, barium sulfate is present in an amount of about 2.5%.

12. The method according to claim 1, wherein, based on the total weight of the composition, mica is present in an amount of about 0.1% to about 5%.

13. The method according to claim 1, wherein, based on the total weight of the composition, mica is present in an amount of about 0.1% to about 3%.

14. The method according to claim 1, wherein, based on the total weight of the composition, mica is present in an amount of about 5%.

15. The method according to claim 1, wherein, based on the total weight of the composition, mica is present in an amount of about 2.5%.

16. The method according to claim 1, wherein, based on the total weight of the composition, barium sulfate and mica are each present in an amount of about 5%.

17. The method according to claim 1, wherein, based on the total weight of the composition, barium sulfate and mica are each present in an amount of about 2.5%.

18. The method according to claim 1, wherein the at least one inorganic UV filter is titanium dioxide, and the average particle size of the titanium dioxide is from about 5 nm to about 20 nm.

19. The method according to claim 18, wherein the at least one inorganic UV filter further comprises zinc oxide, and the average particle size of the zinc oxide is from about 10 nm to about 100 nm.

20. The method according to claim 1, wherein the sunscreen composition does not contain organic UV filters.

21. A method of increasing the visible light protection factor (VL-PF) of a sunscreen composition, the sunscreen composition comprising at least one inorganic UV filter selected from zinc oxide or titanium dioxide; and at least one inorganic pigment selected from iron oxides; the method comprising adding to the sunscreen composition at least two visible light protectants, which comprise barium sulfate and mica, wherein the at least two visible light protectants are present in the sunscreen composition in an amount effective to increase the VL-PF over the electromagnetic wavelength spectrum from about 400 nm to about 800 nm.

22. The method according to claim 21, wherein the electromagnetic wavelength spectrum spans from about 400 nm to about 500 nm.

23. The method according to claim 21, wherein the visible light protection factor is increased by at least about 0.

5.

24. The method according to claim 21, wherein the sunscreen composition does not contain organic UV filters.

25. The method according to claim 21, wherein the sunscreen composition is anhydrous.

26. A sunscreen composition comprising: (a) at least one inorganic UV filter selected from zinc oxide or titanium dioxide; (b) at least one inorganic pigment selected from iron oxides; and (c) at least two visible light protectants, which comprise barium sulfate and mica; wherein the at least two visible light protectants are present in an amount effective to reduce or prevent sunburn caused by visible light.

27. The sunscreen composition according to claim 26, wherein the sunscreen composition is anhydrous.

28. The sunscreen composition according to claim 26, wherein the barium sulfate is present in an amount of from about 0.1% to about 5% based on the total weight of the composition.

29. The sunscreen composition according to claim 26, wherein the barium sulfate is present in an amount of about 2.5% based on the total weight of the composition.

30. The sunscreen composition according to claim 26, wherein the mica is present in an amount of from about 0.1% to about 5% based on the total weight of the composition.

31. The sunscreen composition according to claim 26, wherein the mica is present in an amount of about 2.5% based on the total weight of the composition.

32. The sunscreen composition according to claim 26, wherein the barium sulfate and the mica are each present in an amount of about 2.5% based on the total weight of the composition.

33. The sunscreen composition according to claim 26, wherein the sunscreen composition does not contain organic UV filters.

34. The sunscreen composition according to claim 26, further comprising at least one antioxidant.

35. The sunscreen composition according to claim 34, wherein the at least one antioxidant is selected from the group consisting of vitamin E or its derivatives and vitamin C or its derivatives.

36. The sunscreen composition according to claim 26, wherein (a) the at least one inorganic UV filter is zinc oxide present in an amount of about 10.8% and titanium dioxide present in an amount of about 12.5%; (b) at least one inorganic pigment selected from iron oxides, which is present in an amount of from about 1% to about 3%, such as about 2.75%; and (c) at least two visible light protectants, which include barium sulfate present in an amount of about 2.5% and mica present in an amount of about 2.5%; wherein all amounts are based on the total weight of the composition.

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