Method for determining a protection factor of a skin protectant

Abstract

The invention relates to a method for determining a protection factor of a skin protectant, said method comprising the steps of: emitting radiation from a radiation source (12) of a protection factor evaluation system (1), detecting remitted radiation by a detector unit (13) of a protection factor evaluation system (1), transferring the data on the remitted radiation to an analysis unit (2), and evaluating the protection factor in an evaluation wavelength range, wherein during the evaluation of the protection factor, a correction function is taken into consideration, the correction function describing skin-type-dependent differences.

Description

[0001] Method for determining a protection factor of a skin protectant

[0002] The invention relates to a method for determining a protection factor of a skin protection agent with the method steps of emitting radiation from a radiation source of a protection factor evaluation system, detecting remitted radiation from a detector unit of a protection factor evaluation system, transmitting data of the remitted radiation to an evaluation unit and evaluating the protection factor in an evaluation wavelength range, wherein a correction function is taken into account in the evaluation of the protection factor, wherein the correction function describes skin type-dependent differences.

[0003] State of the art

[0004] The methods currently approved by the European Union (EU) and the U.S. Food and Drug Administration (FDA) for determining SPF (Sun Protect Factor) are all harmful to the test subjects by causing erythema, a light-induced inflammatory reaction of the skin (COLI PA -15 European Cosmetic, Toiletry and Perfumery Association: Colipa SPF Test Method 94 / 289, 1994; ISO Standards 24442, 24443, 24444). Therefore, both the FDA and the EU have repeatedly pointed out that future research activities must focus on new methods for characterizing the protective efficacy of sunscreen products to avoid long-term effects for the test subjects (European Commission, 20 Standardization Mandate Assigned To CEN Concerning Methods For Testing Efficacy Of Sunscreen Products, M / 389 EN, Brussels, 12 July 2006).

[0005] This invention is intended to accomplish this task. Existing methods are defined in various sources:

[0006] Procedures defined in standards and regulations: a. ISO 24444 defines a method for the in vivo determination of SPF. The method is based on the induction of erythema on the skin of volunteers by radiation in the UVB range. Therefore, the method is harmful to the volunteer. b. ISO 24443 defines an in vitro method for the determination of the UVA protection factor (IIVAPF). The sunscreen is applied to a plastic plate so that a transmission spectrum of the sunscreen can be measured. Due to uncontrollable fluctuations in the procedure, the transmission spectrum is adjusted to the result of the erythema test according to ISO 24444 by scaling and is therefore dependent on the way it is carried out. The plastic plate used has a roughened surface and is an unrealistic skin model. c.ISO 24442 defines an in vivo method in which the UVA protection factor is determined using the minimum UVA dose required to produce irreversible pigmentation (suntan) of the skin. This method also requires a change in the subject's skin.

[0007] Patented processes:

[0008] DE 198 28 497 A1 describes a method in which, as in ISO 24444, erythema is induced in test subjects through UV irradiation of the skin. Unlike ISO 24444, these erythemas are detected using reflectance spectroscopy. This method is therefore also harmful. The optical effect (protection) of the sunscreen is not determined by direct optical measurements, but rather by a biological reaction of the body.

[0009] DE 10 2004 020 644 A1 describes a method in which the generation of radicals by UV exposure is quantitatively measured in vivo using electron paramagnetic resonance (ESR). Here, too, the optical effect of the sunscreen is only indirectly measured. Furthermore, measuring ESR is technically complex and requires relatively large, stationary devices (tabletop devices). They are also sensitive to interference from high-frequency radiation or rapid, temporary magnetic field changes, such as those caused by electrical switching processes.

[0010] To determine the label SPF of topically applied sunscreens in vivo, test methods such as ISO 24444, the FDA Guideline, or the Australian Standard are used worldwide. All of these methods are based on inducing an erythemal skin reaction by irradiating the skin with UV light. This is necessary to determine the minimum erythemal dose of untreated (MEDu) and product-treated skin (MEDp). Reliable in vitro methods, in which human skin is replaced by synthetic substrates, are not available for SPF determination.

[0011] Monochromatic devices are known, which use conventional xenon lamps and are therefore expensive to purchase and operate. Built-in monochromators measure different wavelengths one after the other, which is disadvantageous when the subjects are moving. Polychromatic devices also use xenon lamps. The in vivo measured value is weighted using a filter so that it matches the in vivo UVA PF. Multi-LED devices for testing institutes represent another option, but these are significantly larger and more expensive due to the spectroscopic detection.

[0012] It is therefore an object of the invention to provide a method for determining a protection factor of a skin protection agent which provides high-quality analysis results and at the same time can be carried out quickly and easily.

[0013] The object is also achieved by means of the method according to the invention for determining a protection factor of a skin protection agent. Advantageous embodiments of the invention are set forth in the subclaims.

[0014] The method according to the invention for determining a protection factor of a skin protection product comprises four steps: In the first step, radiation is emitted from a radiation source of a protection factor evaluation system. The radiation source generates electromagnetic radiation with an irradiation wavelength between the blue spectral range (approximately 400 nm to 500 nm wavelength) and the UV range (280 nm to 400 nm).

[0015] The wavelength ranges are defined as follows:

[0016] - < 320 nm (UVB) with < 0.1% of the total UV intensity,

[0017] - 320 nm to 340 nm (UVA II) 8% to 20% of the total UVA intensity

[0018] - 340 nm to 400 nm (UVA I) 80% to 92% of the total UVA intensity

[0019] - 400 nm to 500 nm, blue light

[0020] For the purposes of this document, a radiation source is a technical device for generating electromagnetic radiation. A radiation source is therefore not an optical element for guiding, redirecting, or modifying the intensity and / or wavelength of electromagnetic radiation. A radiation source is therefore not, for example, a light guide, grating, prism, or filter.

[0021] In the second method step, remitted radiation is detected by a detector unit of a protection factor evaluation system. The ratio of the intensities of the remitted radiation to the radiation coupled into the measuring body is a measure of the protective capability of the protective device. The detection wavelength, like the irradiation wavelength, preferably covers a wavelength range, with the wavelength range of the detection wavelength preferably lying within the range of the irradiation wavelength or encompassing the entire range of the irradiation wavelength.

[0022] In the third step, data from the remitted radiation is transferred to an evaluation unit. The evaluation unit, for example, is a computer with a suitable computer program.

[0023] In the fourth method step, the protection factor is evaluated in an evaluation wavelength range. The evaluation wavelength is the wavelength for which the protection factor is determined. The evaluation wavelength is different from the wavelength range of the irradiation wavelength and / or the detection wavelength. The evaluation wavelength, like the irradiation wavelength and the detection wavelength, is preferably a wavelength range, wherein the wavelength range of the evaluation wavelength comprises at least the wavelength range of the irradiation wavelength and / or the detection wavelength.

[0024] The protection factor (SPF) is a scientific measure that indicates how much lower the risk of skin damage is due to the use of a protectant. This factor focuses on the time it takes for UVB rays to penetrate a protectant and cause the skin to redden (minimal erythema, MED) compared to the time it takes to do so in the absence of a protectant. The dose of solar radiation required to cause skin reddening is divided by the dose required to cause reddening without a protectant. This calculation is based on the application of 2 milligrams of protectant per square centimeter of skin surface. Currently, the SPF of protectants is determined via in vivo irradiation using a sun simulator (ISO 24444:2010 "Cosmetics - Sun protection test methods - In vivo determination of the sun protection factor (SPF)"), which represents the current state of the art.The basis for current testing of protective agents is that subjects are irradiated before and after the application of protective agents.

[0025] According to the invention, a correction function is taken into account when evaluating the protection factor, whereby the correction function describes skin-type-dependent differences. This allows for a more precise determination of the protective ability of a protective agent, and the determined protective ability is comparable for different skin types.

[0026] In a further development of the invention, the correction function provides a corrected value SF korr or UVA-SF korr In a further embodiment of the invention, the correction function is F (SF) = SF_ korr or F (UVA-SF) = UVA-SF_ korrIn a further embodiment of the invention, the correction function makes the measured values ​​of different skin types comparable through the corrected values. The protective ability of the protective agent can therefore be determined independently of the subject's skin type. In a further embodiment of the invention, the correction function F is a linear factor or an exponential function.

[0027] In a further embodiment of the invention, the correction function has a constant C, where C depends on the skin type or the ITA° value. The calculation of the individual typology angle (ITA) based on spectrophotometric measurements is used to classify skin types into six physiologically relevant groups: very light, light, medium, brown, brown, and dark.

[0028] The determined ITA° values ​​reflect a person's sensitivity to UV radiation and consequently the skin's sensitivity to solar radiation and skin damage such as pigment changes, cancer and aging.

[0029] The CIELAB color space (also known as L*a*b*) is a color space defined by the International Commission on Illumination (CIE). It expresses color along three axes. Additionally, the Individual Typology Angle (ITA°) is automatically calculated from L* (brightness) and b* (yellow color spectrum). ITA° is a recognized parameter for objectifying skin color to predict the biological effects of UV radiation on the skin. The difference along the yellow-blue axis (parameter b*) and along the light-dark axis (parameter L*) determines the intensity of skin pigmentation. For a person with light skin, ITA° is expected to have a more positive value than for a person with a darker skin type.

[0030] The ITA° value is calculated using the following equation:

[0031] ITA° = (arctan(L* -50) / b*)) * 180 / p where L* stands for the luminance in the range from black (0) to white (100) and b* in the range from yellow to blue (12). The higher the ITA° value, the lighter the skin. The resulting ITA° value classifies skin types into 6 physiologically different categories: ITA° > 55° "very light", 55° > ITA° > 41° "light", 41° > ITA° > 28° "intermediate", 28° > ITA° > 10° "tanned", 10° > ITA° > -30° "brown", -30° > ITA° "dark". In a further embodiment of the invention, the skin-type-dependent differences are determined by a measurement. In a further aspect of the invention, the skin-type-dependent differences are determined by a reflection measurement. For this purpose, a probe head is applied to the skin of a test subject. The probe head emits white light. The white light is scattered in all directions by the skin surface, and some of it penetrates the skin surface and is reflected back.This reflected light is measured by the probe head. The remitted spectrum is adjusted to DIN standard values ​​using a special color matrix and expressed as XYZ (tristimulus). The measured color is output as an ITA° value in the CIELAB color space.

[0032] In a further embodiment of the invention, the emitted radiation comprises an irradiation wavelength between 280 nm and 2000 nm, preferably 280 to 800 nm, particularly preferably the range from 280 to 500 nm. The radiation source generates electromagnetic radiation with an irradiation wavelength between the blue spectral range (from about 400 nm to 500 nm wavelength) and the UV range (280 nm to 400 nm).

[0033] In a further embodiment of the invention, the evaluation wavelength range differs from the irradiation wavelength range. The evaluation wavelength is the wavelength for which the protection factor is determined. The evaluation wavelength differs from the wavelength range of the irradiation wavelength and / or the detection wavelength. The evaluation wavelength, like the irradiation wavelength and the detection wavelength, is preferably a wavelength range, wherein the wavelength range of the evaluation wavelength comprises at least the wavelength range of the irradiation wavelength and / or the detection wavelength.

[0034] In a further advantageous embodiment of the invention, the protection factor of the protective agent is evaluated from the remitted radiation and the transmission spectrum. Due to its high absorption properties, human skin does not emit sufficient UVB radiation to measure the absorption spectrum of the applied product in the UVB range. It is therefore necessary to separately record the absorption spectrum of the test material in the UVB part of the spectrum (280–320 nm) using a different technique—a transmission spectrum. A transmission spectrum is determined based on the UV transmittance of protective films in vitro. The substrates to which the protective films are applied only approximately replicate the inhomogeneous surface structure of human skin, such as polymethyl methacrylate (PMMA) plates with a rough surface according to ISO 24443. The transmission spectrum data include intensity versus wavelength, preferably in a digitized format.

[0035] In a further embodiment of the invention, the transmission spectrum data for determining the protection factor is read from a database of the evaluation unit. The evaluation unit has a database in which data from different transmission spectra can be stored, or is connected to such a database.

[0036] In a further embodiment of the invention, the transmission spectrum data are in silico data. The transmission spectrum data are therefore neither determined in vivo on a test subject nor in vitro according to ISO 24443, but rather estimated or determined mathematically. If the properties of the filter substances of a protective agent are known, the transmission can be calculated and simulated. Based on the simulated transmission, the sun protection factor and all parameters that characterize the protection factor can be calculated.

[0037] In a further development of the invention, the wavelength range of the transmission spectrum comprises the evaluation wavelength. The evaluation of the protection factor of the protection agent is carried out from the in vivo remitted radiation and the in silico transmission spectrum. Due to its high absorption properties, human skin does not emit sufficient UVB radiation to measure the absorption spectrum of the applied product in the UVB range. It is therefore necessary to separately record the absorption spectrum of the test material in the UVB part of the spectrum (280-320 nm) using a different technique. The approach applied in this document uses the in vivo evaluation of the absolute UVA absorption spectrum, as measured with an in vivo measurement, with the use of a calculated in silico transmission spectrum to determine the protection factor of the protection agent for a user.The evaluation and hybridization of an in vivo remission spectrum with an in silico transmission spectrum is carried out to obtain a complete UV spectrum, so that the protection factors are calculated according to the formulas of the applicable standard (ISO 24443). For this purpose, the wavelength range of the transmission spectrum includes the evaluation wavelength, which preferably covers the range from 280 nm to 500 nm.

[0038] In a further embodiment of the invention, the evaluation wavelength comprises the wavelength range from 280 nm to 2000 nm, preferably the wavelength range from 280 nm to 800 nm, or particularly preferably the wavelength range from 280 nm to 500 nm. In a further development, the evaluation wavelength comprises a wavelength range from 400 nm to 500 nm, and preferably from 400 nm to 450 nm. Preferably, the wavelength range of blue light bordering the UVA range (up to 400 nm) is evaluated. To determine the protective ability of the protection agent in the UVB wavelength range (<320 nm), this wavelength range can also optionally be evaluated.

[0039] In a further embodiment of the invention, the evaluation of the protective ability of the protective agent for light in a wavelength range from 400 nm to 500 nm is carried out using a different method than the evaluation of the protective ability of the protective agent for light in a wavelength range from 280 nm to 400 nm. Due to its high absorption properties, human skin does not emit sufficient UVB radiation to measure the absorption spectrum of the applied product in the UVB range. It is therefore necessary to separately record the absorption spectrum of the test material in the UVB part of the spectrum (280-320 nm) using a different technique. For this purpose, the in vivo reflectance spectrum in the wavelength range from 320 nm to 400 nm is recorded, the wavelength range from 280 nm to 320 nm, and the wavelength range from 400 nm to 500 nm are recorded using an in silico transmission spectrum.

[0040] In a further embodiment of the invention, the wavelength range of the irradiation wavelength or the wavelength range of the detection wavelength is smaller than the wavelength range of the evaluation wavelength. The wavelength ranges of the irradiation wavelength and the detection wavelength are preferably identical within a wavelength range of a maximum of 320 nm to 400 nm. The wavelength range of the evaluation wavelength comprises a maximum range of 280 nm to 500 nm.

[0041] In a further embodiment of the invention, the wavelength range of the irradiation wavelength or the wavelength range of the detection wavelength is smaller than the wavelength range of the evaluation wavelength. The wavelength ranges of the irradiation wavelength and the detection wavelength are preferably identical within a wavelength range of a maximum of 320 nm to 400 nm. The wavelength range of the evaluation wavelength comprises a maximum range of 280 nm to 500 nm.

[0042] In a further embodiment of the invention, the wavelength range of the irradiation wavelength or the wavelength range of the detection wavelength in the wavelength range of the evaluation wavelength is smaller than the wavelength range of the evaluation wavelength. The wavelength ranges of the irradiation wavelength and the detection wavelength are preferably equal in a wavelength range from 320 nm to 400 nm, with the wavelength ranges of the irradiation wavelength and the detection wavelength being smaller than the aforementioned wavelength range of 320 nm to 400 nm. In the wavelength range of the evaluation wavelength (maximum 280 nm to 500 nm), the wavelength range of the irradiation wavelength or the wavelength range of the detection wavelength in the wavelength range of the evaluation wavelength is then smaller than the wavelength range of the evaluation wavelength.

[0043] In a further development of the invention, the wavelength range of the irradiation wavelength and / or the wavelength range of the detection wavelength is less than 100 nm, preferably less than 50 nm, and particularly preferably less than 25 nm. Therefore, only one beam source is required to emit electromagnetic radiation, which has a narrow wavelength range of the irradiation wavelength. Likewise, a detector capable of detecting the narrow wavelength range of the detection wavelength is required to record the remission spectrum. The beam source and detector can therefore be designed to be cost-effective in manufacture and operation. In a further embodiment of the invention, the irradiation wavelength and / or the detection wavelength only includes light with wavelengths outside the wavelength range of 400 nm to 450 nm. To record an in vivo measurement, the UVA wavelength range (320 nm - 400 nm) is coupled into the measuring body.

[0044] In a further development of the invention, the irradiation wavelength and / or the detection wavelength only includes light with wavelengths outside the wavelength range of 400 nm to 500 nm. In particular, the UVA and UVB wavelength range is irradiated. The greatest risk to human skin lies in this wavelength range, so determining the protective ability of a protective agent is particularly important.

[0045] In a further embodiment of the invention, the evaluation wavelength comprises wavelengths A with A < 400 nm. To record an in vivo measurement, in particular the UVA wavelength range (320 nm - 400 nm) is evaluated.

[0046] In a further embodiment of the invention, the evaluation wavelength comprises wavelengths A with 320 nm < A < 400 nm. To record an in vivo measurement to determine the protective ability of the protective agent, the UVA wavelength range (320 nm - 400 nm) is evaluated in particular. To determine the protective ability of the protective agent in the UVB wavelength range (< 320 nm), this wavelength range can also be optionally evaluated.

[0047] In a further embodiment of the invention, the radiation is emitted in vivo onto human skin. In the case of an in vivo measurement, the measuring body is the human skin covered with the protective agent to be tested. The protection factor evaluation system is suitable for introducing electromagnetic radiation into a measuring body, preferably into human skin, using the radiation source arranged in the protection factor evaluation system. Furthermore, the protection factor evaluation system is suitable for detecting the remitted and / or transmitted electromagnetic radiation using the detector unit arranged in the protection factor evaluation system. In a further advantageous embodiment of the invention, the protective ability of the protective agent is evaluated from two measurements. In a further development of the invention, a first measurement is taken before the protective agent is applied to the measuring body.In a further aspect of the invention, a second measurement is carried out after the protective agent has been applied to the measuring body.

[0048] In a further embodiment of the invention, the beam source generates polychromatic radiation, whereby the generated polychromatic radiation is radiated unfiltered onto the measuring body. The beam source generates radiation in a maximum wavelength range of 280 nm to 500 nm (UVB to blue light). The generated polychromatic radiation is not altered by optical elements (filters, monochromators) in the generated wavelength range from the generation of the polychromatic radiation until it impinges on a measuring body. This achieves a maximum intensity of the generated electromagnetic radiation, a likewise maximum intensity of the remitted or transmitted radiation, and consequently a high signal-to-noise ratio.

[0049] In a further embodiment of the invention, a message is output if the measurement results of the reference measurement deviate from the calibration measurement by more than a threshold. Only if the measurement results of the reference measurement deviate from the calibration measurement by less than a threshold does the radiation emitted from the measuring head occur. This ensures the accuracy and reproducibility of determining the protection factor of a protective device.

[0050] Embodiments of the method according to the invention for determining a protection factor with a protection factor evaluation system are shown in a simplified schematic form in the drawings and are explained in more detail in the following description.

[0051] They show:

[0052] Fig. 1 : Protection factor evaluation system

[0053] Fig. 2: Protection factor evaluation system, external control unit Fig. 3: Method for performing a reflection measurement to determine an in vivo reflection spectrum

[0054] Fig. 4: Method for evaluating the protective ability of a protective agent with a

[0055] Measurement to record a reflection spectrum and a measurement to determine the ITA° value

[0056] Fig. 5: Procedure for performing a reflection measurement to determine an in vivo reflection spectrum, ITA° correction value determination during the procedure

[0057] Fig. 6: Procedure for performing a measurement to determine a transmission spectrum

[0058] Fig. 1 schematically shows an embodiment of the protection factor evaluation system 1 according to the invention for performing an in vivo measurement. The protection factor evaluation system 1 comprises a radiation source device 12. The radiation source device 12 comprises a radiation source and optical elements intended and / or suitable for conditioning and / or redirecting the radiation generated by the radiation source, e.g., optical fibers, filters, monochromators, mirrors, and / or other optical elements.

[0059] By means of a light guide 4.1, the spectrum emitted by the beam source device 12 is introduced via the probe head 5 into the measuring body 3. The light reflected by the measuring body 3 reaches the detector unit 13 via a further light guide 4.2. The detector unit 13 has a monochromator, filter, photomultiplier, spectrometer and / or a photodiode. In this and all subsequent embodiments, the detector unit 13 has a photodiode. The detector unit 13 and the beam source device 12 are connected via data lines 23, 24 to a beam source controller 11, which in turn is connected to the control unit 2 via a further data line 21. The control unit 2 is typically a PC or notebook computer with a suitable computer program. The control unit 2 and the detector unit 13 are also connected to each other via a data line 22.A further exemplary embodiment of the protection factor evaluation system 1 according to the invention is shown in Fig. 2. The protection factor evaluation system 1 also has the beam source device 12. By means of the optical fiber 4.1, the light emitted by the beam source device 12 is introduced via the probe head 5 into the measuring body 3, and the light reflected by the measuring body 3 reaches the detector unit 13 via a further optical fiber 4.2. The detector unit 13 and the beam source device 12 are connected to a beam source control 11 via data lines 23, 24. In this exemplary embodiment, the control unit 2 is arranged remotely from the protection factor evaluation system 1 and is connected to it via the interface 16. The connection can be wired or wireless, e.g., via an IP connection, Bluetooth, etc.Interface 16 and detector unit 13 on the one hand and interface 16 and beam source control 11 are connected to each other via the data lines 21, 22.

[0060] Fig. 3 shows an embodiment of an implementation of the method 100 of an in vivo measurement for detecting the remission spectrum using the inventive protection factor evaluation system 1 from the preceding embodiments (see Fig. 1, Fig. 2). The implementation takes place in vivo. The method 100 of a measurement requires the recording of a remission spectrum of the skin of the test subject 3 not treated with a protective agent and of the skin treated with a protective agent.

[0061] For this purpose, the probe head 5 is applied to the untreated skin of the test subject 3, i.e., the protective agent to be tested is not applied to the skin of the test subject 3. For this purpose, a location on the inside of the forearm or the back of a test subject 3 is typically selected. The first measurement 110 is then performed by the beam source control 11 controlling the beam source device 12 such that the light generated by the beam source is directed through the light guide 4.1 onto the skin of the test subject 3.

[0062] The light generated by the beam source is irradiated unfiltered onto the measuring body 3 to ensure a high S / N ratio. In particular, the light generated by the beam source is polychromatic, with an intensity maximum at a wavelength in the UVA range of 340 nm. The irradiation occurs at an intensity that does not cause acute damage to the skin, which is below the single MED, or below the MZB values, or significantly below the values ​​caused by solar radiation. The light remitted by the skin of the subject 3 is guided through the light guide 4.2 to the photodiode of the detector unit 13, detected by the photodiode, and converted into measured values. The measured values ​​are sent to the control unit 2 and stored in the control unit 2.

[0063] Control unit 2 then asks at 120 whether the second measurement of the skin of test subject 3 treated with protective agent has already been performed. If this is not the case, control unit 2 indicates this. To perform the second measurement 110 with applied protective agent, the protective agent is applied to the skin of test subject 3 130 in the amount of 2.0 mg / cm 2on the skin surface to be tested. The application 130 of the protective agent and the subsequent second measurement 110 are carried out at the same location on the measurement sample 3, in particular on the same location on the skin of a test subject 3, in order to ensure the reproducibility of the first and second measurements 110. Also to ensure reproducibility, the control unit 2 controls the beam source control 11 such that the beam source control 11 controls the beam source of the beam source device 12 such that the light generated by the beam source is guided through the light guide 4.1 onto the skin of the test subject 3, wherein the intensity and exposure time of the first and second measurements 110 correspond.

[0064] The light remitted by the skin of the subject 3 is also detected by the photodiode of the detector unit 13 and converted into measured values, the measured values ​​are sent to the control unit 2 and stored in the control unit 2.

[0065] If the query 120 indicates that the second measurement 110 has already been performed, the ITA° value of the skin of subject 3 is read in and the ITA° correction 150 is performed. The ITA° value of the skin of subject 3 was determined in a separate measurement 125 before performing the method 100 of recording an in vivo reflection spectrum. The reflection measurement is then evaluated 140. For this purpose, the control unit 2 executes a program for calculating the transmission spectrum T in viV o according to equation 1:

[0066] Equation 1 with T in vivo as a function of wavelength A, SF in ViV o the protection value determined by the in vivo method 100, R oreflected intensity of the untreated skin of subject 3 as a function of wavelength A, R reflected intensity of the skin of subject 3 treated with protective agent as a function of wavelength A. The method 100 presented here requires a time expenditure of a few seconds to a few tens of seconds.

[0067] To determine the protection factor, the protective agent is evaluated in the next process step 300. For this purpose, the control unit 2 reads in a transmission spectrum that is calculated in silico or determined according to ISO 24443 (see Fig. 6).

[0068] If the amounts and properties of a protective agent's UV filter substances are known, the UV transmittance can be calculated, taking into account the film's irregularity and photodegradation. Based on the simulated UV transmittance, the protective ability of the protective agent and all parameters that characterize protection against UVA and / or UVB can be calculated in silico.

[0069] The in silico determination of the data of a transmission spectrum is carried out, for example, in a laboratory according to ISO 24443. A plot of 2.0 g / cm 2 Protective agent. In this embodiment, the emitted radiation is in the wavelength range from 280 nm to 500 nm (UVB to blue light). In further embodiments, the irradiation wavelength range can be in the wavelength range between 280 nm and 2000 nm, and preferably between 280 nm and 800 nm.

[0070] The evaluated wavelength range of the transmission spectrum comprises the wavelength range from 280 nm to 2000 nm, preferably the wavelength range from 280 nm to 800 nm or particularly preferably the wavelength range from 280 nm to 500 nm and / or the wavelength range from 400 nm to 500 nm and / or the wavelength range from 400 nm to 450 nm. In this embodiment, the evaluation wavelength range of the transmission spectrum comprises 280 nm to 320 nm.

[0071] The data of the in silico transmission spectrum are stored in a database and can be retrieved from the database at any time. To determine the protection factor of a skin protection product, the in silico transmission spectrum is loaded into the evaluation unit 10, which is connected to the database via an internet connection.

[0072] The results of the evaluations 140, 230 of the in vivo remission spectrum and the in silico transmission spectrum are combined and evaluated by the evaluation unit 10. For this purpose, the hybrid transmission spectrum T hyb , where the in silico transmission spectrum T in si | ico using the reflection spectrum T in viV o is scaled:

[0073] The protective ability of the protective agent for the spectral range from UVA (320 nm) to the HEV spectral range (450 nm) SF is then calculated according to equation 4 (here E = IPD(A) is the IPD spectrum; S = 1(A) is the solar spectrum):

[0074] Eq. 3

[0075] The protective ability of the protective agent in the spectral range of blue light (400 nm to 500 nm) is determined according to equation 5 (here E = IPD(A) is the IPD spectrum; S = 1(A) is the solar spectrum)

[0076] GI.4 The protective ability of the protective agent from 400 nm to 450 nm SF (400 nm-450 nm) is determined according to equation 6 (here E = IPD(A) is the IPD spectrum; S = 1(A) is the solar spectrum):

[0077] Eq.5

[0078] The protective ability of the protectant for the spectral range of UVA (320 - 400 nm)

[0079] UVA-SF is then obtained according to equation 4 (here E = PPD(A) is the PPD spectrum;

[0080] S = 1(A) is the solar spectrum or UVA source for PPD-test.):

[0081] Eq. 6

[0082] The protective ability of the protective agent for the spectral range from UVB to UVA (280 - 400 nm) UV-SF is then given by equation 4

[0083] Eq. 7

[0084] In all equations for SF or UVA-SR, an optional correction function F (SF) = SF_corr or F (UVA-SF) = UVA-SF_corr is used, which describes, for example, skin type-dependent differences. A correction function makes values ​​of different skin types comparable and returns a corrected value SF korr or UVA-SF korr out of.

[0085] For example, F can be a linear factor (ie F(SF)=SF*C) or an exponential function (ie F(SF)=SF C ). C can depend, for example, on the skin type or the ITA° value. As shown in Eq. 4, the formulas in Eqs. 3 to 7 can be written as follows:

[0086] Eq. 8

[0087] Since the in vivo value is measured without photodegradation, photodegradation should be appropriately taken into account. This can be done by using T_ in si | ico with (T insUico irr(A') and without photodegradation and a spectral quotient SRPD is calculated from it

[0088] Eq. 9

[0089] This will then

[0090] ThybJrrW ~ ? hyb(F) * SRPD( )

[0091] Eq.10 calculated.

[0092] The method can be calibrated using suitable reference methods such as electron spin resonance spectroscopy (ESR).

[0093] Fig. 4 shows an embodiment of the method 400 according to the invention for determining the protective ability of a protective agent, wherein an ITA° correction 150 is carried out, which is carried out by means of a measurement 125 to determine the ITA° value. The method 100 of an in vivo measurement to record the remission spectrum is carried out in vivo. For this purpose, the probe head 5 is applied to the untreated skin of the test subject 3. The first measurement 110 is then carried out. The light remitted by the skin of the test subject 3 is guided through the light guide 4.2 to the photodiode of the detector unit 13, detected by the photodiode and converted into measured values. The measured values ​​are sent to the control unit 2 and stored in the control unit 2. The control unit 2 then queries 120 whether the second measurement of the skin of the test subject 3 treated with the protective agent has already been carried out. If this is not the case, the control unit 2 displays this.To perform the second measurement 110 with the protective agent applied, the protective agent is applied to the skin of the test subject 3. The application 130 of the protective agent and the subsequent second measurement 110 are performed at the same location on the measurement sample 3, in particular on the same location on the skin of a test subject 3. The light remitted by the skin of the test subject 3 is also detected by the photodiode of the detector unit 13 and converted into measured values. The measured values ​​are sent to the control unit 2 and stored in the control unit 2.

[0094] If query 120 indicates that the second measurement 110 has already been performed, an evaluation 140 of the reflection measurement is performed as shown in the previous embodiment (see Fig. 3). The ITA° value of the skin of test subject 3 is then read in, and the ITA° correction 150 is performed. The ITA° value of the skin of test subject 3 is used in a separate measurement 125, a colorimetric reflection measurement 126. For this purpose, a probe head is placed on the skin of test subject 3, and white light is irradiated onto and into the skin of test subject 3. The wavelength of the emitted white light is 440-670 nm. The light remitted by the skin of test subject 3 is recorded and converted into measured values. In evaluation 127 of measurement 125, the measured values ​​of the probe head are adjusted as closely as possible to the DIN standard values ​​using a special color matrix and expressed as XYZ (tristimulus).The determined skin color is sent to control unit 2 as an ITA° value in the CIELAB color space and is used to perform the ITA° correction 150.

[0095] Thereafter, as in the above embodiment (see Fig. 3), the data of the transmission spectrum 200 (determined in vitro or in silico) are read into the control unit 2, the evaluation and determination 300 of the protection factor of a protective agent is carried out as described in Fig. 3.

[0096] An advantageous embodiment of the method 400 according to the invention is shown in Fig. 5. In this exemplary embodiment, the measurement 125 for determining the ITA° value of the skin of the test subject 3 is carried out using the same protection factor evaluation system 1 with which the method 400 for evaluating the protective ability of a protective agent is carried out. In addition, the measurement 125 for determining the ITA° value of the skin of the test subject 3 is carried out during the method 400.

[0097] The method 100 of an in vivo measurement for detecting the reflectance spectrum is carried out in vivo as already described in Fig. 3 and Fig. 4. For this purpose, the probe head 5 is applied to the untreated skin of the test subject 3. The first measurement 110 is then carried out. The light remitted by the skin of the test subject 3 is guided through the light guide 4.2 to the photodiode of the detector unit 13, detected by the photodiode and converted into measured values. The measured values ​​are sent to the control unit 2 and stored in the control unit 2. The control unit 2 then queries 120 whether the second measurement of the skin of the test subject 3 treated with protective agent has already been carried out. If this is not the case, the control unit 2 displays this.

[0098] This is followed by the measurement 125 to determine the ITA° value. For this purpose, the probe head 5 of the protection factor evaluation system 1 is placed on the same spot on the skin of a test subject 3. The control unit 2 controls the beam source control 11 such that the beam source device 12 radiates white light with a wavelength range of 440 nm to 670 nm onto the skin of the test subject 3. Alternatively, light in the UV range and / or visual range can also be used. The light remitted by the skin of the test subject 3 is detected, and the control unit 2 determines an ITA° value for the skin of the test subject 3. The application 130 of the protection agent and the second measurement 110 follow thereafter. The determined skin color is used in the CIELAB color space as the ITA° value for performing the ITA° correction 150. Then, as in the previous exemplary embodiment (see Fig.3 ) the data of the transmission spectrum 200 (determined in vitro or in silico) are read into the control unit 2, the evaluation and determination of the protection factor of a protective agent is carried out as described in Fig. 3.

[0099] An exemplary embodiment of the method 200 for an in vitro transmission measurement is shown in Fig. 6. The in vitro measurement 200 is carried out under laboratory conditions on a separate measuring setup from the previous exemplary embodiment (see Fig. 1, Fig. 2). A commercially available spectrometer with a xenon lamp is used, which emits and detects radiation in the wavelength range from 280 nm to 500 nm (UVB to blue light). The resolution of the device is 1 nm.

[0100] For this purpose, the protective agent to be tested is applied to a roughened PMMA plate in an amount of 1.3 mg per cm 2applied 210. The PMMA plate has a roughness of 5 pm. The transmission measurement is then carried out 220 and the subsequent evaluation 230, whereby the protection value for the entire wavelength range from 280 nm to 500 nm SF is determined according to equation 11:

[0101] Gl 11 with S as sun spectrum, E as erythema effect spectrum, T tra n S as transmission and dA as wavelength increment (1 nm).

[0102] B EZ UG S CHARACTERS LIST

[0103] Protection Factor Evaluation System

[0104] Control unit

[0105] Sample / measuring body

[0106] Optical fiber / fiber bundle

[0107] Probe head

[0108] Beam source control

[0109] Beam source device

[0110] Detector unit / spectrometer

[0111] Connection beam source control - control unit

[0112] Connection detector unit / spectrometer - control unit

[0113] Connection beam source control - beam source device

[0114] Connection beam source control - detector unit

[0115] Method for recording a reflection spectrum

[0116] Carrying out a measurement of a reflection spectrum

[0117] query

[0118] Measurement to determine the ITA° value

[0119] Colorimetric reflectance measurement

[0120] Evaluation of the colorimetric reflection measurement

[0121] Application of the protective agent

[0122] Evaluation of the reflection measurement

[0123] ITA° correction

[0124] Method for recording a transmission spectrum

[0125] Application of the protective agent Carrying out a measurement of a transmission spectrum

[0126] Evaluation of the transmission measurement

[0127] Evaluation of the protective agent

[0128] Procedure for examining the protective ability of protective agents

Claims

PATENT CLAIMS 1. Method (400) for determining a protection factor of a skin protection agent, comprising the steps of: • Emitting (110) radiation from a radiation source unit (12) of a protection factor evaluation system (1), • Detecting remitted radiation from a detector unit (13) of a protection factor evaluation system (1), • Transferring data of the remitted radiation to an evaluation unit (10), • Evaluation (300) of the protection factor in an evaluation wavelength range, wherein a correction function is taken into account in the evaluation (300) of the protection factor, wherein the correction function describes skin type-dependent differences.

2. Method (400) for determining a protection factor of a skin protection agent according to claim 1, characterized in that the correction function has a corrected value SF korr or UVA-SF korr issues.

3. Method (400) for determining a protection factor of a skin protection agent according to claim 1 or 2, characterized in that the correction function F (SF) = SF_ korr or F (UVA-SF) = UVA-SF_ korr is.

4. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the correction function makes the measured values ​​of different skin types comparable through the corrected values. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the correction function F is a linear factor or an exponential function. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the correction function has a constant C, where C is dependent on the skin type or the ITA° value. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the skin-type-dependent differences are determined by a measurement (125).Method (400) for determining a protection factor of a skin protection agent according to claim 7, characterized in that the skin type-dependent differences are determined by a reflection measurement. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that. the emitted radiation covers an irradiation wavelength range between 280 nm and 2000 nm, preferably 280 nm to 800 nm, particularly preferably the range from 280 nm to 500 nm. Method (400) for determining a protection factor of a skin protection agent according to claim 7, characterized in that the evaluation wavelength range is different from the irradiation wavelength range. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the protection factor of the protection agent is evaluated (300) from the remitted radiation and a transmission spectrum. Method (400) for determining a protection factor of a skin protection agent according to claim 9, characterized in that the data of the transmission spectrum for determining the protection factor are read in from a database of the evaluation unit (10).Method (400) for determining a protection factor of a skin protection agent according to claim 9 or 10, characterized in that the transmission spectrum data for determining the protection factor are in silico data. Method (400) for determining a protection factor of a skin protection agent according to one or more of claims 9 to 11. characterized in that the wavelength range of the transmission spectrum comprises the evaluation wavelength range. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the evaluation wavelength comprises the wavelength range from 280 nm to 2000 nm, preferably the wavelength range from 280 nm to 800 nm or particularly preferably the wavelength range from 280 nm to 500 nm and / or the wavelength range from 400 nm to 500 nm and / or the wavelength range from 400 nm to 450 nm.Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the evaluation (300) of the protective ability of the protective agent for light in a wavelength range from 400 nm to 500 nm is carried out in a separate method from the evaluation (300) of the protective ability of the protective agent for light in a wavelength range from 280 nm to 400 nm. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the evaluation (300) of the protective ability of the protective agent for light in a wavelength range from 400 nm to 500 nm is carried out in a different method from the evaluation (300) of the protective ability of the protective agent for light in a wavelength range from 280 nm to 400 nm. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the wavelength range of the irradiation wavelength or the wavelength range of the detection wavelength is smaller than the wavelength range of the evaluation wavelength. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the wavelength range of the irradiation wavelength or the wavelength range of the detection wavelength in the wavelength range of the evaluation wavelength is smaller than the wavelength range of the evaluation wavelength.Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the range of the irradiation wavelength and / or the wavelength range of the detection wavelength is less than 100 nm, preferably less than 50 nm and particularly preferably less than 25 nm. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the irradiation wavelength and / or the detection wavelength only comprises light with wavelengths outside the wavelength range from 400 nm to 450 nm. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that. the irradiation wavelength and / or the detection wavelength only comprises light with wavelengths outside the wavelength range from 400 nm to 500 nm. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the evaluation wavelength comprises wavelengths outside the wavelength range from 400 nm to 500 nm. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the evaluation wavelength comprises wavelengths A with A < 400 nm. Method (400) for determining a protection factor of a skin protection agent according to one or more of the preceding claims, characterized in that the evaluation wavelength comprises wavelengths A with 320 nm < A < 400 nm.

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