EP3365641A1

EP3365641A1 - Optically ascertaining the sun protection factor of sunscreens or other radiation protection agents

Info

Publication number: EP3365641A1
Application number: EP16797454.2A
Authority: EP
Inventors: Jürgen HELFMANN; Ingo GERSONDE
Original assignee: Courage and Khazaka Electronic GmbH
Current assignee: Courage and Khazaka Electronic GmbH
Priority date: 2015-10-20
Filing date: 2016-10-20
Publication date: 2018-08-29
Also published as: DE112016004783A5; WO2017067545A1; US20180321139A1; CN109073456A; US11137347B2; JP2018533013A

Abstract

The invention is used to ascertain a sun protection factor for light, for example for cosmetics and sunscreens for which a sun protection factor (SPF) is specified. Two measurements of the light backscattering on the skin surface are carried out in vivo or in vitro or on skin models (animal skin models or artificial skin models) before and after applying the radiation protection means onto the skin, and the sun protection factor is ascertained therefrom. In contrast to standard methods used until now, the distance between the lighting surface and the detection surface on the skin is ascertained for the irradiation path of the measurement method. The skin lighting dose used during the measurement lies below harmful limits. The sun protection factor can be ascertained according to previous standards or for additional wavelengths or wavelength ranges (e.g. UVA, VIS, NIR, IR).

Description

Optical determination of the protective factors of sunscreen or

other radiation protection agents

The invention describes a method for the qualification of cosmetics and sunscreens for which a sun protection factor (SPF) or a protection factor still to be redefined is specified.

The current methods approved by the European Union (EU) and the US Food and Drug Administration (FDA) for the determination of SPF are all harmful to the subjects involved, causing erythema, or light-induced inflammatory reactions of the skin (COLI PA - 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 stated that future research activities must be directed towards new methods for characterizing the protective effect of sunscreens in order to avoid long-term consequences for the subjects (European Commission, Standardization Mandate Assigned to CEN Concerning Methods For Testing Efficacy Of Sunscreen Products, M / 389 EN, Brussels, 12 July 2006). This object is to be perceived with this invention.

The existing procedures are defined in various references:

I. Procedures defined in standards and regulations:

a. ISO 24444 defines a method for the in vivo determination of SPF. The basis of the method is the generation of erythema on the skin of subjects by radiation in the UVB range. Therefore, the process is harmful. In order to reduce the dependency of the result of interindividual variations of the skin characteristics, the procedure must be carried out on several subjects.

b. ISO 24443 defines an in vitro method for determining the UVA protection factor (UVAPF). The sunscreen is applied to a plastic plate so that a transmission spectrum of the sunscreen can be measured. Due to uncontrollable variations of the procedure, the transmission spectrum is scaled to the result of the erythema test according to ISO 24444 and thus depends on its performance. The plastic plate used with a roughened surface is a relatively unrealistic skin model.

c. ISO 24442 defines an in vivo method in which the UVA protection factor is determined by means of the minimum dose of UVA to produce an irreversible pigmentation (tan) the skin is determined. This procedure also causes a change in the skin of the subject.

d. FDA Final Rules 201 1, originally published in the Federal Register of 27 August 2007 (72 FR 49070) and codified as Broad Spectrum Test (21 CFR 201.327 (j)) and Sun Protection Factor (SPF) test (21 CFR 201.327 (i) or in a newer version than 21 CFR 201.352 (http://www.ecfr.gov/cgi-bin/textidx? SID = 5555a0dd8b6d83a8570676d9a44bb6ef & mc = true & node = pt21.5.352 & rgn = div5)

II. Patented methods:

a. DE 198 28 497 A1 describes a method in which, as in ISO 24444, test persons are exposed to erythema by UV irradiation of the skin; in contrast to ISO 24444, these are detected by reflection spectroscopy. The process is thus also damaging, the optical effect (protection) of the sunscreen is not detected by direct optical measurements, but via a biological reaction of the body.

b. DE 10 2004 020 644 A1 describes a method in which the generation of radicals by UV exposure in vivo is measured quantitatively by means of electron spin resonance (ESR). Again, the optical effect of the sunscreen is detected only indirectly. In addition, the measurement of the ESR is technically complex and requires relatively large, stationary devices (desktop devices). Also, they are susceptible to disturbances due to radio frequency radiation or rapid temporary magnetic field changes, e.g. of electrical switching operations.

c. Regarding the technology of WO 2007/100 648, it is to be noted that, although distance-dependent measurements are also described by a light source, they are not included in the scope of protection as a sole feature (only claim 3 names this distance, but refers to claim 2 via claim 2) 1). The feature design over angle of incidence is presumed because the distance-dependent backscatter measurement with this basic arrangement for over 30 years from many references is known and thus is not protected or protected: A. Ishimaru, Single Scattering and Transport Theory, Vol 1 (1978), Academic Press, p. 185 ff

III. Publications:

a. In Bendova H, et al., Toxicology in vitro (2007), 1268-1275, methods of transmission spectroscopy using different films as skin models are compared. The determined protection factors depend strongly on the film used, a significant correlation of protection factors with SPF from ISO 24444 was not found.

b. In Ruvolo E, Kollias N, Cole C, Photodermatol Photoimmunol Photomed (2014), 30: 202-211, a method is presented combining UVB transmission measurement with plastic substrates and in vivo UVA backscatter measurement on the skin become. The transmission measurement is scaled to the UVA backscatter measurement, which gives good agreement with the in vivo test of the SPF to ISO 24444. The measurement arrangement for the UVA backscatter measurement contains a fiber bundle, which is placed on the skin. The measurement takes place via a multiplicity of illumination and detection fibers with different distances from each other. The sum of the light powers from the detection fibers is detected, so there is no defined distance between the illumination surface and the detection surface, but rather a summation of all distances. In the method according to the invention, the backscattering is measured at several well-defined intervals.

c. In Son M, Grain V, Imanidis G, Skin Pharmacol Physiol, (2015), 28: 31-41, skin from pig ear is tested as a substrate for in vitro measurements of transmission. In comparison to the measurement with standardized plastic carriers, there is a better correlation with the SPF determined in vivo. This shows that a realistic skin model is essential for the determination of protective factors. The transmission measurement was carried out with / without sunscreen. However, the error of such a measurement is strongly dependent on the used layer thickness (thickness of the separated layer of the pig's ear) and the surface roughness relative to the change by the (identical, normalized) amount of sunscreen and is in the measurements of the publication only against the ISO 24444 : 2010 evaluated in vivo evaluated SPF, not with each other. Also, only one type of sunscreen (oil-in-water) has been used, which has specific high scattering properties due to oil droplet formation, making the surface changes less effective.

The field of application of the previous methods with UVB radiation (solar simulator, ie "solar simulator" with predetermined wavelength-specific intensity between 290 to 400 nm corresponding to solar radiation at sea level) and with limited opportunities with UVA radiation (erythema does not occur as in UVB, higher penetration as UVB into the skin = larger volume) should be extended without restriction to the UVA, UVB, the visible and near-infrared or infrared range for the determination of corresponding sun protection factors with the solution according to the invention. Disadvantages of previous methods

The method according to the invention is not only desirable but urgently required for a number of important reasons:

• Increased doses of UV radiation can damage tissue and cellular components. Skin aging and, at worst, skin cancer are known to be the consequences. For decades, an increasing number of new cases of skin cancer has been observed, which currently stands at around 20,000 cases per year in Germany. The main cause is a recurring intense UV exposure, as occurs in summer holidays, especially in childhood and youth.

• Existing methods (ie state of the art) for the evaluation of sunscreens are inadequate because they are either tested invasively by erythema on the subject or unphysiologically tested on plastic carriers as a skin model.

• Today's in vivo SPF determination has a number of shortcomings. This provision only refers to a spontaneous biological effect (forced sunburn) caused by UVB radiation. Today, however, it is known that the UVA radiation can lead to severe skin damage to skin cancer. In addition, the determination of the SPF is an invasive procedure, as damage in the form of sunburn is caused in the subjects. Therefore, both the US Food and Drug Administration (FDA) and the European Union have repeatedly stated that future research activities must be directed towards new methods of characterizing the protective effect of sunscreens in order to avoid long-term consequences for the subjects.

• In vivo SPF can only be detected in UVB, whereas long-term damage also occurs through other spectral regions.

The addition of anti-inflammatory substances in sunscreens which "in-vivo" SPF "beautiful", has no effect on a purely physical measurement (eg, in vitro), as in the method according to the invention, thus the falsification of the SPF is excluded.

• The existing in vitro SPF method for UVA detects only the SPF in the UVA in a non-physiological, non-biological matrix on a plastic carrier and is thus completely inadequate in terms of assessing the in vivo behavior during penetration and distribution of the sunscreen , Furthermore, a parallel invasive in-vivo measurement is necessary for its determination in order to adjust the inaccurate measurement method in the UVA later. Basically, a z. For example, In Vo-SPF measured according to the COLI PA protocol only indicates the effectiveness of the UVB protection, while the UVA content of the sunlight is not adequately detected. Since harmful effects due to UVA radiation are also well known, it has been found necessary to establish a general test procedure for determining the UVA protection. This is due to the fact that the UV component of the solar radiation reaching the earth's surface consists of about 5% UVB and about 95% UVA.

In vivo situation for SPF determination in UVA

To date, three in vivo methods have been described for determining U VA protection, IPD (Immediate Pigment Darkening), PPD (Persistent Pigment Darkening) and UVA-PF (UVA Protection Factor). While the IPD method does not always provide accurate readings, the PPD reaction proved stable and reproducible. However, their clinical significance was considered questionable because the PPD action spectrum for wavelengths below 320 nm is not well defined and the PPD response can be overlaid by other UV-induced skin reactions. The UVA-PF method is based on "Minimal Erythematous Responses" and persistent pigmentation caused by UVA A detailed compilation of the PPD and erythema action spectra as well as the UVA and UV-SSR (ultraviolet solar simulated light) spectral irradiance in the 290- 373 nm offer the COLIPA Guidelines from 2009.

In vitro situation for SPF determination in UVA

A comprehensive list of current in vitro protocols for SPF testing is provided by an Application Note on UV / VI S spectrometry from Perkin Elmer:

AS / NZS 2604 Broad Spectrum (2012) The new version of this is based on the test method described in ISO 24443 'Determination of Sunscreen UVA Protection In Vitro'. UVAPF Ratio and critical wavelength requirements are calculated in order to arrive at Broad Spectrum compliance.

ISO -24443 (2012) Determination of Sunscreen UVA protection in vitro. Determines both UVAPF Ratio and Broad Spectrum Compliance. Compliance with AS / NZS 2604.

SO 24442 (2012) This method is being adopted as the harmonized method for determination of UVAPF in vitro and for use in AS / NZS 2604 and Cosmetics Europe, ASEAN and other regions.

UVA-UVB Ratio (2010) Absorption of a 1.3 mg / Square cm film is measured between 290 nm and 400 nm. The ratio of areas between 290 - 320 (UVB region) is 320 nm and 400 nm. Pre-irradiation of the sample is required. (Calculated as TPF x UVA / UVB). Various Substrates can be nominated. Boots Star Rating (2011) The method used by Boots in the UK (not mandated). Absorption of a 1 mg / square cm film is measured between 290 nm and 400 nm. Pre Irradiation of the sample is required. Rating scale is 3 to 5 stars. More stars means more protection (by ratio) in the UVA area.

FDA, Final Rule 2011 The current proposed method for the United States. Absorption of a 0.75 mg / square cm film is measured between 290 nm and 400 nm. The critical wavelength is 90% of the area under the curve, starting at the UVB end. Pre-irradiation of the sample is required.

DIN 67502 (UVA balance) The method is based on that described in the German Standard DIN 67502. The SPF is determined using the values provided in the CIE. The SPF is applied in order to correct the values obtained in vitro. The PPD are derived by applying the values from the PPD Action Spectrum given in the Standard.

COLIPA (UVAPF) (2011) UVAPF / SPF Ratio and Critical Wavelength are calculated from this measurement technique. Compliance with E.U. requirements is thus reported.

Radical protection factor

Radical Protection Factor (RPF) is the determination of the free radicals generated by solar radiation in human skin. However, this method again has the disadvantage that it can only be carried out in vivo using solar simulators, since in vitro samples which are not perfused have a significantly lower oxygen concentration. However, oxygen is the basis for the formation of free radicals. The radical protection factor and the sun protection factor differ.

Medical / technical / objective advantages and disadvantages of competitive procedures

In the case of sun protection measurement in vivo, the greatest disadvantage of the method is skin damage to be avoided. Only the generation of a slight sunburn, ie an inflammation of the skin, can currently reliably measure the UVB sun protection factor. For the UVA, a similar meaningful - albeit damaging - InVo procedure is not available.

However, it is generally to avoid the injury of a subject. This is the main reason why in vitro methods have been developed. The other reason is the extension of the SPF determination to the UVA. This means that there is an urgent need for in vitro methods, which, however, must necessarily be as reliable as the InVo methods.

However, existing in vitro methods have serious deficiencies that need to be addressed: In vitro method on artificial substrates

• Different order, penetration, wetting and thus distribution behavior

• No biological variability

• Light distribution during the measurement does not correspond to the In Vo situation

This is shown by the necessary but very artificial adaptation to the in vivo UVB SPF, which must be applied compulsorily (whereby damage is not avoided). For high and low SPF the in vitro determination deviates strongly from the expectation.

In vitro method on biological substrates (skin tissue), z. B. pig ear

• Penetration and distribution behavior different from vital human skin

• Tissue samples must be laboriously prepared for measurement in thin layers. Changes in the sample due to thermal or chemical preparation are to be expected and there is poor repeatability due to handling difficulties.

By measuring on an intact biological model tissue and taking into account the light distribution both in the measurement for SPF determination as well as in the real situation in the protection of the skin from radiation, the o.g. Problems and weaknesses are overcome with this measuring method according to the invention.

Risks Measures to limit it

There are optical by-passes With the design options on the fiber applicator (crosstalk), the one (metallized fibers, recording plate with light barriers) and clear SRR measurement of handling (defined contact pressure), this can be disturbing. be minimized. Residual crosstalk can be detected and subtracted, if constant) with the measurement of a dark standard.

The extreme differences of the investigations in the visible have shown that light propagation is more problematic in the case without small absorption coefficients (μ ₃ <0.04 mm ^-1 ) or with sunscreen. The SRR method or its closed-loop feedback into optical properties can not solve two orders of magnitude for larger μ ₃ algorithms for SPF. For the reduced provision too. Scattering coefficients can also be resolved two orders of magnitude (Andree et al., J. Biomed Opt 15 (6) (2010)). Risks Measures to limit it

Due to the large differences By choosing the right distance range between the optical properties in the light source and the detection spot for the SRR, the different layers of light propagation can be controlled. The signal continues to the skin, the evaluation is composed of a transmission almost perpendicular to the problematic. Layers at entry and exit and a horizontal one

Transmission, which is determined by the distance. This allows the calculation of the diffuse transmission through the layer with / without sunscreen. It may be necessary to realize different optimum distance ranges in the fiber measuring head for the different wavelength ranges.

The influence of the horny layer on By choosing the distance for the SRR, the proportion of the measurement is changed small against the different skin layers on the signal. In order to influence the residual epidermis must be particularly sensitive to the cornea and the dermis, so that the very small distances are realized, the technological signal contrast by variations are challenging.

the optical properties of the

Horny layer is too small.

The signals are large by varying the integration time of the measurement, an SPF can be too small and the very wide dynamic range can be detected because the required dynamics of the detector signals are linear with the integration time.

Measurement with / without is too big.

The SPF is too heterogeneous locally. Due to the redundant measurement with several fibers for the same distance r, averaging can lead to a stable statement. In addition, some heterogeneity is physiologically realistic and is to be reproduced by the tissue model.

The degree of heterogeneity can also be measured spatially resolved and provide valuable information about the distribution behavior of the sunscreen.

characters

Fig. 1 shows the measuring method according to the invention

Fig. 2 shows the explanations for the derivation of the backscatter measurement according to the invention FIG. 3 shows model calculations on a skin model for the correlation of protection factor and backscatter. The registered line corresponds to equation (4).

Fig. 4 shows the simultaneous measurement of the backscatter at several intervals

FIG. 5 shows an embodiment of the backscatter measurement according to the invention, each having a lighting and detection fiber

FIG. 6 shows embodiments according to the invention of fiber end surfaces of fiber bundles for the backscatter measurement

invention

It is therefore an object of the invention to provide a method and a device which at least partially remedy the stated disadvantages of the prior art and in particular reduce the stress due to the irradiation on the measuring body and at the same time continue to provide high-quality analysis results.

The object is achieved by a method according to claim 1 and an apparatus according to claim 15.

The measuring method according to the invention enables the damage-free determination of protective factors of formulations for light or radiation protection on tissue (skin) in vivo or in vitro or also on skin models (animal skin models or artificial materials). This is achieved by evaluating two measurements of the light backscatter on the skin surface before and after applying the radiation protection agent to the skin. In contrast to previous methods, the distance between the illumination surface and the detection surface on the skin is determined with the beam path of the measuring method (error! Reference source could not be found). The exposure dose of the skin used in the measurement is below the damage limit, which is usually indicated as MED for the UVB range or by means of MZB values for the other wavelength ranges.

The illumination takes place with at least one radiation source which emits relevant radiation at least in the wavelength range for which the protective effect or the SPF is to be defined. Alternatively, the radiation source can emit only a smaller wavelength range of the radiation relevant for the protective effect and determine the existing radiation protection or sun protection factor by means of correlation measurements which precede the determination according to the invention. The emitted radiation is detected by at least one detector, wherein the detection area at the measuring location of the Einstrahlort the radiation source has a defined distance. The measuring cycle for determining the existing radiation protection or SPF consists of at least 2 individual measurements in which the radiation emitted by the radiation source of the illumination is transmitted through the measuring body (in addition to the layer modified by the applied radiation protection means) and hits the detector, the distance between the illumination surface and the detection surface on the measuring body being between the Measurements are predetermined, but different. A downstream device detects the at least two detector signals, amplifies these possibly with different degrees of gain, and analyzes the signal level with an algorithm that determines a sun protection factor. The advantages of this method lie in the lack of damage to the subject in in vivo measurements, in the simple recalculation without consideration of the incident light power must be constant only in the measurements with / without radiation protection, and also in the independence of the chosen distance between irradiation / Illumination and detection, and the existing under the radiation protection skin or optical properties of the measuring body or skin model used. Advantage of the measurement is the use of any spectral intensities in the radiation sources, which no longer require a calibrated "solar simulator". The detection can be carried out with simple detectors, which only have to output a signal above the noise depending on the definition of the sun protection factor for the transmitted radiation in the worst case of the greatest light attenuation by radiation protection means and measuring body.

The method according to the invention gives the best results if the radiation protection agent to be investigated is present as a thin layer and weakens the transmitted radiation (see point 1 below). The attenuation by the radiation protection means can be approximately described by a scalar transmission factor T in this case. For the radiation density Φ in deeper areas of the skin (depth z) then applies

® _without (z) = P _m Uz) without protective agent

Φ _{Μΐ (} (ζ) = Ρ _ιη Τ L (z) with protective _agent

Pin denotes the illumination power, L (z) the path length-dependent light attenuation of the radiation through the skin. The sun protection factor (PF) is defined by the z-independent attenuation of the radiation density in the skin:

1

PF: (2)

T The approach for the determination of the PF is to determine the transmission factor T with backscatter measurements, since the transmission through the skin with and without protective agent layer can not be detected directly. Here, light is irradiated locally into a limited exposure surface of the skin surface. A portion of the light is remitted by scattering processes of the skin and measured in the area of a detection area (error! Reference source could not be found.). Between the detection surface and the illumination surface there is a distance r, which, according to the invention, is chosen to be substantially greater than the layer thickness formed by the radiation protection agent. If the distance r is greater than the layer thickness formed by the radiation protection agent, the radiation transport from the illumination position to the detection surface can be described approximately by three sequential processes:

i. Transmission through the occupied by the radiation protection skin layer with

Transmission factor T

II. Lateral transmission through the deeper area z ~ z _across the skin,

described by the light attenuation L (r)

iii. Repeated transmission of the radiation protection coated layer with

Transmittance factor T ^'

For the detected backscatter R ₀ hne or R _m it is thus approximately

R with = P in T L (Vz transverse) L (Vr) U Vz transverse) Γ where T ~ V

With equations (2) and (3), the sun protection factor PF can be calculated from backscatter measurements before and after application of the radiation protection agent:

The ratio R ₀ hne / Rmit is independent of the distance r and z he _qu. The backscatter is measured spectrally resolved. The resulting spectrum of the transmission factor Τ (λ) can then be used to derive protection factors corresponding to the existing standards.

For example, for the SPF you get:

Ι (λ) is the intensity spectrum of the sun and Ε (λ) the erythema spectrum, ie the spectra with an intensity sufficient for erythema to use. Other Light sources with an illumination spectrum Ι (λ) or a wavelength range Ε (λ) to be protected by the radiation protection agents result analogously in protective factors, which can likewise be determined according to the invention.

The relationship between backscatter and protection factor according to equation (4) can be confirmed with model calculations for UV light on a skin model. Error! Reference source could not be found, showing corresponding results of Monte Carlo calculations for the radiative transfer equation. Radiation protection agents with varying scattering and absorption properties were assumed, furthermore the melanin content of the epidermis was varied. It turns out that the backscatter measurement described here is approximately independent of the special properties of the radiation protection agent, this is not the case for the methods of backscatter measurement described in the prior art.

1. If the lateral distance r between the illumination surface and the detection surface or the radiation protection means with small light protection factors is too small, a portion of the light can transmit transversely through the horn layer without having completely traversed the horny layer in the vertical direction. This leads to a deviation from the relationship described in equation (4). The minimum value for r results from the optical properties of the skin and the radiation protection agent. It results as a minimum value r = 0, from this a sun protection factor can already be determined. Preferably, the minimum value for r is the layer thickness of the layer of radiation protection agent, which results in the standard application of sunscreen approximately 20 μηι, and particularly preferably the minimum value r for UV illumination on the skin r = 60 μηι. A maximum value for r is due to the amount of radiation still striking the detector, that is to say the effect of the light attenuation by the radiation protection means AND of the underlying skin. Here a practical value of 1 mm will be an upper limit for UV irradiation / protection formulation. Preferably, a maximum value of 500 μηι as a value for r. Particularly preferred is a value of r <200 μηι. According to the invention, several remission measurements with different values of r are recorded simultaneously (error! Reference source could not be found). For sufficiently large distances r, the attenuation T is independent of r, so that the measurements can be detected with too small a distance and excluded from the evaluation in order to avoid a wrong determination of the PF.

2. As a further measured value, the backscatter R ° in the area of the illumination surface can be measured. Equation (4) can be calculated using this measurement a correction term g can be extended, which reduces errors in the prediction of the PF. Thus, the formula for determining a corrected sun protection factor is:

3. The skin has furrows and crevices, which lead to a laterally inhomogeneous application of the radiation protection agent and thus to a location-dependent fluctuation of the sun protection factor and also influence the backscatter by different formation of the skin in this area. These influences are only recorded when taking measurements on the skin. The methods mentioned in the prior art and based on PMMA substrates do not detect this, or restrict them in the case of embossed structures. By means of an embodiment of the solution according to the invention, a localized remission measurement is carried out with which this heterogeneity of the transmission can be determined by multiple measurements at adjacent positions. This can be determined on the one hand from a suitable averaging a mean attenuation and thus a mean PF. On the other hand, the variance of the damping can be determined, so that properties of the radiation protection agent with respect to the application to the skin can be examined.

To describe the wetting behavior, the abrasion behavior and in the distribution of the radiation protection agent over the service life can thus be provided by the measuring method described a method for further qualification.

By directly measuring the optical effect of the radiation protection agent, the method described here has a wider range of applications compared to the existing methods which use erythema, pigment or radical formation. In contrast to the existing procedures can be measured repeatedly on a sample; once induced erythema or pigmentation can not be repeatedly generated. Furthermore, the sun protection factor can be detected spectroscopically in all required wavelength ranges.

In a separate embodiment of the measuring method, the measurements are sequentially at the same location on the measuring body, z. As the skin performed. This is done by measuring continuously for short periods of time and for longer ones Time intervals with measurement pauses, in which the optical interface of the measuring device is removed from the measuring location and periodically replaced at the same location. Since the measurement does not change the skin (redness) or measuring body, the advantage of the method is that it can be performed several times at the same measuring location without distorting the measured values. If multiple measurements are made, on the one hand the progress of the protective effect can be observed, which is not carried out with previous MED-based methods for ethical reasons due to the large number of sample sites / sites with invasive measurement. At the same site of measurement, the MED-based procedure can not be used because the determination is based on the appearance of redness, but it does not (as in sunburn) decrease in relevant protection periods (hours). Furthermore, the skin is pre-damaged at the site and does not provide reliable information on the duration until a complete regeneration (days) until damage occurs.

In a separate embodiment of the measuring method, the measurement is carried out at measuring sites loaded with different amounts and / or types of radiation protection agent, or after interaction with the applied radiation protection agent at the same measuring location. This is done by the optical interface of the measuring device removed, an application of further radiation protection agent or an interaction takes place at the measuring location (wiping / rubbing with a defined procedure, rinsing with water or the like, bleaching with light, etc.) and then another measurement takes place, which is based on the original measurement without radiation protection. It is also conceivable to refer the measurement to the measurement carried out before the interaction. The advantage of the method is the detection of mechanical effects on the radiation protection and the possibility at the same measuring location (for example spine as usual or forehead) to quantify these influences more easily. For a good quantification, a group of probands whose individual measured values must be separated from the influences by the interaction by statistical evaluation must currently be measured. Only with the method according to the invention is it possible to carry out a rapid measurement of interactions at the same measuring body and measuring location and thus to exclude influences of the measuring body or measuring location and to easily and without great effort evaluate a product development or the resistance of the radiation protection agent against the interactions carried out.

In a separate embodiment of the measuring method, the measurement takes place at different measuring locations with the same distance from the illumination surface to the detection surface. Specifically, this means that a sun protection factor, which is usually collected on the back with more practice-relevant sites for radiation protection, such as the face or forehead or the bald head in the case of sun protection or in other radiation protection situations, for example, exposed to radiation hands. This is done by the optical interface of the measuring device is positioned at these locations. There must be no change in the measurement procedure or on the device. So far, a measurement with the "solar simulator" for ethical and cosmetic reasons (there remains a rectangular redness) not at naturally exposed sites. The inventive method is due to the low illumination dose without damage or redness and can also be placed on almost any location on the skin of a subject or other skin models, also due to the geometry of the optical interface.

In an optional development according to the invention, a plurality of detectors are arranged such that they have the same distance to one of the radiation sources.

In a separate embodiment of the measuring method, the measurement is carried out several times without removing the optical interface of the measuring device, and analyzes the temporally successive measurements. The successively determined sun protection factors are also analyzed and the measurement is ended when the successive sun protection factors differ less than a standard deviation of 1 σ from one another, ie assume a stable value. Other stability criteria are also in accordance with the invention. Deviations of the determined sun protection factors can result from the bleaching behavior, the penetration behavior into the measuring body or the skin or technical influences in the measuring device. The method allows, without limitation, the multiple measurement and the analysis is not time-consuming, since the measured values are calculated by a pre-established algorithm from the detector-derived, wavelength-resolved signals.

In a development of the method according to the invention for the non-invasive determination of the sun protection factor of a radiation protection agent, a plurality of measurement projects are carried out. The measurement projects are carried out at different positions on the measuring body. When analyzing the sun protection factor of the radiating agent, the measured values obtained at the different positions are averaged. This has the advantage that the locally introduced radiation dose can be minimized if the measuring body is exposed to radiation at a large number of positions. Furthermore, irregularities that may be present as a result of the inhomogeneity of the measuring body or the order of the radiation protection agent and thus complicate or prevent accurate measurement of the mean SPF, are taken into account in the evaluation.

In a further development of the invention, it is further provided first to perform a measurement on the measuring body to which no radiation protection agent has been applied. This measurement is then done using the same parameters and the same Position as the previously performed measurement repeated. This has the advantage of being able to take into account the influence of the measuring body on the effect of the radiation protection agent in the analysis of the protective effect of the radiation protection agent.

To evaluate the influence of external agents on the protective effect of a radiation protection agent, the measurement projects are also repeated. For this purpose, the measurement bodies acted upon by the radiation protection agent are measured a first time between the individual measurement projects. After this first measurement the measuring body may be exposed to the protective effect of the radiation protection agent. Subsequent to this, the measurement project is then repeated. This happens at best with the same parameters and at the same position we the first measuring project. The influences acting externally on the protective effect of the radiation protection agent can be time, water, abrasion, the action of the radiation or other influences. Measurements before and after exposure to the effects can be used to determine the effects on the protective effect. This makes it possible to optimize the protective agent in terms of resistance to the influences and thus to ensure the best possible protection. In one embodiment of the invention, it is further provided first to perform a measurement on the measuring body to which no radiation protection agent has been applied. Optionally, before the first measurement to determine the effect of external influences on the protective effect of the radiation protection agent, a measurement can be carried out on the measuring body before the radiation protection agent has been applied to the measuring body.

In one development of the invention, the radiation is detected spectrally separated for wavelengths or wavelength ranges and then analyzed for the separate wavelengths or wavelength ranges. The spectrally separated wavelengths or wavelength ranges may include UV-A, UV-B and / or the visible light. The spectral separation can be done directly behind the radiation source and before the penetration of radiation into the measuring body. Alternatively, the radiation backscattered by the measuring body can be spectrally separated into a plurality of wavelengths or wavelength ranges.

In a further embodiment of the invention, characteristic values of different types are determined from the measured values. These characteristics are based on different damage functions. These damage functions can be the effect of UV-A radiation or completely different wavelength ranges on the skin or in continuation on other biological materials (eg wood for wood preservatives) by acute reactions or other damage (eg DNA strand breaks in living biological material ). On the one hand, this procedure has the advantage that the locally acting radiation dose can be reduced if the spectral separation takes place before penetration of the radiation into the measuring body. On the other hand, this approach has the advantage that the calculation of the sun protection factor can be independent of the respective spectrum and also independent of the detector characteristic.

In a development according to the invention, the radiation is irradiated to a limited area. This area is separated from the detector area.

In a further embodiment of the invention, the sun protection factor of the radiation protection agent according to the formula

R 1

without PF ^

^R with T ²

certainly.

In a further embodiment of the invention, the measuring head is cleaned before the measurement project. The cleaning is preferably carried out by means which leave no residue and / or have no influence on the characteristic of the radiation. This has the advantage that all measurement projects can be carried out under the same optimal conditions. In this way, the radiation dose can be lowered further, since no contamination for the intensity of the radiation falling on the measuring body has to be taken into account.

In a further embodiment of the invention, the individual measurements are carried out for a plurality of distances between the detector and the radiation source. The distances are in this case in a range of 0 mm to 1 mm, preferably from 20 μηι to 0.5 mm and more preferably from 60 μηι to 200 μηι be varied.

This method has many advantages over the prior art. Thus, in the method according to the invention, only a small dose of light below a MED (minimum erythema dose, individually for skin types) or below the maximum permissible irradiation (MZB value, for UV and also other wavelength ranges) is irradiated onto the measuring body. Due to these low doses of light, the method is also suitable for damage-free in vivo use. This has the advantage that the identical physiological conditions are present during the SPF testing and in the application in the sun. The inventive method is also applied non-invasively. Furthermore, in the method, the light propagation in the skin is taken into account and thereby an increased measurement accuracy is achieved. The consideration of the physiological properties by a more realistic skin model lead to an improvement of the determination of the sun protection factor in the UVA and in the visible spectral range. Furthermore, one is Alignment of in vivo (human skin) and in vitro test (-► tissue model = protected) possible. In addition, the method can be used for a very large wavelength range, not limited by lamp spectra, erythem spectrum, reactions of the measuring body, or the like. The method according to the invention also offers the possibility of the spectral range (SPF is defined only for UVB) for the measurement expand, since only with UVB skin reactions (MED) are to be found. As a result of the small dose of light irradiated to the measuring body, no restrictions with regard to the measuring location are to be observed. Even measurements on the sensitive scalp are possible. Furthermore, the influence of substances on the measurement according to the invention is avoided, which influences skin rash or UV-induced erythema. The inventive method is simpler and more meaningful than the previously known methods and associated with lower costs.

Furthermore, the object is achieved by a device for non-invasive determination of the sun protection factor of a radiation protection agent comprising a sensor unit, wherein the sensor unit comprises at least one radiation source and two detectors, wherein the detectors have different distances to the radiation source, or either at least two radiation sources and a detector, wherein the radiation sources have different distances to the detector, or a radiation source and a detector, wherein the distance between the radiation source and the detector is variable. The radiation source is suitable for emitting light in the region in which the protective effect is to be defined, the distances between the individual radiation sources and the detectors being determined. This range includes in particular the visually visible light (VIS) as well as the UV-B and the UV-AB range. Also in the NIR range or the IR range, the radiation source can emit light. Furthermore, the device according to the invention has a controller for controlling the radiation source, wherein the controller is adapted to control the radiation source such that the radiation source emits a maximum light dose of small MED and / or MZB, via an analysis unit which is suitable, the detected radiation taking into account respective distances between the radiation source and the detector to analyze and an output unit that outputs the determined value. In an optional development of the invention, the radiation sources and detectors are arranged in Rückstreuanordnung.

In a further embodiment, the device according to the invention has the possibility of changing test parameters such as wavelength, distance r between radiation source and detector and / or spot sizes. This offers the possibility to adapt the measuring parameters and in particular the light dose to the measuring conditions in such a way that the measurements on the Measuring body radiated light dose can be minimized without affecting the quality of the analysis.

In a further embodiment of the invention, the distance of a radiation source and a detector is selected so that the detected radiation has passed completely through the layer of the measuring body in which the applied radiation protection agent is located. In a further optional embodiment of the invention, the distance between one or more radiation sources and one or more detectors between 0 and 1 mm, wherein the distance is selected so that the penetration depth of the radiation greater than the layer thickness and / or penetration depth of the radiation protection agent in the Skin is. This ensures that the relevant for the determination of the sun protection factor areas of the measuring body are completely irradiated.

In a further development of the invention, the device has one or more radiation sources and at least one illumination surface, wherein the illumination surface of the radiation sources between a circle with 07 μηι and 1 mm ² , preferably between a circle with 0100 μηι and 250 μηι ² and more preferably between a circle with 0 200 μηι and a circle with 0 400 μηι lies. An optional embodiment of the invention has one or more detectors and at least one detection surface, wherein the detection surface between a circle with 07 μηι and 1 mm ² , preferably between a circle with 0100 μηι and 250 μηι ² and more preferably between a circle with 0 200 μηι and a circle with 0 400 μηι lies. As a result, the advantage is achieved that the illumination surface of the radiation sources on the one hand is large enough to bring in enough light, but not too large, that from a certain size only edge region is effective and increases the etendue. This also limits the light dose required for the analysis.

In a further embodiment of the device according to the invention, the radiation source emits light in accordance with the solar spectrum. Optionally, the analysis unit resolves the measurement spectrally with subsequent weighting according to the typical solar spectrum. This corresponds to the product of light intensity of the radiation source and detector sensitivity to the product of solar spectrum and Wirkbzw. Damage spectrum. This has the advantage that no special radiation sources or detectors for the device must be used because the weighting is done later in the analyzer and can be adapted to the given from the existing procedures for determining a sun protection factor product of solar spectrum and effect or damage spectrum or also other rules for the determination of a sun protection factor. In a development according to the invention, the device for measuring the measured quantities has fiber arrangements or optically imaging systems with reducing optics. This ensures that the spatial resolution can be significantly improved, or inexpensive components can be used, which can produce the same illumination or detection surface through the reduction optics.

Possible embodiments of the measuring arrangements for the local distance-dependent

Backscatter:

For the measurement of the distance-dependent backscattering, it is possible to select fiber arrangements or also optical systems which image light sources and detectors on the skin surface. The light from one or more light sources is radiated into the skin over a limited illumination surface, light backscattered from one or more detection surfaces of the skin is detected by detectors or by a spectrometer. The backscatter must be measured before and after the application of the radiation protection agent at the same position on the skin. To find the measuring position with the least possible error, a positioning aid is favorable. The spectrally resolved backscatter first results in a spectrum Τ (λ) of the transmission factor (equation (4)), from which, for example, for sunscreen formulations with equation (5), a standard-compliant protection factor is calculated. As an alternative to the spectrally resolved measurement, the spectrum of the light source and the spectral sensitivity of the detectors can be chosen so that the measured detector signal is proportional to the integral in equation (5).

A simple arrangement consists, for example, of an illumination fiber and a detection fiber, which are placed on the skin surface at a suitable distance from each other (error! Reference source could not be found) and thus determine the illumination and detection area.

4. A higher light output and the possibility to measure at the same time at several distances between the illumination surface and the detection surface is achieved by a fiber bundle, as for example in Fehler! Reference source could not be found.). Detection fibers with the same distance to the illumination fiber are combined on the output side and coupled to a detector. Instead of the detectors, an imaging spectrometer can be used to simultaneously measure the backscatter spectrum for each distance. In an extended embodiment, the backscatter signal is measured in each detection fiber. The variance of the signals allows conclusions to be drawn about the inhomogeneity of the protective properties of the investigated radiation protection agent erroneous measurements or incorrect application of the radiation protection agent can be detected.

5. With an arrangement with multiple lighting fibers, as shown in Figure Errors! Reference source not found. a), the transmission factor can be averaged over a larger spatial area, or its variance can be determined. Outlier or erroneous measurements can be detected by comparing the measurements at different distances r and at different positions of the skin and excluded from the evaluation. Instead of in error! Reference source not found. b) configuration can also be several units of error! Reference source not found. a) sketched configuration are combined into a fiber bundle. B here denotes the illumination fiber, 1 to 4, the different fibers at certain intervals (1 near, 4 maximum removed). a. Repetitive measurements at different measuring points either by automatic shifting of the measuring arrangement or by manual displacement further increase the statistical accuracy.

b. In general, with the measuring arrangement light cans can be used, which are below a possible damage.

Practical considerations for measurement:

6. Due to the non-harmful measurement can be measured at any point on the skin and not as previously in the damaging procedures only on aesthetically acceptable sites such as the back. In particular, can be measured on the skin in the face, which is exposed to the greatest risk of damage.

7. By using fiber couplings for the measurement, a stable measurement can take place with a defined spot size in the contact and a defined numerical aperture or defined light propagation. By a pressure measurement or also a support aid with an enlarged surface, the pressure dependence of the measurement can be reduced and the vertical support controlled, the latter prevents the optical crosstalk of illumination and detection. By using absorbent or reflective materials between the fibers, optical crosstalk can be reduced, thus further improving channel separation. By using low-fluorescence materials, incorrect measurements are prevented. 8. When using an imaging optics for the transmission of illumination and detection optics can be stably adjusted with a window in the skin contact both the distance between the optics and the skin surface, as well as the respective spot sizes and numerical apertures. The image size can be used to adapt the spot size to suitable detectors.

9. Interchangeable films which are attached by means of a fiber applicator or window can prevent the spread of radiation protection agents and ensure sterile use ((also used in the method described in the literature by Ruvolo et al., See page 3) )). For measurements without film, a suitable cleaning must be carried out between the measurements at different measuring locations or test persons. The contamination of the sensor can be detected by the measuring arrangement itself, for example, by taking a measurement in the free space or in a dark measuring chamber inside.

10. For an improved measurement, it may be useful to cream the skin with a radiation protection agent without light-attenuating effect (index matching) before measuring with the radiation protection agent.

11. By switching the light source on and off with simultaneous measurement can be detected by the measuring apparatus, the influence of ambient light on the measurement and thus a faulty placement of the measuring arrangement and thus a faulty measurement (lock-in technology, etc.).

12. The spectral dependence of the remission can be determined by using a spectrometer or by illuminating the skin with multiple light-emitting diodes. The measurement for different spectral ranges can be done simultaneously or sequentially to either adjust the amount of light for a good signal-to-noise ratio on the detector side or to allow the spectral resolution.

The inventive method is further characterized by the following independently combinable with each other features:

• The measuring head is positioned perpendicular to the sample surface before the measurement.

• stray light incident on the measuring range is filtered out for the wavelength range for which the evaluation of the measurement is to take place.

• The disturbance light is filtered out by modulation techniques, eg lock-in techniques. • A correction of the measured data is carried out taking into account the backscatter at the illumination position.

The detected radiation is analyzed separately for individual radiation source / detector pairs.

• the determined measured data are analyzed with regard to implausible measured values or erroneously determined measured values

• The measurement projects are carried out in vivo or in vitro

• the sun protection factors are separated for different

Wavelength ranges analyzed, with the different

Wavelength ranges light from the spectra UV-A and / or UV-B and / or VIS VIS and / or IR includes.

The device according to the invention is furthermore distinguished by the following features which can be combined with one another independently of one another:

• the measurement is performed with distance = 0 between the radiation source and the detector.

• the distance = 0 measurement between the radiation source and the detector is used for calibration. The calibration is only necessary with respect to the spectral position, an intensity does not have to be calibrated, since the relative measurements with / without radiation protection mean that the measurements of the irradiated intensity are independent of the measurements, provided that they do not change appreciably between the measurements.

• It has means to minimize the interference.

• Devices are provided which shield the detectors from radiation that has not been transmitted through the protective cream and / or skin or measuring body.

• The analysis unit of the device is suitable for detecting outliers and erroneous measurements.

embodiments

In one exemplary embodiment of the method according to the invention, a point on the inside of the lower arm is first subjected to a formulation similar to the radiation protection agent but without a light-damping effect. This serves to compare the measurements with / without radiation protection agent and increases the accuracy, but is not mandatory for carrying out the method or determining a sun protection factor. Thereafter, this location is measured with the measuring device by light at a defined area of about 200 μηι diameter - generated, for example by placing an optical fiber (illumination fiber) with a core diameter of

0 200 μηι - is irradiated. The irradiation takes place with an intensity that does not cause any acute damage in the skin, which is approximately 5 μ \ Λ /, or below the simple MED, or below the MZB values, or significantly below the values caused by solar radiation , 1 MED equals the lowest irradiation dose which, when read after 24 hours, caused a sharply limited erythema (redness) of the skin. This dose varies greatly even among people with the same skin type. In fair-skinned people of skin type II 1 MED equals about 250-400 J / m ² (25-40 mJ / cm ² ). Damage can also be prevented by falling below the MZB values. MZB are in the DIN EN 60825-1 "Safety of laser equipment - Part 1: Classification of equipment, requirements and user guidelines", the international standard IEC 60825-

1 corresponds. The accident prevention regulation "Laser Radiation" (BGV B 2) also contains these values, additions and changes, in particular on the basis of DIN EN 60825-1: 2001-1 1, are listed in BG Information 832 "Operation of Lasers". The underlying limit values come from the ICNIRP (International Commission on Non-Ionizing Radiation Protection).

This light passes through the skin of the sample and passes at a predefined distance - for example, 60μηι - from a detection surface, which in turn may consist of a patch optical fiber (detection fiber), which has a core diameter of 200μηι. To increase the sensitivity, or further decrease the illumination intensity, a plurality of detection fibers can be arranged equidistant from the edge of the illumination fiber in an optical measuring head, which is in direct contact with the measuring location, and be guided together to a detection device and thus the intensity can be measured , Depending on the magnitude of the intensity and the selected detector, the signal generated by the radiation is amplified by a defined factor, which also provides a signal above the noise for the subsequent measurement of the weaker intensity. The detection is carried out with wavelength resolution. The resolution may be, for example, 1 nm and should be selected depending on the definition of the sun protection factor.

Subsequently, the measuring location with a radiation protection of a predetermined type, for which the sun protection factor is to be determined acted upon. The standards provide for a procedure that can be followed or deviated from without affecting the performance of the measurement process. Only the meaning of the determined sun protection factor for the application scenarios of the radiation protection agent is dependent on the type of exposure. After exposure to the radiation protection agent, a further measurement of the same type is carried out at the same measuring location. This completes the measuring cycle after two individual measurements. This similar second measurement is charged with the first measurement, for example, according to the above equation (4). This calculation is carried out with wavelength resolution for the area in which the SPF is to be defined. An SPF, for example, is the SPF, which is valid for sunscreen in the UV-B range. It is determined as described in equation (5). The spectra Ι (λ) - the intensity spectrum of the sun - and Ε (λ) - the erythema spectrum - are defined in the standard ISO 24444 or in medical literature [MCKINLAY, AF, and BL DIFFEY (1987) "A reference action spectrum for ultraviolet induced erythema in human skin. " In: "Human Exposure to Ultraviolet Radiation" (Eds. Passchier, WF and BFM Bosnjakovic) Excerpta Medica, Amsterdam, pp. 83-88].

In a modification of the above embodiment also a repetition of the individual measurements during a measuring cycle is conceivable, wherein the individual measurements are averaged or added up (accumulated). The measurement cycle thus includes, for example, 10 to 50 individual measurements without radiation protection agent (or without light attenuation in the radiation protection agent) and an equal number of measurements after application of the radiation protection agent. To avoid other influences, the measurements after application of the radiation protection agent can be detected only after a waiting time after the application of, for example, 2 minutes. Other types of analysis are also conceivable wherein the wavelength resolved signal values of the individual measurements are all taken into account without being contracted to a wavelength resolved value prior to analysis (equation (4)).

A modification of one of the preceding embodiments is also a measurement cycle only with a limited wavelength range, for example with illumination by coupling a 365nm LED into the illumination fiber. For this purpose, preliminary work is required, which takes place with the radiation protection agent and a broader wavelength range and forms a basis for correlating the values in the restricted wavelength range with an SPF. It must be ensured as a prerequisite for a correlation that the measurement at 365 nm does not show different spectral light attenuation compared to the comparative measurements for the type of radiation protection agent used in the case of preliminary work and measurement. As a further preparatory work, the preceding determination of the sun protection factors is assigned to a measured light attenuation at 365 nm. In the already described measurement cycle with only one spectrally limited irradiation, the light protection factors are then determined by comparison with previously known values in the analysis apparatus via this assignment (correlation). In a modification of one of the preceding exemplary embodiments, a third measurement after an interaction of the same type is also to be carried out at the same measuring location. For this purpose, the measuring device is used similarly. The interaction may be, for example, ten times light pressure wiping and a wet terry towel, or other light, mechanical, or moisture or combination effects. This third measurement is evaluated against the first measurement according to equation (4) and gives a 'sun protection factor after interaction' which is compared to the 'sun protection factor without interaction' (determined from the first and second measurements) and from this the effect of the interaction on the protective effect can be determined. It makes sense to use such a method with interaction in tests for water resistance of the radiation protection agent and in statements on the change of the sun protection factor by mechanical effects by dressing and changing, which should be part of a product information.

The interaction may also be to detect the change of the radiation protection agent over time by measurement after a short period of time - for example during the first minutes after exposure - or over a longer period of time - for example 2 hours after exposure. The procedure is the same. At longer intervals, it is according to the invention to remove the optical measuring head and set up at the same location after the predetermined time. With such measurements, chemical changes of the radiation protection agents can be detected or the pull-in behavior and its effect on the sun protection factor. The individual measurement takes a few seconds, the analysis either takes place immediately (several hundred milliseconds) or the measuring signals of the detectors are buffered.

As an extension of one of the above exemplary embodiments, third measurements are carried out periodically, for example every 5 seconds, and analyzed until the deviation of the successive values lies below the simple standard deviation, ie shows stable values. Such an evaluation takes place in the analysis device, which ends the measurement when the stable values are reached and signals this to the user.

In a modification of one of the preceding exemplary embodiments, a further measurement is also to be carried out at another measuring location in the same way. Thus, the SPF of the same radiation protection can be compared with similar job at different locations. Likewise according to the invention, a first measurement (individual measurement without radiation protection agent) at the additional measuring location is used as the basis for the analysis of the further measurement. List of reference numbers

1 lighting

2 detection

3 skin

4 epidermis

5 horny layer

6 protective agents

7 backscatter

8 detector

Abbreviations

SPF sun protection factor determined according to a regulation

UVAPF UVA protection factor according to the in vitro method according to ISO 24443

MED minimal erythema-producing dose; corresponds to the minimum dose until it reaches a reddening of the skin

MZB maximum allowable irradiation, e.g. determined by regulations or by a radiation protection commission

UVA wavelength range of light from 380 nm to 315 nm

UVB wavelength range of light from 315 nm to 280 nm

VIS wavelength range of light from 380 nm to 780 nm

NIR wavelength range of light from 780 nm to 1400 nm

IR wavelength range of light from 780 nm to 1 mm

r Distance between detection surface and illumination surface

T scalar transmission factor (wavelength dependent) characterizes the

Light attenuation by the protective agent

otmeiz) Radiation density in the depth range z of the skin without radiation protection

Φι α (ζ) Radiation density in the depth range z of the skin with applied

Radiation protection products

Pin irradiated on the skin surface lighting performance Lquer (r) path length dependent light attenuation through the skin (wavelength dependent) PF protection factor

Rohne detected backscatter without radiation protection

Rmit detected backscatter with applied radiation protection agent detected backscatter of the illumination surface

λ wavelength

Ι (λ) intensity spectrum of the sun

Ε (λ) Spectrum for the effect of the radiation to be protected from

Spectrum of activity, for example for the formation of erythema or pigment g (R ° without, R ° with, Rohne, Rmit) correction function for the determination of the PF according to equation (6)

Claims

claims

Method for the non-invasive determination of the sun protection factor of a radiation protection agent comprising the method steps

• Control of at least one radiation source by a controller for emitting radiation to a measuring body

Emitting radiation from the at least one radiation source

wherein the controller controls the at least one radiation source in such a way that the at least one radiation source emits a maximum light dose of small MED and / or MZB,

wherein the radiation source emits light at least in the area in which the protective effect of the sun protection factor is to be defined,

Detecting the radiation emitted by the radiation source in at least one detector

one measurement cycle comprising several individual measurements,

the radiation emitted by the at least one radiation source being detected by at least one detector in at least two individual measurements, the distance between the radiation source and the detector of the first individual measurement being different from the distance between the radiation source and the detector of the second individual measurement,

Analyzing the detected radiation taking into account the respective distances between the radiation source and the detector.

Method for the non-invasive determination of the sun protection factor of a radiation protection agent according to claim 1

characterized in that

For a measuring project, several measuring cycles are carried out at the same position on the measuring body.

3. A method for non-invasive determination of the sun protection factor of a

Radiation protection agent according to claim 1 or 2

characterized in that

For the determination of the SPF several measurement projects are carried out, the measurement projects are carried out at locations of the measuring body having a different exposure to the radiation protection agent, the measurement project are preferably carried out at the same position of the measuring body.

4. A method for the non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 1 to 3

characterized in that

one measurement cycle several individual measurements equidistant from

Includes illumination surface to detection surface,

wherein the individual measurements are performed at the same distance at different positions on the measuring body.

5. Method for non-invasive determination of the sun protection factor of a

Radiation protection agent according to claim 4

characterized in that

the measurement cycles are repeated until the light protection factor determined from the radiation of the at least one radiation source and the radiation detected in the at least one detector is less than one

Standard deviation of 1 σ to the previously determined sun protection factors

differs.

6. Method for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 1 to 5

characterized in that

several measurement projects are carried out,

wherein the measurement projects are performed at different positions on the measuring body and wherein the measured values determined at the different positions are averaged for determining the sun protection factor of the radiation agent.

7. A method for the non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 1 to 6

characterized in that

Measurement projects are carried out repeatedly,

wherein between the measuring project exposed to the radiation protection means measuring body is exposed to the protective effect of the radiation protection agent acting influences,

these influences include attrition, water, time and / or exposure to radiation.

8. A method for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 1 to 7

characterized in that

the detected radiation is recorded and evaluated spectrally separated for wavelengths or wavelength ranges,

wherein the spectral separation may comprise the wavelength ranges UV-A, UV-B and / or the visible light.

9. A method for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 1 to 8

characterized in that

characteristic values of different types are determined from the measured values

these characteristics are based on different damage functions.

10. A method for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 1 to 9

characterized in that

the radiation is irradiated on a limited area, which is separated from the detector surface.

1 1. A method for non-invasive determination of the sun protection factor of a radiation protection agent according to one or more of claims 1 to 10

characterized in that

the determination of the sun protection factor of the radiation protection agent according to the formula

R 1

PF ^

T ²

he follows.

Method for the non-invasive determination of the sun protection factor of a radiation protection agent according to one or more of claims 1 to 11

characterized in that

a measurement project without previously applied to the measuring body protection means and a measurement project is carried out with previously applied to the measuring body protection means.

13. A method for non-invasive determination of the sun protection factor of a radiation protection agent according to one or more of claims 1 to 12

characterized in that

before the measuring project, the measuring head is cleaned.

Method for the non-invasive determination of the sun protection factor of a radiation protection agent according to one or more of Claims 1 to 13

characterized in that

the individual measurements are carried out for several distances,

wherein the distances are at least over a range of 0 mm to 1 mm, preferably from

20 μηι to 0.5 mm and more preferably from 60 μηι to 200 μηι be varied.

15. Device for non-invasive determination of the sun protection factor of a radiation protection agent comprising

• one sensor unit

• comprising the sensor unit a) at least one radiation source and two detectors,

wherein the detectors have different distances to the radiation source, or

b) at least two radiation sources and a detector,

wherein the radiation sources have different distances to the detector, or

c) a radiation source and a detector,

wherein the distance between the radiation source and the detector is variable

wherein the radiation source is adapted to emit light in the area in which the protective effect is to be defined

wherein the distances between the individual radiation sources and the detectors are determined

• a controller for controlling the radiation source

• wherein the controller is adapted to control the radiation source such that the radiation source emits a maximum light dose of small MED and / or MZB

An analysis unit which is suitable for analyzing the detected radiation taking into account the respective distances between the radiation source and the detector

• an output unit that outputs the determined value.

16. A device for non-invasive determination of the sun protection factor of a

Radiation protection agent according to claim 15

characterized in that

Radiation sources and detectors are arranged in Rückstreuanordnung.

17. Apparatus for non-invasive determination of the sun protection factor of a

Radiation protection agent according to claim 15 or 16

characterized in that

the device has the possibility to change experimental parameters such as wavelength, distance r between radiation source and detector and / or spot sizes.

18. Apparatus for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 15 to 17

characterized in that

the distance between a radiation source and a detector is selected so that the detected radiation has previously entered the measuring body at least partially in depth through the layer acted upon by radiation protection agent.

19. A device for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 15 to 18

characterized in that

have one or more radiation sources and at least one illumination surface,

wherein the illumination surface between a circle with 07 μηι and 1 mm ² , preferably between a circle with 0100 μηι and 250 μηι ² and more preferably between a circle with 0 200 μηι and a circle with 0 400 μηι.

20. Apparatus for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 15 to 19

characterized in that

have one or more detection surfaces,

wherein the detection surfaces are merged onto a detector,

wherein the detection surface between a circle with 07 μηι and 1 mm ² , preferably between a circle with 0100 μηι and 250 μηι ² and more preferably between a circle with 0 200 μηι and a circle with 0 400 μηι.

21. Apparatus for the non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 15 to 20

characterized in that

the distance between one or more radiation sources and one or more detectors is between 0 and 1 mm, wherein the distance is selected so that the penetration depth of the radiation is greater than the layer thickness and / or penetration depth of the radiation protection agent into the skin.

22. Apparatus for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 15 to 21

characterized in that

the radiation source emits light according to the solar spectrum

or the analysis unit spectrally resolves the measurement with subsequent weighting corresponding to the typical solar spectrum

such that the product of light intensity of the radiation source and

Detector sensitivity according to the product of solar spectrum and Wirk- or

Damage spectrum is.

23. A device for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 15 to 22

characterized in that

the apparatus for measuring the measured quantities has fiber arrangements or optically imaging systems with reducing optics.

24. Apparatus for non-invasive determination of the sun protection factor of a

Radiation protection agent according to one or more of claims 15 to 23

characterized in that

the determination of the sun protection factor of the radiation protection agent takes place as averaged value from a plurality of measurements from one or more measuring locations.