DE10322413A1 - Measurement device for measuring UV transmitted by a cosmetic or pharmaceutical product comprises a membrane on which it is deposited and fiber optics for collecting the transmitted light and transmitting it to a radiometer - Google Patents

Abstract

External product is applied on the top side of an UV-transparent support layer or membrane. Product and support are then irradiated with radiation between 280 and 420 nm and the transmitted radiation measured with a radiometer, optimally in a frequency resolved manner. The light transmitted through the membrane or support is collected with optical fibers arranged beneath the membrane or support and further transmitted to the radiometer. An independent claim is made for a device for measuring the light transmission properties of a cosmetic or pharmaceutical product that is applied to the skin.

Description

The The invention relates to a method and an apparatus for measurement the influence of cosmetic or pharmaceutical externals on the Transmission of the human skin.

The optical transmission of the skin after exposure to externa is for a number pharmaceutical and cosmetic products of importance. These include covering, mostly pigment-containing formulations, products that are intended to color or tan the skin, those that are supposed to protect against infrared light and preparations, the predominantly reduce the transmission of UV light through the skin (sunscreen). Can continue Externa wanted or as unwanted Effect the permeability of the Skin for increase electromagnetic radiation. The Studies of such effects are particularly important if one increased Skin sensitivity to light avoided by using external preparations shall be.

The currently the most important application of methods for measuring the optical Transmission of externa on human skin provides the measurement the effectiveness of light stabilizers. The following explained the technical state of the process is essentially related on the measurement of light stabilizers, but is also for the others mentioned questions are valid.

The exam effectiveness of light stabilizers is usually done in vivo with the help of measurement series on selected test subjects. One determines the radiation time until the erythema threshold dose is reached, with a redness occurs, and forms the quotient from the ratio of erythema threshold time with sunscreen and erythema swelling time without sunscreen.

The Sun protection factor calculated in this way indicates how much longer the protected by the means Skin compared to unprotected Skin can be exposed to the sun.

In Europe, the method for determining the sun protection factors was standardized by the association of European cosmetics manufacturers "Colipa" and is the basis for the European harmonization of the sun protection factor test. According to this standard procedure, the test substances are applied in an area concentration of 2 mg / cm ² on the back of the test subjects The measuring surfaces are then exposed to a filtered xenon lamp, the spectrum of which roughly corresponds to the spectral distribution of natural sunlight. The radiation dose is gradually increased by 25% from measuring surface to measuring surface. The sun protection factor is then calculated from the radiation doses that are just now have created a minimal erythema.

at The method is a source of error that the reddening not measured on the skin, but determined by the examiner's visual inspection becomes. On the other hand, the test person is exposed to a radiation dose. For all Types of radiation exposure applies, however, that no limit is given in which exposure is considered to be completely harmless. For this reason, the radiation exposure is for ethical reasons for subjects during an exam preferably to keep low.

you therefore has in vitro methods for determining the sun protection factor and UV-A protection from light stabilizers designed to be completely without Subjects get along. A procedure is described in the German patent application 196 32 687. A test specimen is made of quartz or transparent Plastic proposed that in the wave range of 290 to 400 nanometers is optically transparent and a test area for recording the external having. It is then the transmission through the test specimen and the applied external measured frequency-resolved using a radiometer.

adversely What is particular about this measuring method is that the transmitted UV light only after a relatively long distance of several millimeters is measured. As a result, the measurement result is caused by scattering effects of the measuring light falsifies what makes the procedure imprecise.

task The invention is therefore a method for measuring the influence cosmetic and pharmaceutical externalities on the transmission of to propose human skin in which the radiation exposure for subjects preferably is small, but a higher one Measuring accuracy than with the known in vitro measurement methods.

The solution of this invention Task provides that the transmitted radiation from one onwards the bottom of the backing or membrane guided Optical fiber is picked up and forwarded to the radiometer. In this method, the use of an optical fiber transmitted electromagnetic radiation at a single point directly below the carrier layer or membrane are included. The captured light will then forwarded through the light guide to a radiometer with almost no loss and the intensity measured wavelength-resolved. As a result, the measurement result is not a longer exit path falsified and increases the measurement accuracy yourself.

Becomes instead of a rigid backing, such as quartz glass, a permeable membrane as a carrier material used, it's over it possible insert the light guide into the interior of the membrane and there the transmission measure directly. This will change the distance between the layers of the external and the measuring point shortened and falsifying influences the backing layer on the measurement signal are minimized.

at The layers of human skin lie with the entering UV light interact, mainly depending on the wavelength in a range from 10 μm to 300 μm in the epidermis. To be as close as possible to the properties of human skin to come with a support layer or membrane is advantageous with a diameter of less than 500 μm and / or an optical fiber with a diameter of less than 150 μm is used.

at The externum is the previously known and described in vitro measurements on a support surface, for example a quartz plate, applied. In contrast to these test specimens but the human skin is not a homogeneous, inert solid, but histologically it consists of one above the other lying layers with differentiated cell types and non-cellular components. When exposed to UV measurement light, this occurs due to this structure within the skin itself to wavelength-dependent reflection, scattering, Absorption and fluorescence effects. These interactions occur not for a transmission measurement using a simple quartz plate on. This falsifies the measurement result because it is the real situation only insufficiently reproduces.

On there is another difference between in vitro and in vivo measurements in that the externum there when applied to an inert support surface remains. When using an external on human skin However, this does not remain on the skin surface, but instead is absorbed by the skin. The different components of the protective agent then diffuse depending on their size and their polar properties in the skin layers, extracellular spaces, cell membranes or cells. This process is changing the optical properties of the skin.

Also has the skin has a certain temperature that is above ambient lies. This also allows the properties of the external are changed.

The optical and mechanical interactions of skin, external and Measuring lights are not recorded in the known in vitro methods. she are therefore not included in the measurement result.

This basic lack of in vitro measurement methods can now be surprising Fix it in such a way that the light guide into the, as a carrier layer for the Externally used, human skin inserted and the measurement performed in vivo becomes. As a result, the above-mentioned influencing factors are fully taken into account, since the emerging light after it has passed through human skin is measured directly. So there are the advantages of in vitro Procedure, namely the Objective measurement of the transmission without the procedure mentioned disadvantages, namely lack of significant influencing factors.

By doing the light guide in the area between the horny layer of the epidermis and When the basement membrane of the skin is inserted horizontally, the light is accurate in the area of the skin where the cell damage is caused by the UV radiation takes place.

There the measurement is made directly through the skin, it is not necessary a reddening of the skin to create. Therefore, the radiation duration and intensity of the measuring light used be kept below the erythema threshold. This will reduce the radiation exposure for the Subjects kept much lower than in the test after the Colipa standard.

Thereby, that the device has a light guide for receiving and forwarding of the radiation, the transmitted electromagnetic radiation recorded at a single point directly below the support layer or membrane become. As a result, the measurement result is not a longer exit path falsified and increases the measurement accuracy yourself.

at The layers of human skin lie with the entering UV light interact, mainly depending on the wavelength in a range from 10 μm to 300 μm in the epidermis. To be as close as possible to the properties of human skin the carrier layer has to come or membrane with a diameter of less than 500 μm and / or the light guide Diameter of less than 150 μm. Due to the small diameter of the light guide, it is also possible almost painless in the upper layers of human skin introduce, without causing an injury.

Around to focus the radiation and to specific test conditions to adapt, the light guide for receiving the radiation has a Micro optics.

When inserted into the skin, the risk of undesirable effects on the skin is reduced by the fact that the light guide is a biocompatible mate rial is formed.

Around the radiation exposure for The radiometer as a photomultiplier is to further reduce the number of subjects or diode array system. hereby the sensitivity of the measuring device is increased. When using a diode array system can also All wavelengths can be measured quickly and simultaneously. hereby the measuring process is accelerated and the radiation exposure continues decreased.

Around the distance and / or the angle between the light exit face of the Infinitely adjustable optical fiber and sensor input of the radiometer, is a connector provided between the two. This allows the power transmission from the fiber optic to the sensor input. This happens by inserting the optical fiber into the connector and is fixed. Then the distance and angular position are in small Levels changed and the signal strength measured until the maximum is found.

The Invention is referenced in a preferred embodiment on a drawing described by way of example, with further advantageous details the figures of the drawing can be seen.

Functionally the same Parts are provided with the same reference numerals.

The Figures of the drawing show in detail:

1 : A schematic circuit diagram of the measuring device and the skin with an inserted optical fiber in a sectional view.

In 1 the skin with the inserted light guide and the measuring apparatus are shown. It is shown how very precise measurements can be carried out in vivo using the described method and the described devices. It is a schematic representation that does not necessarily show the proportions in the correct relationship to each other.

With 9 . 10 . 11 . 12 different layers of the human skin are designated, which is shown in a schematic sectional view. It is 9 the skin surface, 10 the epidermis, 11 the basal cell layer and 12 the lower layers of skin.

The skin is treated with a UV lamp 5 irradiated, the UV radiation 6 emits in the wavelength range of 280-420 nm and thus exposes the skin. The light first hits the surface of the skin 9 , shines through it and then the epidermis 10 down to the basal cell layer 11 , The radiation is absorbed by the skin layers, so that no or very little light penetrates the lower skin layers 12 reached. The known "sunburn" mainly damages cells that are above the basal cell layer 11 lie; it is therefore advisable to carry out the measurement at this skin depth. For other wavelengths, such as visible light and infrared, depending on the problem, measurements can also be carried out in deeper layers.

A thin light guide is inserted into the skin 1 introduced relatively painless, for example up to the basal cell layer 11 , Depending on the measurement conditions, the light guide 10 up to several 100 μm below the skin surface. The light transmitted by the skin layers is then from the optical waveguide on its end face 14 recorded and to the radiometer 2 forwarded with little loss. The light emerges at the exit surface 15 of the optical fiber 1 and hits the sensor 13 of the radiometer 2 , Through the connector 3 can be the distance and the angle between exit surface 15 and sensor 13 changed and optimized for maximum signal strength. A monochromator is used to resolve the signal by wavelength. The sensitivity of the entire measuring device and the speed of the measuring process can be increased considerably as a sensor 13 a photomultiplier or preferably a diode array system is used. When using a diode array system, all wavelengths can be measured quickly and simultaneously. This speeds up the measuring process and lowers the radiation exposure. The recorded signal is then saved and evaluated by the PC.

In this way it is first a measurement without an applied external 7 performed, which serves as a reference. Then the external 7 on the skin surface 9 applied and a new measurement carried out. The external 7 remains partially on the skin surface 9 , partially it also penetrates the skin surface 9 and into the epidermis 8th on. This changes the absorption properties within the skin. Since the skin is measured in vivo, these effects are fully taken into account in the measurement.

From the measurement with external, together with the reference measurement, the sun protection factor of the external can 7 be measured. Since no radiation dose that produces erythema is necessary for the measurement, the radiation exposure for the test subjects can be kept very low.

This surprisingly proposes a device and a method with which the influence of cosmetic or pharmaceutical shear externalities on the transmission of human skin in vivo very precisely, but can be measured under realistic conditions but with a very low radiation exposure for the test person.

1

optical fiber

2

radiometer

3

joint

4

PC

5

UV lamp

6

UV radiation

7

externum on the skin surface

8th

Absorbed externum

9

skin surface

10

epidermis

11

basal cell

12

Lower skin layers

13

sensor

14

Entrance area of the optical fiber

15

Exit surface of the optical fiber

Claims (12)

Method for measuring the influence of cosmetic or pharmaceutical externals on the transmission of human skin, the externum being applied to the top of a UV-permeable carrier layer or membrane, both components by means of a UV light source in a suitable wavelength range, in particular from 280-420 nm, be examined and the intensity of the transmitted radiation, preferably frequency-resolved, is measured with a radiometer, characterized in that the transmitted radiation is received by a light guide guided to the underside of the carrier layer or membrane and passed on to the radiometer. Method of measuring the influence of cosmetic or pharmaceutical externals on the transmission of human Skin according to claim 1, characterized in that the transmitted Radiation from a light guide guided into the interior of the carrier layer or membrane recorded and forwarded to the radiometer. Method of measuring the influence of cosmetic or pharmaceutical externals on the transmission of human Skin according to claim 1 or 2, characterized in that a carrier layer or membrane with a diameter of less than 500 μm and / or an optical fiber with a diameter of less than 150 μm is used becomes. Method according to one or more of the preceding Expectations, characterized in that the light guide in, as a support layer for the Externally used, human skin inserted and the measurement performed in vivo becomes. Method according to one or more of the preceding Expectations, characterized in that the light guide in the area between Horny layer of the epidermis and basement membrane of the skin is inserted lying. Method according to one or more of the preceding Expectations, characterized in that the radiation duration used and -intensity is below the erythema threshold. Device for measuring the influence of cosmetic or pharmaceutical externals on the transmission of human Skin with a UV light source, a UV-permeable carrier layer or membrane and a radiometer for measuring the intensity and / or frequency of the transmitted electromagnetic radiation, characterized in that the Device a light guide for receiving and forwarding the Has radiation. Device according to one or more of the preceding Expectations, characterized in that the carrier layer or membrane has a diameter of less than 500 μm and / or the light guide has a diameter of less than 150 μm. Device according to one or more of the preceding Expectations, characterized in that the light guide has micro-optics. Device according to one or more of the preceding Expectations, characterized in that the light guide as biocompatible Material is formed. Device according to one or more of the preceding Expectations, characterized in that the radiometer as a photomultiplier or is preferably designed as a diode array system. Device according to one or more of the preceding Expectations, characterized in that a connecting piece between the light exit face of the Optical fiber and sensor input of the radiometer for stepless Setting the distance and / or the angle is provided.