KR101695843B1 - Method for evaluating persistence of sun screen products - Google Patents

Abstract

The present invention relates to a method for evaluating the persistence of sunscreen agents. The present invention provides a method for evaluating the persistence of a sunscreen agent, which comprises applying an ultraviolet screening agent to the skin, irradiating the skin with artificial ultraviolet rays, and evaluating the persistence of the ultraviolet screening agent based on the content of the ultraviolet screening agent remaining on the skin irradiated with the artificial ultraviolet ray do. According to the present invention, the persistence of the sunscreen agent can be objectively and accurately evaluated in a short time.

Description

METHOD FOR EVALUATING PERSISTENCE OF SUN SCREEN PRODUCTS FIELD OF THE INVENTION [0001]

The present invention relates to a method for evaluating the persistence of a sunscreen agent, and more particularly, to a method for assessing the persistence of a sunscreen agent in an objective and accurate manner in a short time.

Ultraviolet rays refer to a part of the spectrum of the sunlight corresponding to a wavelength range of about 280 nm to 400 nm. Ultraviolet rays are classified into UVA, UVB and UVC depending on the wavelength. Excessive exposure to ultraviolet light promotes skin aging and, in severe cases, causes DNA damage and skin cancer. To reduce skin damage caused by ultraviolet rays, a product (ultraviolet ray blocking agent) having an ultraviolet blocking effect is continuously being developed.

In general, the efficacy of sunscreen agents is assessed using the SPF (Sun Protection Factor) index and the PA (Protection Factor of UVA) index. SPF and PA are used as an evaluation index for the blocking power of ultraviolet rays. SPF is used to show UV protection against UVB, and PA is used to show UV protection against UVA. SPF is obtained by dividing the amount of light (minimum erythema, Minimal Erythema Dose) at the time when erythema starts to appear when the ultraviolet screening agent is applied to the skin after the application of ultraviolet light, by the minimum erythema amount when the ultraviolet screening agent is not applied. In addition, the minimum sustained blackening (MPPD) at which the blackening begins to occur after application of the sunscreen to the skin is determined by the minimum sustained blackening amount (MPPD) when the sunscreen agent is not applied We divide and obtain.

Recently, as interest in sunscreen agents has increased and various products have been developed, a method for evaluating additional efficacy besides the efficacy indicated by SPF and PA is needed. In particular, it is necessary to study the persistence of the ultraviolet screening agent, that is, the effect of the ultraviolet screening agent applied to the skin after the exposure to the sunlight (ultraviolet ray). In other words, there is a need for a method for evaluating the persistence (persistence) of sunscreen products, as well as the blocking power of ultraviolet screening agents.

However, conventional evaluation methods are limited to evaluating the blocking power against UVB and UVA through SPF and PA index. The prescribed evaluation method for evaluating the persistence of sunscreen agents is not yet formalized. It is difficult to evaluate the persistence of ultraviolet rays by the conventional ultraviolet shielding force evaluation method, and it is not objective or accurate. It is difficult to evaluate all activities that can affect test results in a controlled environment for a long time after applying sunscreen to the skin. That is, it is difficult to confirm the persistence of the sunscreen agent by testing the human body in a controlled environment for a long time due to the characteristics of the test method for evaluating ultraviolet shielding power by applying the product directly to the human body. In addition, the reproducibility, objectivity and accuracy of test results are not high because the test results are highly likely to be influenced by various external factors such as temperature, humidity, clothes, and activities.

Accordingly, it is an object of the present invention to provide a method for evaluating the persistence of a sunscreen agent that can objectively and accurately evaluate the persistence of a sunscreen agent in a skin coated with a sunscreen agent in a short time.

According to an aspect of the present invention,

Provided is a method for evaluating the persistence of a sunscreen agent, which comprises applying an ultraviolet screening agent to skin, irradiating the skin with artificial ultraviolet light, and evaluating the persistence of the ultraviolet screening agent based on the content of the ultraviolet screening agent remaining on the skin irradiated with the artificial ultraviolet light.

Further, according to the present invention,

A sunscreen agent for evaluating the persistence of the ultraviolet screening agent based on the ratio of the content of the ultraviolet screening agent remaining on the skin after the artificial ultraviolet ray irradiation to the content of the ultraviolet screening agent remaining on the skin after the ultraviolet screening agent is applied to the skin before the artificial ultraviolet ray irradiation, And the like.

According to a preferred embodiment, the method for evaluating the persistence of a sunscreen according to the present invention comprises:

(I) measuring the content of the sunscreen remaining in the skin sample to which the sunscreen is applied;

(Ii) measuring the content of the ultraviolet screening agent remaining in the skin sample after irradiating artificial ultraviolet rays on the skin coated with the ultraviolet screening agent; And

(Iii) calculating the relative amount of the ultraviolet screening agent using the following equation (1).

[Equation 1]

In the above equation,

X: Relative residual amount ratio of sunscreen agent (%)

A: Content of the ultraviolet screening agent remaining in the skin sample after ultraviolet irradiation (weight)

P: Amount of skin sample after ultraviolet irradiation (weight)

A ': content of sunscreen remaining in skin sample before UV irradiation (weight)

P 'is the amount (weight) of the skin sample before ultraviolet irradiation.

In addition, the method for evaluating the persistence of an ultraviolet screening agent according to the present invention comprises:

A method for evaluating the persistence of an ultraviolet screening agent containing 1 to n ultraviolet screening raw materials,

(I) measuring the content of the ultraviolet screening agent remaining in the skin sample coated with the ultraviolet screening agent;

(II) measuring the content of the ultraviolet screening agent remaining in the skin sample after irradiating artificial ultraviolet rays on the skin coated with the ultraviolet screening agent; And

(III) It is preferable to include a step of calculating a relative ratio of residual amount of each ingredient of the ultraviolet screening agent using the following equation (2).

&Quot; (2) "

In the above equation,

X _i : Relative residual ratio of raw material of sunscreen (%)

A _i : Content of ultraviolet screening raw material remaining in skin sample after ultraviolet irradiation (weight)

P: Amount of skin sample after ultraviolet irradiation (weight)

A _i ': content of the ultraviolet shielding raw material remaining in the skin sample before ultraviolet irradiation (weight)

P ': amount of skin sample before ultraviolet irradiation (weight)

i: 1 to n (n is a natural number)

According to the present invention, a formalized method for assessing the persistence of sunscreen agents is provided. Further, the present invention has the effect of objectively and accurately evaluating the persistence of the ultraviolet screening agent in a short time.

FIG. 1 is a graph showing the results of the persistence analysis of raw materials of the ultraviolet screening agent evaluated according to the embodiment of the present invention.
FIG. 2 is a graph showing changes in the residual amount of the ultraviolet screening agent with respect to the raw material according to the time evaluated according to the comparative example.

As described above, a method for evaluating the persistence of sunscreen agents has not yet been formulated. And it is difficult to evaluate the persistence of ultraviolet rays by conventional ultraviolet shielding evaluation method, and it is not objective or accurate.

Therefore, as a result of repeated studies on the persistence of ultraviolet screening agents, it has been found that the amount of ultraviolet screening agent remaining in the skin after the artificial ultraviolet ray irradiation on the skin coated with the ultraviolet screening agent is analyzed, And that it is accurate and objective in the sustainability evaluation. In particular, it was found that the ratio of residual amount after irradiation of artificial ultraviolet ray was very accurate and objective in the evaluation of persistence of ultraviolet ray blocking agent.

Hereinafter, the present invention will be described in detail.

The method for evaluating the persistence of an ultraviolet screening agent according to the present invention (hereafter abbreviated as "evaluation method") is a method for evaluating the persistence of an ultraviolet screening agent according to the present invention by applying an ultraviolet screening agent to the skin and then irradiating it with artificial ultraviolet light, (Remaining amount). The physical quantities (content, residual amount, etc.) used in the present invention all mean weight. In the present invention, the skin may be exemplified by keratin.

At this time, the irradiation of the artificial ultraviolet ray irradiates the ultraviolet ray corresponding to the amount of external activity for a certain period of time through the artificial light source in a short time. The artificial light source may be a general lamp or an ultraviolet ray emitter. The irradiation intensity (light amount) and the irradiation time of the artificial ultraviolet ray are not particularly limited. The ultraviolet ray irradiation amount is determined by measuring the intensity of the ultraviolet ray when exposed to sunlight (natural light) for a certain period of time The intensity (light amount) and time of the ultraviolet ray corresponding to the amount may be sufficient. Although not particularly limited, the artificial ultraviolet ray can be irradiated at an intensity of, for example, 0.1 to 10.0 mW / cm 2, preferably 0.1 to 2 mW / cm 2. The irradiation time may be, for example, 1 second to 30 minutes, preferably 1 second to 20 minutes. The total light amount (light intensity x irradiation time) is not particularly limited, but may be, for example, 1.0 mJ / cm 2 to 1800 mJ / cm 2, preferably 500 to 1500 mJ / cm 2. However, the light intensity, the irradiation time, and the light amount are not limited by the above-mentioned range, but it is sufficient that the light intensity, the irradiation time and the light amount correspond to the amount of external activity for a certain period of time as described above. However, the shorter the irradiation time, the better. The intensity (amount of light) and the irradiation time of the artificial ultraviolet ray can be determined by the tester (evaluator), and it depends on the amount of sunlight (natural light) received when the external activity is performed for a certain period of time.

The 'period of time' is a time period during which a person can be exposed to sunlight (natural light), and is not particularly limited. The 'period of time' is determined within a range of, for example, 1 hour to 18 hours And can be, for example, 3 hours, 6 hours, 9 hours, 12 hours or 15 hours.

The ultraviolet screening agent is not particularly limited, but can be applied to the skin at a coverage of 0.1 to 50 mg / cm 2 in basis weight. In this case, when the amount of the ultraviolet screening agent applied is less than 0.05 mg / cm 2, the amount of the ultraviolet screening agent remaining in the skin sample after the artificial ultraviolet ray irradiation (residual amount) is small and analysis may be difficult. In the case of exceeding 200 mg / The synergy effect may not be very large. Preferably, the coating is carried out at a coating amount of 0.5 to 5 mg / cm 2, but is not limited thereto.

According to the present invention, the artificial ultraviolet ray corresponding to the amount of external action for a certain period of time after applying the ultraviolet screening agent to the skin is irradiated in a short time, and the skin irradiated with the artificial ultraviolet ray is collected, Based on the content (remaining amount) of the ultraviolet screening agent, the persistence of the ultraviolet screening agent can be accurately and objectively evaluated in a short time. That is, it is evaluated that the persistence of the ultraviolet screening agent is better as the content (residual amount) of the ultraviolet screening agent remaining on the skin is greater.

According to a specific embodiment, the evaluation method according to the present invention may include the following steps (1) to (4).

(1) applying sunscreen to the skin

(2) irradiating artificial ultraviolet rays to the skin coated with the ultraviolet screening agent

(3) collecting the skin sample irradiated with the artificial ultraviolet ray

(4) analyzing (measuring) the content (remaining amount) of the ultraviolet screening agent remaining in the sampled skin sample

At this time, it is evaluated that the longer the content (residual amount) analyzed (measured) in the step (4) is, the better the persistence of the ultraviolet screening agent is. For example, in the case of evaluating the sustainability of the product of Company K and the product of Company L, it is evaluated that the product having a large residual amount analyzed in the above step (4) has good sustainability. At this time, the amounts of skin application of the products of Company K and the product of Company L are the same, and the weights of the collected skin samples are also sampled from the same area, and then quantified by the same weight. High-performance liquid chromatography (HPLC) can be used for analyzing the remaining amount of the ultraviolet screening agent remaining in the skin sample, for example, in the step (4).

In addition, the residual amount analyzed (measured) in the step (4) may be calculated as a 'residual amount ratio (%)', which can be used as an index of evaluation. Specifically, the remaining amount ratio (%) is calculated through the following Equation (1), and the persistence can be evaluated based on the calculated remaining amount ratio (%). That is, as the value of the residual ratio (%) calculated by the following formula 1 is larger, the sustainability is evaluated to be higher.

<Formula 1>

(%) = {Content (weight) of the ultraviolet screening agent remaining in the skin sample after artificial ultraviolet ray irradiation / amount of ultraviolet ray blocking agent skin application amount (weight) before artificial ultraviolet ray irradiation} x 100

According to a preferred embodiment of the present invention, the persistence evaluation is based on the ratio of the content of the ultraviolet screening agent remaining on the skin after artificial ultraviolet irradiation to the content of the ultraviolet screening agent remaining on the skin before applying the ultraviolet screening agent to the skin, . That is, evaluation is preferably performed based on the ratio of the relative residual amount before and after irradiation of the artificial ultraviolet ray.

Specifically, the evaluation method according to the present invention includes the following steps (i) to (iii) according to a preferred embodiment.

(I) measuring the content of the remaining ultraviolet screening agent in the skin sample to which the ultraviolet screening agent has been applied

(Ii) measuring the content of the ultraviolet screening agent remaining in the skin sample after irradiating artificial ultraviolet rays on the skin coated with the ultraviolet screening agent

(Iii) calculating a relative ratio of the ultraviolet screening agent using the following equation

[Equation 1]

In the above equation,

X: Relative residual amount ratio of sunscreen agent (%)

A: Content of the ultraviolet screening agent remaining in the skin sample after ultraviolet irradiation (weight)

P: Amount of skin sample after ultraviolet irradiation (weight)

A ': content of sunscreen remaining in skin sample before UV irradiation (weight)

P 'is the amount (weight) of the skin sample before ultraviolet irradiation.

According to a more specific embodiment, the steps (i) to (iii) may be subdivided into the following steps (a) to (f).

(a) applying a sunscreen to the skin

(b) collecting the skin sample coated with the ultraviolet screening agent

(c) irradiating artificial ultraviolet rays to the skin coated with the ultraviolet screening agent

(d) collecting the skin sample irradiated with the artificial ultraviolet light

(e) measuring the amount (remaining amount) of the ultraviolet screening agent remaining in the skin sample in the steps (b) and (d)

(f) calculating a relative ratio (%) of the ultraviolet screening agent using the formula (1)

In the formula (1), P 'and P are the amount (weight) of the skin sample before and after irradiation of the ultraviolet ray, and the weight of the skin itself (for example, ) Or the sum of the weight of the skin itself and the weight of the ultraviolet screening agent contained in the skin sample.

As described above, when it is based on the relative residual amount ratio (%) before / after the ultraviolet ray irradiation, more accurate and objective evaluation can be achieved. As the value of X (%) calculated according to the equation (1) in the step (iii) or (f) is larger, the sustainability is evaluated to be higher.

On the other hand, the ultraviolet screening agent generally may contain other ingredients besides the ultraviolet shielding raw material, that is, the effective ingredient (raw material) that substantially exerts the ultraviolet shielding power. For example, solvents, thickeners, oils, perfumes and the like, which are added for dispersing, diluting, formulating, feeling, etc. of the ultraviolet shielding raw material (active ingredient), may be included. The ultraviolet shielding agent may contain 1 to n ultraviolet shielding raw materials (effective components) (n is an arbitrary natural number). Specifically, the ultraviolet shielding agent may contain only one component as an ultraviolet shielding raw material, (e.g., 2 to 5) n components.

As described above, when the ultraviolet screening agent contains 1 to n ultraviolet shielding raw materials (effective components), the evaluation method according to the present invention includes the following steps (I) to (III) according to a preferred embodiment good.

(I) Measuring the content of the sunscreen agent remaining in the skin sample applied with the sunscreen agent

(II) measuring the content of the ultraviolet screening agent remaining in the skin sample after irradiating artificial ultraviolet rays on the skin coated with the ultraviolet screening agent

(III) Calculating the relative ratio of the ultraviolet screening agent to the raw material using the following formula (2)

&Quot; (2) &quot;

In the above equation,

X _i : Relative residual ratio of raw material of sunscreen (%)

A _i : Content of ultraviolet screening raw material remaining in skin sample after ultraviolet irradiation (weight)

P: Amount of skin sample after ultraviolet irradiation (weight)

A _i ': content of the ultraviolet shielding raw material remaining in the skin sample before ultraviolet irradiation (weight)

P ': amount of skin sample before ultraviolet irradiation (weight)

i: 1 to n (n is a natural number)

According to a more specific embodiment, the steps (I) to (III) may be subdivided into the following steps (A) to (F).

(A) applying a sunscreen to the skin

(B) collecting a skin sample coated with the ultraviolet screening agent

(C) irradiating artificial ultraviolet rays to the skin coated with the ultraviolet screening agent

(D) collecting the skin sample irradiated with the artificial ultraviolet ray

(E) measuring the content of the ultraviolet screening agent remaining in the skin sample in the steps (B) and (D)

(F) calculating a relative residual ratio of each ingredient of the ultraviolet screening agent using Equation (2)

The evaluation method comprising the steps (I) to (III) or the steps (A) to (F) is useful for the persistence evaluation of a sunscreen agent containing two or more ultraviolet shielding raw materials (active ingredients) do. At this time, through the above steps (I) to (III), or (A) to (F), it is possible to evaluate the persistency of each kind of raw material contained in one kind of ultraviolet screening product as well as various kinds of ultraviolet screening products .

For example, when the sustainability is evaluated for the products of S company (containing two or more raw materials) and H company products (containing two or more raw materials) or two or more kinds of products, Calculate the X _i value for each raw material. Then, the sum (or average value) of the X _i values of each product is obtained, and the product of the company having a large sum (or average value) of the X _i values per raw material can be evaluated as having a good sustainability. For example, if the product S contains two raw materials a1 and a2, the product H contains two raw materials but contains a3 and a4 different from the product of the company S, the above formula to calculate the relative amount of the residual ratio values X ₁ and X ₂ value of a1 and a2 of the S manufactured by each sum (X ₁ + X ₂ ). Further, by calculating the relative amount of the residual ratio value X _3, and X ₄ the value of a3 and a4 of H manufactured by each sum (X ₃ + X ₄ ) is obtained. If the sum of the ratios is larger than that of the company S (ie, X ₃ + X ₄ > X ₁ + X ₂ ), and the sustainability of company H is better than that of company S. As another example, there are two raw materials for the S company, three raw materials for the H company, and the relative residual ratio X _{i for} each raw material (S company is 2, H company 3), and the average value of these can be obtained and compared (S company has two average values, H company has three average values).

As described above, the sustainability of each raw material contained in one kind of ultraviolet screening product can also be evaluated through the steps (I) to (III) or (A) to (F). When the ultraviolet screening product contains, for example, raw materials a1, a2, a3 and a4, and four or more different raw materials (active ingredients) as an effective ultraviolet shielding ingredient (raw material) Calculate the percentage of relative remaining amount (%). Specifically, X ₁ , X ₂ , X _3, and X ₄ values are calculated as the relative ratio (%) of the respective materials a ₁ , a ₂ , a _3, and a ₄ using Equation (2). The higher the calculated X value, the better the sustainability. That is, when the X ₂ value is the largest among the calculated X ₁ , X ₂ , X ₃ and X ₄ values, the raw material a 2 is evaluated as having the best sustainability.

When the evaluation is carried out through the steps (I) to (III) or the steps (A) to (F) as described above, not only the various types of ultraviolet screening agents but also the persistence Can also be evaluated.

The evaluation method according to the present invention may further comprise the following steps (IV) or (G) following the steps (I) to (III) or the steps (A) to (F) It is preferable to further include a step.

(IV) or (G): calculating the total amount (W) of the relative residual amount of the ultraviolet screening agent according to the content ratio of the ultraviolet screening raw material, using the following equation (3)

&Quot; (3) &quot;

In the above equation,

W is the sum of the relative residual amounts of the sunscreen agents,

C _i : The content ratio (% by weight) of the ultraviolet screening raw material contained in the ultraviolet screening agent. (i = 1 to n, n is an arbitrary natural number), and X _{i is a} relative residual ratio (%) of the ultraviolet screening agent per raw material, calculated according to Equation (2).

In the above formula (3), ΣC _i is the sum of the content ratio (% by weight) of the ultraviolet shielding raw material (active ingredient), which represents the total content (%) of the ultraviolet shielding agent. As described above, the ultraviolet screening agent is generally formulated into a composition containing a solvent, an aging agent, an oil, a perfume, etc. in addition to an ultraviolet shielding raw material (effective ingredient). In the formula (3), ΣC _i is the total content (% by weight) of the ultraviolet shielding agent (ultraviolet shielding raw material) in the entire ultraviolet shielding composition. In one example, the sunscreen composition comprises a1, a2, a3 and a4 as an ultraviolet shielding raw material (active ingredient) and a solvent, an enhancer, an oil and a flavoring as an additional ingredient, the content of which includes the total weight of the sunscreen composition As a standard, a1 is 25 wt%, a2 is 15 wt%, a3 is 10 wt%, a4 is 5 wt%, solvent is 35 wt%, agglomerate is 3 wt%, oil is 5 wt% %, ΣC _i in the above formula (3) is 55 wt% (= 25 + 15 + 10 + 5).

It is evaluated that the value obtained through the formula (3) of the step (IV) or (G), that is, the greater the W value, the better the persistence of the ultraviolet screening agent. The W value is a total of the relative residual amount of the ultraviolet screening agent according to the content ratio of the ultraviolet screening raw material, which can be an indicator of objective and accurate persistence evaluation in evaluating the persistence of the ultraviolet screening agent.

In addition, when a certain range is set for the W value and a rating is set for each range, a criterion for the persistence evaluation of the sunscreen agent can be provided. For example, you can set the rating according to the range of W values as shown below.

Class A: If the W value is 94 or higher

Class B: 92 ≤ W <94

Class C: 90 ≤ W <92

Class D: 88 ≤ W <90

E class: 80 ≤ W <88

Class F: If the value of W is less than 80

In addition, as described above, a grade (A to F class) according to a certain range of the W value is determined, and a grade for the UV blocker is determined based on the W value calculated according to the formula (3) The effect can be reviewed.

INDUSTRIAL APPLICABILITY As described above, according to the evaluation method of the present invention, after the irradiation with artificial ultraviolet light, the content (remaining amount) of the ultraviolet screening agent remaining in the skin sample is used as a measure, preferably, It is possible to objectively and accurately evaluate the persistence of the ultraviolet screening agent applied to the skin within a short period of time. Based on the evaluation results, the persistence effect of the ultraviolet screening agent used in the evaluation can be examined.

Hereinafter, embodiments of the present invention will be exemplified. The following examples are provided to illustrate the present invention in order to facilitate understanding of the present invention, and thus the technical scope of the present invention is not limited thereto. The following examples are for skin care products, but the accuracy and objectivity of the evaluation according to the present invention are not limited thereto.

[Example]

(One) Subject  selection

Among the healthy men and women aged 18 to 60 years without skin disease, skin types classified according to the Fitzpatrick skin type classification criteria are type I to type III, and have never experienced optical allergy or photosensitization, , Acne, and erythema were selected as subjects to be tested.

(2) Selection of artificial light source

As an artificial light source, an Oriel solar simulator (Oriel instrument, USA) was used as an ultraviolet light emitter equipped with a 1000 W xenon arc lamp (Ozonless Co., USA). The ultraviolet ray emitter emits ultraviolet rays with a diameter of 8 x 8 inches through a light guide. In the process of irradiating ultraviolet rays, a light intensity controller feedback system The intensity of ultraviolet light was kept constant. At this time, the UVC wavelength and the wavelength of the visible light region were removed using a dichroic mirror, and the light amount was measured using a smart meter GRP-1 (Smartmeter GRP-1, manufactured by Oriel Instruments, USA) Lt; / RTI &gt;

(3) Application of sunscreen (sample)

A UV shielding composition containing Neo heliopan E1000 (raw material a), OMC (raw material b), Escalol 587 (raw material c) and Tinosorb-S (raw material d) and more than 4 ultraviolet shielding raw materials (effective components) Respectively. In this case, the ultraviolet shielding agent composition (sample) contains 2% by weight of the raw material a, 7% by weight of the raw material b, 4.5% by weight of the raw material c, And the raw material d: 3% by weight. And the remaining amount is other components such as a solvent.

The sample (the ultraviolet shielding agent composition containing the same amount of the raw material a to the raw material d) was applied to the back except for the vertebral region of the subject. At this time, 100 μl of a sample was taken using a micro-pipette (Gilson Co., USA, USA), the weight was measured with an electronic balance, and then the volume of a sample corresponding to 80 mg was calculated. Then, the applied amount of the calculated sample was taken and applied uniformly to an area of 40 cm 2 (8 cm x 5 cm) of the subject's back with a finger wearing surgical gloves. After application, the stabilization time was set to 15 minutes.

(4) Collection of skin samples (ultraviolet irradiation group and ultraviolet ray Non-coordination )

The ultraviolet irradiation group was irradiated with ultraviolet rays for 15 minutes at a light intensity of 1.17 mW / cm 2 (12 cm 2 (3 cm x 4 cm)) using the artificial ultraviolet emitter (artificial light source) And the total amount of light was about 1050 mJ / cm 2. Then, keratin samples of the same site (irradiated area) were collected by repeating a total of 5 times using D-squame.

The UV-uncoordinated group was allowed to stand for the same time (15 minutes) as that of the irradiation group in the absence of ultraviolet light, and then keratinous samples were collected by the same method.

(5) Calculating the percentage of the relative amount of sunscreen agent to raw material (%)

The amount of keratin extracted from each D-squame of the ultraviolet irradiation group and the non-treatment group was quantified using Squamescan, and then the remaining amount (weight) of each UV blocking material in the keratin sample was analyzed by HPLC.

(%) Of each of the raw materials a to d remaining in the keratin materials with respect to each raw material was calculated through the following Equation (2).

<Formula 2>

(%) = {(Weight of ultraviolet ray blocking agent in ultraviolet ray irradiation group / weight of stratum corneum) / (weight of ultraviolet ray blocking agent in ultraviolet ray-untreated group / weight of stratum corneum)} x 100

At this time, the keratin weight of the formula 2 was the sum of the weight of the pure keratin and the weight of the raw materials contained in the keratin. For example, the raw material a is calculated according to the following formula (2a).

<Formula 2a>

(%) Of the raw material a = {(weight of a in keratin in ultraviolet irradiation group / keratin weight) / (weight of kerosene in keratin in ultraviolet ray noncondensation group) x 100

Here, the keratin weight in formula (2a) was calculated as the weight of pure keratin.

(6) Calculate the sum of relative remaining amount (W)

Next, the total amount (W) of the relative remaining amount of the ultraviolet screening agent in accordance with the content ratio of the raw materials a to d was calculated using the following formula (3).

<Formula 3>

(Relative content of raw material a) + (content ratio of raw material b (% by weight) x relative amount of raw material b (total amount of relative amount of raw material b) (%)) + (Content ratio of raw material c (% by weight) x relative ratio of raw material c (%)) + (content ratio of raw material d (wt%) x relative ratio of raw material d )} / (Total content (% by weight) of ultraviolet screening agent)

In this case, the total content (% by weight) of the ultraviolet screening agent is 16.5% by weight (2 + 7 + 4.5 + 3% by weight) as the sum of the content ratios (% by weight) of the raw materials a to d.

The above results are shown graphically in Fig. In Fig. 1, "self-dispersing agent " means &quot; ultraviolet screening agent &quot;.

As shown in FIG. 1, the relative amount of the raw material a (Neo heliopan E1000) was 85.30%, the relative amount of the raw material b (OMC) was 85.73%, the content of the raw material c (Escalol 587) The relative residual ratio was 104.36%, and the relative residual ratio of the raw material c (Tinosorb-S) was 106.50%. And the total amount (W) of the relative residual amount through Equation (3) was 94.54.

When the total amount (W) of the ultraviolet screening agent is calculated by calculating the ratio of the ultraviolet screening agent to the amount of the ultraviolet screening agent remaining in the dead skin, It was found that about 94.5% by weight was maintained.

On the other hand, in order to verify the above evaluation results, 10 subjects were evaluated as follows.

The ultraviolet ray blocking agent containing the above-mentioned same samples as Neo heliopan E1000 (raw material a), OMC (raw material b), Escalol 587 (raw material c) and Tinosorb-S (raw material d) The composition was spread evenly on the back of the subject and exposed to a light source of the same intensity (light amount) as the sunlight for 12 hours. At this time, the test subject's activity was controlled so that the coated sample was not exposed to the light source. Then, keratinous samples were sampled in the same manner as above, and the respective weights of the raw materials a to d were analyzed by HPLC.

As a result of gravimetric analysis, it was found that a <b <c <d. The total residual amount (% by weight) of the ultraviolet screening agent remaining in the keratinous sample was calculated by the following Equation 4, and was estimated to be about 94.36% by weight.

<Formula 4>

Total residual amount (% by weight) of blocking agent = (total amount (weight) of analyzed raw materials a to d / total amount (weight) of raw materials a to d at initial application) x 100

As described above, it was found that the remaining amount of the raw material coincides with the result of Fig. 1 in the order of a <b <c <d. Further, the total remaining amount (% by weight) of the ultraviolet screening agent was about 94.36% by weight, which was almost identical to the result (W value) according to the above-mentioned formula (3).

Through the above experiments, the objectivity and accuracy of the evaluation method according to the present invention were confirmed, and the following comparative experiments were conducted.

[Comparative Example]

In the same manner as in the above example, 10 subjects were applied with ultraviolet screening agent to all the testees, and the keratin of the test subjects was collected by time for 12 hours to confirm the amount of the ultraviolet screening agent remaining. The subjects were allowed to freely live their daily lives in an uncontrolled environment. At this time, a product containing IMC, EHMC, TS, and three or more ultraviolet shielding raw materials (active ingredient) was used as a commercially available product. The remaining amount (remaining amount) of each ingredient of the sunscreen agent was analyzed by HPLC (0.25 to 12 hr) using the HPLC. The results are shown in FIG. 2 as a graph. In Fig. 2, "self-dispersing agent " means &quot; ultraviolet screening agent &quot;.

As shown in FIG. 2, the content (remaining amount) of the remaining ultraviolet screening agent in the keratin is decreased by 50% by weight and decreased by 80% by weight after 12 hours from 1 hour after application of the ultraviolet screening agent Able to know.

As can be seen from the above results, in the method of directly analyzing the ingredients of the ultraviolet screening agent in the keratin for 12 hours after applying the product to the subject, the amount of loss due to the difference of the activity of the subject or the living environment is large . In addition, since there is no consideration of a lost sunscreen agent, it is difficult and time-consuming to evaluate objectively and precisely the persistence of a pure sunscreen agent.

However, according to the embodiment of the present invention, it can be seen that objective and accurate evaluation is possible in a short time if artificial ultraviolet rays are irradiated and evaluated based on the relative remaining amount ratio before and after irradiation.

Claims (10)

delete delete As a method for evaluating the persistence of an ultraviolet screening agent,
(I) measuring the content of the sunscreen remaining in the skin sample to which the sunscreen is applied;
(Ii) measuring the content of the ultraviolet screening agent remaining in the skin sample after irradiating artificial ultraviolet rays on the skin coated with the ultraviolet screening agent; And
(Iii) calculating a relative ratio of the ultraviolet screening agent to the ultraviolet screening agent using the following equation (1):
[Equation 1]

In the above equation,
X: Relative residual amount ratio of sunscreen agent (%)
A: Content of the ultraviolet screening agent remaining in the skin sample after ultraviolet irradiation (weight)
P: Amount of skin sample after ultraviolet irradiation (weight)
A ': content of sunscreen remaining in skin sample before UV irradiation (weight)
P 'is the amount (weight) of the skin sample before ultraviolet irradiation.
The method of claim 3,
The method for evaluating the persistence of the ultraviolet screening agent,
A method for evaluating the persistence of an ultraviolet screening agent containing 1 to n ultraviolet screening raw materials,
Wherein the step (iii) includes the step of calculating the relative ratio of the ultraviolet screening agent to the raw material using the following equation (2) instead of the equation (1):
&Quot; (2) &quot;

In the above equation,
X _i : Ratio of relative amount of sunscreen agent to raw material (%)
A _i : Content of ultraviolet screening raw material remaining in skin sample after ultraviolet irradiation (weight)
P: Amount of skin sample after ultraviolet irradiation (weight)
A _i ': content of the ultraviolet shielding raw material remaining in the skin sample before ultraviolet irradiation (weight)
P ': amount of skin sample before ultraviolet irradiation (weight)
i: 1 to n (n is a natural number)
5. The method of claim 4,
Further comprising the step of calculating a sum of the relative remaining amount of the ultraviolet screening agent according to the content ratio of the ultraviolet screening raw material using the following equation (3): &lt; EMI ID =
&Quot; (3) &quot;

In the above equation,
W: Sum of the relative residual amount of sunscreen agent
C _i : The content ratio (% by weight) of the ultraviolet screening raw material contained in the ultraviolet screening agent.
6. The method according to any one of claims 3 to 5,
Wherein the skin is horny.
6. The method according to any one of claims 3 to 5,
Wherein the artificial ultraviolet light is irradiated with artificial ultraviolet light corresponding to an amount of external activity for one hour to 18 hours on the skin to which the ultraviolet screening agent has been applied.
6. The method according to any one of claims 3 to 5,
Wherein the artificial ultraviolet light is irradiated to the skin to which the ultraviolet screening agent has been applied at an intensity of 0.1 to 10.0 mW / cm 2 · sec.
9. The method of claim 8,
Wherein the artificial ultraviolet ray is irradiated to the skin to which the ultraviolet ray blocking agent has been applied for 1 to 30 minutes.
6. The method according to any one of claims 3 to 5,
Wherein the ultraviolet light blocking agent is applied to the skin at a coverage of 0.1 to 50 mg / cm &lt; 2 &gt;.

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