Method for measuring skin absorbability

Abstract

A method for measuring skin absorbability of a substance, which includes measuring the amount of the substance which is penetrated into hair follicles; and using the resultant data as an index representing the amount of the substance which is absorbed through skin pores, to thereby determine the amount of the substance absorbed through skin pores and a method for measuring skin absorbability of a substance, which includes bringing the substance into contact with a first surface of a thin film that mimics the skin surface layer, a second surface of the film being brought into contact with artificial sebum; and evaluating the sebum transferability of the substance by using the degree of transfer of the substance to the artificial sebum as an index, are disclosed. A kit for performing the measurement method of the present invention is also disclosed.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for screening an ingredient which is to be applied to the hair; a kit for carrying out the screening; and a composition comprising an ingredient exhibiting effects to accelerate absorption of an active ingredient through skin pores (hereinafter the absorption will be referred to as “skin-pore absorption”) and transfer of the active ingredient to sebum, the effects being confirmed by means of the screening method. [0003] 2. Background Art [0004] An important step in the development of a hair-growing agent is to confirm that an active ingredient exhibits excellent hair-growing effect and has penetrability so as to reliably reach a target site. Whether or not the active ingredient reliably reaches the target site greatly depends on the properties of the active ingredient or the base ingredient of the hair-growing agent. [0005] The mechanism of absorption of a drug or an active ...

AI Technical Summary

Benefits of technology

[0013] The sebum transferability of a drug is considered a useful index to evaluate whether or not the drug easily reaches a specific target site in the skin, but can not be easily evaluated in vivo. Therefore, a specific object of the present invention is to provide means for accurately and conveniently evaluating the sebum transferability of a drug in vitro.

[0014] The present inventors have performed extensive studies, and have found that, when the amount of a substance which is penetrated into hair follicles, the amount being determined in vitro or in vivo, is employed as an index of the amount of the substance which is absorbed through skin pores, the skin-pore absorbability of the substance can be conveniently and reliably determined, to thereby measure the skin absorbability of the substance.

[0022] The present inventors have also found that the sebum transferability of a substance can be easily evaluated in vitro by use of a skin model comprising artificial sebum.

[0024] The present inventors have also found that, by means of measurement methods 1 and 2, an oily ingredient having an I.O.B. value of 0.06-4.0 exhibits excellent effects of accelerating skin-pore absorption and sebum transfer of extensive polar substances from water-soluble substances to fat-soluble substances.

[0028] According to the present invention, there is provided means for conveniently and accurately measuring the skin absorbability of a test substance through quantification of the skin-pore absorbability or sebum transferability of the test substance. By means of the method, there is provided means for accelerating the skin-pore absorption or sebum transfer of a drug or an active ingredient, for example in a hair-growing agent, by which the drug or active ingredient effectively reach the target site; i.e., the hair follicle.

Problems solved by technology

The sebum transferability of a drug is considered a useful index to evaluate whether or not the drug easily reaches a specific target site in the skin, but can not be easily evaluated in vivo.

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