WO2012083527A1 - Method for evaluating cosmetic state of hair or effect of cosmetic treatment on hair by measuring inter-scale distance - Google Patents

Method for evaluating cosmetic state of hair or effect of cosmetic treatment on hair by measuring inter-scale distance Download PDF

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Publication number
WO2012083527A1
WO2012083527A1 PCT/CN2010/080079 CN2010080079W WO2012083527A1 WO 2012083527 A1 WO2012083527 A1 WO 2012083527A1 CN 2010080079 W CN2010080079 W CN 2010080079W WO 2012083527 A1 WO2012083527 A1 WO 2012083527A1
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Prior art keywords
hair
sample
inter
growth rate
scale distance
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PCT/CN2010/080079
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French (fr)
Inventor
Céline SAINT OLIVE BAQUE
Didier Saint-Leger
Sylvain Kravtchenko
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L' Oreal
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Priority to PCT/CN2010/080079 priority Critical patent/WO2012083527A1/en
Publication of WO2012083527A1 publication Critical patent/WO2012083527A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
    • A61B5/1072—Measuring physical dimensions, e.g. size of the entire body or parts thereof measuring distances on the body, e.g. measuring length, height or thickness
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/44—Detecting, measuring or recording for evaluating the integumentary system, e.g. skin, hair or nails
    • A61B5/448—Hair evaluation, e.g. for hair disorder diagnosis

Definitions

  • the present invention relates to a method for evaluating the cosmetic state of hair or the effect of a cosmetic treatment on a straight hair by measuring the inter- scale distance of a sample of the straight hair.
  • the biology of hair growth is generally measured through several parameters, namely the growth rate, the diameter and the length of the hair, which should be a direct reflect of the quantity of cells produced by the follicle, and thus of the growth fiber.
  • the measurements of these parameters can also be very useful in order to study the efficiency of a cosmetic treatment those particularly which are capable of modifying the growth rate of the hair.
  • the documents FR 2802678 and FR 2802679 describe the measurement of the growth rate based on the phototrichogram method.
  • the phototrichogram method is a technique that allow s the in vivo study of the hair growth cycle in order to determine the rate of hair growth, the size of hair fibers, the frequency of telogen hair follicles and the quantification of shed hair. More particularly, this method namely consists of shaving a small area of the scalp and taking macroscopic pictures of this area. Then, a second set of pictures of the same shaved areas is taken few day s later. By comparing the two pictures, one can see which hair fibers have grown or not, the rate of hair growth and the density of the hair in the studied area.
  • the phototrichogram method is time-consuming, invasive (shaving) and requires the volunteers to come several times.
  • FR 28 12190, FR 28 12192 and FR 27449 16 describe the measurement of the growth rate based on the study of the surviving follicle.
  • This method involves isolating a fairly thin strip of scalp from a scalp biopsy. The adipose tissue around the follicles is then removed with microtweezers, while taking care not to damage the hair bulb. Under a microscope, the follicle is cut away using a scalpel to separate it from its epidermal and dermal environment. The fragments obtained are then cultured under specific conditions and studied at different periods of time. It means that this method needs to be carried out during several days in order to record the growth rate of the fiber as it is needed to do the evaluation on models at different periods of time. Thus, this method is quite complex, invasive and time-consuming.
  • inter- scale distance there are linear relationship s between inter- scale distance and growth rate in hair and between inter- scale distance and diameter in hair. Moreover the determination of inter- scale distance is easy to be obtained in very short times. Some methods for this determination are also non invasive methods.
  • one subj ect of the present invention is a method for evaluating the cosmetic state of hair or the effect of a cosmetic treatment on hair, which comprises the steps of:
  • G corresponds to the growth rate of the said sample
  • T corresponds to the inter- scale distance of the said sample
  • D ⁇ .(C - T)
  • D corresponds to the diameter of the said sample
  • T corresponds to the inter- scale distance of the said sample.
  • a, b, c, d being values determined from a calibration curve.
  • a calibration curve has to be determined for each type of hair.
  • a calibration curve is drawn from a hair sample for which the values G and T or D and T are already known. Based on the resulting curve, the values a, b, c and d values can be calculated (see example 1 ) . It is then po ssible for a new hair sample of the same type to determine the values D and G from the measurement of the T value.
  • the method for evaluating the cosmetic state of hair and the effect of a cosmetic treatment on hair according to the present invention is based on the measurement of the inter- scale distance of a hair sample and on the equations relying the hair growth rate and the hair diameter to the inter- scale distance of a straight hair sample.
  • the method according to the present invention is thus more precise and more obj ective than the other traditional classifications and can be carried out in a simple way.
  • the hair growth rate and the hair diameter are directly linked to one geometrical parameter of the hair, namely the inter- scale distance, which represents an obj ective parameter. It means that the measurement of the inter- scale distance of a hair sample with a standard measuring instrument can lead to the information of the hair growth rate and of the hair diameter, and thus to the information of the cosmetic state of the hair.
  • the measurement of the inter- scale distance of a straight hair sample allow s determining by means of the equations (I) and (II) if the hair grow normally, namely at a standard speed, too slowly or too quickly and if the hair are more thick or more thin that they should be.
  • the method according to the present invention allow s determining the growth rate and the thickness of the all head of hair by measuring fiber by fiber the inter- scale distance. Therefore, this method may be used to determine if the head of hair includes mainly thick or thin hair or if the growth rate of the head of hair is homogeneous.
  • the measurement of the inter- scale distance of a hair sample with a standard measuring instrument can be very useful to determine if a co smetic treatment is able to modify the hair growth and/or the hair thickness.
  • the comparison between the values of the growth rate and the hair diameter before and after the cosmetic treatment allows ending if this treatment has been efficient or not.
  • the method according to the present invention proposes to evaluate in a simple way the cosmetic state of hair and the effect of a cosmetic treatment on hair without destroying the hair sample or being time-consuming.
  • the terms "method for evaluating the cosmetic state of hair” mean a method which is able to evaluate cosmetic parameters of hair such as the hair growth rate and the hair diameter.
  • the method of the present invention aims to evaluate co smetic parameters.
  • a straight hair means a hair having a round cro ss- section by opposition with a curled hair having a flattened cross- section. More generally, a straight hair corresponds to a hair which does not present waves or bends in its structure. Chinese and Japanese hair fibers, or generally speaking Natural asian hair constitute a good example of straight hair although not restricted to these human sub-groups . In fact these types of hair can be found in Caucasian' s too .
  • the method according to the present invention comprises the steps of:
  • Go corresponds to the growth rate of the said first sample before performing the said cosmetic hair treatment
  • a and b being values determined from a calibration curve
  • c and d being values determined from a calibration curve
  • Gi corresponds to the growth rate of the said second sample after having performed the said cosmetic hair treatment
  • Ti corresponds to the inter-scale distance of the said second sample after having performed the said cosmetic hair treatment, a and b values being the same values as the one obtained from the determination of Go;
  • Di corresponds to the diameter of the said second sample after having performed the said cosmetic hair treatment
  • Ti corresponds to the inter-scale distance of the said second sample after having performed the said cosmetic hair treatment
  • the value of the growth rate Gi is higher than the value Go, it implies that the hair growth rate has increased thanks to the cosmetic treatment which means that the said cosmetic treatment is efficient for increasing the growth of hair.
  • the value of the growth rate Gi is lower than the value Go, it implies that the hair growth rate has decreased thanks to the cosmetic treatment which means that the said cosmetic treatment is efficient for slowing the growth of hair.
  • the value of the hair diameter Di is lower than the value of Do, it implies that the hair thickness has decreased thanks to the cosmetic treatment which means that the cosmetic treatment is efficient for thinning the hair.
  • the cosmetic treatment suitable for increasing the hair growth rate is considered as being efficient when the value Gi is statistically significant different from Go, and preferably superior at least by 3% with regard to Go-
  • the cosmetic treatment suitable for slowing the hair growth rate is considered as being efficient when the value Gi is statistically significant and preferably inferior at least by 3% with regard to Go-
  • the cosmetic treatment suitable for thickening the hair is considered as being efficient when the value Di is statistically significant and preferably superior at least by 1 % with regard to Do.
  • the cosmetic treatment suitable for thinning the hair is considered as being efficient when the value Di is statistically significant and preferably inferior at least by 1 % with regard to the value Do.
  • the method of the present invention can determine the type of co smetic treatment that a person needs to use in order to modify the hair growth rate and/or the thickness of the hair.
  • the said co smetic hair treatment implies the use of a topical or an oral composition which is able to modify the growth rate and/or the thickness of the hair.
  • the said topical or oral composition is chosen among a compo sition comprising one or more anti-hair lo ss actives, a compo sition comprising one or more actives suitable for slowing the hair growth, a composition comprising one or more actives suitable for thickening the hair, a composition comprising one or more actives suitable for thinning the hair or a mixture of those compositions.
  • the oral composition may appear in particular in a shape chosen among the group constituted by a tablet, pastille, capsule or a gel.
  • the various excipients to be added into the oral composition according to the reserved galenic shape are known from the man skilled in the art.
  • the quantity of the actives principles and the excipients will be adjusted by the man skilled in the art to obtain the oral compo sition.
  • the cosmetic hair treatment comprises the application on the hair of a topical composition which is able to modify the growth rate and/or the thickness of the hair.
  • the topical compo sition may appear in particular in the form of emulsion simple or complex (H/E, E/H, H/E/H or E/H/E) such as a cream, a lotion, a milk, a gel, a gel-cream, a powder and can be possibly conditioned in spray and appear in the form of foam or of spray.
  • the topical compo sition may be a shampoo compo sition or a conditioner.
  • the topical compo sition suitable for modifying the hair growth rate and/or the thickness of the hair may be applied several times on the hair.
  • compositions suitable for anti-hair los s activity may comprise 2,4-diaminopyrimidine 3Noxyde (Aminexil) .
  • the duration before collecting the second sample of hair is supposed to be sufficient so that the cosmetic treatment acts.
  • the duration is comprised between 1 and 12 months, more particularly between 4 and 12 weeks.
  • the samples of hair are collected in root in vertex area on non-alopecia volunteers. More preferably, the hair samples are collected in vertex area on Chinese, Japanese and Caucasian non- alopecia volunteers.
  • inter- scale distance corresponds to the distance between two consecutive scale edges along the longitudinal axis of the hair fiber.
  • the inter- scale distance of a hair fiber can be measured with various instruments which are able to detect the scale edges located on a hair fiber, such as for example optical microscope, scanning electron microscope (SEM) , macroscope, binocular glass, confocal microscope, profilometer, atomic force microscopy (AFM) , a camera and portable systems such as a portable camera with portable analysis sy stems.
  • various instruments which are able to detect the scale edges located on a hair fiber, such as for example optical microscope, scanning electron microscope (SEM) , macroscope, binocular glass, confocal microscope, profilometer, atomic force microscopy (AFM) , a camera and portable systems such as a portable camera with portable analysis sy stems.
  • the inter- scale distance of a sample of straight hair is measured with a Scanning Electron Micro scope (SEM) .
  • SEM Scanning Electron Micro scope
  • the Scanning Electron Microscope takes an image of the hair fiber and then the scale edges are detected along the fiber in various places over the whole image.
  • the inter- scale distance of the hair fiber is then evaluated by averaging the distance between the detected scale edges
  • the method of the present invention is preferably used for straight hair.
  • the length of the straight hair sample is higher than 5 mm and is comprised more preferably between 20 and 100 mm.
  • FIG. 1 illustrates schematically a portion of a hair fiber wherein scale edges are detected
  • FIG. 2 represents a graphic wherein hair growth rate measurements are plotted regarding hair diameters measurements (curve Ci) and inter- scale distance measurements are plotted regarding diameters measurements (curve C 2 ) for Chinese, Japanese and Caucasian volunteers,
  • FIG. 3 represents a graphic wherein inter- scale distance measurements are plotted regarding hair growth rate measurements (curve C 3 ) for Chinese, Japanese and Caucasian volunteers.
  • 1 cm 2 of hair is shaved on volunteers in winter and is then collected after 1 month of growth.
  • Hair i s collected in root in vertex area on 13 Chinese, 14 Japanese and 7 Caucasian non-alopecia volunteers.
  • 25 hair fibers have been collected on each Chinese volunteer
  • 25 hair fibers have been collected on each Japanese volunteer
  • 50 hair fibers have been collected on each Caucasian volunteer.
  • fine, medium and coarse hair fibers have been selected in order to be representative of the head of hair of each volunteer.
  • the collected hair is natural. All volunteers are young (age below 40 years old), except 1 Caucasian (60 years old) and have straight hair. The repartition between genders is balanced.
  • the hair growth rate is determined for each collected sample by measuring the length of each collected sample. Therefore, the hair growth rate of each sample is calculated in mm per day.
  • each hair fiber is then measured by means of a scanning electron microscope (SEM) .
  • SEM scanning electron microscope
  • the measure is made on the same fibers as the ones for which growth rate has been calculated.
  • the scanning electron micro scope takes an image of each hair fiber and then the transversal distance of each hair fiber is measured on the acquired image.
  • the diameter of each hair fiber is given in ⁇ .
  • the inter-scale distance is then measured by means of a scanning electron microscope (SEM). This measure is made on 12 hair fibers belonging to the Japanese volunteers, 12 hair fibers belonging to the Chinese volunteers and on 25 hair fibers belonging to the Caucasian volunteers.
  • SEM scanning electron microscope
  • the scanning electron microscope takes an image of each hair fiber and then the scale edges are detected along the fiber in various places over the whole image.
  • the inter-scale distance of the hair fiber is then evaluated by averaging the distance between the detected scale edges.
  • figure 1 represents schematically an image which may be acquired by a scanning electron microscope (SEM) of a portion of a hair fiber 1.
  • the hair fiber 1 contains the scales 2, 3, 4 and 5.
  • the scale edges are detected.
  • the edges 2', 3', 4', 5' are detected on line a
  • the edges 2", 3", 4", 5" are detected on line b
  • the edges 2"', 3"', 4"' and 5"' are detected on line c.
  • the distance between the scale edges represents the inter-scale distance.
  • the distance between the scales 2 and 3 are determined by averaging the distance between the edges 2' and 3', 2" and 3" and 2"' and 3"'.
  • the distance between the scales 3 and 4, 4 and 5 are determined in the same manner.
  • the inter-scale distance of a hair fiber is determined by averaging the inter-scale distance measured between each scale.
  • the inter-scale distance of the hair fiber 1 is determined by averaging the inter-scale measured between the scales 2 and 3, 3 and 4 and 4 and 5.
  • the growth rate, the diameter and the inter-scale distance are determined.
  • Results Each measured hair fiber is collected into groups of diameter.
  • the length of each diameter group is 10 ⁇ , and groups start from below 50 ⁇ and above 120 ⁇ .
  • Figure 2 represents the measurements of growth rate (G) and inter- scale distance (T) in the light of groups of diameters (D) for Chinese, Japanese and Caucasian volunteers. It means that for each diameter group, the average value of the growth rate and the inter- scale distance are plotted.
  • the curve Ci represented in figure 2 show s that growth rate (G) linearly increases with diameter (D) with a strong linear regression coefficient (R) according to the following equation:
  • Figure 3 represents the measurements of inter- scale distance in the light of the growth rate for Chinese, Japanese and Caucasian volunteers.
  • the curve C 3 represented in figure 3 shows that inter- scale distance (T) linearly decreases with growth rate (G) with a strong linear regression coefficient according to the following equation:
  • the calculated linear regressions are comparable for Chinese, Japanese and Caucasian hair fibers with less than 5 % deviation from the global regression which means that the Japanese and Chinese hair fibers and the Caucasian straight hair fibers obey to the same law regarding to the hair growth rate and the hair diameter.
  • equations (I) and (II) allow establishing a method for evaluating the co smetic state of hair or the effect of a cosmetic treatment on a straight hair. Indeed, this method based on the measurement of the inter- scale distance and on the equations (I) and (II) allow establishing the growth rate and the diameter of the head of hair of a person having straight hair.

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Abstract

A method for evaluating the cosmetic state of hair or the effect of a cosmetic treatment on hair by measuring the inter-scale distance of a sample of hair is provided. The method involves measuring the inter-scale distance of a sample of a hair and calculating the growth rate and/or the diameter of the said sample according to the inter-scale distance and a calibration curve. The method is more precise and more objective than the other traditional classifications and can be carried out in a simple way.

Description

METHOD FOR EVALUATING COSMETIC STATE
OF HAIR OR EFFECT OF COSMETIC TREATMENT ON HAIR BY MEASURING INTER-SCALE DISTANCE
The present invention relates to a method for evaluating the cosmetic state of hair or the effect of a cosmetic treatment on a straight hair by measuring the inter- scale distance of a sample of the straight hair.
The biology of hair growth is generally measured through several parameters, namely the growth rate, the diameter and the length of the hair, which should be a direct reflect of the quantity of cells produced by the follicle, and thus of the growth fiber. The measurements of these parameters can also be very useful in order to study the efficiency of a cosmetic treatment those particularly which are capable of modifying the growth rate of the hair.
These parameters have been often studied in the literature and mainly apprehended through the traditional classification, classifying the hair into three ethnic human sub-groups, such as Caucasian, Asian and African. For example, this literature already showed that the Asian population has thicker hair fibers and a faster growth rate.
However, such broad classification hardly accounts for the high complexity of human mixed origins as well as the diversity of hair on a single head. There is indeed a wide variety of hair fibers inside each ethnic group as well as inside each head of hair which implies an important variation of hair parameters.
Several analytical, metrological or physico-chemical methods have been developed in the state of the art in order to evaluate tho se parameters and then deducing the co smetic state of hair. These methods generally have the disadvantages of being quite complex, time-consuming and invasive, leading sometimes to the destruction of the sample after measurement.
For example, the documents FR 2802678 and FR 2802679 describe the measurement of the growth rate based on the phototrichogram method. The phototrichogram method is a technique that allow s the in vivo study of the hair growth cycle in order to determine the rate of hair growth, the size of hair fibers, the frequency of telogen hair follicles and the quantification of shed hair. More particularly, this method namely consists of shaving a small area of the scalp and taking macroscopic pictures of this area. Then, a second set of pictures of the same shaved areas is taken few day s later. By comparing the two pictures, one can see which hair fibers have grown or not, the rate of hair growth and the density of the hair in the studied area. Thus, the phototrichogram method is time-consuming, invasive (shaving) and requires the volunteers to come several times.
In addition, the patent applications FR 28 12190, FR 28 12192 and FR 27449 16 describe the measurement of the growth rate based on the study of the surviving follicle. This method involves isolating a fairly thin strip of scalp from a scalp biopsy. The adipose tissue around the follicles is then removed with microtweezers, while taking care not to damage the hair bulb. Under a microscope, the follicle is cut away using a scalpel to separate it from its epidermal and dermal environment. The fragments obtained are then cultured under specific conditions and studied at different periods of time. It means that this method needs to be carried out during several days in order to record the growth rate of the fiber as it is needed to do the evaluation on models at different periods of time. Thus, this method is quite complex, invasive and time-consuming.
There is a genuine need to develop a method for evaluating the cosmetic state of hair and the effect of a cosmetic treatment on hair, especially on straight hair, which is more accurate and obj ective than the traditional classification based on hair origins and which does not suffer from the disadvantages of being quite complex, time-consuming and invasive like the methods described above.
Thus, it has been found that there are linear relationship s between inter- scale distance and growth rate in hair and between inter- scale distance and diameter in hair. Moreover the determination of inter- scale distance is easy to be obtained in very short times. Some methods for this determination are also non invasive methods.
Thus, one subj ect of the present invention is a method for evaluating the cosmetic state of hair or the effect of a cosmetic treatment on hair, which comprises the steps of:
measuring the inter- scale distance of a sample of hair,
- calculating the growth rate and/or the diameter of the said sample according to the following formulas: G = (a - T) (I) wherein:
G corresponds to the growth rate of the said sample,
T corresponds to the inter- scale distance of the said sample, and D = ^ .(C - T) wherein:
D corresponds to the diameter of the said sample, and
T corresponds to the inter- scale distance of the said sample.
a, b, c, d being values determined from a calibration curve.
In a specific embodiment, for straight human hair, the values are as follow s:
a= 12.484
b= 10.9 12
c=9 ,2558
d=0.2464.
In the scope of the invention, a calibration curve has to be determined for each type of hair. To do this, a calibration curve is drawn from a hair sample for which the values G and T or D and T are already known. Based on the resulting curve, the values a, b, c and d values can be calculated (see example 1 ) . It is then po ssible for a new hair sample of the same type to determine the values D and G from the measurement of the T value.
The method for evaluating the cosmetic state of hair and the effect of a cosmetic treatment on hair according to the present invention is based on the measurement of the inter- scale distance of a hair sample and on the equations relying the hair growth rate and the hair diameter to the inter- scale distance of a straight hair sample.
The method according to the present invention is thus more precise and more obj ective than the other traditional classifications and can be carried out in a simple way. Indeed, according to the method of the present invention, the hair growth rate and the hair diameter are directly linked to one geometrical parameter of the hair, namely the inter- scale distance, which represents an obj ective parameter. It means that the measurement of the inter- scale distance of a hair sample with a standard measuring instrument can lead to the information of the hair growth rate and of the hair diameter, and thus to the information of the cosmetic state of the hair. In other words, the measurement of the inter- scale distance of a straight hair sample allow s determining by means of the equations (I) and (II) if the hair grow normally, namely at a standard speed, too slowly or too quickly and if the hair are more thick or more thin that they should be.
More generally, the method according to the present invention allow s determining the growth rate and the thickness of the all head of hair by measuring fiber by fiber the inter- scale distance. Therefore, this method may be used to determine if the head of hair includes mainly thick or thin hair or if the growth rate of the head of hair is homogeneous.
In addition, the measurement of the inter- scale distance of a hair sample with a standard measuring instrument can be very useful to determine if a co smetic treatment is able to modify the hair growth and/or the hair thickness. Indeed, one can measure the inter- scale distance of hair sample in order to determine the growth rate and/or the diameter of the hair fiber before performing a co smetic treatment suitable for modifying the hair growth and/or the hair thickness. Then, after a given time, one can measure the inter- scale distance of another hair sample in order to determine the growth rate and/or the diameter of the hair fiber after the said co smetic treatment has been carried out. The comparison between the values of the growth rate and the hair diameter before and after the cosmetic treatment allows ending if this treatment has been efficient or not.
Finally, the method according to the present invention proposes to evaluate in a simple way the cosmetic state of hair and the effect of a cosmetic treatment on hair without destroying the hair sample or being time-consuming.
Other aims and characteristics, aspects and advantages of the invention will become apparent from the following description and examples.
According to the present invention, the terms "method for evaluating the cosmetic state of hair" mean a method which is able to evaluate cosmetic parameters of hair such as the hair growth rate and the hair diameter. The method of the present invention aims to evaluate co smetic parameters.
The term "a straight hair" according to the present invention means a hair having a round cro ss- section by opposition with a curled hair having a flattened cross- section. More generally, a straight hair corresponds to a hair which does not present waves or bends in its structure. Chinese and Japanese hair fibers, or generally speaking Natural asian hair constitute a good example of straight hair although not restricted to these human sub-groups . In fact these types of hair can be found in Caucasian' s too .
This term also covers class (I) to class (IV) of the classification described in the document "Diversite des frisures a travers le monde:une nouvelle methode devaluation. Saint Leger D, De la Mettrie R, Loussouarn G et al, les nouvelles dermatologiques, 2007 , vol 26, n° supp 9 , pages 6-9.
According to one preferred embodiment, the method according to the present invention comprises the steps of:
collecting a first sample of hair before performing a cosmetic hair treatment able to modify the growth rate and/or the thickness of the hair,
measuring the inter- scale distance of the said first sample To, calculating the growth rate Go and/or the diameter Do of the said first sample accordin to the following formulas:
Figure imgf000006_0001
wherein:
Go corresponds to the growth rate of the said first sample before performing the said cosmetic hair treatment,
To corresponds to the inter- scale distance of the said first sample before performing the said co smetic hair treatment; a and b being values determined from a calibration curve;
and
D = -^ (c - To ) (Π' ) a
wherein: Do corresponds to the diameter of the said first sample before performing the said cosmetic hair treatment,
To corresponds to the inter-scale distance of the said first sample before performing the said cosmetic hair treatment ; c and d being values determined from a calibration curve;
performing a cosmetic hair treatment able to modify the growth rate and/or the thickness of the hair,
collecting a second sample of a straight hair in the same area where the said first sample of a straight hair has been collected after a given time,
measuring the inter-scale distance of the said second sample Ti, calculating the growth rate Gi and/or the diameter Di of the said second sample according to the following formulas:
Gi =^ (a-Ti) (I") wherein:
Gi corresponds to the growth rate of the said second sample after having performed the said cosmetic hair treatment,
Ti corresponds to the inter-scale distance of the said second sample after having performed the said cosmetic hair treatment, a and b values being the same values as the one obtained from the determination of Go;
and
Figure imgf000007_0001
wherein:
Di corresponds to the diameter of the said second sample after having performed the said cosmetic hair treatment,
Ti corresponds to the inter-scale distance of the said second sample after having performed the said cosmetic hair treatment,
c and d values being the same as the one obtained from the determination of Do ;
comparing the values of the growth rate of the first sample Go and of the second sample Gi and/or the values of the hair diameter of the first sample Do and of the second sample Di.
By comparing the value of the growth rate after having performed the said cosmetic treatment Gi and the value of the growth rate before having performed the said cosmetic treatment Go and/or the value of the hair diameter after having performed the said cosmetic treatment Di and the value of the hair diameter before having performed the said cosmetic treatment Do, one can analyse if the said cosmetic treatment is efficient.
Indeed, if the value of the growth rate Gi is higher than the value Go, it implies that the hair growth rate has increased thanks to the cosmetic treatment which means that the said cosmetic treatment is efficient for increasing the growth of hair.
On the other hand, if the value of the growth rate Gi is lower than the value Go, it implies that the hair growth rate has decreased thanks to the cosmetic treatment which means that the said cosmetic treatment is efficient for slowing the growth of hair.
In the same manner, if the value of the hair diameter Di is higher than the value of Do, it implies that the hair thickness has increased thanks to the cosmetic treatment which means that the said cosmetic treatment is efficient for increasing the hair thickness.
On the other hand, if the value of the hair diameter Di is lower than the value of Do, it implies that the hair thickness has decreased thanks to the cosmetic treatment which means that the cosmetic treatment is efficient for thinning the hair.
If the values of the growth rate and the hair diameter remain quite identical before and after having performed the cosmetic treatment, it means that the cosmetic treatment used for modify the grow rate or the thickness of the hair is not efficient.
Moreover, the cosmetic treatment suitable for increasing the hair growth rate is considered as being efficient when the value Gi is statistically significant different from Go, and preferably superior at least by 3% with regard to Go- Conversely, the cosmetic treatment suitable for slowing the hair growth rate is considered as being efficient when the value Gi is statistically significant and preferably inferior at least by 3% with regard to Go-
In the same manner, the cosmetic treatment suitable for thickening the hair is considered as being efficient when the value Di is statistically significant and preferably superior at least by 1 % with regard to Do. Conversely, the cosmetic treatment suitable for thinning the hair is considered as being efficient when the value Di is statistically significant and preferably inferior at least by 1 % with regard to the value Do.
It means that the method of the present invention can determine the type of co smetic treatment that a person needs to use in order to modify the hair growth rate and/or the thickness of the hair.
In a preferred embodiment, the said co smetic hair treatment implies the use of a topical or an oral composition which is able to modify the growth rate and/or the thickness of the hair.
Preferably, the said topical or oral composition is chosen among a compo sition comprising one or more anti-hair lo ss actives, a compo sition comprising one or more actives suitable for slowing the hair growth, a composition comprising one or more actives suitable for thickening the hair, a composition comprising one or more actives suitable for thinning the hair or a mixture of those compositions.
The oral composition may appear in particular in a shape chosen among the group constituted by a tablet, pastille, capsule or a gel. The various excipients to be added into the oral composition according to the reserved galenic shape are known from the man skilled in the art. The quantity of the actives principles and the excipients will be adjusted by the man skilled in the art to obtain the oral compo sition.
More preferably, the cosmetic hair treatment comprises the application on the hair of a topical composition which is able to modify the growth rate and/or the thickness of the hair.
The topical compo sition may appear in particular in the form of emulsion simple or complex (H/E, E/H, H/E/H or E/H/E) such as a cream, a lotion, a milk, a gel, a gel-cream, a powder and can be possibly conditioned in spray and appear in the form of foam or of spray. In addition, the topical compo sition may be a shampoo compo sition or a conditioner.
The topical compo sition suitable for modifying the hair growth rate and/or the thickness of the hair may be applied several times on the hair.
For example typical compositions suitable for anti-hair los s activity may comprise 2,4-diaminopyrimidine 3Noxyde (Aminexil) .
According to one embodiment of the present invention, the duration before collecting the second sample of hair is supposed to be sufficient so that the cosmetic treatment acts. Preferably, the duration is comprised between 1 and 12 months, more particularly between 4 and 12 weeks.
Preferably, the samples of hair are collected in root in vertex area on non-alopecia volunteers. More preferably, the hair samples are collected in vertex area on Chinese, Japanese and Caucasian non- alopecia volunteers.
The term "inter- scale distance" according to the present invention corresponds to the distance between two consecutive scale edges along the longitudinal axis of the hair fiber.
The inter- scale distance of a hair fiber can be measured with various instruments which are able to detect the scale edges located on a hair fiber, such as for example optical microscope, scanning electron microscope (SEM) , macroscope, binocular glass, confocal microscope, profilometer, atomic force microscopy (AFM) , a camera and portable systems such as a portable camera with portable analysis sy stems.
According to one embodiment of the present invention, the inter- scale distance of a sample of straight hair is measured with a Scanning Electron Micro scope (SEM) .
The Scanning Electron Microscope (SEM) takes an image of the hair fiber and then the scale edges are detected along the fiber in various places over the whole image. The inter- scale distance of the hair fiber is then evaluated by averaging the distance between the detected scale edges
The method of the present invention is preferably used for straight hair.
The length of the straight hair sample is higher than 5 mm and is comprised more preferably between 20 and 100 mm.
Other features and advantages of the present invention will become more apparent in the detailed examination of the example describing a method for evaluating the co smetic state of a straight hair or the effect of a cosmetic treatment on a straight hair according to the present invention when taken in conj unction with the appended drawing s wherein:
- figure 1 illustrates schematically a portion of a hair fiber wherein scale edges are detected,
- figure 2 represents a graphic wherein hair growth rate measurements are plotted regarding hair diameters measurements (curve Ci) and inter- scale distance measurements are plotted regarding diameters measurements (curve C2) for Chinese, Japanese and Caucasian volunteers,
- figure 3 represents a graphic wherein inter- scale distance measurements are plotted regarding hair growth rate measurements (curve C3) for Chinese, Japanese and Caucasian volunteers.
Example of a method according to the present invention
1. Hair collection
1 cm2 of hair is shaved on volunteers in winter and is then collected after 1 month of growth. Hair i s collected in root in vertex area on 13 Chinese, 14 Japanese and 7 Caucasian non-alopecia volunteers. In particular, 25 hair fibers have been collected on each Chinese volunteer, 25 hair fibers have been collected on each Japanese volunteer and 50 hair fibers have been collected on each Caucasian volunteer. For each ethnic group, fine, medium and coarse hair fibers have been selected in order to be representative of the head of hair of each volunteer.
The collected hair is natural. All volunteers are young (age below 40 years old), except 1 Caucasian (60 years old) and have straight hair. The repartition between genders is balanced.
2. Hair characterization
2. 1. Hair growth rate (G)
The hair growth rate is determined for each collected sample by measuring the length of each collected sample. Therefore, the hair growth rate of each sample is calculated in mm per day.
2.2. Hair diameter (D)
The diameter of each hair fiber is then measured by means of a scanning electron microscope (SEM) . The measure is made on the same fibers as the ones for which growth rate has been calculated. The scanning electron micro scope takes an image of each hair fiber and then the transversal distance of each hair fiber is measured on the acquired image. The diameter of each hair fiber is given in μπι.
2.3. Inter-scale distance (T)
Through the hair fibers for which growth rate and diameter have been characterized, the inter-scale distance is then measured by means of a scanning electron microscope (SEM). This measure is made on 12 hair fibers belonging to the Japanese volunteers, 12 hair fibers belonging to the Chinese volunteers and on 25 hair fibers belonging to the Caucasian volunteers. The scanning electron microscope takes an image of each hair fiber and then the scale edges are detected along the fiber in various places over the whole image. The inter-scale distance of the hair fiber is then evaluated by averaging the distance between the detected scale edges.
For example, figure 1 represents schematically an image which may be acquired by a scanning electron microscope (SEM) of a portion of a hair fiber 1. As illustrated in figure 1, the hair fiber 1 contains the scales 2, 3, 4 and 5. For each scale, the scale edges are detected. For example, the edges 2', 3', 4', 5' are detected on line a, the edges 2", 3", 4", 5" are detected on line b and the edges 2"', 3"', 4"' and 5"' are detected on line c.
The distance between the scale edges represents the inter-scale distance. For example, the distance between the scales 2 and 3 are determined by averaging the distance between the edges 2' and 3', 2" and 3" and 2"' and 3"'. The distance between the scales 3 and 4, 4 and 5 are determined in the same manner.
Thus, the inter-scale distance of a hair fiber is determined by averaging the inter-scale distance measured between each scale. For example, the inter-scale distance of the hair fiber 1 is determined by averaging the inter-scale measured between the scales 2 and 3, 3 and 4 and 4 and 5.
Therefore, for each hair fiber, the growth rate, the diameter and the inter-scale distance are determined.
3. Results Each measured hair fiber is collected into groups of diameter. The length of each diameter group is 10 μπι, and groups start from below 50 μπι and above 120 μπι.
Figure 2 represents the measurements of growth rate (G) and inter- scale distance (T) in the light of groups of diameters (D) for Chinese, Japanese and Caucasian volunteers. It means that for each diameter group, the average value of the growth rate and the inter- scale distance are plotted.
The curve Ci represented in figure 2 show s that growth rate (G) linearly increases with diameter (D) with a strong linear regression coefficient (R) according to the following equation:
G = 0,0226 x D + 0,2958 R = 0,9906 (IV)
The curve C2 represented in figure 2 shows that inter- scale distance (T) linearly decreases with diameter (D) with a strong linear regression coefficient (R) according to the following equation:
T = -0,2464 x D + 9,2588 R = 0,9774 (V)
Figure 3 represents the measurements of inter- scale distance in the light of the growth rate for Chinese, Japanese and Caucasian volunteers.
The curve C3 represented in figure 3 shows that inter- scale distance (T) linearly decreases with growth rate (G) with a strong linear regression coefficient according to the following equation:
T = - 10,9 12 x G + 12,484 R = 0,9877 (VI)
From the equations (V) and (VI) , one can deduce the equation (I) and (II) defined above which are:
Figure imgf000013_0001
From these results, one can conclude that growth rate and inter- scale, which are two parameters traducing the biology of hair growth, are directly related with hair diameter, and not with hair origins.
These determinations settle the basis of the above mentioned calibration curve ; Of course it is po ssible to reduce the number of samples but this calibration curve has to be obtained from at least two samples of hair.
Furthermore, one can also conclude that the thicker the hair, the faster it grow s and the shorter the inter- scale is.
Moreover, the calculated linear regressions are comparable for Chinese, Japanese and Caucasian hair fibers with less than 5 % deviation from the global regression which means that the Japanese and Chinese hair fibers and the Caucasian straight hair fibers obey to the same law regarding to the hair growth rate and the hair diameter.
Thus, these equations (I) and (II) allow establishing a method for evaluating the co smetic state of hair or the effect of a cosmetic treatment on a straight hair. Indeed, this method based on the measurement of the inter- scale distance and on the equations (I) and (II) allow establishing the growth rate and the diameter of the head of hair of a person having straight hair.

Claims

1. A method for evaluating the co smetic state of a straight hair or the effect of a cosmetic treatment on a hair, characterized in that it comprises the steps of:
measuring the inter- scale distance of a sample of a hair,
calculating the growth rate and/or the diameter of the said sample according to the followin formulas:
Figure imgf000015_0001
wherein:
G corresponds to the growth rate of the said sample,
T corresponds to the inter- scale distance of the said sam le, and
Figure imgf000015_0002
wherein:
D corresponds to the diameter of the said sample, and
T corresponds to the inter- scale distance of the said sample;
a, b, c, d being values determined from a calibration curve.
2. The method according to claim 1 , characterized in that it comprises the steps of:
collecting a first sample of a hair before performing a co smetic hair treatment able to modify the growth rate and/or the thickness of the hair,
measuring the inter- scale distance of the said first sample To, calculating the growth rate Go and/or the diameter Do of the said first sample accordin to the following formulas:
Figure imgf000015_0003
wherein:
Go corresponds to the growth rate of the said first sample before performing the said cosmetic hair treatment,
To corresponds to the inter- scale distance of the said first sample before performing the said co smetic hair treatment; a and b being values determined from a calibration curve;
and D0 = ±-.{c - T0 ) (ΙΓ ) wherein:
Do corresponds to the diameter of the said first sample before performing the said cosmetic hair treatment,
To corresponds to the inter- scale distance of the said first sample before performing the said co smetic hair treatment; c and d being values determined from a calibration routine;
performing a co smetic hair treatment able to modify the growth rate and/or the thickness of the hair,
collecting a second sample of a straight hair in the same area where the said first sample of a straight hair has been collected after a given time,
measuring the inter- scale distance of the said second sample Ti , calculating the growth rate Gi and/or the diameter D i of the said second sample accordin to the following formulas:
Figure imgf000016_0001
wherein:
Gi corresponds to the growth rate of the said second sample after having performed the said cosmetic hair treatment,
Ti corresponds to the inter- scale distance of the said second sample after having performed the said co smetic hair treatment; a and b being the same values as the one obtained from the determination of Go ; and
Figure imgf000016_0002
wherein:
D i corresponds to the diameter of the said second sample after having performed the said co smetic hair treatment,
Ti corresponds to the inter- scale distance of the said second sample after having performed the said cosmetic hair treatment, c and d being the same values as the one obtained from the determination of Do ; comparing the values of the growth rate of the first sample Go and of the second sample Gi and/or the values of the hair diameter of the first sample Do and of the second sample D i .
3. The method according to claim 2, characterized in that the cosmetic hair treatment comprises the use of a topical or an oral compo sition able to modify the growth rate and/or the thickness of the hair.
4. The method according to claim 3 , characterized in that the said topical or oral composition is chosen among a composition comprising one or more anti-hair lo ss actives, a compo sition comprising one or more actives suitable for slowing the hair growth, a compo sition comprising one or more actives suitable for thickening the hair, a composition comprising one or more actives suitable for thinning the hair or a mixture of those compositions.
5. The method according to any of claims 2 to 4, characterized in that the co smetic hair treatment comprises the application on the hair of a topical compo sition able to modify the growth rate and/or the thickness of the hair.
6. The method according to any of claims 2 to 5 , characterized in that the second sample is collected after duration comprised between 1 and 12 months, more particularly between 4 and 12 weeks.
7. The method according to any one of the preceding claims, characterized in that the sample of hair is collected in root in vertex area on non-alopecia volunteers.
8. The method according to any one of the preceding claims, characterized in that the inter- scale distance of the sample of hair is measured with optical micro scope, scanning electron micro scope (SEM) , macroscope, binocular glass, confocal microscope, profilometer, atomic force microscopy (AFM) , a camera and portable systems such as a portable camera with portable analysis sy stems
9. The method according to any one of the preceding claims, characterized in that the inter- scale distance of the sample of hair is measured with a Scanning Electron Micro scope (SEM) .
10. The method according to any of the preceding claims, characterized in that the length of hair of the said sample is higher than 5 mm and more preferably is comprised between 20 and 100 mm.
1 1. The method according to any of the preceding claims, characterized in that calibration curve is made with at least two samples of hair
12. The method according to any of the preceding claims, characterized in that it is used for straight hair.
13. The method according to any of the preceding claims, characterized in that
a= 12.484
b= 10.9 12
c=9 ,2558
d=0.2464
PCT/CN2010/080079 2010-12-21 2010-12-21 Method for evaluating cosmetic state of hair or effect of cosmetic treatment on hair by measuring inter-scale distance WO2012083527A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1267501A (en) * 1999-03-22 2000-09-27 宋努·阿蒙西里巴尼猜 Method for measuring general quality parameter of hairs
CN1565380A (en) * 2003-06-10 2005-01-19 李邻峰 Hair growth digitized detecting method and instrument
US6993168B2 (en) * 1999-12-21 2006-01-31 L'oreal System and process for the analysis and predictive simulation of the temporal evolution of a hair region, and more particularly of the human scalp

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1267501A (en) * 1999-03-22 2000-09-27 宋努·阿蒙西里巴尼猜 Method for measuring general quality parameter of hairs
US6993168B2 (en) * 1999-12-21 2006-01-31 L'oreal System and process for the analysis and predictive simulation of the temporal evolution of a hair region, and more particularly of the human scalp
CN1565380A (en) * 2003-06-10 2005-01-19 李邻峰 Hair growth digitized detecting method and instrument

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