Permanent wave hair compositions containing transition metal oxide compounds

Keratinous material, such as human hair, in which disulfide linkages have been ruptured to form sulfhydryl groups can be permanently set using transition metal oxide compounds.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the treatment of keratinous material, such 
as attaining permanently waved or straightened hair. 
2. The Related Art 
Keratin is a major constituent of horns, hoofs, nails and feathers and 
mammalian hair, such as wool or human hair. Keratin consists of long 
polypeptide chains crosslinked to one another by cystine disulfide 
linkages, the crosslinkages conferring structural rigidity on a 
keratin-containing material. 
Permanent hair deformation, i.e. permanent waving and permanent 
straightening, involves rearrangement of the keratin polypeptide chains. 
Hot waving methods employ heat above 140.degree. F., frequently as high as 
300.degree. F., and the action of steam and alkali. Hot waving methods 
have virtually disappeared because they are too complicated and are 
excessively damaging to the hair. Moreover, hairdressers can not be 
certain with such methods that the desired results would consistently be 
obtained. Hot waving, therefore, has gradually been replaced by cold 
waving. 
Permanent hair straightening is sometimes done using a hot metal comb and 
covering the hair with lipid compounds or an emulsion. More frequently, 
straightening gels or emulsions containing various proportions of strong 
bases are used. These permanent hair straightening methods are irritant to 
the scalp, and careless handling may cause hair damage. Straighteners are 
sometimes formulated like cold wave products. 
In cold permanent waving or straightening, disulfide crosslinkages in hair 
keratin are ruptured by using various reducing agents. Common reducing 
agents include inorganic sulfides, sulfites, hydrosulfites, cyanides, 
mercaptans, thioglycolic acid and various other compounds. Sulfhydryl 
groups are formed in place of the disulfide linkages. The shaping of the 
hair into a desired conformation has conventionally been carried out by 
contacting the hair with a reducing agent in the form of liquids, creams 
or gels while the hair has been mechanically formed into the desired new 
shape. The reducing composition is applied to the hair for a sufficient 
time to allow shaping to occur by the reductive disruption of the 
disulfide linkages. Finally, disulfide crosslinkages are reformed or novel 
disulfide linkages are created by applying to the hair oxidizing or 
crosslinking agents, while maintaining hair in a form which it is desired 
to render permanent. The final step of establishing disulfide 
crosslinkages, which may be referred to as the neutralizing or fixing 
step, is important in order to make the new conformation permanent, to 
increase tensile strength, to avoid damage to the hair and to remove the 
sulfhydryl groups as reactive sites. 
Oxidative crosslinking employs a number of the usual chemical oxidizing 
agents or atmospheric oxygen to convert sulfhydryl groups to the 
corresponding disulfide. Hydrogen peroxide, perborate and bromates have 
been widely used in permanent hair deformation. Oxidation of sulfhydryl 
groups with chemical oxidizing agents may be catalyzed by metals. German 
Patent 1,198,012 discloses the use of small amounts of alkali metal 
metavanadates, i.e. 0.00025% by weight, to catalyze the bromate-based 
oxidation of hair. 
The oxidative method employing atmospheric oxygen, termed 
"self-neutralizing", depends on air oxidation to destroy any reducing 
agent on the hair and to reform disulfide linkages. This method does not 
necessitate subsequent application of a separate neutralizing solution to 
the hair; self-neutralizing waving lotions sometimes include metal 
catalysts in addition to a reducing agent. Den Beste et al., U.S. Pat. No. 
2,540,980 and Lang et al., U.S. Pat. No. 4,532,950 disclose addition of 
manganese chloride or sulfates of cobalt, copper or iron as oxidation 
catalysts to a waving lotion containing a reducing agent. Wainer, U.S. 
Pat. No. 2,707,697 discloses incorporation of iron sulfate in a waving 
lotion containing citric acid. Self-neutralizing waving lotions are poorly 
suited for professional use or for hair straightening applications and 
have not gained consumer acceptance. 
It is also possible to convert sulfhydryl linkages to disulfide 
crosslinkages in a non-oxidative manner by using crosslinking agents such 
as alkylene dihalides or dihalocarboxylic acids as in U.S. Pat. No. 
2,739,033 or dimaleimides as in U.S. Pat. No. 2,850,351. Speakman, U.S. 
Pat. No. 2,261,094 discloses the use in permanent hair waving of 
polyvalent metals, namely, sulfates of bivalent metals, such as calcium, 
barium, zinc, copper and nickel. In practice, when bivalent metal sulfates 
disclosed by the Speakman patent are employed, it has been found desirable 
to mix such crosslinking reagents with traditional oxidizing agents, such 
as hydrogen peroxide. The Speakman patent teaches desirability of such 
mixtures to reduce the time of treatment at col. 4, lines 10-17. Moreover, 
crosslinkages of bivalent metals with sulfur atoms have been considered 
ionic and unstable by Patterson et al., J. Res. Nat. Bur. Stand., 27:89. 
Complexes of dissolved cysteine (reduced cystine) with molybdenum in 
aqueous solution in the pH range of 4 to 6 have been described by Spence 
et al., Inorg. Chem., 2 (1963) 319. Spence et al. observed little complex 
formation above pH 6.5. 
Many neutralizing agents which have been proposed heretofore are toxic and 
thus are difficult to employ. Others are volatile and may be hazardous to 
use. A crosslinking reagent is desirable that is not encumbered by the 
difficulties of the past but is as effective as traditional oxidizing 
treatments. 
Therefore, it is an object of the present invention to provide a 
crosslinking composition for forming disulfide linkages in a keratinous 
material in which disulfide linkages have been disrupted and replaced by 
sulfhydryl groups. 
It is a further object of the present invention to provide a product for 
permanent hair waving or straightening comprising a composition for 
reducing disulfide bonds to form sulfhydryl groups and the aforementioned 
crosslinking composition. 
A still further object of this invention is to provide a method for 
treating a keratinous material in which disulfide linkages have been 
ruptured, which method includes contacting the keratinous material with 
the aforementioned crosslinking composition. 
These and other objects will become more apparent by consideration of the 
detailed description and examples that follow. 
SUMMARY OF THE INVENTION 
The attainment of the above objects is made possible by this invention 
which includes a crosslinking composition containing a transition metal 
oxide compound. The crosslinking composition of the invention converts 
sulfhydryl groups to disulfide crosslinkages in the keratinous material in 
which sulfhydryl groups have been previously formed by rupturing disulfide 
linkages. 
The inventive method for treating a keratinous material includes a step of 
contacting the crosslinking composition containing an effective amount of 
a transition metal oxide compound with the keratinous material in which 
disulfide linkage have been previously disrupted. 
According to this invention, the crosslinking composition may be included 
in a product for permanent hair deforming such as permanent hair waving or 
permanent hair straightening, the product also containing a reducing 
composition to effect disruption of disulfide crosslinkages and formation 
of sulfhydryl groups. 
While a wide group of keratin-containing materials and articles made 
therefrom can be treated in accordance with the present invention, 
including animal hair such as camel hair, mohair, wool, horsehair, cattle 
hair, hog bristles and the like; and feathers such as from chicken, duck, 
turkey and the like, the invention is particularly directed to waving or 
straightening human hair whether in vivo or in vitro, i.e. in the form of 
wigs. The invention is particularly directed to cold waving and hair 
straightening systems and will be discussed in connection therewith. The 
inventive composition, product and method can be used professionally in 
beauty salons or by unskilled consumers in their own homes. 
DESCRIPTION OF THE INVENTION 
Herein is disclosed a crosslinking composition containing a transition 
metal oxide compound, useful for forming disulfide crosslinkages in 
keratinous material in which disulfide linkages have been previously 
ruptured. 
The essential component of the inventive composition is a transition metal 
oxide compound. 
Although the exact nature of the species formed when reduced hair is 
contacted with a solution of transition metal oxide compound is not known, 
it is proposed that a transition metal ion, oxygen and sulfur form a mixed 
complex. Such complexes are stable, unlike ionic bonds of bivalent metal 
cations with sulfur described in U.S. Pat. No. 2,261,094, i.e. hair 
deformation is rendered permanent and resistant to moisture and alkali. 
Transition metal oxide compounds wherein a transition metal ion is chosen 
from groups 4b-6b of the Periodic Table, such as molybdenum, vanadium and 
tungsten are particularly suitable for use in this invention, molybdenum 
being most preferred. 
The following list is illustrative of the transition metal oxide compounds 
employed in this invention, suppliers indicated in parenthesis: 
Ammonium Molybdate, (NH.sub.4).sub.6 Mo.sub.7 O.sub.24 .times.4H.sub.2 O, 
(Aldrich Chemical Co., Alfa Products, Fisher Scientific) 
Ammonium Molybdate VI, (NH.sub.4).sub.2 MoO.sub.4, (Aldrich Chemical Co., 
Alfa Products, Fisher Scientific) 
Ammonium Tungstate, (NH.sub.4).sub.2 WO.sub.4, (Aldrich Chemical Co.) 
Ammonium Vanadate, NH.sub.4 VO.sub.3, (Fisher Scientific) 
Potassium Tungstate, K.sub.2 WO.sub.4, (Alfa Products) 
Sodium Orthovanadate, Na.sub.3 VO.sub.4, (Aldrich Chemical Co.) 
Sodium Metavanadate, NaVO.sub.3 .times.nH.sub.2 O, (Aldrich Chemical Co.) 
Sodium Tungstate, Na.sub.2 WO.sub.4, (Aldrich Chemical Co.) 
Sodium Molybdate, Na.sub.2 MoO.sub.4, (Aldrich Chemical Co.) 
Vanadyl Sulfate, VOSO.sub.4 .times.nH.sub.2 O (Fisher Scientific) 
Potassium Molybdate, K.sub.2 MoO.sub.4, (Alfa Products) 
Of course, other transition metal oxides may be employed. Ammonium 
molybdate is most preferred due to its availability and performance. 
The transition metal oxide compound is incorporated in the crosslinking 
composition of the invention in an effective amount to crosslink a 
sufficient amount of sulfhydryl groups to permanently set the keratinous 
material. Preferably, the amount of transition metal oxide compound in the 
crosslinking composition is about 0.01% to about 10% weight per volume, 
most preferably about 0.5% to about 5%. As used herein the term "% weight 
per volume" is intended to mean "grams per 100 milliliters". 
The crosslinking composition of the invention is useful whenever it is 
desirable to render permanent a particular rearrangement of keratin 
polypeptide chains and is particularly useful in products or processes for 
cold permanent hair waving or straightening. Advantageously, the 
crosslinking composition of the invention is as effective in forming 
stable disulfide linkages as traditional oxidizing agents such as hydrogen 
peroxide or bromates. Thus, the crosslinking composition of the invention 
is effective even in the absence of traditional oxidizing agents. 
The crosslinking composition can also contain a wetting agent or surfactant 
which is non-reactive with the crosslinking reagent or the hair to destroy 
crosslinking sites. The surfactant can be anionic, such as soaps, and 
alkyl sulfates, such as sodium dodecyl sulfate; cationic such as 
quaternary ammonium compounds; nonionic, such as glycol esters, glycerol 
esters, sorbitan esters, polyoxyalkylene esters, polyoxyalkylene ethers, 
and modified lanolin, as well as amphoteric surfactants. The surfactant is 
used in an amount of about 0.1% to about 60%, the amount being sufficient 
to assist in wetting the hair with the crosslinking reagent, depending on 
the efficiency of the surfactant. 
According to this invention, the crosslinking composition may be a part of 
the product for permanent hair deforming and the product may be 
conveniently formulated and packaged to provide a complete treatment of 
hair resulting in permanently waved or straightened hair. 
The product of the invention necessarily contains the inventive 
crosslinking composition and a separate reducing composition for forming 
sulfhydryl groups in place of disulfide crosslinkages. 
The reducing agents most commonly used in cold waving hair lotions for 
rupturing cystine linkages are thiols or mercaptans as well as sulfites 
and/or bisulfites. A number of mercaptans can only provide acceptable 
efficiency at high pH levels whereas others with a lower pK and a high 
ionization constant can be effective at lower pH levels. For example, the 
ammonium salt of thioglycolic acid can provide acceptable waving 
efficiency (reduction) if the pH of the solution exceeds 9. Other 
compounds such as thioglycolamides or glycol thioglycolates, sulfites 
and/or bisulfites can be used at neutral or slightly acidic pH. The 
following are mercaptans and thiols which have commonly been used in cold 
waving lotions: thioglycolic acid or salts thereof, thiolactic acid, 
cysteine, thioglycerol, thioglycolic hydrazide, thioglycolamide, glycerol 
monothioglycolate, beta-mercapto-propionic acid, N- hydroxyethyl 
mercapto-acetamide, N-methyl mercapto- acetamide, 
beta-mercapto-propionamide, 2-mercapto- ethanesulfonic acid, 
dimercapto-adipic acid, dithiothreitol, homocysteinethiolactone, cysteine 
derivatives, and polythiol derivatives formed by the addition of 
cysteamine onto a maleic anhydride-alkylvinylether copolymer. The sulfites 
and/or bisulfites which can be used are those normally used in hair waving 
such as sodium and ammonium salts. The amount of the reducing agent used 
is that sufficient to rupture a sufficient number of disulfide bonds for 
effective hair waving or hair straightening as would be appreciated by one 
of ordinary skill in the art. Preferably, the amount of reducing agent 
employed is between about 1% and about 20%, most preferably between about 
7.5% and 11% at a pH between about 9.3 and about 9.5, the concentration 
being adjusted to the quality of the hair to be deformed. For example, 
bleached hair, which is very porous, brittle, and lacking in disulfide 
linkages, must be treated with low concentration of a reducing agent. 
Reducing and crosslinking compositions based on the actives described above 
can be prepared in various physical forms including lotions, solutions, 
creams, gels, aerosols and dry forms. 
By the breaking of the disulfide bonds to form free sulfhydryl groups 
pendant on the hair, the hair can be formed or shaped as desired such as 
by winding on rollers or pins, or combed out as in the case of hair 
straightening. The breaking of the disulfide bonds is generally 
accomplished in accordance with the usual practice, which involves 
applying the reducing agent to the hair wound on curlers. Heat can be 
provided at this point. 
The deformed hair, while curled or straightened, is then wetted with the 
crosslinking composition of the invention in water or a pharmaceutically 
acceptable carrier or base such as lotion or cream, preferably buffered. 
The crosslinking composition is preferably water-soluble or made water 
soluble by known techniques. The carriers are of known types and are 
similar to those presently in use in waving and neutralizing compositions. 
The water or carrier desirably holds the crosslinking reagent in contact 
with the hair for a period of time sufficient to effect permanent setting 
of the hair. The crosslinking composition is applied under conditions 
conducive to effective crosslinking. A pH of between about 6 and about 9 
(less than that which would cause permanent breakdown of the hair protein) 
has been found effective for that purpose using the composition of the 
invention. 
Reducing compositions based on the actives described above can be prepared 
in various physical forms including lotions, solutions, creams, gels, 
aerosols and dry forms. 
Any or a combination of alkali metal phosphates, acetates, borates and the 
like which are non-reactive with the crosslinking reagent and cannot 
destroy crosslinking sites, can be used to maintain the pH of the hair 
treated with the crosslinking composition within the range specified. Any 
pH effects caused by the reducing agent can be offset by thorough washing 
of the hair with water prior to the application of the crosslinking 
composition. 
The hair is treated for a period of time sufficient to effect the 
crosslinking to provide the desired permanent shape desired and, in some 
instances, the desired tensile strength increase. Illustrative times 
include from about 3 minutes to any time practical that avoids 
deterioration of the hair, though lesser times can be used if lesser 
effect on the hair is desired. 
The crosslinking reagent is preferably applied in aqueous solution at a 
temperature between the ranges of about 10.degree. C. and 93.degree. C. 
Time of treatment may vary within wide limits depending on the temperature 
of the solution, the particular reducing and crosslinking agents used, and 
the nature of the keratinous material being treated. 
The hair may be further treated with additional neutralizing agents and 
crosslinking reagents in order to oxidize any free sulfhydryl groups to 
disulfide linkages as would be appreciated by one of ordinary skill in the 
art. The oxidizing or neutralizing chemicals used can be any of the 
oxidizing agents capable of restoring the disulfide linkages in the hair 
keratin during the resetting state, such as aqueous solution of hydrogen 
peroxide, alkali metal bromates, alkali metal perborates, urea hydrogen 
peroxide, sodium sesquicarbonate, etc. Rinsing alone with water may 
restore the broken linkages as well, but it will be much slower. However, 
as pointed out above the crosslinking compositions of the invention are 
effective in the absence of peroxygen or bromate oxidizing agents. 
The permanent hair deforming product of the invention can be designed for 
professional as well as home application. The product and its compositions 
can contain ingredients normal to such compositions. Fragrance compounds, 
coloring agents, thickening agents, opacifying agents, sequestering 
agents, solubilizing agents, gelling agents, surfactants, conditioning 
agents, such as amino acids, proteins, and silicones, mineral oils and the 
like may be added to compositions of this invention in amounts 
conventionally used in hair waving and straightening compositions. Any 
compound which will react with the crosslinking reagent to remove or 
neutralize reactive sites thereon is preferably avoided. These ingredients 
are fully outlined in The Science of Hair Care, edited by Charles Zviak, 
Vol. 7 of a series entitled Dermatology, Marcel Dekker, Inc., 1986, which 
is incorporated herein by reference.

The Examples which follow illustrate the present invention in greater 
detail. However, it should be understood that the present invention in its 
broadest aspect is not necessarily limited to these Examples. 
EXAMPLE I 
Swatches (40 milligrams; 8.1 inches in length) of European brown Caucasian 
hair were wrapped around curling rods and treated with various 
commercially available permanent wave products according to manufacturers' 
instructions. All products tested utilize thioglycolate in a reducing 
composition and hydrogen peroxide in a neutralizing composition of the 
hair. Typical treatment time for a neutralization step is 5 to 10 minutes. 
Following the treatment, the standard evaluation procedure was employed as 
follows: 
The swatches were unrolled from curlers, straightened by hand, trimmed to 
length of 7 inches and hung to dry for 24 hours. The swatches were then 
suspended for 2 hours in a 4-liter beaker containing 2 drops of 29% sodium 
lauryl sulfate in 4 l of cold tap water. The swatches were hung to dry for 
24 hours and the final dry curl length was measured. All measurements were 
done from the edge of the tape. 
Data that was generated is summarized in Table I. Products tested were 
ranked per final dry curl length. 
TABLE I 
______________________________________ 
Final Dry Curl 
Product Length (inches) 
______________________________________ 
LOREAL .RTM. 5.8-6.0 
LILT .RTM. 
CLAIROL PROFESSIONAL .RTM. 
REVLON .RTM. 6.1-6.5 
TONI .RTM. 
______________________________________ 
Commercial formulations employing hydrogen peroxide resulted in final dry 
curl length of about 5.8 inches to about 6.5 inches. 
EXAMPLE II 
Swatches (40 milligrams; 8.1 inches in length) of European brown Caucasian 
hair were wrapped around curling rods and treated with commercially 
available thioglycolate waving lotion LOREAL.RTM. (normal hair) for 20 
minutes to rupture the disulfide crosslinkages. The swatches were then 
rinsed for 2 minutes with running tap water and immersed in aqueous 
solutions of various neutralizing agents at room temperature. 
Final dry curl length of the swatches was evaluated according to the 
standard procedure described in Example I. Data that was generated is 
summarized in Table II. 
TABLE II 
______________________________________ 
Final Dry 
Neutralization 
Neutralization 
Curl Length 
Sample # 
Agent Time (minutes) 
(inches) 
______________________________________ 
1 Water 2 6.4 
2 2% Hydrogen 5 5.7 
Peroxide 
3 5% Ammonium 5 5.9 
Molybdate 
______________________________________ 
At room temperature, final dry curl length obtained with ammonium molybdate 
was equal, within the experimental error, to final dry curl length 
obtained with hydrogen peroxide and significantly better than the final 
dry curl length obtained if a neutralizing agent is omitted (sample 1). 
The final dry curl length (5.9 inches) in 5 minutes with ammonium 
molybdate solution was within the range of 5.8 to 6.5 inches obtained in 
Example I with commercial products. 
EXAMPLE III 
Swatches (40 milligrams; 8.1 inches in length) of European brown Caucasian 
hair were wrapped around curling rods and treated with commercially 
available thioglycolate waving lotion LOREAL.RTM. (normal hair) for 20 
minutes to rupture the disulfide crosslinkages. The swatches were then 
rinsed for 2 minutes with running tap water and immersed at room 
temperature in aqueous solutions of ammonium molybdate at various 
concentrations and for various lengths of time as indicated in Table III. 
Hair swatches were evaluated for final dry curl length according to the 
standard procedure described in Example I. Data that was generated is 
summarized in Table III. 
TABLE III 
______________________________________ 
Final Dry 
Ammonium Molybdate 
Neutralization 
Curl Length 
Concentration Time (inches) 
______________________________________ 
0.05% 20 minutes 5.9 
0.5% 20 minutes 6.1 
5.0% 20 minutes 5.9 
0.05% 20 hours 4.1 
0.5% 20 hours 4.0 
5.0% 20 hours 4.0 
______________________________________ 
Final dry curl length was independent of concentration of ammonium 
molybdate. A longer neutralization period improved final dry curl length, 
perhaps representing effect of prolonged diffusion of ammonium molybdate 
into the hair fiber. 
EXAMPLE IV 
Swatches (40 milligrams; 8.1 inches in length) of European brown Caucasian 
hair were wrapped around curling rods and reduced with commercially 
available thioglycolate waving lotion LOREAL.RTM. (normal hair) for 20 
minutes to rupture the disulfide crosslinkages. The swatches were then 
rinsed for 2 minutes with running tap water, followed by a rinse with 
aqueous solutions of ammonium molybdate at various concentrations as 
indicated in Table IV. The swatches were then placed in a bag and heated 
in a water bath at about 50.degree. C. for 20 minutes. 
Hair swatches were evaluated for final dry curl length according to the 
standard procedure described in Example I. Data that was generated is 
summarized in Table IV. 
TABLE IV 
______________________________________ 
Final Dry Curl 
Ammonium Molybdate 
Length 
Sample # (% Concentration) 
(inches) 
______________________________________ 
1 0.05 5.1 
2 0.5 5.0 
3 5.0 4.8 
______________________________________ 
Application of heat in neutralization step improved performance of ammonium 
molybdate when compared to samples 1, 2 and 3 of Example III. 
EXAMPLE V 
Reduced hair treated with ammonium molybdate was studied using atomic 
absorption spectroscopy (AAS) and photoelectron spectroscopy (PES). 
Hair swatches (0.5 g) were reduced with LOREAL.RTM., rinsed with tap water 
and immersed in ammonium molybdate for 72 hours. Other hair swatches, used 
as control, were reduced with LOREAL.RTM., rinsed with tap water, 
neutralized according to LOREAL.RTM. instructions with hydrogen peroxide 
for 10 minutes and thereafter aged with ammonium molybdate treated 
samples. After 72 hours all swatches were rinsed with tap water and 
allowed to air-dry. The swatches were analyzed using AAS and PES. 
AAS analysis detected no molybdenum in the control sample. 0.4% (3600 ppm) 
of molybdenum was absorbed in molybdenum treated samples. 
PES confirmed that molybdenum was present in the molybdenum-treated sample 
and evenly dispersed throughout the hair sample. 
EXAMPLE VI 
Swatches (40 mg, 8.1 inches in length) of European brown Caucasian hair 
were wrapped around curlers and reduced with 0.6 N thioglycolic acid 
solution, adjusted to pH 9.4 with concentrated ammonium hydroxide. The 
reduction was performed at room temperature for 20 minutes. After a rinse 
with warm tap water (37.degree. C.), the hair swatches were rinsed with a 
neutralizing candidate and allowed to react for 20 minutes at either room 
temperature or 50.degree. C. A warm rinse followed the neutralization 
step. Final dry curl length of the hair swatches was evaluated using the 
standard procedure described in Example I. 
Data that was generated is summarized in Table VI. 
TABLE VI 
______________________________________ 
Neutralization Agent 
Final Dry Curl Length (Inches) 
______________________________________ 
Control.sup.1 
5.5 + 0.1 
Ammonium molybdate 
5.2 
Sodium molybdate 
5.3 
Potassium molybdate 
5.4 
Vanadyl sulfate 
5.3 + 0.3 
Ammonium vanadate 
4.8 + 0.4 
Sodium metavanadate 
5.1 + 0.1 
Sodium orthovanadate 
4.5 + 0.6 
Potassium tungstate 
4.6 
______________________________________ 
.sup.1 Combination of H.sub.2 O and H.sub.2 O.sub.2 treatments at 
50.degree. C. and at room temperature. 
Transition metal oxide compounds are equal to or better than water and/or 
hydrogen peroxide when used as neutralizing agents for reduced hair 
keratin. 
The foregoing description and Examples illustrate selected embodiments of 
the present invention and in light thereof variations and modifications 
will be suggested to one skilled in the art, all which are in the spirit 
and purview of this invention.