Permanent hair dyes

Formazans and their metal complexes are used as textile dyes by direct application. The in situ reduction of tetrazolium salts has not been used to introduce the dyes to their substrates. Treatment with triaryl mono and bis tetrazolium salts followed by a reducing agent such as ascorbic acid or thioglycolic acid has been claimed as a method of introducing formazans as permanent hair dyes.641 There are some references to their use as therapeutic agents.642 544... 

The nitro group is commonly encountered as a substituent in dyes and pigments of most chemical classes, but it acts as the essential chromo-phore in only a few dyes. Nitro dyes are a small group of dyes of some importance as disperse dyes for polyester and as semi-permanent hair dyes. Picric acid, 139, was historically the first nitro dye, although it was... 

The use of permanent hair dyes or the occupational exposure to these cosmetic products has recently been discussed because of a possible link to adverse long term effects like genetic effects or carcinogenic effects (l9 2, 3) Epidemiological studies seem to indicate an overrepresentation of lung and breast cancer among occupationally exposed people ( 3). Previously, 2,U-diaminotoluene (TDA), a very common product in hair dyes, has been proven to be an animal carcinogen after oral administration and subcutaneous injection k) ... 

Aromatic amines as a compound class account for many of the known carcinogenic organic chemicals. Perhaps the most widely publicized compounds are benzidine and 3,31-dichlorobenzidine (DCB)(4>5)which until recently were widely used in the manufacture of dyestuffs. Another widely publicized suspected car-cinogenic aromatic amine is 4-methoxy-m-phenylenediamine (MMPDA)(6)which is used as an ingredient in many permanent hair dye formulations. 4,4,-methylenebis(2-chloroaniline) or MBOCA(Z)and 4,4-methylenedianiline (MDA) are widely used as curing agents in polyurethane resins and are said to be carcinogenic. ... 

Determination Of MMPDA In Human Urine. MMPDA is widely used in permanent hair dye formulations and has been shown to be carcinogenic in rodents. A question exists as whether or not MMPDA can be absorbed through the scalp to enter the blood stream of persons using the dye. In order to answer this question a sensitive, reliable analytical procedure for MMPDA in urine is needed. For this reason we decided to investigate the usefulness of HPLC/EC in this problem. 

Permanent hair dyes also include metal salt dyes, which produce a finely dispersed metal deposit on the hair. Metal oxides or sulfides may also be formed this process can be promoted by the addition of sulfur compounds [9, p. 240], A... 

A survey in 2000, carried out in Los Angeles by a group at the University of Southern California School of Medicine, found a link with bladder cancer. It involved 1541 people with this condition and they were compared to 897 people who were not so afflicted. Adjustments were made to take into account smokers, who are liable to be more at risk of this disease in any case, and it found that those who used permanent hair dyes every month had a slightly higher risk of bladder cancer, especially if they had used hair dyes continuously for 15 or more years. Hairdressers had an even higher risk. This revelation prompted the Scientific Committee on Cosmetic Products and Non-Food Products ofthe EU (SCCNFP) to issue a discussion paper in February 2002. This was followed in December that year by a requirement that manufacturers must submit by July 2005 all their data on hair dyes together with studies to assess their safety in terms of cancer and toxicity. The outcome of this has yet to be published, but it will take the form of an approved list of hair dyes which will be issued in 2007. 

Permanent hair dyes are often derivatives of an aromatic amine, discovered as a hair dye in 1883, called /Mra-phenylenediamine (H2N-C6H4-NH2), including primary intermediates such as pcirci-aminophenol, dihydroxybenzene, 4-methylaminophenol, tetraaminopyrimidine, 2-aminomethyl-4-aminophenol, and / ara-aminodiphenylamine. The / zrra-phenylenedi-amine compound produces a black color, with its derivative parci- mmo-diphenylaminesulfonic acid used in blond formulations. Couplers are generally aromatic phenols or amines that have an available site that is subject to electrophilic interaction. Typical couplers include chemicals such as resorcinol, wrte-phenylenediamine, 2,4-diaminoanisole, mrm-aminophenol,... 

For permanent hair dyes where small shade changes to a lighter color are required, bleaching is also involved. For these systems of permanent dyes, extra peroxide is formulated into the creme developer for the necessary bleaching action. For formulas of this type, see the section of Chapter 6 that describes the formulation of permanent hair dyes. 

Oxidation dyes are often referred to as permanent hair dyes and are the most important of the commercial hair dyes. Permanent hair dyes generally consist of p-diamines and p-aminophenols that are oxidized by hydrogen peroxide to active intermediates [3]. These active intermediates then react inside the hair with color couplers to provide shampoo-resistant hair dyes. 

For forensic or commercial evaluations, light microscopy can readily determine whether or not hair of unknown history has been dyed with a permanent hair dye or has recently been dyed with a semipermanent dye. Human scalp hair does not generally contain pigment in the cuticle. Therefore, a light microscopic evaluation of fiber cross sections or even an optical section can readily reveal whether the hair in question has been treated with a commercial hair dye by determining whether the cuticle has been dyed. 

Oxidation Dyes or Permanent Hair Dyes Compositions and Dyeing Conditions... 

An intense black eumelanin-type pigment is produced by reacting DOPA with controlled amounts of potassium ferricyanide. Simple analogs of intermediates of the melanic pathways such as 8-hydroxy-l,4-dihydrobenzoth-iazine or thio-substituted catechols when oxidized with different oxidants at specific pH conditions and sometimes in the presence of oxidation dye nucloephiles provide different colors similar to those of permanent hair dyes [10]. These systems are still developmental and have not been commercialized to date, but they do appear to offer promise for the future. 

Gago-Dominguez, M., Castelao, J.E., Yuan, J.M., Yu, M.C., and Ross, R.K. (2001). Use of permanent hair dyes and bladder-cancer risk. International Journal of Cancer, 94, 903-906. 

Hydrogen peroxide is an oxidizing agent used as a topical antiseptic and as part of permanent hair-dyes, color-removing preparations and as a neutralizing agent in permanent waving. It is an irritant. 

Synonyms 2-methyl-i,4-benzenediamine sulfate (1 1) 2,5-diaminotoluene sulfate (1 1) p-toluenediamine sulfate (1 1) toluene-2,5-diamine sulfate(i i) 2,5-diaminotoluene sulfate 2,5-toluenediamine sulfate (1 1) toluene-2,5-diamine sulfate C.I. 76042 Uses primary intermediate in various permanent hair dyes. TOLUENE-2,5-DIAMINE SULFATE A... 

Figure 2.14 Correlation between calculated and experimental series of nitroarylamine semi-permanent hair dyes.

---