EFFECT OF BASE COMPONENTS ON OXIDATION HAIR DYES 439 amines. It should be noted here that 15% levels of these products, even in a bland base, may be rather irritating and must not be used as dye base additives without extensive safety testing. Quaternary Ammonium Compounds Table X summarizes the findings with six strongly cationic quater- nary ammonium compounds used at levels which are perhaps totally unrealistic from a safety standpoint since some of them produce corneal opacity when introduced into the eye at levels as low as 0.2%. They were used at 7.5% and 15% nevertheless, to give a comparison to the other materials tested in this study. It should also be pointed out that they were probably completely neutralized as cationic agents in the presence of the ammonium oleate soap base, thus greatly changing their irritation potential. There was definite evidence that the shade pro- duced by dye bases containing such quaternary ammonium cationic surfactants reddened as the solution aged. The phenomenon seems to apply to the class as a whole it is not restricted to individual com- pounds, nor to specific conditions of aging. In general, even at the "massive" levels tested, there was no effect on either the pH of the dye bases, nor on temperature rise upon mixing with peroxide. None greatly increased the initial viscosity. Dimethyl distearyl ammonium chloride (at 15% in Base Solution #1) produced the largest viscosity increase after addition of peroxide (from 30 cps initially, to 2060 cps five minutes after the peroxide was added, to 2580 cps after thirty minutes) and gave the best control of drop-move- ment of the whole group (0.5 in. or less at every stage tested). Di- methyl cetyl benzyl ammonium chloride (#7, Table X), in contrast, gave excellent viscosity build-up, but no control at all over drop-movement. In all cases, the 15% level appeared necessary for viscosity build-up and drop-movement control performance fell off sharply at the 7.5% level. There was solidification and separation when samples 1, 3, 4, 6, and 8 were aged at 2 øC. With sample #5 (stearyl quaternary imidazoline, 15%) the solution turned green after aging 1000 hours at 48 øC and addi- tion of the peroxide. It also showed a temperature rise of 7 øC. The color produced after aging at 48 øC was lighter and redder than when aged at 2 øC. Miscellaneous A dditives--Polypeptides, ED TA Polypeptides are currently being added to many hair products to take advantage of their protective colloid effect in preventing fiber damage

440 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS during oxidative processes, such as dyeing and bleaching, and for their substantivity (in hair care products). It was therefore decided to test their effect in a routine manner, simply as another dye base additive in this series. Table XI shows the detailed results. Used at a concentra- tion of 1% (solids basis) in Base Solution #2, there appeared to be no effect on the shade or depth of color achieved, but there was a distinct falling off in initial viscosity as a result of its presence. It should be remembered that Base Solution #2 already contains an (hydroxyethyl- stearyl) amide thickener this base solution was devised especially for testing various miscellaneous additives. Final viscosity, achieved 30 minutes after addition of the peroxide, was not affected by the poly- peptides. Drop-movement control was not affected at this level either, nor was pH. At 2% (solids basis) however, drop-movement was con- siderably affected. A very slight increase in temperature was possibly due to the polypeptide presence. The same Base Solution #2 was also used to test the effect of adding EDTA (ethylene diamine tetraacetic acid), a sequestrant for heavy metals, commonly recommended for use in oxidation hair dyes for two reasons: to counteract the deleterious "tippy dyeing" effects of iron on these dyes, and to help ensure controlled release of oxygen from the peroxide by sequestering heavy metals which catalyze such release. The EDTA (disodium salt) was used at two levels, 0.2% and 0.5%. Under the conditions of this test procedure, perhaps since deionized water was being used throughout, no effect on shade or depth of dyeings was noted. This sequestrant did not affect drop-movements in the amounts tested at 0.5%, it did raise viscosity somewhat over that achieved with 0.2% this is perhaps due only to a salting out effect of the amide. Sodium Sulfite The final additive checked was sodium sulfite, tested in Base Solu- tion #4. This reducing agent is commonly included in oxidative hair dye bases as an antioxidant, to prolong shelf-life by using up any free oxygen left in the head space after the bottle has been filled with dye base. It also keeps the oxidation dye intermediates in a reduced state, thus ensuring their complete solubility in the dye base, which must be essentially uncolored (amber) and clear at the time it reaches the ulti- mate user. Sodium sulfite also acts as a salt in such solutions, however, as can be seen from inspection of Table XII which shows viscosity vary- ing considerably as the proportion of sodium sulfite was increased from