Amended Final Report on the Safety Assessment of Cocamide DEA

Final Report on the Safety Assessment of Cocamide MEA

Cocamide MEA is a mixture of ethanolamines of fatty acids derived from coconut oil. This cosmetic ingredient functions as a surfactant—foam booster and an aqueous viscosity-increasing agent. To supplement the available data on Cocamide MEA, data from previous safety assessments of Coconut Oil and its derivatives, Monoethanolamine (MEA), and Cocamide DEA (Diethanolamine) were included in this safety assessment. These data suggest little acute, short-term, or chronic toxicity associated with dermal application. MEA vapor, however, is highly toxic. Although DEA is readily nitrosated to form N-nitrosodiethanolamine, a known animal carcinogen, MEA has not been found to form a stable nitrosamine. Dermal application of Cocamide MEA at concentrations of 50% was nonirritating to mildly irritating in animal tests. For comparison, Cocamide DEA at a concentration of 30% was a moderate irritant; Coconut Oil was nonsensitizing; and MEA was irritating and corrosive. Cocamide MEA was negative in the Ames Test. Cocamide DEA was positive in some mutagenesis assays, but negative in others. In clinical tests, Cocamide MEA at a concentration of 50% was not irritating in a single-insult patch test. Cocamide DEA at 2% in formulation caused irritation, but not sensitization. Predictive patch tests with a surfactant containing Cocamide DEA at 10% produced no adverse effects. Inhalation of MEA by humans is toxic. Based on the limited data available data on Cocamide MEA, and on the data on those ingredients previously reviewed, particularly Cocamide DEA, it was concluded that Cocamide MEA is safe as used in rinse-off products and safe at concentrations up to 10% in leave-on products. It was further concluded, however, that Cocamide MEA should not be used as an ingredient in cosmetic products in which N-nitroso compounds are formed or in formulations that will be aerosolized.

Laboratory and clinical trials of cocamide diethanolamine lotion against head lice

Context. During the late 1990s, insecticide resistance had rendered a number of treatment products ineffective; some companies saw this as an opportunity to develop alternative types of treatment. We investigated the possibility that a surfactant-based lotion containing 10% cocamide diethanolamine (cocamide DEA) was effective to eliminate head louse infestation.

Settings and Design. Initial in vitro testing of the lotion formulation versus laboratory reared body/clothing lice, followed by two randomised, controlled, community-based, assessor blinded, clinical studies.

Materials and Methods. Preliminary laboratory tests were performed by exposing lice or louse eggs to the product using a method that mimicked the intended use. Clinical Study 1: Children and adults with confirmed head louse infestation were treated by investigators using a single application of aqueous 10% cocamide DEA lotion applied for 60 min followed by shampooing or a single 1% permethrin creme rinse treatment applied to pre-washed hair for 10 min. Clinical Study 2: Compared two treatment regimens using 10% cocamide DEA lotion that was concentrated by hair drying. A single application left on for 8 h/overnight was compared with two applications 7 days apart of 2 h duration, followed by a shampoo wash.

Results. The initial laboratory tests showed a pediculicidal effect for a 60 min application but limited ovicidal effect. A longer application time of 8 h or overnight was found capable of killing all eggs but this differed between batches of test material. Clinical Study 1: Both treatments performed badly with only 3/23 (13%) successful treatments using cocamide DEA and 5/25 (23.8%) using permethrin. Clinical Study 2: The single overnight application of cocamide DEA concentrated by hair drying gave 10/56 (17.9%) successes compared with 19/56 (33.9%) for the 2 h application regimen repeated after 1 week. Intention to treat analysis showed no significant difference (p = 0.0523) between the treatments. Over the two studies, there were 18 adverse events possibly or probably associated with treatment, most of which were increased pruritus after treatment.

Conclusions. Cocamide DEA 10% lotion, even when concentrated by hair drying, showed limited activity to eliminate head louse infestation.

Safety Assessment of Diethanolamides as Used in Cosmetics

Cocamide diethanolamine (DEA) and some of the other diethanolamides are mainly used as surfactant foam boosters or viscosity increasing agents in cosmetics, although a few are reported to be used as hair and skin conditioning agents, surfactant-cleansing or surfactant-emulsifying agents, or as an opacifying agent. The Cosmetic Ingredient Review (CIR) Expert Panel considered new data and information from previous CIR reports to assess the concerns about the potential for amidases in human skin to convert these diethanolamides into DEA and the corresponding fatty acids. The Expert Panel concluded that these diethanolamides are safe as used when formulated to be nonirritating and when the levels of free DEA in the diethanolamides do not exceed those considered safe by the Panel. The Panel also recommended that these ingredients not be used in cosmetic products in which N-nitroso compounds can be formed.

Amended safety assessment of dodecylbenzenesulfonate, decylbenzenesulfonate, and tridecylbenzenesulfonate salts as used in cosmetics

Sodium dodecylbenzenesulfonate is one of a group of salts of alkylbenzene sulfonates used in cosmetics as surfactant-cleansing agents. Sodium dodecylbenzenesulfonate is soluble in water and partially soluble in alcohol, with dermal absorption dependent on pH. Dodecylbenzenesulfonate salts are not toxic in single-dose oral and dermal animal tests, and no systemic toxicities were observed in repeat-dose dermal animal studies. In dermal animal studies, no evidence of reproductive or developmental toxicity was reported. At 15% concentrations, sodium dodecylbenzenesulfonate was severely irritating to rabbit skin. The Cosmetic Ingredient Review Expert Panel concluded that the irritant properties of these ingredients are similar to those of other detergents, with severity dependent on concentration and pH. Products containing these ingredients should be formulated to ensure that the irritancy potential is minimized.

Percutaneous penetration of diethanolamine through human skin in vitro: Application from cosmetic vehicles

Concern has been raised over the safety of diethanolamine (DEA) which may be present as a minor component of alkanolamide ingredients of cosmetic formulations. Skin penetration data were therefore generated for a range of typical formulations under in-use conditions. Seven rinse-off formulations (A-E, G and H), a leave-on emulsion (F), representing prototype cosmetic formulations and containing representative levels of DEA were prepared. Target levels of DEA were attained by inclusion of DEA as either (14)C-DEA or a combination of (14)C-DEA and unlabeled DEA. Skin permeation and distribution were evaluated using human skin in vitro, static diffusion cells and phosphate buffered saline (pH 7.4) as the receptor phase. At least 12 replicate epidermal membranes were prepared from a minimum of four donors for each test group. Receptor phase samples were taken at appropriate time intervals. At the end of the test period, radioactivity remaining on the skin surface and on the diffusion cell donor cap was determined before the skin samples were tape-stripped. The remaining tissue was solubilized and radioactivity determined. Permeation was very low from all vehicles applied under in-use conditions (range 1-48 ng/cm(2) over 24 h). Comparison was also made between permeation and distribution of DEA from an infinite dose of a simple aqueous solution and the leave-on formulation (F) through paired samples of fresh and frozen full thickness skin from the same donors. When applied as an infinite dose in aqueous solution DEA permeation at 24 h was greater through frozen than through fresh skin. From the leave-on formulation, permeation was similar and very low for both fresh and frozen skin. Recovery of DEA after application of the aqueous solution to fresh human skin and subsequent aqueous and organic extraction of the epidermal and dermal tissue indicated that the majority (>98%) of DEA was in the aqueous extract, suggesting that DEA was in the free state and not associated with the lipid fraction. These data provide a basis for the estimation of the potential systemic exposure and safety margins for DEA in representative cosmetic formulations.

In vitro human skin penetration of diethanolamine

Concerns about the safety of diethanolamine (DEA) have been raised by the National Toxicology Program (NTP). Therefore, we measured the extent of DEA absorption in human skin relevant to exposures from shampoos, hair dyes and body lotions. Radiolabeled [14C]-DEA was added to two commercial products from each class and applied to excised viable and non-viable human skin in flow-through diffusion cells. The products remained on the skin for 5, 30 and 24 h for shampoos, hair dyes and body lotions, respectively. After 24 h, most of the absorbed dose was found in skin: 2.8% for shampoos, 2.9% for hair dyes and 10.0% for body lotions. Only small amounts were absorbed into the receptor fluid: 0.08%, 0.09% and 0.9% for shampoos, hair dyes and body lotions respectively. There was no significant difference in the absorption of DEA through viable and non-viable skin or from product application doses of 1, 2 or 3 mg lotion/cm2. In 72 h daily repeat dose studies with a lotion, DEA appeared to accumulate in the skin (29.2%) with little diffusing out into the receptor fluid. Therefore, skin levels of DEA should not be included in estimates of systemic absorption used in exposure assessments.