Studies of in vitro cell transformation and mutagenicity by surfactants and other compounds

Re-evaluation of sorbitan monostearate (E 491), sorbitan tristearate (E 492), sorbitan monolaurate (E 493), sorbitan monooleate (E 494) and sorbitan monopalmitate (E 495) when used as food additives

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of sorbitan monostearate (E 491), sorbitan tristearate (E 492), sorbitan monolaurate (E 493), sorbitan monooleate (E 494) and sorbitan monopalmitate (E 495) when used as food additives. The Scientific Committee on Food (SCF) allocated an acceptable daily intake (ADI) of 25 mg/kg body weight (bw) per day for E 491, E 492 and E 495 singly or in combination; and a separate group ADI for E 493 and E 494 singly or in combination of 5 mg/kg bw per day calculated as sorbitan monolaurate in 1974. The Panel noted that after oral administration sorbitan monostearate can be either hydrolysed to its fatty acid moiety and the corresponding anhydrides of sorbitol and excreted via urine or exhaled as CO 2 or excreted intact in the faeces. The Panel considered that sorbitan esters did not raise concern for genotoxicity. Based on the no observed adverse effect level (NOAEL) of 2,600 mg sorbitan monostearate/kg bw per day, taking into account the ratio between the molecular weight of sorbitan monostearate (430.62 g/mol) and sorbitan (164.16 g/mol), and applying an uncertainty factor of 100, the Panel derived a group ADI of 10 mg/kg bw per day expressed as sorbitan for sorbitan esters (E 491-495) singly or in combination. This group ADI of 10 mg sorbitan/kg bw per day is equivalent to 26 mg sorbitan monostearate/kg bw per day. The Panel concluded that the exposure at the mean and the 95th percentile level, using non-brand-loyal scenario, did not exceed the ADI in any of the population groups. The Panel on the request for an amendment of specifications regarding the removal of 'congealing range' concluded that it could be eventually replaced by another identification parameter such as melting point.

3 Final Report on the Safety Assessment of Sorbitan Stearate, Sorbitan Laurate, Sorbitan Sesquioleate, Sorbitan Oleate, Sorbitan Tristearate, Sorbitan Palmitate, and Sorbitan Trioleate

The Sorbitan esters, including Sorbitan Stearate, Sorbitan Laurate, Sorbitan Sesquioleate, Sorbitan Oleate, Sorbitan Tristearate, Sorbitan Palmitate, and Sorbitan Trioleate, are used in cosmetic products as emulsifiers and stabilizers at concentrations normally under 5 percent. Toxicity was reported in subchronic and chronic studies at concentrations above that normally used in cosmetics. They are generally mild skin irritants but nonsensitizers in animals. They have the potential to induce cutaneous irritation in humans but not sensitization to normal skin.

Carcinogenic studies using Sorbitan Stearate and Laurate were negative. At concentrations of 10 percent or greater, Sorbitan Laurate is a tumor promoter in mouse skin. It is concluded that the latter is not relevant to the use of the Sorbitan esters at low concentrations in cosmetics and that the Sorbitan esters reviewed in the report are safe as cosmetic ingredients under present conditions of concentration and use.

Final Report on the Safety Assessment of Lauramine Oxide and Stearamine Oxide

Lauramine Oxide and Stearamine Oxide are aliphatic tertiary amine oxides that are used mostly in hair care products as foam builders and stabilizers, viscosity enhancers, emollients, conditioners, emulsifiers, antistatic agents, and wetting agents. Both compounds are susceptible to nitrosation and can form nitrosamines in the presence of nitrosating agents. In rats, up to 40% of Lauramine Oxide applied to the skin was absorbed. In two human volunteers, 92% of the dose applied to the skin was recovered from the skin. The oral LD50 in rats for a formulation containing 0.3% Lauramine Oxide was estimated to be >20 g/kg. At a concentration of 30%, Lauramine Oxide produced severe dermal reactions in rabbits, but at 0.3% only slight to moderate erythema with slight edema, Assuring, and slight to moderate epithelial desquamation were found. Stearamine Oxide applied to rabbit skin at 5% did not cause irritation. Both ingredients caused mild, transient ocular irritation in rabbits. Clinical data showed dermal exposure to 3.7% Lauramine Oxide to be a mild irritant, with a slight potential for mild cumulative skin irritation at concentrations as low as 2%. At 0.3%, Lauramine Oxide was not a sensitizer in clinical studies. Lauramine Oxide was nonmutagenic in the Ames assay, but was mutagenic after nitrosation. Lauramine Oxide at 0.1% in drinking water was not carcinogenic in rats, but at 0.1% with 0.2% sodium nitrate did increase the incidence of liver neoplasms. Based on this animal data, neither ingredient should contain N-ni-troso compounds nor be used in formulations containing nitrosating agents. On the basis of the available animal and clinical data, it is concluded that Lauramine Oxide and Stearamine Oxide are safe as cosmetic ingredients for rinse-off products, but that the concentration in Lauramine Oxide leave-on products should be limited to 3.7% and that of Stearamine Oxide limited to 5%.

7 Final Report on the Safety Assessment of Cocamide DEA, Lauramide DEA, Linoleamide DEA, and Oleamide DEA

Cocamide DEA, Lauramide DEA, Linoleamide DEA, and Oleamide DEA are fatty acid diethanolamides that may contain 4–33% diethanolamine. These ingredients are used in cosmetics at concentrations of <0.1–50%, with most products containing 1–25% diethanolamide. Cocamide DEA and Lauramide DEA are inactive ingredients in prescription drugs.

These four fatty acid alkanolamides were slightly toxic to nontoxic to rats in formulations and inert vehicles via acute oral administration. Lauramide DEA was not a significant subchronic oral toxin in rats or dogs. Cocamide DEA, Lauramide DEA, and Linoleamide DEA were not dermal toxins in acute and subchronic animal studies.

Cocamide DEA was a minimal eye irritant and a moderate skin irritant in rabbits. Lauramide DEA and Linoleamide DEA were mild to moderate eye irritants and mild to severe skin irritants. Undiluted Oleamide DEA was not an eye irritant and was a moderate skin irritant in single and cumulative applications.

Lauramide DEA did not demonstrate mutagenic activity in three different Ames-type assays. No data were available on the mutagenic or carcinogenic activity of Cocamide DEA, Linoleamide DEA, and Oleamide DEA.

The clinical information on these ingredients was confined to Cocamide DEA, Lauramide DEA, and Linoleamide DEA. Generally, these products were mild skin irritants but not sensitizers or photosensitizers.

Final Report on the Safety Assessment of Cetrimonium Chloride, Cetrimonium Bromide, and Steartrimonium Chloride

Cetrimonium Bromide, Cetrimonium Chloride, and Steartrimonium Chloride are quaternary ammonium salts used for a variety of purposes in cosmetics at concentrations of up to 10%. Cetrimonium Bromide given orally is poorly absorbed from the intestine and is excreted in feces. Cetrimonium Bromide applied dermally is absorbed into the skin, but not rapidly. Dermal irritation and sensitization and ocular irritation are seen with these quaternary ammonium salts. Cetrimonium Bromide was embryotoxic and teratogenic in mice following intraperitoneal injection of 35 mg/kg; only teratogenic effects were observed with 10 mg/kg. Embryotoxic effects consistent with maternal toxicity were seen in a rat-feeding study using 50 mg/kg/day. Dermal exposure to 2% Cetrimonium Chloride produced no evidence of teratogenieity; nor did 2.5% Steartrimonium Chloride. All mutagenesis assays used were negative. Repeated insult patch tests of concentrations of up to 0.25% Cetrimonium Chloride produced no sensitization reactions, although irritation was observed during induction. Based on the available data Cetrimonium Bromide, Cetrimonium Chloride, and Steartrimonium Chloride are considered safe for use in rinse-off cosmetic products but are safe only at concentrations of up to 0.25% in leave-on products.

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.

Study on OELs for enzyme-containing detergent in China

This study is aimed at setting occupational exposure levels for total detergent dust and enzymes in detergent industries. The study population consisted of 795 workers from four enzyme-containing detergent manufacturing plants (A1, A2, B1 and B2), and 156 control workers from an electronic assembly factory. Work environment monitoring was conducted using high volume of air sampler fro measuring the concentration of total dust (mg/m3), and analyzing the level of enzyme (ng/m3) by ELISA method. A standard questionnaires, pulmonary function test, and skin prick test are used to assess health effects. The levels of detergent total dust varied from 0.2 mg/m3 to 12.54 mg/m3. For enzyme levels, in A1, B1 and B2, the concentration ranged from non-detectable to 9.92 ng/m3 and in A2, the concentration was analyzed by enzyme activity methods and was expressed as Gu/m3 (1 Gu/m3 = 16 ng/m3). The concentration is between 0.16-31.36 ng/m3. Non-specific irritation rates in exposed workers were significantly higher than that in controls. Based on the data collected from A1, B1 and control plants, 95% benchmark dose lower bound were calculated as 1.17 mg/m3. The difference of pulmonary function between exposed workers and controls is not significant. The results of SPT showed that neither Savinase- nor Alcalase-induced sensitization was found in controls. The prevalence rates of sensitization for Savinase and Alcalase were ranged between 3.2% and 31% in all enzyme-containing detergent manufacturers investigated. No case of occupational asthma was observed. For total dust, 1 mg/m3 is suggested as permissible concentration-time weighted average (PC-TWA), and 2 mg/m3 as permissible concentration-short term exposure limit (PC-STEL). For the enzyme Subtilisins, 15 ng/m3 is suggested as PC-TWA, and 30 ng/m3 as PC-STEL.

Final report on the safety assessment of sorbitan caprylate, sorbitan cocoate, sorbitan diisostearate, sorbitan dioleate, sorbitan distearate, sorbitan isostearate, sorbitan olivate, sorbitan sesquiisostearate, sorbitan sesquistearate, and sorbitan triisostearate

Sorbitan fatty acid esters are mono-, di-, and triesters of fatty acids and sorbitol-derived hexitol anhydrides. They function as surfactants in cosmetic formulations. Previously, the Cosmetic Ingredient Review (CIR) Expert Panel had reviewed the safety of several of these sorbitan fatty acid esters (Sorbitan Laurate, Sorbitan Oleate, Sorbitan Palmitate, Sorbitan Sesquioleate, Sorbitan Stearate, Sorbitan Trioleate, and Sorbitan Tristearate). This safety assessment is an addendum to that report that includes Sorbitan Caprylate, Sorbitan Cocoate, Sorbitan Diisostearate, Sorbitan Dioleate, Sorbitan Distearate, Sorbitan Isostearate, Sorbitan Olivate, Sorbitan Sesquiisostearate, Sorbitan Sesquistearate, and Sorbitan Triisostearate. Although concentrations of these ingredients up to 25% have been reported to be used, most commonly they are used at less than 10%. These esters may be hydrolyzed to the fatty acid and anhydrides of Sorbitol. Fatty Acids are absorbed and metabolized. Sorbitan fatty acid esters were relatively nontoxic via ingestion in acute and long-term studies. They were generally minimal to mild skin irritants in animal studies, except that Sorbitan Isostearate applied to the skin was a moderate irritant in one rabbit study and when injected intradermally caused mild to severe irritation in guinea pigs. Sorbitan fatty acid esters did not sensitize guinea pigs. The fatty acid component, tested alone, typically caused only slight irritation and sensitization, and was not photosensitizing. Sorbitan fatty acid esters were not ocular irritants. Fatty acids are normal components of diet for which no data were available concerning reproductive or developmental toxicity, but Sorbitol had no adverse effects on the reproduction of CD rats during a multigeneration feeding study and was not a reproductive toxin at doses of 3000 to 7000 mg/kg/day for 2 years. Overall these esters and their corresponding fatty acids were not mutagenic, but Sorbitan Oleate was reported to reduce DNA repair following ultraviolet radiation exposure in human lymphocytes in culture. Sorbitan Laurate and Sorbitan Trioleate were cocarcinogens in one mouse study, but Sorbitan Trioleate and Sorbitan Oleate were not tumor promoters in another study. In clinical tests, Sorbitan fatty acid esters were generally minimal to mild skin irritants and were nonsensitizing, but Sorbitan Sesquioleate did produce an allergic reaction in fewer than 1% of patients with suspected contact dermatitis and addition of Sorbitan Sesquioleate to the components of a fragrance mix used in patch testing increased both irritant and allergic reactions to the fragrance mix. Careful consideration was made of the data on the cocarcinogenesis of Sorbitan Laurate and Sorbitan Trioleate, but the high exposure levels, high frequency of exposure, and absence of a dose-response led to the conclusion that there was not a cocarcinogenesis risk with the use of these ingredients in cosmetic formulations. Accordingly, these ingredients were considered safe for use in cosmetic formulations under the present practices of use.

The pH 6.7 Syrian hamster embryo cell transformation assay for assessing the carcinogenic potential of chemicals

Cell transformation models have been established for studying the cellular and molecular basis of the neoplastic process. Transformation models have also been utilized extensively for studying mechanisms of chemical carcinogenesis and, to a lesser degree, screening chemicals for their carcinogenic potential. Complexities associated with the conduct of cell transformation assays have been a significant factor in discouraging broad use of this approach despite their reported good predictivity for carcinogenicity. We previously reported that many of the experimental difficulties with the Syrian hamster embryo (SHE) cell transformation assay could be reduced or eliminated by culturing these cells at pH 6.7 culture conditions compared to the historically used pH 7.1-7.3. We and others have shown that morphological transformation (MT), the earliest recognizable phenotype in the multi-step transformation process and the endpoint used in the standard assay to indicate a chemical's transforming activity, represents a pre-neoplastic stage in this model system. In the collaborative study reported here, in which approx. 50% of the chemicals were tested under code in one laboratory (Hazelton) and the other 50% evaluated by several investigators in the second laboratory (P & G), we have evaluated 56 chemicals (30 carcinogens, 18 non-carcinogens, 8 of inconclusive carcinogenic activity) in the SHE cell transformation assay conducted at pH 6.7 culture conditions with a standardized, Good Laboratory Practices-quality protocol. An overall concordance of 85% (41/48) between SHE cell transformation and rodent bioassay results was observed with assay sensitivity of 87% (26/30) and specificity of 83% (15/18), respectively. The assay exhibited a sensitivity of 78% (14/18) for Salmonella assay negative carcinogens, supporting its value for detecting non-mutagenic carcinogens. For maximum assay sensitivity, two exposure durations were required, namely a 24-h exposure and a 7-day exposure assay. Depending on the duration of chemical treatment required to induce transformation, insight into the mechanism of transformation induction may also be gained. Based on the data reported here, as well as the larger historical dataset reviewed by Isfort et al. (1996), we conclude that the SHE cell transformation assay provides an improved method for screening chemicals for carcinogenicity relative to current standard genotoxicity assays.

Comparison of the standard and reduced pH Syrian hamster embryo (SHE) cell in vitro transformation assays in predicting the carcinogenic potential of chemicals

A comprehensive review of the Syrian Hamster Embryo (SHE) cell transformation literature was performed in order to catalogue the chemical/physical entities which have been evaluated for in vitro cell transformation potential. Both reduced pH (pH 6.7) and standard pH (pH 7.1-7.3) SHE cell testing protocols were considered. Based upon this analysis, over 472 individual chemical/physical agents and 182 combinations of chemical/physical agents have been tested under the standard pH conditions, while over 56 chemical/physical agents have been tested under reduced pH conditions. Of the 472 chemical/physical agents tested at the standard pH, 213 had in vivo carcinogenicity data available. Of these 213 chemical/physical agents, 177 were carcinogens while 36 were non-carcinogens. The results of testing the SHE transformability of these 213 chemical/physical agents indicates that the standard pH SHE cell transformation assay had a concordance of 80% (171/213), a sensitivity of 82% (146/177), and a specificity of 69% (25/36). Of these 213 chemical/physical agents, 53% (112/213) were tested more than once often in more than one laboratory, with a 82% (92/112) interlaboratory agreement rate, thus providing confirmatory results. Carcinogenicity data were available for 48 of the 56 chemical/physical agents tested for SHE cell transformation under the reduced pH conditions. The SHE cell transformation assay under reduced pH conditions had a concordance of 85% (41/48), a sensitivity of 87% (26/30), and a specificity of 83% (15/18). For Salmonella-negative carcinogens, the standard pH SHE assay correctly predicted carcinogenicity 75% (48/64) of the time while the reduced pH SHE assay correctly predicted carcinogenicity for Salmonella-negative carcinogens 78% (14/18) of the time. For chemical/physical agents tested under both the reduced pH and standard pH conditions, the standard pH and reduced pH SHE cell assays had a 69% (22/32) agreement rate. Under the reduced pH conditions, the SHE assay correctly predicted rodent carcinogenicity in 86% (25/29) of the chemicals tested under both reduced and standard pH conditions. Under standard pH conditions, the SHE assay correctly predicted rodent carcinogenicity in 69% (20/29) of the chemicals tested under both reduced and standard pH conditions. Collectively, these data indicate that the SHE cell transformation assay is predictive for rodent carcinogenicity under either reduced or standard pH conditions. Importantly, the assay displays better performance and appears to have improved carcinogen prediction capability under reduced pH conditions.

A comprehensive protocol for conducting the Syrian hamster embryo cell transformation assay at pH 6.70

Studies from our laboratory have demonstrated several advantages of conducting the Syrian hamster embryo (SHE) cell transformation assay at pH 6.70 compared to that done historically at higher pH values (7.10-7.35). These include reduction of the influence of SHE cell isolates and fetal bovine serum lot variability on the assay, an increase in the frequency of chemically induced morphological transformation (MT) compared to controls, and an increased ease in scoring the MT phenotype. The purpose of this paper is to report a comprehensive protocol for conduct of the pH 6.70 SHE transformation assay including experimental procedures, a description of criteria for an acceptable assay and statistical procedures for establishing treatment-related effects. We have also identified several assay parameters in addition to pH which can affect transformation frequencies, particularly the critical role colony number per plate can have on transformation frequency. Control of this parameter, for which details are provided, can greatly increase the reproducibility and predictive value of the assay.

Two-dimensional gel electrophoresis analysis of Syrian hamster embryo cells: morphological transformation is not cell type specific

Studies were conducted to investigate the protein phenotype of normal and morphologically transformed Syrian hamster embryo (SHE) cells. Based upon two-dimensional gel protein phenotype analysis, we conclude that (i) SHE cells are a mixture of multiple cell types including mesenchymal and epithelial cells and (ii) several cell types present in the SHE cell population can be morphologically transformed by a variety of genotoxic and non-genotoxic carcinogens.

Evaluation of olestra in short-term genotoxicity assays

Olestra, a mixture of hexa-, hepta- and octa-esters formed from the reaction of sucrose with long-chain fatty acids, was evaluated for its genotoxic potential in the Salmonella/mammalian microsome test, the L5178Y thymidine kinase (TK+/-) mouse lymphoma assay, an unscheduled DNA synthesis assay in primary rat hepatocytes, and an in vitro cytogenetic assay in Chinese hamster ovary cells. The results indicated that olestra was non-genotoxic in these assays.

An interlaboratory comparison of enhanced morphological transformation of Syrian hamster embryo cells cultured under conditions of reduced bicarbonate concentration and pH

Initial studies performed in our laboratory indicated that early passage Syrian hamster embryo (SHE) cells exhibit optimal clonal proliferation when cultured in medium with a sodium bicarbonate concentration of 8.9 mM and pH of 6.70 instead of 44 mM and pH 7.35 as used previously by others. Subsequent studies indicated that morphological transformation frequency induced by benzo[a]pyrene (BP) was also enhanced at pH 6.70 compared to 7.35 and the level of enhancement was affected by cell density and duration of culture. With optimal conditions identified, the carcinogens BP, 3-methylcholanthrene, N-methyl-N'-nitro-N-nitrosoguanidine, 2-acetylaminofluorene and the non-carcinogen anthracene were tested at pH 6.70 and 7.35 in our laboratory and at Microbiological Assoc. Inc. under code. Additionally, the non-carcinogens 4-acetylaminofluorene, and caprolactam were tested in our laboratory. Results from these studies indicate that all carcinogens tested caused a significant increase in morphological transformation frequency compared to controls at pH 6.70. In contrast, only BP caused a significant increase in the morphological transformation frequency at pH 7.35. The non-carcinogens did not significantly increase the morphological transformation frequency compared to controls. Interlaboratory comparisons were in qualitative agreement despite the fact that different lots of serum and hamster cell isolates were used by the two laboratories. However, different dose-response curves for the various chemicals were observed between the two labs. It was also demonstrated that the enhanced morphological transformation frequency is not due to a decrease in culture medium osmolality or Na concentration, a condition which accompanies media with a reduced bicarbonate concentration and pH. These results demonstrate that the chemicals tested, low pH transformation of SHE cells agrees with carcinogenic potential and that assay variability is minimized. The implications of these results regarding use of the SHE cell assay as a short-term test for predicting the carcinogenic potential of chemicals are discussed.

Surfactants: a survey of short-term genotoxicity testing

The available results for tests on over 200 surfactants in nine short-term genotoxicity assay systems were reviewed. These tests included the Salmonella/microsome mutation assay, bacterial DNA repair tests, mitotic recombination in Saccharomyces cerevisiae, the mouse lymphoma cell-mutation assay, unscheduled DNA synthesis and sister chromatid exchange assays in mammalian cells, mammalian chromosome damage tests in vitro and in vivo, the dominant lethal test in rodents, and mammalian cell-transformation tests. The collected data cover all four major classes of surfactants: anionic, cationic, nonionic and amphoteric. The results of these genotoxicity tests were overwhelmingly negative. Although there were occasional positive results in bacterial or cell-transformation systems, the testing performed to date indicates that surfactants have negligible potential to cause genetic damage. The available data also indicate that none of the assays were incompatible with testing surfactants for genotoxicity.