Cocamide DEA is a mixture of ethanolamides of Coconut Acid that is used as a surfactant-foam booster and viscosity-increasing agent-aqueous in cosmetic products. Production formulation data submitted to the Food and Drug Administration in 1994 indicated that this ingredient was used in 745 products. The Cosmetic Ingredient Review (CIR) Expert Panel had previously evaluated the safety of Cocamide DEA, Lauramide DEA, Linoleamide DEA, and Oleamide DEA in cosmetics and concluded that they were safe as cosmetic ingredients at the concentrations that were currently being used (50%). CIR's decision to reevaluate the safety of Cocamide DEA in cosmetics is based on occupational studies indicating that this ingredient may have sensitization potential; however, the Expert Panel has determined that these studies are not relevant to cosmetic use. Furthermore, the Panel agreed that its original conclusion on Cocamide DEA should be clarified relative to use of this ingredient in rinse-off and leave-on products. Clarification of the original conclusion is based on the results of a skin irritation test in which 15 volunteers were tested with a surfactant solution containing 10% Cocamide DEA, the highest concentration tested in predictive patch tests. Additional comments that were made during the Panel's review of other data in the present report include that the severe ocular irritation reactions induced by a chemical (p H 9–10.5) containing >64% Cocamide DEA were likely a result of p H; that the renal effects noted in Fischer 344 rats in the National Toxicology Program (NTP) subchronic dermal toxicity study may be species-related and not test substance-related; and with reference to an ongoing NTP two-year chronic study that was initiated in 1993, that the results will be reviewed when the study is available. On the basis of the animal and clinical data presented in the present report, the Expert Panel concluded that Cocamide DEA is safe as used in rinse-off products and safe at concentrations 10% in leave-on cosmetic products. It was also concluded that Cocamide DEA should not be used as an ingredient in cosmetic products in which N-nitroso compounds are formed.
liver in rodents. This reinforces the critical role of pharmacokinetic data for comparing biological reactivity and assessing the hazard potential of a class of chemicals. This book chronicles the evolution of the development of experimental design for safety evaluation studies. Although the early studies had fewer animals than current standards recommend, these studies were enriched with analyses of serum levels to substantiate oral dose regimens and a variety of concomitant or cohort studies to elucidate biological effects and reversibility. Thus, these studies epitomize the Hill criteria of causation, that is, strength of association, consistency, specificity, relationship with time, biological gradient (dose-response relationship), biological plausibility, coherence of the evidence, observed change following intervention, and analogous findings. They also illustrate the challenge of assessing therapeutic and toxicological effects of biologically active agents during the development of new chemotherapeutic entities. The maximum tolerated dose of fibrates was limited by their pharmacological activity. Thus, the administered dose of a toxicology study of a pharmacologically active agent is often a multiple of the therapeutic dose. This monograph provides a rich source of data that will be useful to the experimental toxicologist as well as the specialist. The experimental toxicologist can enhance hidher skills in experimental design and interpretation of data through a careful analysis and comparison of the interspecies differences of the biological effects of fibrates. This recognizes the role of expert judgment in discerning biologically significant effects. The specialist can utilize the information in this monograph to expand the design of mechanistic studies from a greater knowledge of the long-term effects of fibrates and chemically diverse agents that share the property of peroxisome induction.
This study was designed to assess the hypothesis that large differences between male and female Wistar and Sprague-Dawley rats in susceptibility to carbon tetrachloride (CCl4)-induced hepatotoxicity are related to the differential capacity to repair tissue damage. This hypothesis was evaluated via two complementary approaches, (a) Separate groups of rats were administered a minimum lethal dose (LD10) of CC14, with colchicine (CLC) given at 24, 48, or 72 h after CCl4, and assessed for survival, (b) Rats were given a modestly hepatotoxic dose of CC14 and evaluated in terms of the rate and magnitude of damage and the efficiency of repair activities. The mortality for Wistar rats was high for both males (70%) and females (90%) treated with CLC at 24 h after CC14 administration but fell to 33% for females while remaining high (67%) for males treated with CLC at 48 h after CC14 administration. Both male and female Sprague-Dawley rats also exhibited a high mortality rate (70–80%) when administered CLC 24 h after CC14. As in the Wistar rats, the mortality in the Sprague-Dawley females declined to 36% while it remained high among males (67%) when CLC was administered 48 h after the CC14 dose. Male and female Wistar and Sprague-Dawley rats were dosed with CC14 (0.3 ml/kg, 1:1, vol/vol in corn oil, i.p.), and the alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were monitored at 0, 24, 48, and 72 h after treatment. In the Sprague-Dawley strain, AST and ALT values were markedly increased in the female as compared with the male at 24, 48, and 72 h. Both sexes displayed decreasing serum enzyme values starting at 48 h. In contrast to Sprague-Dawley rats, male Wistar rats showed progressive increases and significantly higher AST/ALT values than the females at 48 h; conversely, by 48 h the female rats were starting to display decreasing serum enzyme levels indicative of tissue repair. The findings support the hypothesis that the enhanced susceptibility to CCl4-induced hepatotoxicity of the male compared with the female Wistar rat is principally due to a slower capacity for hepatic tissue repair. In contrast, the principal cause for the enhanced susceptibility of the female compared with the male Sprague-Dawley rat to CC14-induced hepatotoxicity is most likely related to its greater susceptibility for the production of liver damage rather than a less efficient tissue-repair process. Key Words: Carbon tetrachloride-Hepatotoxicity-Sex differences-Tissue repair
Leucrose, D-glucopyranosyl-α(l 5)-D-fructopyranose, is produced by treatment of sucrose with the α(1 6)-glucosyltransferase isolated from Leuconostoc mesenteroides, a nonpathogenic, nontoxigenic microorganism. Rats, dogs, and humans metabolize leucrose efficiently and rapidly in the jejunum by enzymatic hydrolysis into its constituent glucose and fructose. Only traces of leucrose appear in plasma and urine of rats and humans, whereas somewhat larger amounts are seen in plasma and urine of dogs. No toxic or other biological effects were detected in 13-week studies in rats and dogs. Leucrose is not teratogenic in rats and rabbits, and is not genotoxic. It is noncariogenic in humans and rats, and resists attack by the microorganisms present in the human oral cavity.
Sodium m-Nitrobenzenesulfonateis a water-soluble ingredient that is used as a chemical additive in hair dyes and colors and has been used as a base component in semipermanent hair coloring products. Product formulation data submitted to the Food and Drug Administration in 1994 indicated that this ingredient was used in 25 products, all of which were hair dyes and colors. In an acute oral toxicity study involving rats, the median lethal dose was not achieved at a dose of 5,000 mg/kg Sodium m-Nitrobenzenesulfonate. The results of a chronic oral toxicity study of a composite hair dye formulation containing 2.25% Sodium m-Nitrobenzenesulfonate indicated neither gross nor microscopic changes in beagle dogs that were related to test substance administration. The same hair dye formulation (administered in the diet at concentrations of 0.005% and 0.02%) was not classified as a reproductive toxicant in studies involving rats and rabbits. Moderate ocular irritation and mild skin irritation reactions to Sodium m-Nitrobenzenesulfonate were observed in rabbits. Based on these data, however, the safety of use of Sodium m-Nitrobenzenesulfonate in cosmetic products cannot be documented and substantiated. Additional safety test data are needed, including (1) purity and impurity data; (2) a 28-day dermal toxicity study and, if positive, then dermal absorption and distribution data in animals; (3) significantly absorbed, two different genotoxicity assays (one using a mammalian system) and, if positive, a dermal carcinogenicity study using National Toxicology Program methods; and (4) ocular irritation data in animals (if available). The currently available data are insufficient to support the safety of Sodium m-Nitrobenzenesulfonate as used in cosmetic products.
Butoxyethanol is an ether alcohol used as a solvent in hair and nail products at concentrations up to 10%. This ingredient is absorbed through the skin, metabolized to butoxyacetic acid, and excreted in urine. Acute inhalation toxicity was related to concentration and duration of exposure; pathological changes occur in the kidneys, liver, and lungs. Butoxyethanol was only slightly toxic in an acute oral study in rats and in a dermal study in rabbits. Butoxyethanol was nephrotoxic in an intravenous study in rats, but not when administered intraperitoneally. No evidence of genotoxicity was seen in a battery of tests with metabolic activation, but positive and negative effects were seen in the absence of metabolic activation. A dermal study of a cosmetic product containing 10% Butoxyethanol was not carcinogenic in rats, whereas a rust-preventive product containing 2.5% Butoxyethanol was carcinogenic (90.9% of the rust preventive was a petroleum distillate). There is some evidence for reproductive and developmental toxicity in oral and inhalation studies involving rats, rabbits, and mice, but no such effects in dermal studies in rats. Clinical tests and reports from occupational exposures indicate Butoxyethanol to be an irritant when inhaled. Butoxyethanol was not a sensitizer or photosensitizer in clinical tests. Undiluted Butoxyethanol is recognized to be a severe ocular irritant, but aqueous concentrations of 15 and 5% produced only moderate and no corneal injury, respectively. In consideration of these data, the Cosmetic Ingredient Review Expert Panel concluded that this ingredient may be used safely in hair and nail cosmetic products at concentrations up to 10%.
The halogen compound Methyldibromo Glutaronitrile is used in a wide variety of cosmetics as a preservative. Concentrations in cosmetic formulations reportedly range from 0.0075 to 0.06%. The oral LD50 in rats is 640 mg/kg. Dogs on a diet of 4,000 ppm Methyldibromo Glutaronitrile for 13 weeks developed thyroid hyperplasia; those on a diet of 167 ppm exhibited no hyperplasia, although the thyroid glands were enlarged. Application of Methyldibromo Glutaronitrile at a level of 4.0 g/kg to the skin of rats for 21 days produced severe irritation. A concentration of 0.025% applied to the skin of rabbits in a 28-day dermal toxicity study resulted in only slight to moderate irritation. No evidence of sensitization was found in guinea pig studies, nor was photosensitization reported in mouse studies. No reproductive or developmental toxicity was noted in two rat studies. Methyldibromo Glutaronitrile was not mutagenic in a series of mammalian system tests. Clinical data using repeat insult patch testing (HRIPT) methods indicated that concentrations as low as 0.025% produced a positive reaction in a few individuals. To limit the possibility that formulations containing this ingredient will lead to sensitization, it was concluded that leave-on formulations should contain 0.025% Methyldibromo Glutaronitrile. Rinse-off formulations, because the duration of exposure is much less, are considered safe as currently used
The polymer Polyvinyl Acetate (PVAc) is used in cosmetics as a binder, emulsion stabilizer, and hair fixative. Current reported uses are limited to a few eye makeup formulations. As used in cosmetic formulations, PVAc is an emulsion containing 55 to 60% resin, The Cosmetic Ingredient Review (CIR) Expert Panel had previously published a review of the safety of this ingredient in J Am Coil Toxicol (1992;11:465-74) concluding that the available data were not sufficient to support safety. The report included mutagenesis and carcinogenesis studies with negative findings. Data from pregnant rabbits indicated that PVAc was not transferred to the fetus, even when administered by the i.v. route, suggesting that present cosmetic use practices preclude any reproduction or developmental toxicity hazard to humans. Composition and impurities data and human skin irritation and sensitization data, however, were not available. Data received since that assessment include the nature of the ingredient as used in cosmetics, the identity of many of the impurities, and the test results of human exposure to aqueous emulsions containing less than or equal to 50% PVAc. Less than 2 ppm of arsenic and <20 ppm of heavy metals reportedly will be in a typical emulsion. The clinical testing of an aqueous emulsion with 50% PVAc produced no irritation or sensitization. Based on the recent information, this ingredient is found to be safe for use as a cosmetic ingredient in the present practices of use.
A series of experiments was conducted to assess the effects of prior dosing and/or multiple modest blood withdrawal on subsequent carbon tetrachloride (CCl4)-induced hepatotoxicity. Adult male Wistar rats were randomly assigned to the following treatments: oil-CCl4, oil-bleed-CCl4, CCl4-CCl4, and CCl4-bleed-CCl4, with bleed groups having 1 ml of blood removed at baseline (time 0), 24, 48, 72, and 120 h. At these times the levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were determined. The serum enzyme levels of the CCl4 (0.9 ml/kg, vol/vol in corn oil, per os) treated rats (treated at time 0) had returned to untreated levels prior to the administration of the second dose (120 h). Serum enzyme (AST/ALT) levels were measured again 24 and 48 h after the second CCl4 (0.9 ml/kg, 1:1 vol/vol in corn oil, per os) treatment. The results indicated that the prior dose of CCl4 (0.9 ml/kg, 1:1 vol/vol in corn oil, per os) enhanced the hepatotoxicity of a subsequent identical dose of CCl4 three- to six-fold when the two doses were separated by 2–14 days, although the prior dose was protective when administered 24 h before the second dose. Prior multiple blood drawing also enhanced the hepatotoxicity of a subsequent dose of CCl4 (0.9 ml/kg, 1:1 vol/vol in corn oil, per os) three-fold. The effect of blood drawing has been demonstrated to cross sex and strain when tested on male and female Sprague-Dawley and Wistar rats. The combination of the two procedures (with the two CCl4 doses separated by 5 days) enhanced the hepatotoxicity of a subsequent identical dose of CCl4 (0.9 ml/kg, 1:1 vol/vol in corn oil, per os) 10-fold. Subsequent sham bleed experiments indicated that the increase in serum enzyme levels previously associated with blood withdrawal is substantially associated with the handling (i.e. stress) involved in blood withdrawal rather than the removal of modest amounts of blood per se.
The United States Environmental Protection Agency and the Organization for Economic Cooperation and Development have recommended incorporating measurement of motor activity into routine toxicity studies to provide a screen for potential neurotoxic effects. However, there is little information on how to interpretate motor activity levels when an animal's clinical state is altered by systemic toxicity. Because systemic toxicity often includes nonspecific effects, such as reduced feed consumption, this physiologic condition was mimicked by limiting the feed of healthy rats to 10–15 g/rat/day and by limiting appetite through induction of endotoxemia. Injection of animals with endotoxin lowered motor activity by 50%. Combining feed restriction with endotoxin treatment resulted in reduced motor activity 2 days after injection, when signs of endotoxemia were not apparent. Animals treated with endotoxin but fed ad libitum had motor activity levels comparable to the control group 2 days after injection. The results suggest that motor activity levels can be altered by reduced feed consumption in the presence of subclinical systemic toxicity. Significant feed restriction in the absence of systemic toxicity appears unlikely to result in lowered motor activity levels. Key Words: Neurotoxicity-Motor activity-Endotoxin-Systemic toxicity-Feed restriction.
The objective of this study was to determine the effects of hydrogen peroxide alone and in combination with 7,12-dimethylbenza[a]anthracene (DMBA) in the oral cavity because H2o2, has been implicated as a complete carcinogen or cocarcinogen in two animal models. In the two independent studies, golden Syrian hamsters were used to evaluate the carcinogenic and cocarcinogenic potential of dentifrices containing H2o2 and NaHCO3. In the first study, the cocarcinogenic potential of a dentifrice containing 0.75% H2O2/ 5% baking soda was compared with that of a commercial dentifrice with similar ingredients except baking soda and H2O2. In the second study, the cocarcinogenic potential of a dentifrice formulated with 1.5% H, sb>2O2/7.5% baking soda was compared with a mixture of 3% H2O2/baking soda. All materials were applied to the right cheek pouches of experimental animals, and the left cheek pouches were untreated. In the first study. 0.5% DMBA was administered five times weekly for 20 weeks, and the dentifrices were applied immediately after the DMBA. Dentifrices or mineral oil alone were also applied five times weekly. In the second study. 0.5% DMBA or 0.25% DMBA were applied three times weekly for 16 weeks; dentifrices (or 3% H2O2/baking soda) were applied five times weekly for 16 weeks. The dual-phase dentifrice containing 0.75% H2O2/5% baking soda was not carcinogenic, and in combination with DMBA resulted in no observable acceleration of tumor onset, compared with DMBA alone. In fact, animals treated with 0.5% DMBA and the H2O2/baking soda dentifrice had a significantly delayed onset of tumor formation than did animals treated with DMBA alone. In the second bioassay, an increased latency period for tumor formation was observed with 0.5% DMBA and a dual-phase dentifrice containing 1.5% H2O2/7.5% baking soda, compared with 0.5% DMBA alone. With 0.25% DMBA, latency was not affected by addition of the dual-phase dentifrice. In contrast, animals receiving 0.25% DMBA and 3% H2O2/ NaHCO3 had a significantly lower rate of tumor formation and overall mass incidence. Croton oil also reduced the rate of tumor formation when applied with 0.25% DMBA. Histopathologic examination of cheek pouches revealed squamous cell carcinomas in the majority of DMBA-treated animals. Cheek pouches of DMBA-treated animals killed at interim times indicated a progression from keratotic changes and/or dyskeratosis at 6 weeks with the occurrence of carcinomas in approximately half the animals examined at 12 weeks. No significant histopathologic abnormalities were observed in animals not receiving DMB A other than slight keratosis in the oral mucosa of one or two animals per group. These results demonstrated that an oral product containing baking soda and hydrogen peroxide was not carcinogenic, and that baking soda and H2O2 did not enhance the tumorigenicity of DMB A. Furthermore, the tumor-igenic response of DMBA was reduced by coadministration of 3% H2O2 and sodium bicarbonate.
Our previous reports revealed the usefulness of investigating the changes in the weight, cellularity, and histology in the spleen caused by alkylating agents to evaluate immunotoxicity, compared with the plaque-forming cell (PFC) assay using appropriate conditions. In this study, dose–response relationships of weight, cellularity, PFC response, and histology in the spleen in rats treated with antimetabolites were studied. A single administration of azathioprine or 6-mercaptopurine (6-MP) caused decreases in spleen weights and cellularity and the PFC response at nearly the same dose level. In the rats treated with these agents for 7 days, spleen weights and cellularity tended to be decreased at doses lower than those suppressing the PFC response. In the rats singly treated with 5-fluorouracil (5-FU), spleen weights and cellularity were decreased at a dose lower than that suppressing the PFC response. At low and middle doses, the PFC response was inversely enhanced by this agent. A 7-day administration of 5-FU caused reductions in spleen weights and cellularity and PFC response at the same dose level. In addition, the spleen in the rats dosed with azathioprine, 6-MP, or 5-FU was histopathologically examined and indicated a dose-related decrease in the size of the spleen without changes in the tissue architecture at doses suppressing the PFC response. On the other hand, in the red pulp, the extramedullary hematopoiesis disappeared by these antimetabolites at the doses. These results indicate that decreases in the weight and cellularity and histological changes in the spleen caused by antimetabolites are detectable at doses suppressing the PFC response.
The effects of sodium cyanide (CN, 0.1-10 mM) were studied on the action potentials elicited by stimulation of hybrid NG108-15 neuroblastoma cells differentiated with 1 mM dibutyryl cAMP. Concentration of CN less than 2 mM had no effect on the amplitude or time course of Na+ and Ca2+ spikes. In a suppopulation of cells showing repetitive discharges elicited by a single pulse, CN (2-10 mM), reversibly abolished repetitive firing within 15 min. In cells exhibiting a single action potential with no repetitive firing, CN up to 10 mM produced no change in the amplitude or time course of Na+ and Ca2+ spikes. In both classes of cells, stimulation at 1 Hz in the presence of CN (up to 5 mM) produced no appreciable use-dependent depression of either Na+ or Ca2+ spike. The ATP and phosphocreatine levels were not depressed in NG108-15 cells exposed to CN (0.1-10 mM) for up to 45 min. Action-potential-generating mechanisms were not depressed by CN when ATP reserves in the cells were greatly depleted by prior exposure to the glycolytic inhibitor 2-deoxyglucose (2-DG). The only significant change was that in the presence of 2-DG cessation of repetitive discharges to single stimuli occurred, even in 0.2 mM CN. This action is most likely due to a reversible depression of the spike after-hyperpolarization. In general, metabolic processes that maintain ionic gradients across the membrane do not appear to be affected by CN at concentrations used in this study, as indicated by the maintenance of membrane potential and the persistence of action-potential generation. It appears that when the oxidative metabolic pathway is blocked by CN via inhibition of cytochrome-e oxidase, energy needs in NG 108-15 cells are met by glycolysis, which is able to sustain the physiological activity of the cell. When both oxidative and glycolytic pathways are blocked by CN and 2-DG, respectively, cellular function continues to be maintained for at least some time despite severely reduced metabolic reserves.
The mechanism of action of the alkylating agent bis-(2-chloroethyl)sulfide (sulfur mustard, HD) was studied in an in vitro cell culture model. Exposure of mouse neuroblastoma-rat glioma hybrid NG108-15 cells in culture to 0.3 mM HD increased isotopically labeled arachidonic acid [H-3-AA] release from cellular membranes and decreased membrane fluidity. Both changes occurred before any appreciable cell viability loss occurred. Membrane fluidity was studied by electron paramagnetic resonance spectroscopy using 12-doxyl stearic acid as the spin probe. A regression analysis of the relationship between HD-induced AA release and membrane fluidity decrease showed a linear correlation (r(2) = 0.99) indicating that the membrane fluidity decrease was associated with AA release. These results support a proposed calcium-mediated cytotoxic mechanism of HD via AA release and membrane fluidity decrease.
An extensive computer search was conducted, and a comprehensive overview of the current status of alternatives to animal eye irritation tests was obtained. A search of Medline and Toxline databases (1988 to present) was supplemented with references from sources regarding in vitro eye irritation. Particular attention was paid to soap and detergent products and related ingredients. Eighty-five references are included in the review; the in vitro assays are categorized, and their predictive values for assessing acute ocular irritation are evaluated and compared with the Draize rabbit eye irritation assay and with each other. The present review shows that the increased activity of scientists from academia, industry, and regulatory agencies has resulted in substantial progress in developing alternative in vitro procedures and that a number of large, interlaboratory evaluations and international workshops have assisted in the selection process. However, none of these methodologies has obtained acceptance for regulatory classification purposes. Conclusions drawn from this review include that (a) no single in vitro assay is considered capable of replacing the Draize eye irritation test; (b) the chorioallantoic membrane vascular assay (CAMVA) or the hen egg test-chorio-allantoic membrane test (HET-CAM), the chicken or bovine enucleated eye test, the neutral red and plasminogen activation assays for cytotoxicity, and the silicon microphysiometer appear to have the greatest potential as screening tools for eye irritation; and (c) choosing a specific assay or series of assays will depend on the type of agent tested and the impact of false-negative or false-positive results. New assays will continue to be developed and should be included in future evaluations, when sufficient data are available.
The roles played by the nose as a portal of entry, site of metabolism, and potential target of inhaled foreign substances are thoroughly explored in this impressive volume. With over 100 contributors to 22 full chapters and 33 substantial abstracts, the coverage is both thorough, from the point of view of the toxicologist, and up to date. Each chapter is prepared in the form of a journal article; the entire book is a also a supplement to volume 6 of Inhalation Toxicology , a peer-reviewed journal edited by Donald Gardner, an experienced inhalation toxicologist. The level of documentation is admirable, with about 70 photographs (most are of stained sections, and many are in color), 135 drawings and graphs, 43 tables, hundreds of references to the literature, and an extensive and useful topic index. This wealth of scientific information resulted from a 3-day symposium held in Durham, NC, in September of 1993. Objectives of the meeting, and of the book, “were (1) to assess the current state-of-knowledge concerning nasal dosimetry and toxicity in humans and other animals, (2) to examine issues encountered in using animal data to assess human risks, and ( 3 ) to identify research areas that would improve future interspecies comparisons of nasal dosimetry and toxicity of inhaled chemicals.” It is clear that the key experts were assembled and that the objectives were largely achieved. Section 1, an overview consisting of five chapters, includes a brief historical perspective written by Donald Proctor, followed by chapters on research strategies for assessing human risks by Roger McClellan, toxicity end points by Donald Leopold, comparative dosimetry and lesion distribution by Kevin Morgan, and dosimetry modeling by James Ultman. The overview covers the scope of modern nasal toxicity studies, including clinical assessments, gross and cellular anatomy of the nasal regions of humans and of the more common laboratory animal models, as well as several quantitative computational models for gas and vapor uptake by various tissues of the nose. The necessity for, and utility of animal studies are clearly presented and defended. Section 2 takes up nasal dosimetry in common laboratory animals and humans. Related chapters cover dosimetry models for rats and primates by J. S. Kimbell, human nasal dosimetry by Peter Scherer and colleagues, and in vivo measurements of uptake (of gases and vapors) by John Morris. Additional chapters describe case studies of gas uptake in the dog by John Overton and Richard Graham, ozone dosimetry by Gary Hatch and colleagues, rapidly metabolized vapors in the
