Oral 1-Generation Rat Reproduction Study of Isobornyl Acetate: An Evaluation Through Sexual Maturity in the F1 Generation.

Reproductive toxicity of isobornyl acetate (IA), a widely used fragrance ingredient, was investigated in a 1-generation reproduction study in which 25 Crl: CD (Sprague-Dawley) rats/sex/group were gavaged with dosages of 0 (corn oil vehicle), 30, 100, or 300 mg/kg/d during premating, mating, gestation, and lactation. After weaning, 25 F1 generation pups/sex/dosage group were randomly selected for evaluation until sexual maturity. The following parameters were evaluated in P generation males and females: viability, clinical signs, body weights, feed consumption, mating and fertility, organ weights, gross and microscopic observations, sperm assessments (motility and concentration), natural delivery and litter observations, and ovarian follicle counts. In F1 generation pups, viability, body weights, sexual maturation, anogenital distance (days 1 and 22 postpartum), nipple eruption (day 12 postpartum), and gross necropsy observations were recorded. Isobornyl acetate did not adversely affect any of the investigated parameters. Based on the results of this investigation, the no observable adverse effect level (NOAEL) for toxicity of IA is considered to be 300 mg/kg/d. Increased incidences of excess salivation occurred in P generation male and female rats at 100 and/or 300 mg/kg/d throughout the dosage period, and low incidences of urine-stained abdominal fur were seen in females at 300 mg/kg/d during the gestation period. These clinical signs were not considered as adverse effects of IA administration. Thus, the NOAEL for reproductive toxicity in the P generation rats and the NOAEL for viability and growth of the F1 generation offspring is considered to be ≥300 mg/kg/d.

Oral and dermal developmental toxicity studies of phenylethyl alcohol in rats.

Phenylethyl alcohol (PEA) was tested for developmental toxicity. Pregnant rats were fed 0, 83, 266, or 799 mg/kg/d PEA on gestation days (GDs) 6 to 15; only minimal, nonsignificant effects were observed. In dermal studies, PEA (neat) was applied to the skin on GDs 6 to 15 at dosages of 0, 140, 430, or 1400 mg/kg/d and at 0, 70, 140, 280, 430, or 700 mg/kg/d in a corroborative study. Observations included maternal and embryo-fetal toxicity/abnormalities at 1400 mg/kg/d, increased incidences of rudimentary cervical ribs at ≥430 mg/kg/d, and reduced fetal body weights at ≥140 mg/kg/d. Dermal maternal and developmental no-observed-adverse-effect levels are 70 mg/kg/d, based on dermal irritation and reductions (nonsignificant) in fetal body weights. Human exposure from fragrances is 0.02 mg/kg/d, resulting in a margin of safety >2600, when marked differences in dermal absorption between rats and humans are considered. Under normal fragrance use conditions, PEA is not a developmental toxicity hazard for humans.

The pharmacokinetics of phenylethyl alcohol (PEA): safety evaluation comparisons in rats, rabbits, and humans.

The present studies were conducted to compare the dermal absorption, plasma pharmacokinetics, and excretion of phenylethyl alcohol (PEA) by pregnant and nonpregnant rats, rabbits, and humans. The PEA is a natural fragrance material that is widely used in perfumes, soaps, and lotions and is a major ingredient of natural rose oil. Following dermal (430, 700, or 1400 mg/kg body weight [bw]), gavage (430 mg/kg bw), or dietary (430 mg/kg bw) administration of PEA to rats, plasma concentrations of PEA were found to be low regardless of the route of administration. The plasma concentrations of phenylacetic acid (PAA, the major metabolite of PEA) greatly exceeded the concentrations of PEA and were highest after gavage, followed by dermal then dietary administration. Absorption, distribution, metabolism, and excretion were compared following topical application of ¹4C-labeled PEA to rats, rabbits, and humans (specific activities of dosing solutions: 58-580, 164, and 50 µCi/mL, respectively). In rabbits, the plasma concentration-time profile for PAA was markedly prolonged compared to rats or humans. In humans, only 7.6% of the applied dose of PEA was absorbed, versus 77% in rats and 50% in rabbits. Based on a human dermal systemic exposure of 0.3 mg/kg per day from the use of multiple consumer personal care products containing PEA, a rat dermal no observed adverse effect level of 70 mg/kg per day, and the percentage of dose absorbed in humans, the margin of safety exceeds 2600 concluding that, under normal fragrance use conditions, PEA is not a developmental toxicity hazard for humans.

Uterotrophic assay of percutaneous lavender oil in immature female rats.

The estrogenic potential of lavender oil was evaluated in a percutaneous uterotrophic bioassay in immature female rats. Four groups of 10 immature female rats each were randomly selected on postpartum day (PPD) 16. During the 3-day treatment period (PPDs 19-21), the immature rats were separated from the dams, caged in groups of 5 in a litter box for 6 hours, and administered the vehicle control article (corn oil) or lavender oil at 20 or 100 mg/kg per day. All dosages were administered as a 5 mL/kg volume in a Hilltop Chamber (25 mm diameter; absorbent material removed) placed on the shaved back of each immature rat, and secured with micropore tape and Vetrap. A positive control group was gavaged twice daily with 2.5 µg/kg per day of 17α-ethinyl estradiol. Daily observations included viability, clinical signs, body weights, and body weight gains. All rats were euthanized 24 hours after the third and final treatment, the uteri and ovaries were removed, and the paired ovaries and wet and blotted uterine weights were recorded. No unscheduled deaths occurred. No skin reactions were observed. Both dosages of lavender oil significantly reduced body weight gains after the third day of treatment, but terminal body weights and mean absolute and relative uterine weights did not differ significantly from vehicle control values. Positive controls showed significant increases in body weight and increased mean absolute and relative uterine weights as expected. Based on these data, lavender oil, at dosages of 20 or 100 mg/kg, was not active in the rat uterotrophic assay and gave no evidence of estrogenic activity.

Evaluation of the developmental toxicity of 4-tert-butylcyclohexyl acetate in Sprague-Dawley rats.

The fragrance ingredient 4-tert-butylcyclohexyl acetate (4-tBCHA) was evaluated for potential developmental toxicity in pregnant rats at oral dosages of 0, 40, 160, or 640 mg/kg per d in corn oil on gestational days 7 to 20. Increased salivation was observed at 160 and 640 mg/kg per d. The 640 mg/kg per d dosage was associated with the presence of a red perioral substance, ungroomed, sparse hair coat on the limbs, localized alopecia, reduced feed and body weight gains, or body weight losses, and mortality. Fetal body weights also were reduced at 640 mg/kg per d. This effect was associated with transient delays in fetal development, including significant increases in fetal incidences of moderate enlargement of the renal pelvis and reversible delays in ossification of the caudal vertebrae, fore and hind limb phalanges, and hind limb metatarsals. Maternal and developmental no observable adverse effect levels (NOAELs) were 160 mg/kg per d. It was concluded that 4-tBCHA is not a developmental toxicant in rats.

Does the new standard for eugenol designed to protect against contact sensitization protect those sensitized from elicitation of the reaction?

BACKGROUND: Potential fragrance allergens used in daily products should have a concentration limited to levels that are at, or below, acceptable exposure levels based on the quantitative risk assessment for the induction of dermal sensitization. To date, there are insufficient data to discern any quantitative relationship between induction and elicitation concentrations for fragrance ingredients that have a potential for dermal sensitization. When available, these data should be used to confirm the effectiveness of quantitative risk assessment-based risk management procedures. OBJECTIVE: In this study, the relationship between the allergen concentration and the time to elicit allergic contact dermatitis in eugenol-sensitized patients was studied. The products used to elicit allergic contact dermatitis had a concentration of eugenol that was equal to, or below, the International Fragrance Association standard. METHODS: Volunteers with and without known sensitization to eugenol were patch tested with various concentrations of eugenol (dilution series) and also underwent repeated open application tests (ROATs). This study model has previously been successfully used with stronger sensitizers. RESULTS: In this study, allergic contact dermatitis, as evidenced by a positive ROAT, could not be elicited by any of the concentrations studied, including in those patients where the patch tests were positive. CONCLUSIONS: When tested in a 3-week ROAT at, or below, its current International Fragrance Association Standard, eugenol did not induce reactions even in those known to be sensitized. Whether this represents a false-negative result for a weak allergen is unknown.

A pilot study aimed at finding a suitable eugenol concentration for a leave-on product for use in a repeated open application test.

BACKGROUND: Knowledge of sensitization and elicitation thresholds and the time-dose relationship for elicitation of contact dermatitis is important in order to provide safe products for consumers. OBJECTIVE: Since previous studies performed with eugenol had showed negative results in a repeat open application study (ROAT) study, we wanted to perform a ROAT with higher concentration (maximum allowed) and longer ROAT. MATERIALS: 5 volunteers previously tested positive to eugenol were studied. They performed a ROAT test for maximum 4 weeks with four different solutions. Results. Four of five reacted to the maximum concentration of eugenol in the ROAT. CONCLUSION: In patients sensitized to eugenol, with the maximum allowed concentration of eugenol and given a prolonged ROAT (4 weeks), there is a clear risk of elicitating an allergic contact dermatitis.

Ninety-day toxicity study of alpha-iso-methylionone in rats.

Alpha-iso-methylionone (AIM), a fragrance ingredient, was evaluated for systemic toxicity in rats. Male and female Sprague Dawley rats were administered 0, 5, 30, or 500 mg/kg/d AIM via gavage for 90 days. Statistically significant changes in blood chemistry parameters (reduced aspartate aminotransferase [AST], and increased cholesterol, creatinine, and total protein) were observed in both sexes at 500 mg/kg/d. There were statistically significant increases in liver and kidney weights in both sexes and in spleen weights in males at 500 mg/kg/d. Adaptive hepatocyte enlargement was observed in both sexes at 500 mg/kg/d. Globular accumulations of eosinophilic material were observed in the renal tubular epithelium in males at ≥30 mg/kg/d. Thyroid and bone marrow histopathological changes were observed in males at 500 mg/kg/d. The no-observed-effect level was 5 mg/kg/d for males and 30 mg/kg/d for females. Based on histopathological changes in the kidney in males, the no-observed-adverse-effect level was 30 mg/kg/d.

Evaluation of the developmental toxicity of dihydromyrcenol in rats.

Dihydromyrcenol, a widely used fragrance ingredient, was evaluated for developmental toxicity in pregnant Sprague-Dawley rats (25/group). Oral dosages of 0, 250, 500, or 1000 mg/kg/d in corn oil were administered on gestational days 7 to 17. Rats were observed for viability, clinical signs, body weights, and feed consumption. Caesarean sectioning and necropsy occurred on gestational day 21. Fetuses were weighed and examined for sex, gross external changes, and soft tissue or skeletal alterations. All rats survived until scheduled termination. No clinical signs were attributed to dihydromyrcenol. There were no gross tissue changes at necropsy. The 1000-mg/kg/d dosage group had reduced mean maternal body weight gains of 5% compared with controls, whereas absolute and relative feed consumption were significantly reduced during the dosage period. This threshold systemic maternal toxicity was associated with threshold developmental toxicity in the 1000-mg/kg/d dosage group. Fetal effects included a minimal approximately 3% reduction in fetal body weight; reversible variations in ossification, including retarded ossification of the metatarsal bones in the hindpaws; and an increase in supernumerary thoracic ribs with associated increases or decreases in thoracic and lumbar vertebrae, respectively. Based on these data, maternal and developmental no observable effect levels of 500 mg/kg/d and maternal and developmental no observable adverse effect levels of 1000 mg/kg/d were established for dihydromyrcenol. It was concluded that dihydromyrcenol is not a selective developmental toxicant in rats under the conditions of this study and that a margin of safety of 25 000 exists between reversible developmental delays in rats and the estimated daily human exposure level of 0.02 mg/kg/d.

Evaluation of the developmental toxicity of 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl) ethanone (OTNE) in rats.

The developmental toxicity of 1-(1,2,3,4,5,6,7,8-Octahydro-2,3,8,8-tetramethyl-2-naphthalenyl) ethanone (OTNE), a widely used fragrance ingredient, was evaluated in pregnant Sprague-Dawley rats (25/group) gavaged with dosages of 0 (water), 96, 240, or 480 mg/kg/d on days 7 through 17 of gestation (GDs 7-17). Rats were observed for clinical signs, abortions, premature deliveries, body weights, and feed intake. Caesarean section and necropsy were performed on GD 21. Fetuses were weighed and examined for gender, gross external changes, and soft tissue or skeletal alterations. No deaths or premature deliveries were attributed to OTNE. OTNE-related clinical signs included significantly increased incidences of excessive salivation in all 3 treatment groups, and urine-stained abdominal fur in the high dosage group. Mean body weight gains were significantly reduced by all OTNE dosages on GDs 7-10, while at 480 mg/kg/d, significant reductions continued through the remainder of the dosage period. Feed consumption generally paralleled body weight gains. Fetal body weights were reduced by 480 mg/kg/d, but not to a statistically significant degree. No fetal gross external, soft tissue, or skeletal malformations or variations were attributable to OTNE. Based on these data, maternal and developmental no-observable-adverse-effect-levels (NOAELs) of 240 mg/kg/d were established for OTNE. It was concluded that OTNE is not a developmental toxicant in rats under the conditions of this study, and that a margin of safety greater than 2700 exists between reversible developmental delays in rats and the calculated daily human exposure level of 0.086 mg/kg/d.

Evaluation of the developmental toxicity of methyl dihydrojasmonate (MDJ) in rats.

Methyl dihydrojasmonate (MDJ) is a widely used fragrance ingredient. MDJ was evaluated for developmental toxicity in presumed pregnant Sprague-Dawley rats (25/group) at oral dosages of 0, 40, 80 or 120 mg/kg/day in corn oil administered on gestational days 7-20. Dams were observed for viability, clinical signs, body weights, and feed consumption. Caesarean-sectioning and necropsy occurred on gestational day 21. Fetuses were weighed and examined for gender, gross external changes, and soft tissue or skeletal alterations. No maternal or fetal deaths occurred. MDJ-related maternal clinical signs included an increased incidence of sparse hair coat and ungroomed appearance at 120 mg/kg/day. Two dams in this group also had tan areas in the liver and a pale spleen. The 120 mg/kg/day dosage also caused reduced mean maternal body weight gains and body weights during the dosage period and reduced absolute and relative maternal feed consumption for the entire dosage period. No Caesarean-sectioning or litter parameters were affected by dosages of MDJ as high as 120 mg/kg/day, although at the highest dosage a tendency toward slightly reduced, but not statistically significant, fetal mean body weight was observed. No fetal gross external, soft tissue or skeletal changes were attributable to dosages of MDJ as high as 120 mg/kg/day. Based on these data, maternal No-Observable-Adverse-Effect-Level (NOAEL) of 80 and developmental NOAEL of equal to or greater than 120 mg/kg/day were established for MDJ. It is concluded that MDJ is not a developmental toxicant in rats under the conditions of this study.

Evaluation of the developmental toxicity of linalool in rats.

The developmental toxicity of linalool, a widely used fragrance ingredient, was evaluated in presumed pregnant Sprague-Dawley rats (25/group). Oral dosages of 0, 250, 500, or 1000 mg/kg/day linalool were administered by gavage on gestational days 7 to 17. The presence of spermatozoa and/or a copulatory plug in situ was designated as gestational day 0. Rats were observed for viability, clinical signs, body weights, and feed consumption. Caesarean sectioning and necropsy occurred on gestational day 21. Uteri were examined for number and distribution of implantations, live and dead fetuses, and early and late resorptions. Numbers of corpora lutea were also recorded. Fetuses were weighed and examined for gender, gross external changes, and soft tissue or skeletal alterations. There were no maternal deaths, clinical signs, or gross lesions that were considered related to linalool. During the dosage period, mean relative feed consumption was significantly reduced by 7% and mean body weight gains were reduced by 11% at 1000 mg/kg/day. During the postdosage period, feed consumption values at 1000 mg/kg/day were significantly higher than vehicle control values, which corresponded to the increase in body weight gains during this period. Caesarean section and litter parameters, as well as fetal alterations, were not affected by linalool at any of the three dosages tested. On the basis of these data, the maternal no observed adverse effect level (NOAEL) of linalool is 500 mg/kg/day, whereas the developmental NOAEL is > or = 1000 mg/kg/day. It is concluded that linalool is not a developmental toxicant in rats at maternal doses of up to 1000 mg/kg/day.

The Research Institute for Fragrance Materials' human repeated insult patch test protocol.

With implementation of the dermal sensitization QRA approach for fragrance ingredients, IFRA/RIFM are recommending use of the RIFM standard human repeated insult patch test (HRIPT) protocol for generation of confirmatory human data for the induction of dermal sensitization in a normal human population. Details of this standard HRIPT protocol are provided in this paper. The study protocol consists of two phases--Induction and Challenge. In the Induction phase, patches treated with fragrance ingredients in 75% diethyl phthalate/25% ethanol are applied to backs of volunteers for 24h. Following patch removal there is a 24-h rest period and volunteers are patched again at the same site. This procedure is repeated to achieve 9 applications over a 3-week period. There is an approximate 2-week rest period followed by a Challenge phase of a single 24-h patch application of test article applied to a naïve site on the back. Skin reactions at the naïve site observed at Challenge may be suggestive of dermal sensitization, and a Rechallenge is performed to confirm the nature of the reactivity. This study is designed to confirm the No-Observed-Effect-Level for induction of dermal sensitization in a normal human population.

Evaluation of the developmental toxicity of alpha-iso-methylionone in rats.

Alpha-iso-methylionone, a widely used fragrance ingredient, was evaluated for developmental toxicity in presumed pregnant Sprague-Dawley rats (25/group). Oral dosages of 0, 3, 10, or 30 mg/kg/day alpha-iso-methylionone in corn oil were administered by gavage on gestational days 7 to 17. The presence of spermatozoa and/or a copulatory plug in situ was designated as gestational day. Rats were observed for viability, clinical signs, body weights, and feed consumption. Caesarean sectioning and necropsy occurred on gestational day 21. Uteri were examined for number and distribution of implantations, live and dead fetuses, and early and late resorptions. Numbers of corpora lutea were also recorded. Fetuses were weighed and examined for gender, gross external changes, and soft tissue or skeletal alterations. No maternal or fetal deaths occurred. No fragrance ingredient-related clinical signs were observed. Feed consumption, body weight gains, gross tissue changes at necropsy, and caesarean section or litter parameters, as well as fetal developmental morphology, were unaffected by dosages of alpha-iso-methylionone as high as 30 mg/kg/day. Based on these data, maternal and developmental no observed adverse effect levels of equal to or greater than 30 mg/kg/day were established for alpha-iso-methylionone. It is concluded that alpha-iso-methylionone is not a developmental toxicant in rats at maternal doses of up to 30 mg/kg/day.

The effects of vehicles on the human dermal irritation potentials of allyl esters.

Allyl esters, frequently used in the fragrance industry, often contain a certain percentage of free allyl alcohol. Allyl alcohol is known to have a potential for delayed skin irritation. Also present in the finished product are different solvent systems, or vehicles, which are used to deliver the fragrances based upon their intended application. This study was conducted to determine whether different vehicles affect the skin irritation potential of five different allyl esters. The allyl esters tested were allyl amyl glycolate, allyl caproate, allyl (cyclohexyloxy)acetate, allyl cyclohexylpropionate, and allyl phenoxyacetate in the vehicles diethyl phthalate, 3:1 diethyl phthalate:ethanol, and 1:3 diethyl phthalate:ethanol at concentrations of 0.1%, 0.5%, 1.0%, and 2.0% (w/w). A modified cumulative irritation test was conducted in 129 human subjects. Test materials (0.3 ml) were applied under occlusion to skin sites on the back for 1 day (24 h) using Hill Top chambers. Irritation was assessed at 1, 2, 4, and 5 days following application of test materials. Cumulative irritation scores varied considerably among test materials. There were no delayed irritation observations. The highest irritation scores were observed at the 2.0% concentration for all test materials. The irritation scores for allyl amyl glycolate, allyl (cyclohexyloxy)acetate, and allyl phenoxyacetate were highest in 1:3 diethyl phthalate:ethanol, thus the resulting calculated no-observed-effect levels, 0.12%, 0.03%, and 0%, respectively, were much lower for this vehicle compared to the diethyl phthalate vehicle, 0.33%, 0.26%, 0.25%, respectively. These data showed a trend for lower concentration thresholds to induce irritation when higher levels of ethanol were used in the vehicle.