Abstract  In vivo irritant or corrosive effects of squalan were determined using EPA OPPTS 870.2500 guideline. The test item was applied on rabbit skin during 4h. The test sites were scored for dermal irritation at 60min after removal of wrappings and scored again at 24, 48 and 72h. The modied Primary Irritating Index is 0.22. In conclusion, in this study, the squalan is considered non-irritant.

Abstract  Biodegradability was conducted according to OECD guideline n°301B. Sample biodegradability was equal to 55.9% after 28 days and 66.3% after 36 days.

Abstract  Among several bacterial species belonging to the general Gordonia, Mycobacterium, Micromonospora, Pseudomonas, and Rhodococcus, only two mycobacterial isolates, Mycobacterium fortuitum strain NF4 and the new isolate Mycobacterium ratisbonense strain SD4, which was isolated from a sewage treatment plant, were capable of utilizing the multiply branched hydrocarbon squalane (2,6,10,15,19, 23-hexamethyltetracosane) and its analogous unsaturated hydrocarbon squalene as the sole carbon source for growth. Detailed degradation studies and high-pressure liquid chromatography analysis showed a clear decrease of the concentrations of squalane and squalene during biomass increase. These results were supported by resting-cell experiments using strain SD4 and squalane or squalene as the substrate. The degradation of acyclic isoprenoids and alkanes as well as of acids derived from these compounds was also investigated. Inhibition of squalane and squalene degradation by acrylic acid indicated the possible involvement of beta-oxidation in the degradation route. To our knowledge, this is the first report demonstrating the biodegradation of squalane by using defined axenic cultures.

Abstract  Squalane and Squalene have been identified as natural components of human sebum. Both ingredients are used in a variety of cosmetics at concentrations ranging from 5 0.1 to > 504b. Animal studies indicate Squalene is slowly absorbed through the skin, while both compounds are poorly absorbed from the gastrointestinal tract. The acute animal toxicity of these ingredients by all routes is low. Both compounds are nonirritants to rabbit skin and eye at 100% concentration. Formulations containing Squalene indicate it is not a significant human skin irritant or sensitizer. limited contact sensitization tests indicate Squalene is not a significant contact allergen or irritant. It is concluded that both Squalane and Squalene are safe as cosmetic ingredients in the present practices of use and concentration.

Abstract  Production of biosurfactants by acidophilic mycobacteria was demonstrated in the course of aerobic degradation of hydrocarbons (n-tridecane, n-tricosane, n-hexacosane, model mixtures of D-14-D-17, D(12)aEuro'D-19, and D-9-D-21 n-alkanes, 2,2,4,4,6,8,8-heptamethylnonane, squalane, and butylcyclohexane) and their complex mixtures (hydrocarbon gas condensate, kerosene, black oil, and paraffin oil) under extremely acidic conditions (pH 2.5). When grown on hydrocarbons, the studied bacterial culture AG(S10) caused a decrease in the surface and interfacial tension of the solutions (to the lowest observed values of 26.0 and 1.3 mN/m, respectively) compared to the bacteria-free control. The rheological characteristics of the culture changed only when mycobacteria were grown on hydrocarbons. Neither the medium nor the cell-free culture liquid had the surfactant activity, which indicated formation of an endotype biosurfactant by mycobacteria. Biodegradation of n-alkanes was accompanied by an increase in cell numbers, surfactant production, and changes in the hydrophobicity of bacterial cell surface and in associated phenomena of adsorption and desorption to the hydrocarbon phase. Research on AGS10 culture liquids containing the raw biosurfactant demonstrated the preservation of its activity within a broad range of pH, temperature, and salinity.

Abstract  A biochemical method was employed to study the response of rabbit skin to isopropyl myristate, squalane, and decane. The results showed that decane damaged the skin so severely that the biosyntheses of lipids, RNA and DNA were reduced markedly for the first 3 days after application, but increased rapidly after that due to the repair. The effect of squalane was found to be weaker than that of isopropyl myristate, though both oils induced the stimulation of biosynthese in the epidermis. The magnitude of the biochemical effects of the 3 oils on the skin was increased in the order of squalane, isopropyl myristate and decane, which was consistent with the results of macroscopic and histological observations. From the profiles of the effects, it is postulated that the repairing processes are controlled by some feedback mechanisms.

Abstract  Here we report a new method for measuring the heterogeneous chemistry of sub-micron organic aerosol particles using a continuous flow stirred tank reactor. This approach is designed to quantify the real time heterogeneous kinetics, using a relative rate method, under conditions of low oxidant concentration and long reaction times that more closely mimic the real atmosphere than the conditions used in a typical flow tube reactor. A general analytical expression, which couples the aerosol chemistry with the flow dynamics in the chamber is developed and applied to the heterogeneous oxidation of squalane particles by hydroxyl radicals (OH) in the presence of O(2). The particle phase reaction is monitored via photoionization aerosol mass spectrometry and yields a reactive uptake coefficient of 0.51 +/- 0.10, using OH concentrations of 1-7 x 10(8) molecule cm(-3) and reaction times of 1.5-3 h. In general, this approach provides a new way to connect the chemical aging of organic particles measured at short reaction times and high oxidant concentrations in flow tubes with the long reaction times and low oxidant conditions in smog chambers and the real atmosphere.

Abstract  The particle/gas partition coefficient Kp is an important parameter affecting the fate and transport of indoor semivolatile organic compounds (SVOCs) and resulting human exposure. Unfortunately, experimental measurements of Kp exist almost exclusively for atmospheric polycyclic aromatic hydrocarbons, with very few studies focusing on SVOCs that occur in indoor environments. A specially designed tube chamber operating in the laminar flow regime was developed to measure Kp of the plasticizer di-2-ethylhexyl phthalate (DEHP) for one inorganic (ammonium sulfate) and two organic (oleic acid and squalane) particles. The values of Kp for the organic particles (0.23 ± 0.13 m3/μg for oleic acid and 0.11 ± 0.10 m3/μg for squalane) are an order of magnitude higher than those for the inorganic particles (0.011 ± 0.004 m3/μg), suggesting that the process by which the particles accumulate SVOCs is different. A mechanistic model based on the experimental design reveals that the presence of the particles increases the gas-phase concentration gradient in the boundary layer, resulting in enhanced mass transfer from the emission source into the air. This novel approach provides new insight into experimental designs for rapid Kp measurement and a sound basis for investigating particle-mediated mass transfer of SVOCs.

Abstract  Percutaneous absorption of ethyl-alcohol (64175), perhydrosqualene (111013), and p-cymene (99876) was investigated. Male albino-mice were treated topically with 0.1 milliliter of radio labeled solutions of one of the test agents. In some tests with ethyl-alcohol and perhydrosqualene, the stratum corneum was removed before treatment. At selected times, the skin was removed and analyzed for radioactivity. Absorption rates were 10.5 and 0.12 nanomoles per square centimeter per minute for ethyl-alcohol and perhydrosqualene, respectively, for nonabraded skin. When the stratum corneum was removed, ethyl-alcohol penetration rate increased to 200 nanomoles per square centimeter per minute, but the rate for perhydrosqualene did not change. The penetration rate of p-cymene was 32 nanomoles per square centimeter per minute over 1 hour. The authors conclude that dermal absorption is affected by the epidermal barrier and the removal capacity of the blood. The liposolubility of the agent also affects its penetration through the epidermal stratum.

Abstract  The adsorption coefficient of Squalane (CAS 111-01-3) has been determined to be greater than 4.27 x 105, log10 Koc greater than 5.63, using the HPLC screening method, designed to be compatible with Method C19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.

Abstract  The ready biodegradation of the squalane was determined by the carbon dioxide evolution test method (OCDE guideline 301B). Tests of ready biodegradability are stringent tests that provide limited oppotunity for acclimation and biodegradation to occur. In the CO2 test, inoculated mineral medium was dosed with a known amount of test substance as the nominal sole source of organic carbon and aerated with CO2 -free air. The CO2 produced from the mineralization of organic carbon within the test chambers was displaced by the ow of CO2 -free air and trapped as K2CO3 in KOH trapping solution. The amount of CO2 produced by the test substance is expressed as a percentage of the theoretical amount of CO2 that could have been produced if complete biodegradation of the substance occurred. The test contained a blank control, three reference groups and one treatment group. Each group contained two replicate test chambers. The blank control was used to measure the background CO2 production of the inoculum and was dosed with a carbon source. The reference chambers were dosed with either canola oil, Synuid or Ultra Low Sulfur Diesel at a concentration of 10 mg C/L. The treatment group test chambers were used to evaluate the test substance at concentration of approximately 10 mg C/L. The results indicated that the activated sludge inoculum was active, degrading the canola oil reference 99.9%. The average cumulative percent biodegradation for squalane was 64.7%. However, squalane may be considered inherently biodegradable because it reached 60% of TCO2, though not within a 10 -days window of reaching 10% TCO2.

Abstract  Absorption, distribution, and release of squalane were studied in rainbow trout fed a diet containing 0.05% of this alkane. Estimated squalane absorption was about 40% of the dose. After three months of exposure, the residues in the whole body reached a steady equilibrium value of about 16- 18 micrograms/g. The most pronounced deposition occurred in the liver (1671 micrograms/g after 10 months), while the concentration of squalane in the adipose tissue was below 2 micrograms/g. During the depuration period, half of the contaminated trout were fed a squalane-free diet, while the others were starved. After two months, the body burden amounted to 65% and 80% of the alkane previously accumulated in starved and fed trout, respectively. In the starved group, 43% of the squalane initially stored in the liver was lost, whereas the loss in the fed fish liver was 52%. These results were compared with existing data on other alkanes. (Author 's abstract)

Abstract  The heterogeneous reaction of OH radicals with sub-micron squalane particles, in the presence of O-2, is used as a model system to explore the fundamental chemical mechanisms that control the oxidative aging of organic aerosols in the atmosphere. Detailed kinetic measurements combined with elemental mass spectrometric analysis reveal that the reaction proceeds sequentially by adding an average of one oxygenated functional group per reactive loss of squalane. The reactive uptake coefficient of OH with squalane particles is determined to be 0.3 +/- 0.07 at an average OH concentration of similar to 1 x 10(10) molecules cm(-3). Based on a comparison between the measured particle mass and model predictions it appears that significant volatilization of a reduced organic particle would be extremely slow in the real atmosphere. However, as the aerosols become more oxygenated, volatilization becomes a significant loss channel for organic material in the particle-phase. Together these results provide a chemical framework in which to understand how heterogeneous chemistry transforms the physiochemical properties of particle-phase organic matter in the troposphere.