Abstract  The development of a non-toxic selective cytoprotective agent that preferentially protects normal tissues from chemotherapy toxicity, without protecting malignant tissues, is a major challenge in cancer chemotherapy research. The available cytoprotective agents are either toxic or lack selective cytoprotective activity. Here, we report the in vitro selective cytoprotective activity of squalene, an isoprenoid molecule with antioxidant properties. Normal human bone marrow (BM) derived colony-forming unit (CFU) growth was increased by squalene in a dose-dependent manner. Squalene (12.5-25 muM) treatment significantly protected the CFUs from cisplatin-induced toxicity; the protective effect was equivalent to reduced glutathione (GSH), a known cytoprotective agent. Squalene also increased the long-term survival of cisplatin-treated 4-week-old CFUs. Cisplatin-induced apoptosis of CFUs as measured by the TUNEL assay was reduced by squalene. To examine the squalene-induced protection of tumours, several neuroblastoma cell lines, including five MYCN-amplified cell lines, were grown in monolayers, as well as in anchorage-independent cultures, in the presence of squalene and cisplatin. Squalene did not protect the neuroblastoma (NBL) cell lines from cisplatin-induced toxicity. In addition, squalene did not protect the NBL cells from carboplatin, cyclophosphamide, etoposide and doxorubicin-induced toxicity. In conclusion, our results suggest that squalene has a selective in vitro cytoprotective effect on BM-derived haematopoietic stem cells that is equipotent to GSH. (C) 2003 Elsevier Ltd. All rights reserved.

Abstract  The residual fractions remaining after microbial degradation of diesel fuel, different deparaffinized raffinates and extracts from long-term contaminated soils were analyzed by liquid chromatography, gas chromatography, infrared spectrometry and mass spectrometry. The quantity of saturated hydrocarbons decreased after the microbial treatment, whereas the portion of polar compounds increased. The total content of aromatics changed only insignificantly. n-Paraffins < C26 were found to be no longer present in mineral oils degraded to exhaustion. Infrared spectrometry revealed oxygen compounds in the residues, mainly ketones, fatty acids and esters. Elementary analysis confirms the presence of nitrogen, oxygen and sulphur compounds in the degraded products. The gas chromatograms of high boiling oils, as well as of residues and extracts, consist mainly of a large base "envelope" (about 95% of the total area); thus gc/ms coupling reaches the limits of its applicability. However, mass spectrometry with direct inlet gives valuable information regarding hydrocarbon type analysis. The results revealed the preferable degradation of alkanes, 1-ring aliphatics and benzenes and an enrichment of condensed cycloaliphatics and aromatics. The latter compounds are known to be resistant to microbial attack.

Abstract  Gas liquid chromatography was used for analysis of a mixture of seven chlorinated hydrocarbons. Experiments were conducted using columns containing the solvents squalane (111024), di-n-butyl-tetrachlorophthalate (3015665) (DBTP), dinonyl-phthalate (84764) (DNP), tricresyl-phosphate (1330785) (TCP), and polyethylene-glycol (25322683) (PEG) as the stationary phase. Chlorinated hydrocarbons in the mixture tested were: 1-chloropropane (540545), tetrachloromethane (56235), dichloromethane (75092), 1,2-dichloroethane (107062), trichloroethylene (79016), cis-1,2-dichloroethylene (156592), and trichloromethane (67663). Carbon-tetrachloride (56235) was used as the reference solute. The extremes of polarity ran from squalane to PEG, from low to high. Combinations of packings with PEG together with squalane, DBTP, DNP, or TCP were evaluated. Order of elution using squalane was 1-chloropropane, tetrachloromethane, dichloromethane, trichloroethylene, cis-1,2-dichloroethylene, trichloromethane, and 1,2-dichloroethane. For squalane, the most difficult pair to separate was cis-1,2-dichloroethylene and trichloromethane. Efficiencies of the combined stationary phase packings were excellent, better than the optimum loaded squalane column. Analysis was completed in 50 percent of the time required with squalane for all solvent combinations except DBTP with PEG. Helium (7440597) or hydrogen (1333740) as carrier gas improved analysis time. The authors conclude that the window technique for the choice of optimum binary solvent composition is used to attain the shortest possible analysis time, rather than the minimum number of separation plates required for baseline separation.

Abstract  We demonstrate the first capture and analysis of secondary organic aerosol (SOA) on a droplet suspended in an aerosol optical tweezers (AOT). We examine three initial chemical systems of aqueous NaCl, aqueous glycerol, and squalane at ∼75% relative humidity. For each system we added α-pinene SOA-generated directly in the AOT chamber-to the trapped droplet. The resulting morphology was always observed to be a core of the original droplet phase surrounded by a shell of the added SOA. We also observed a stable emulsion of SOA particles when added to an aqueous NaCl core phase, in addition to the shell of SOA. The persistence of the emulsified SOA particles suspended in the aqueous core suggests that this metastable state may persist for a significant fraction of the aerosol lifecycle for mixed SOA/aqueous particle systems. We conclude that the α-pinene SOA shell creates no major diffusion limitations for water, glycerol, and squalane core phases under humid conditions. These experimental results support the current prompt-partitioning framework used to describe organic aerosol in most atmospheric chemical transport models and highlight the prominence of core-shell morphologies for SOA on a range of core chemical phases.

Abstract  The reaction kinetics of the three-phase CO2 methanation for a commercial Ni/SiO2 catalyst suspended in a liquid phase is studied in a continuous stirred-tank slurry reactor at a CO2 partial pressure of 1 bar and temperatures from 220 degrees C to 320 degrees C. By applying different liquids, namely squalane, octadecane, and dibenzyltoluene, showing different gas solubilities, it is found that the gas concentration in the liquid phase and not the partial pressure in the gas phase is the driving force for the CO2 methanation reaction kinetics. The liquid phase does not influence the reaction kinetics but reduces the available gas concentrations and H-2/CO2 ratio on the catalyst surface. Based on these findings, a kinetic rate equation for the three-phase CO2 methanation is developed additionally incorporating the chemical equilibrium limitations relevant in the temperature regime.

Abstract  Compatibility between oligomers and polymers was systematically assessed using differential scanning calorimetry (DSC) and was correlated with similarity in saturation and solubility parameter. These measurements enabled validation of detailed volume of mixing calculations using Statistical Association Fluid Theory (SAFT-γ Mie) and molecular dynamics (MD) simulations, which can be used to predict behaviour beyond the experimentally accessible conditions. These simulations confirmed that squalane is somewhat more compatible with poly(isoprene), "PI" than poly(butadiene), "PB", and further enabled prediction of the temperature dependence of compatibility. Surface and interfacial segregation of a series of deuterated oligomers was quantified in rubbery polymer films: PI, PB and hydrogenated poly(isoprene) "hPI". A striking correlation was established between surface wetting transition and mixtures of low compatibility, such as oligo-dIB in PB or PI. Segregation was quantified normal to the surface by ion beam analysis and neutron reflectometry and in some cases lateral segregation was observable by AFM. While surface segregation is driven by disparity in molecular weight in highly compatible systems this trend reverses as critical point is approached, and surface segregation increases with increasing oligomer molecular weight.

Abstract  In the 1980s long-lived radical species were identified in cigarette tar. Since then, environmentally persistent free radicals (EPFRs) have been observed in ambient particulate matter, and have been generated in particulate matter generated from internal combustion engines. For the first time, we measure in situ the formation and decay of EPFRs through the heterogeneous reaction of ozone and several polycyclic aromatic compounds (PAC). Solid anthracene (ANT), pyrene (PY), benzo[a]pyrene (BAP), benzo[ghi]perylene (BGHIP), 1,4-naphthoquinone (1,4NQ), and 9,10-anthraquinone (AQ) were reacted with gas-phase ozone in a flow system placed in the active cavity of an electron paramagnetic resonance (EPR) spectrometer, and the formation of radicals was measured on the timescale of tens of minutes at ambient levels of ozone down to 30 ppb. For most substrates the net radical production is initially rapid, slows at intermediate times, and is followed by a slow decay. For oxidized solid BAP, radical signal persists for many days in the absence of ozone. To evaluate the effect of substrate phase, the solid PAHs were also dissolved in squalane, an organic oil inert to ozone, which yielded a much higher maximum radical concentration and faster radical decay when exposed to ozone. With higher mobility, reactants were apparently able to more easily diffuse and react with each other, yielding the higher radical concentrations. The EPR spectra exhibit three radicals types, two of which have been assigned to semiquinone species and one to a PAH-derived, carbon-centered radical. Although our system uses levels of PAC not typically found in the environment it is worth noting that the amounts of radical formed, on the order of 10(18) radicals per g, are comparable to those observed in ambient particulate matter.

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  Double oxide,SrxCa1-xCuOy has a layered structure in which Ca(Sr) is sandwiched between CuO2 layers. This crystal structure is expected to give low friction due to its low shear strength between laminas, In this work, various kind of SrxCa1-xCuOy with x=0.0 to 1.0 were prepared from SrCO3, CaCO3 and CuO by sintering method. The compositions of these products were examined by X-ray diffraction. The sample powders were blended in oil (squalane) and grease, and their load carrying capacities were evaluated by a cylinder-on-plate type tribometer and a four-ball machine, respectively. As a result of the tests, SrxCa1-xCuOy with x=0.0, 0.14, 0.90 and 1.0 showed low friction (about 0.1) and high load carrying capacity (4900 N). It was found from SEM and EPMA results that the worn surface was smooth, and that a thin solid lubricating him containing Ca, Sr and Cu was formed on the rubbing counterface. Also, the oxides with x=0.9 and 1.0 showed superior properties under extreme pressure in four-ball machine testing.

Abstract    Squalene (SQ), a precursor of sterols and terpenoids is a functional lipid of high importance in the food and pharmaceutical sectors. SQ oxidation studies are rather limited compared with those for other olefins. The aim of the present study was to monitor the formation of SQ oxidation products under different conditions (temperature, air supply), to characterise the most abundant of them by spectroscopic techniques and then examine their pro-oxidant activity in a model lipid substrate. Squalane (SQA), the saturated analogue of SQ, was used as a reference compound. FT-MIR analysis indicated the presence of alcohols, epoxides, aldehydes, and ketones. GC-MS was used to characterise SQ primary oxidation and scission products. The presence of epoxides was further confirmed by means of 1H NMR and 13C NMR spectroscopy. It could be argued that SQ stability is due to its stereochemistry and specifically to the presence of methyl groups next to the double bonds. The pro-oxidant activity of SQ oxidation products was evident at 62 and 40°C and suppressed only in the presence of primary antioxidants, not of SQ. The present work adds to the characterisation of SQ oxidised products. To our knowledge their pro-oxidant activity has never been examined before. Practical applications: Characterisation of squalene oxidation products and assessment of their activity as pro-oxidants present both scientific interest regarding the kinetics and product identity as well as a practical impact in case this bioactive lipid is provided for consumption as a functional product. In the past, cholesterol oxidation products and more recently phytosterol ones attracted the interest of researchers, who studied the stability of the respective parent compounds for food safety reasons. Monitoring of the formation of SQ oxidation products under different conditions (temperature, air supply) and chemical characterisation of the most abundant of them by spectroscopic techniques. Examination of their pro-oxidant activity in a model lipid substrate. Squalene may exert a weak antioxidant activity due to competitive oxidation phenomena with the lipid substrate while its oxidation products have a pro-oxidant activity on purified olive oil model substrate that was suppressed only in the presence of primary antioxidants. [PUBLICATION ABSTRACT]

Abstract  Squalene is a natural triterpenoid present virtually in all taxonomic groups. Its use for improving human health is rooted in ancient human history as several Pacific nations consumed the oil from livers of deep-sea sharks with high squalene content to improve their health and extend the life. In addition to the use as nutritional supplement, this molecule finds today many applications in pharmacology and cosmetics, or as a valuable industrial lubricant. Broad application potential of squalene is related to its physico-chemical characteristics, antioxidant activity and to its ability to interact with cell membranes. The industrial use of squalene is limited by short natural resources. Even today squalene is acquired mainly from shark liver oil; however, this source is no more tenable from the environmental viewpoint. Plant sources (e.g. olives, amaranth seeds) and particularly microbial production are thus gaining importance as promising alternatives for extended industrial use of squalene.

Abstract  Gelatin capsules containing squalane partially purified bone morphogenetic protein (BMP) complex were placed on the perimuscular membrane of rats. Two kinds of control, gelatin capsules containing only BMP and those bearing squalane only, were used. The embedded areas were histopathologically examined at 3 and 6 wk after the operation. The observations revealed that the squalane/BMP complex elicited wide heterotopic bone formation with bone marrow tissue, suggesting that squalane is a possible carrier of BMP for clinical applications.

Abstract  Over the past several years, we have conducted a variety of elastic neutron diffraction and quasielastic neutron scattering experiments to study the structure and the dynamics of films of two intermediate-length alkane molecules (C sub( n)H sub(2n+2)), adsorbed on a graphite basal-plane surface. The two molecules are the normal alkane n-tetracosane [n-CH sub( 3)(CH sub(2)) sub(22)CH sub(3)] and the branched alkane squalane (C sub(30)H sub(62) or 2, 6, 10, 15, 19, 23-hexamethyltetracosane) whose carbon backbone is the same length as teteracosane. The temperature dependence of the monolayer structure of tetracosane and squalane was investigated using elastic neutron diffraction and evidence of two phase transitions was observed. Both the low-coverage tetracosane (C sub( 24)H sub(50)) and squalane (C sub(30)H sub(62)) monolayers have crystalline-to-"smectic" and "smectic"-to-isotropic fluid phase transitions upon heating. The diffusive motion in the tetracosane and squalane monolayers has been investigated by quasielastic neutron scattering. Two different quasielastic neutron scattering spectrometers at the Center for Neutron Research, National Institute of Standards and Technology (NIST) have been used. The spectrometers differ in both their dynamic range and energy resolution allowing molecular motions to be investigated on time scales in the range 10 super(-13)--10 super( -9) s. On these time scales, we observe evidence of translational, rotational, and intermolecular diffusive motions in the tetracosane and squalane monolayers. We conclude that the molecular diffusive motion in the two monolayers is qualitatively similar. Thus, despite the three methyl sidegroups at each end of the squalane molecule, its monolayer structure, phase transitions, and dynamics are qualitatively similar to that of a monolayer of the unbranched tetracosane molecules. With the higher resolution spectrometer at NIST, we have also investigated the molecular diffusive motion in multilayer tetracosane films. The analysis of our measurements indicates slower diffusive motion in the bottom layer of a bilayer tetracosane film compared to that in a monolayer, while the rate of diffusive motion in the bottom two layers of the trilayer film is comparable to that in a monolayer.

Abstract  Squalane is obtained by hydrogenation from squalene, an unsaturated terpene hydrocarbon found mainly in shark liver oil. It is a very stable liquid, and has a remarkably low capacity to irritate the skin. Squalane is used as an important component in various kinds of cosmetics and has a considerably beneficial effect on faecal excretion of the highly toxic 2, 3, 4, 7, 8-pentachlorodibenzofuran (PenCDF). The distribution, excretion and subacute toxicity of squalane after oral administration has already been examined. We considered that squalane, applied subcutaneously, might be an effective carrier of drugs. Furthermore, we found an application of squalane as a carrier of bone morphogenetic protein (BMP). As there were no data on the tissue reaction to squalane administered subcutaneously, we decided to make a histopathological evaluation of squalane fluid in vivo (DBO).

Abstract  In the previous papers, we demonstrated, by using rats, that squalane (2,6,10,15,19,23-hexamethyltetracosane) could stimulate the fecal excretion of 2,3,4,7,8-pentachlorodibenzofuran, which was regarded as the most important etiologic agent of yusho among PCB and PCDF congeners found in the causal rice oil. We also reported that, in rats, squalane was not essentially absorbed from the gastrointestinal tract, and did not show any appreciable side effects during the 3-month treatment. In the present paper, we have investigated the distribution, excretion and subacute toxicity of squalane in beagle dogs. The fecal excretion of squalane accounted for about 83% of dose during the initial 2 days after administration at a single oral dose of 1,200 mg/kg to male dogs. On day 3, absorbed squalane was mostly distributed to the hair and the skin, and the concentrations in these tissues were decreased on day 6. These results suggested that most of squalane administered orally was not absorbed from the gastrointestinal tract, but a part was absorbed and excreted through the hair. In addition, squalane distributed into the liver was found to be eliminated rather slowly. A long-term (13-week) treatments with squalane orally at doses of 400 mg/kg/day or 1,200 mg/kg/day in male and female dogs, resulted also in accumulation of squalane in the liver at a level of about 3% (400 mg/kg) or about 6% (1,200 mg/kg) of the daily dose. This accumulation of squalane in the liver was highest among all the tissues. Nevertheless, no appreciable toxic signs were observed in the serum biochemical tests and the hepatic functional test for squalane groups. Therefore, squalane accumulating in the liver, did not seem to disturb the hepatic physiological functions. It was suggested also in a long-term treatment that the skin and the hair played the most important role in the elimination of squalane. In conclusion, the present studies on subacute toxicity tests suggested that squalane did not give any significant toxic effects on dogs as well as rats.

Abstract  Female mice were given 100 mg HCB/kg body weight i.p. and fed diets containing 0, 2.5, 5.0, and 7.5% of squalane. After 3 weeks samples of liver, blood and abdominal fat were analysed for HCB as well as for squalane. HCB concentrations were significantly lowered as compared to controls in all tissues and at all dietary concentrations of squalane to a maximum of about 36% in fat, 44% in liver and 47% in blood. The effect of squalane upon HCB concentrations was strongly dose dependent in abdominal fat. In contrast, no significant differences were seen with liver and blood between animals fed 5.0 or 7.5% of squalane. Squalane was detected in considerable amounts in the livers (50-100 ppm) but not in abdominal fat (less than 1 ppm) of mice fed squalane.

Abstract  Microfluidized squalene or squalane emulsions are efficient adjuvants, eliciting both humoral and cellular immune responses. Microfluidization stabilizes the emulsions and allows sterilization by terminal filtration. The emulsions are stable for years at ambient temperature and can be frozen. Antigens are added after emulsification so that conformational epitopes are not lost by denaturation and to facilitate manufacture. A Pluronic block copolymer can be added to the squalane or squalene emulsion. Soluble antigens administered in such emulsions generate cytotoxic T lymphocytes able to lyse target cells expressing the antigen in a genetically restricted fashion. Optionally a relatively nontoxic analog of muramyl dipeptide (MDP) or another immunomodulator can be added; however, the dose of MDP must be restricted to avoid systemic side effects in humans. Squalene or squalane emulsions without copolymers or MDP have very little toxicity and elicit potent antibody responses to several antigens in nonhuman primates. They could be used to improve a wide range of vaccines. Squalene or squalane emulsions have been administered in human cancer vaccines, with mild side effects and evidence of efficacy, in terms of both immune responses and antitumor activity.

Abstract  This study focused on an investigation into the experimental quantities inherent in the determination of partition coefficients from gas-liquid chromatographic measurements through the use of capillary columns. We prepared several squalane a (2,6,10,15,19,23-hexamethyltetracosane) a containing columns with very precisely known phase ratios and determined solute retention and hold-up times at 30, 40, 50 and 60 degree C. We calculated infinite dilution partition coefficients from the slopes of the linear regression of retention factors as a function of the reciprocal of the phase ratio by means of fundamental chromatographic equations. In order to minimize gasasolid and liquid-solid interface contributions to retention, the surface of the capillary inner wall was pretreated to guarantee a uniform coat of stationary phase. The validity of the proposed approach was first tested by estimating the partition coefficients of n-alkanes between n-pentane and n-nonane, for which compounds data from the literature were available. Then partition coefficients of sixteen aliphatic alcohols in squalane were determined at those four temperatures. We deliberately chose these highly challenging systems: alcohols in the reference paraffinic stationary phase. These solutes exhibited adsorption in the gas-liquid interface that contributed to retention. The corresponding adsorption constant values were estimated. We fully discuss here the uncertainties associated with each experimental measurement and how these fundamental determinations can be performed precisely by circumventing the main drawbacks.

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  1. The intestinal excretion of hexachlorobenzene (HCB) was studied in rats using the method of pendular perfusion. One and four weeks after i.p. application of 100 micrograms HCB/kg body weight segments of jejunum, ileum and colon were perfused with light liquid paraffin or squalane for 5 h. 2. The highest amount of HCB was excreted into jejunum, followed by ileum and colon. After 5 h HCB concentration in jejunal perfusion medium equals that in plasma. 3. Serosal tissue of intestinal segments contained higher HCB concentrations as compared to mucosa. 4. Paraffin treatment decreased the HCB content in both serosal and mucosal tissue of jejunum and ileum but not of colon.

Abstract  The efficacy of a new vaccine preparation against Epstein-Barr (EB) virus was investigated in cotton-top tamarins. The vaccine consists of fast protein liquid chromatography-purified EB virus membrane antigen glycoprotein of 340 Kd (MA gp340) mixed with a synthetic muramyl dipeptide adjuvant emulsified in squalane containing a pluronic polymer; it is suitable for both scaled-up batch production and eventual administration to man. Vaccinated tamarins rapidly developed ELISA detectable high titre antibodies to MA gp340, and their sera became strongly EB virus-neutralising. After challenge with a massive 100% carcinogenic dose of EB virus, the vaccinated tamarins had a strikingly low level of circulating EB virus-carrying mononuclear cells, in contrast to a control animal, and remained entirely free of tumours. This first-generation vaccine has thus been validated in experimental animals and the way opened for a phase I human trial.

Abstract  The ability of nontoxic monophosphoryl lipid A (MPL) to stimulate nonspecific resistance against viral infection was investigated. Mice pretreated intravenously with squalane-in-water emulsions of MPL, alone or in combination with other immunostimulants, were given an aerosol of influenza virus three weeks after the pretreatment. Complete protection against lethal influenza virus infection was conferred when MPL was combined with trehalose dimycolate (TDM). The protective activity of MPL plus TDM combination was corroborated by a significant reduction of the lung virus titers. Combination of lower doses of MPL with TDM extracted from Mycobacterium bovis, but not with that of M. phlei, induced significant resistance to influenza virus. Preparations containing MPL alone, or combined with mycobacterial cell wall skeleton or muramyl dipeptide, were not effective. The adjuvant activity of MPL on bivalent influenza subunit vaccine was also studied. The primary antibody responses to influenza A and influenza B antigens were enhanced by the addition of MPL and were higher than the vaccine associated with aluminum hydroxide. The adjuvant activity of MPL was confirmed by the elevated secondary response. High levels of circulating antibodies were still present in the MPL group when antibody titers in the controls were waning.

Abstract    The solute retention mechanism in gas-liquid chromatography was studied for the hydrocarbon solute-nonpolar stationary liquid phase (squalane) system. The retention volume of the solute and the specific surface area of the liquid-coated, modified alumina were determined as a function of the liquid loading. On the basis of the previous reasoning, distribution constants for the bulk solution partition and some adsorption equilibria taking part in the solute retention could be estimated. The results prove to be quite different from those of the polar liquid phases used previously: that is, squalane formed a bulk liquid layer on the modified alumina after the solid support was completely covered with the monolayer.

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.