Petrolatum (petroleum), oxidized, calcium salt

Endpoint summary

Additional information

In Vitro Genetic Toxicity

No in vitro genetic toxicity studies have been reported for severely refined petrolatum, but data have been reported for paraffin and hydrocarbon waxes which are similar to constituents of severely refined petrolatum.

 

In a reverse gene mutation assay in bacteria (TNO, 2005a), strains of S. typhimurium (TA 1535, TA 1537, TA 98, TA 100) and E. coli (WP 2 uvrA) were exposed to extracted Sasolwax 5203 in DMSO. A highest dose of 100% extract was tested. In total, five dose levels ranging from 1.23 to 100% of the extract were tested, which is comparable to nominal concentrations of 62 to 5000 μg of the test substance per plate. The positive controls induced the appropriate response in the corresponding strains. There was no evidence of induced mutant colonies over background.

 

Supporting data from a gene mutation assay in bacteria (Petro Labs, Inc. 2000) also demonstrates that oxidized petrolatum is not mutagenic when tested in Salmonella typhimurium.

 

One key read across study (TNO, 2005c) was identified to evaluate the in vitro cytogenicity of sufficiently refined petrolatum in mammalian cells.

 

In a chromosome aberration study (TNO 2005c), two mammalian cell chromosome aberration tests were performed. In the first test, Chinese hamster ovary (CHO) cells were exposed to extracts of Sasolwax 5203 at concentrations of 0.034, 0.069, 0.138, 0.277, 0.625, 1.25, 2.5, 5, or 10 mmol/L for four hours with or without metabolic activation at 37°C under 5% CO2. In the second chromosome aberration test, extracts of Sasolwax 5203 were tested at concentrations of 2.78, 4.17, 5.56, 6.94, 8.33, or 10 mmol/L for 18 hours continuous treatment without metabolic activation or 4 hours pulse treatment with metabolic activation at 37°C under 5% CO2. None of the extract concentrations analysed induced a statistically significant increase in the number of aberrant cells with or without metabolic activation or at pulse or continuous exposure. In both chromosomal aberration tests, the positive control substances mitomycin C (in the absence of a metabolic activation system) and cyclophosphamide (in the presence of a metabolic activation system) induced the expected statistically significant increases in the incidence of structural chromosomal aberrations.

 

One key read across study (TNO, 2005b) was identified to evaluate the in vitro gene mutation potential of sufficiently refined petrolatum in mammalian cells.

 

In a mammalian cell gene mutation assay of the TK-locus (TNO, 2005b), mouse lymphoma L5178Y cells were exposed to Sasolwax 5203 in DMSO at nominal concentrations of 0.018, 0.037, 0.074, 0.15, 0.29, 0.59, 1.2, 1.7, 2.4, 3.4, 4.9, 7.0, or 10 mmol/L in the presence or absence of mammalian metabolic activation by Aroclor 1254-induced male Wistar rat liver S-9 fraction for 24 hours at 37°C under 5% carbon dioxide.

 

Sasolwax 5203 was tested up to 10 mmol/L. The positive controls methyl methanesulphonate (MMS) and 3 -methylcholanthrene (MCA) induced the appropriate response. The negative control (DMSO) was within acceptable range. Increased mutant frequency was observed at a single dose level of 2.4 mmol/L in the absence of S-9 mix. Study authors concluded that the reading was caused by an unaccountably low value of the cloning efficiency and is not indicative of mutagenicity. There was no evidence that Sasolwax 5203 induced mutant colonies over background.

 

In Vivo Genetic Toxicity

  

No in vivo genetic toxicity studies have been reported for sufficiently refined petrolatum or constituents of these materials, paraffin and hydrocarbon waxes and white mineral oils. However, studies have been reported (McKee et al., 1990) for lubricant base oils and serve as the basis for a worst case assessment

 

In a CD-1 mouse bone marrow micronucleus assay (McKee et al., 1990), male and female mice were given a single intraperitoneal injection of 5 different lubricant base oils (IP 346 < 3%) in corn oil vehicle at doses of 0, 1.0, 2.5, or 5.0 g/kg.  Bone marrow cells were harvested at 24, 48, and 72 hours post-dosing.  One animal did not survive to scheduled sacrifice, but there were no gross signs of toxicity.  The micronucleus frequency was significantly greater than the concurrent negative control in bone marrow cells of male mice given 5.0 g/kg at 48 hours post-dosing, but the negative control was unusually low in this instance, and therefore this result is not considered significant.

 

The following information is taken into account for any hazard / risk assessment:

Multiple studies were available to evaluate the in vitro and in vivo genetic toxicity potential of sufficiently refined petrolatum. Sufficiently refined petrolatum was not found to be mutagenic or clastogenic in vitro or in vivo.

Justification for classification or non-classification

The potential genetic toxicity of petrolatum is associated with the biologically available / active impurities such as polycyclic aromatic compounds (PAC) found in the entrained oil of the wax material. Sufficiently refined petrolatums, produced from refined feedstocks which contain significantly reduced amount of PAC and other impurities, are not genotoxic.  Based on the data available, sufficiently refined petrolatums do not meet EU CLP Regulation (EC No. 1272/2008) criteria for in vitro or in vivo mutagenicity.