Identification and Use: Dipropylene Glycol is used as medication, as an antifreeze agent, in air sanitation, and as a stabilizer in cosmetic preparations. It is also used as an intermediate for polyester resins, solvent extraction of aromatic hydrocarbons, steam set printing inks, stabilizer in cosmetics. As an inert ingredient, dipropylene glycol facilitates delivery of formulated pesticide chemical products that are used as herbicides, fungicides, insecticides, growth regulators and attractants on various commodities. It is also used in targeting odor-causing bacteria, animal pathogenic bacteria (G- and G+ vegetative), and animal viruses. Human Toxicity Studies: Repeated application of a shaving preparation containing 7.2% dipropylene glycol did not induce sensitization in 50 subjects when applied in 24/48 hr (presumably covered) patches, 3 days/wk for 3 weeks, followed by a challenge patch after a 2 wk rest period. Covered 48 hr application of a 50% solution of dipropylene glycol (DiPG; unspecified solvent) caused irritation in 14 of 34 persons and was equivocally irritant in a further 17. No local effects were induced when 20% DiPG in petrolatum was in 48 hr covered contact with the skin of an unspecified number of volunteers. Similarly, no effects were observed in 59 subjects exposed to a shaving preparation containing 7.2% DiPG in a 4 wk controlled use test or in 101 subjects following 48 hr uncovered contact, repeated after 2 wk in conjunction with exposure to UV light. However, the same shaving preparation in 48 hr covered contact with the skin, caused mild irritation in 6 of 101 subjects, with an additional two subjects also giving mild reactions when the patch was applied 2 wk later. It is more acutely depressant to CNS than ethylene, diethylene or propylene glycol. A case of a 32-year-old man who ingested more than 500 mL of dipropylene glycol-containing Fantasia fog solution (High Energy Lighting, Houston, TX) and subsequently developed acute renal failure, polyneuropathy, and myopathy. The toxicological profiles of monopropylene glycol (MPG), dipropylene glycol (DPG), tripropylene glycol (TPG) and polypropylene glycols (PPG; including tetra-rich oligomers) are collectively reviewed, and assessed considering regulatory toxicology endpoints. None of the glycols reviewed presented evidence of carcinogenic, mutagenic or reproductive/developmental toxicity potential to humans. Animal Toxicity Studies: Undiluted /dipropylene glycol/ caused mild irritation when 500 mg was applied to rabbit skin for 24 hours. When dipropylene glycol was applied repeatedly for prolonged periods (10 applications in 12 days) to skin of rabbits it had negligible irritating action and there was no indication that toxic quantities were absorbed through intact skin. Rabbits /were given/ 2-4 g/kg bw administered iv for 1-21 days. Two animals died at the fourth day with lesions in the kidneys. The remaining 8 were killed during the following 21 days. The kidneys of 3 animals exhibited similar lesions and one of these also had involvement of the liver. /New Zealand white/... rabbits (24/group) were artificially inseminated /and given 200, 400, 800, 1200 mg/kg bw/day by gavage on days 6-19 of gestation/. Animals were observed daily for clinical signs of toxicity. Mean food and body weights were calculated for each group on gestation days (GD) 0, 6, 9, 12, 15, 25, and 30. All animals were killed on GD 30 and examined for maternal body and organ weights, implant status, fetal weight, sex and morphological development. No maternal lethality occurred in the study. Pregnancy rates were 95%, 83%, 91%, and 82% in the control to high dose dipropylene glycol (DPG) groups, respectively. No effect that could be attributed to exposure to DPG was noted on maternal body weight, food consumption, or clinical signs. Necropsy of the maternal animals revealed no effects on kidney and liver weights. In utero DPG exposure did not affect the frequency of post-implantation loss, mean fetal body weight per litter, or external, visceral, or skeletal malformation. NOEL >1200 mg/kg/day. /Tested externally on eyes, rated numerically on scale of 1 to 10 according to degree of injury observed after 24 hr, paying particular attention to condition of cornea. Most severe injuries have been rated 10/. Rats received 12% /dipropylene glycol/ in the diet for 15 weeks. The treatment resulted in depression of running activity. Moderate degenerative changes in kidneys were found. ...The concentration of 10% /dipropylene glycol/ in drinking water caused death in some animals. Histology examination revealed hydropic degeneration of kidney tubular epithelium and liver parenchyma. Rats were not affected by 5% dipropylene glycol in their drinking water for 77 days. ...Administration level of 10%, some died with hydropic degeneration of kidney tubular epithelium and liver parenchyma. ...Effects were similar to those of diethylene glycol but less severe and less uniformly produced. Time-mated /Sprague-Dawley/ rats were dosed with /800, 2000, or 5000 mg/kg/day dipropylene glycol/ (DiPG) or the distilled deionized water vehicle /by gavage/. Animals were observed daily beginning on gestation day (GD) 6 for clinical signs of toxicity. All sperm-positive rats were killed on GD20. The maternal body, liver and intact uterus were weighed and corpora lutea were counted. The fetuses were examined in detail. Maternal toxicity and lethality were observed at 2000 and 5000 mg/kg/day (mortality rate: 4% and 9%), establishing the maternal NOAEL as 800 mg/kg/day. There were no significant differences between the DiPG exposed groups and the control. NOAEL was 5000 mg/kg/day. DiPG has no teratogenetic or embryonal effect. Dipropylene glycol markedly stimulated choleresis, /SRP: Secretion of bile/, when injected intraduodenally at 1 mL/kg into rats. Propylene glycol and dipropylene glycol were tested for mutagenic or genotoxic potential and found to be negative in a battery of studies: a bacterial gene mutation assay using Salmonella typhimurium, and in vitro Chinese hamster ovary (CHO) mutation assay, an in vitro Chinese hamster ovary (CHO) chromosomal aberration assay and an in vitro sister chromatid exchange assay. Dogs... after survival of repeated gastric dosage of dipropylene glycol showed only moderate degenerative changes in kidneys and only minimal evidence of liver damage. Ecotoxicity Studies: /Authors/ were able to feed chicks a diet containing 5% dipropylene glycol for 27 days without adverse effects. The chicks were unable to use it as an energy source.
