Abstract  The monomethyl ethers of monopropylene, dipropy-lene and tripropylene glycols are powerful solvents of nitro-cellulose and synthetic resins. They are non-corrosive and thermally stable; and are miscible with many organic liquids, as well as with water. Now available in commercial quantities, they are useful in numerous industrial processes. This extensive study deals with possible toxic hazards from making, handling and using these substances. Repeated doses were given orally to rats; eye contacts were made on rabbits; single closes and repeated doses were applied to the skin of rabbits; skin sensi-tization tests were carried out on human beings; and, more particularly, rats, guineapigs, rabbits and monkeys were exposed for varying periods to inhale different concentrations of the vapour of these monomethyl ethers. All the ethers were found to be low in single-dose oral toxicity; but LD50 values were obtained with white rats of 6-6 ml. per kgm. for mono-, 5-4 for di-, and 3-3 for tripropylene glycol methyl ether. Doses of 1 ml. per kgm. of monopropylene glycol ether given daily 5 days a week for 35 days to rats had no effect. Narcosis and some deaths were caused by large doses of mono- and tripropylene glycol ethers absorbed through the skin, but not by dipropylene glycol ether in similar doses. Depression of the central nervous system and occasionally eye, nose, and lung irritation followed inhalation if the concentrations were sufficiently great. The conclusion is that these compounds have so low a single-dose toxicity that they may be safely used industrially; however, prolonged, extensive contact of large areas of skin with mono- and tripropylene glycol monomethyl ether should probably be avoided.

Abstract  The subacute percutaneous toxicity of dipropylene glycol monomethyl ether (DPM) in male rats dosed 5 days/week for 4 weeks under both occluded and unoccluded conditions has been assessed and compared to the percutaneous toxicity of ethylene glycol monomethyl ether (EGM). DPM caused no significant changes in the clinical chemistry, haematology, or pathology, whereas EGM caused changes in the haematology and clinical chemistry, and both testicular and bone marrow damage at doses of 1000 mg/kg per day.

Abstract  Propylene glycol methyl ether (PGME) and dipropylene glycol methyl ether (DGME) were applied via occluded cotton pads to clipped, abraded abdominal skin of male rabbits (5/group; strain not reported) 5 times/week for 3 months. Control animals received distilled water via occluded cotton pads. Doses of 7 and 10 cc/kg PGME or 10 cc/kg DGME produced narcosis leading to death. No effects were seen at any dose on hematological parameters nor on gross appearance of organs. An increase in renal weight occurred with 10 cc/kg PGME. No observable effects were seen at doses of 1 or 5 cc/kg of either substance.