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Diss Factsheets

Administrative data

Link to relevant study record(s)

Description of key information

Dermal penetration study (in vivo) on DPnP
Supporting toxicokinetics data from structurally related substances, Di propylene glycol n-butyl ether (DPnB) and Dipropylene glycol methyl ether (DPM)

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential
Absorption rate - oral (%):
Absorption rate - dermal (%):
Absorption rate - inhalation (%):

Additional information

There are no toxicokinetics studies available for DPnP. However, data on two category members, DPnB and DPM are available and these are used to provide an insight into the likely ADME characteristics of DPnP. Both oral and inhalation absorption rates were set at 100%. Dermal absorption rate was set at 20%. For detailed information, refer to read-across justification document for P-series glycol ethers.



Based on its MW of 176, high water solubility, lack of charge and log Kow of 0.88 it is predicted that DPnP would be readily absorbed in the gastrointestinal tract. This is consistent with the data on DPM and DPnB, both of which are >90% bioavailable via the oral route. Therefore, 100% absorption is assumed by this route.


The vapour pressure of DPnP is low (10 Pa) and therefore exposure to vapour is unlikely. However, due to its high water solubility and MW <200 it is predicted that if inhaled it would be well absorbed, and as such, 100% absorption is assumed via this route.


In a dermal absorption study of 14C-dipropylene glycol n-propyl ether (DPnP) in New Zealand White rabbits following a single 6-hour dermal exposure, a total of 86-90% of the administered radioactivity applied was recovered. The majority of the applied radioactivity, 61-72%, was recovered in the 6-hour application-site wash material, jacket, and occlusive bandage. A mean of 19% of the administered radioactivity was absorbed and detected in the feces/urine, CO2, charcoal traps, tissues, cage wash, and final cage wash. The majority (12%) of the absorbed administered dose was in the combined feces/urine sample, with evidence suggesting urine is the primary route of elimination. A total of 5% of the administered dose was recovered in the CO2 and charcoal traps. Derived radioactivity from absorbed 14C-DPnP was quickly eliminated, with the majority recovered within 24 hours of application. The data is indicative of dermal absorption of undiluted 14C-DPnP when applied dermally to rabbits. Based on these findings a dermal bioavailability of 20% is assumed.


There are no metabolism data available for DPnP. However data are available on category members, DPM and DPnB and these data show consistency in the way these substances are metabolised.


After oral dosing of C14 radiolabelled DPM, the expired air, excreta and tissues were analysed for 14C activity and metabolites in urine were isolated and identified. Approximately 60% of the 14C DPM was excreted in urine, while 27% was eliminated as 14CO2 within 48 hours after an oral dose of 14C DPM. Less than 3% of the dose was recovered in feces, indicating that the test material was effectively absorbed. The primary metabolic process is the hydrolysis of the Ether bonds. This results in the production of dipropylene glycol, propylene glycol methyl ether, (PGME), propylene glycol and CO2. Only a small percentage of the absorbed dose (3%) is excreted unchanged in the urine. In addition to the hydrolysis, sulphate and glucuronide conjugates are also formed (approximately 18% of the absorbed dose).


The disposition and metabolism and excretion of 14C-DPnB (dipropylene glycol n-butyl ether) was assessed in male Fischer-344 rats after a single oral dose of 0.4 or 4.4 mmol DPnB/kg BW. Urine, faeces, expired air, blood and tissues were collected and analyzed for total 14C-activity. Urinary metabolites were identified structurally. The following urinary metabolites were identified: the sulfate conjugate of DPnB, propylene glycol n-butyl ether, dipropylene glycol, and propylene. Also parent material was found in the urine. These findings are highly consistent with those of DPM, indicating a common metabolic pathway for these glycol ethers.

Based on the consistency in the metabolism between DPM and DPnB it is predicted that DPnP will be extensively metabolised in the liver, with the major metabolites being sulphate conjugates, dipropylene glycol, propylene glycol, propylene glycol butyl ether and CO2.


The Log Kow of DPnP is 0.88 and it is highly water soluble. This indicates that it is unlikely ot accumulate in tissues and will tend to move with the body fluids. In the toxicokinetics study with DPnB, radiolabled material was found in the carcas after 48 hours, and the highest concentrations were in the liver, kidneys and bone marrow. However there was no evidence of accumulation in these or any other tissues.


No data area available for DPnP, however in the toxicokinetics studies using DPnB and DPM it is apparent that the 2 main routes of excretion are urine and CO2, with approximately 40 -60% excreted in the urine and 30 -40% in the exhaled air. The excretion of these substances appears to be rapid with approximately 90% of the absorbed dose excreted within 48 hours. This would indicate half lives for excretion (assuming linearity) of approximately 14 -16 hours.