Safety assessment of the pharmacological excipient, diethylene glycol monoethyl ether (DEGEE), using in vitro and in vivo systems

Diethylene glycol monoethyl ether (DEGEE) is widely used as a solubilizer in cosmetics as well as in oral, topical, transdermal and injectable pharmaceutical formulations. Due to the unavailability of detailed toxicological studies on DEGEE, the Scientific Committee on Consumer Products (SCCP) found its toxicological reports to be unsatisfactory, comprising only summaries. Also, a few reports have raised concern on the use of DEGEE as it might cause damage to the kidneys.

Safety assessment of DEGEE using in vitro and in vivo models.

In vitro effects of DEGEE (0.5-25 mg/ml) were assessed in the HEK293 human embryonic kidney cells. In vivo effects were evaluated after single acute exposure of DEGEE via intraperitoneal route in Swiss albino mice and further, a 28 days subchronic exposure study was conducted where DEGEE was administered orally, once daily.

DEGEE was cytotoxic to HEK293 cells, and an IC₅₀ of 15 mg/ml was established. An increase in the intracellular levels of ROS and alteration in the mitochondrial membrane potential led to nuclear fragmentation and induction of apoptosis in these cells. Survival rate of animals administered intraperitoneally with a single acute dose of 1000 mg/kg DEGEE was 100% with no significant changes in the behavioural and histological parameters. However, the dose of 3000 mg/kg and above led to total mortality within 14 days of acute exposure. Subchronic oral exposure of 500-2000 mg/kg DEGEE showed no significant changes in the hematological, biochemical and histopathological parameters.

The in vitro findings indicate that the nephrotoxic potential of DEGEE cannot be ruled out. The results of the in vivo studies reveal that the degree of toxic effects shown by DEGEE varies, depending on the dose, duration of exposure and routes of administration. Therefore, the present findings are of relevance and thorough studies should be conducted before using this substance in clinical formulations. Graphical abstract Evaluation of the toxic potential of Diethylene glycol monoethyl ether.