Iqubal, Mohammad Kashif team published research on European Journal of Pharmaceutics and Biopharmaceutics in 2021 | 111-90-0

111-90-0, Diethylene glycol monoethyl ether appears as a colorless, slightly viscous liquid with a mild pleasant odor. Flash point near 190°F. Used to make soaps, dyes, and other chemicals.
Diethylene glycol monoethyl ether is a primary alcohol that is ethanol substituted by a 2-ethoxyethoxy group at position 2. It has a role as a protic solvent. It is a diether, a primary alcohol and a hydroxypolyether. It derives from a diethylene glycol., Reference of 111-90-0

Ethers do have nonbonding electron pairs on their oxygen atoms, 111-90-0, formula is C6H14O3, Name is Diethylene Glycol Monoethyl Ether. The ability to form hydrogen bonds with other compounds makes ethers particularly good solvents for a wide variety of organic compounds and a surprisingly large number of inorganic compounds. Reference of 111-90-0.

Iqubal, Mohammad Kashif;Iqubal, Ashif;Imtiyaz, Khalid;Rizvi, M. Moshahid A.;Gupta, Madan Mohan;Ali, Javed;Baboota, Sanjula research published 《 Combinatorial lipid-nanosystem for dermal delivery of 5-fluorouracil and resveratrol against skin cancer: Delineation of improved dermatokinetics and epidermal drug deposition enhancement analysis》, the research content is summarized as follows. In the present study, combinatorial nanostructured lipid carrier gel of 5-fluorouracil and resveratrol was formulated, optimized and characterized to enhance permeation in between epidermis and dermis layers of the skin to obtain a synergistic effect against skin cancer. After extensive trials, a newly modified emulsiosonication method was developed and addnl., for the first time, stability studies were done in the beginning to optimize formulation technique, which exhibited two major benefits simultaneously; first, it provided best-optimized technique for preparation of combinatorial lipid-nanosystem, and secondly, it also demonstrated a detailed report card of durability of formulations. In vitro release study showed a significantly improved, slow and prolonged release of drugs from the optimized lipid-nanosystem (***p < 0.05), which followed non-Fickian Higuchi kinetics. Besides, mechanism of skin permeation enhancement study, dermatokinetic assessment, and depth anal. of optimized formulation on skin exhibited improved permeation and well distribution of drugs up to the dermis layer of skin. Moreover, combinatorial linogel possessed significantly greater efficacy (**p < 0.01) on the A431 cell line, as compared to the conventional formulation. Thus, findings revealed that modified method of preparation for dual drug-loaded lipid-nanosystem lead to the production of a stable formulation that also improved the retention of both 5-fluorouracil and resveratrol in between the epidermis and dermis region of skin thereby helping in the management and treatment of skin cancer.

111-90-0, Diethylene glycol monoethyl ether appears as a colorless, slightly viscous liquid with a mild pleasant odor. Flash point near 190°F. Used to make soaps, dyes, and other chemicals.
Diethylene glycol monoethyl ether is a primary alcohol that is ethanol substituted by a 2-ethoxyethoxy group at position 2. It has a role as a protic solvent. It is a diether, a primary alcohol and a hydroxypolyether. It derives from a diethylene glycol., Reference of 111-90-0

Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem