PEG-75 is the INCI name of a chemical substance from the group of polyoxyethylene glycols. It is a safe, non-toxic substance that complies with the European Pharmacopeia. As a solid, it satisfies the Pharmacopeia’s quality requirements, which makes it admissible for use in the pharmaceutical industry. The global CAS number of PEG-75 is 25322-68-3.
Other names used for PEG-75 tell us more about its structure. These are: polyoxyethylene glycol, polyethylene glycol, and Macrogol 3350. The first two are chemical names, which indicate that it is a physically solid polymer classified as a polyether, which is hygroscopic, colourless or slightly yellowish, and has the consistency of wax. It usually takes the form of flakes. It mixes very well with water and dissolves in many commonly used organic solvents such as 96% ethanol, glycerol, chloroform, acetone and glycols. Just like other polyoxyethylene glycols, PEG-75 is not absorbed by the human body, but at the same time it is a very good solvent for osmotically active substances. The customary name, Macrogol 3350, also belongs to polyalkylene glycols; PEG-75 is the one with a molecular mass of 3350 daltons. The freezing point of PEG-75 is approx. 53-57ᵒC.
The main application of PEG-75 arises from the fact that it meets the quality requirements of the Pharmacopeia. Therefore, it is an ingredient in pharmacological formulations. Examples of its use include the production of tablets, capsules, micro-capsules, globules and eye drops, where it acts as a binding agent, solubilizer or the carrier of active pharmaceutical ingredients (API). When combined at a proper ratio with fluid, low-molecular polyethylene glycols, it forms a blend with a sticky consistency, which is an excellent base for ointment production. Macrogol 3350, with a specifically defined composition as per the U.S. Pharmacopeia, consisting of the substance and an appropriate electrolyte, is used as a laxative. The most important properties of the PEG-75, reflected in its application, include softening properties, spreadability, solubilization, moistening, and an antistatic effect.
