The difference between high molecular weight polyethylene glycol

Polyethylene glycol is a linear, non-ionic polymer with a wide range of molecular weights, from low molecular weight liquids to high molecular weight solids. When the molecular weight of polyethylene glycol exceeds about 1000, it typically appears in a solid state. Polyethylene glycol 2000, 4000, and 6000 refer to polyethylene glycol with average molecular weights of approximately 2000, 4000, and 6000 daltons, respectively.

The main differences between polyethylene glycol with different molecular weights include:

1. Molecular weight:

PEG 2000: molecular weight between 3600-4400.

PEG 4000: molecular weight between 5500-7500.

PEG 6000: Molecular weight between 5500-6500, but typically defined as around 6000.

2. Physical properties:

As the molecular weight increases, the melting point and softening point of polyethylene glycol also increase. PEG with higher molecular weight, such as PEG 6000, typically has a higher melting point and a harder texture. The viscosity also increases with the increase of molecular weight.

3. Solubility and compatibility:

All polyethylene glycol is soluble in water and many organic solvents. However, the solubility of high molecular weight PEG may slightly decrease in certain solvents.

4. Application areas:

In the pharmaceutical and cosmetics industries, PEG with different molecular weights has different uses.

For example, PEG 4000 and PEG 6000 are commonly used as matrix materials in pharmaceutical formulations, such as making drop pills or suppositories. PEG 2000 may be more commonly used in formulations that require lower molecular weight PEG, such as as as a dispersant or solubilizer.

5. Pharmacological effects:

PEG 4000 can be used as a laxative to soften feces and help relieve constipation by absorbing water and swelling. PEG with different molecular weights may have different bioavailability and in vivo behavior.

6. Toxicity:

PEG is generally considered to be low toxicity, but the safety of PEG with different molecular weights may vary under specific conditions.

The selection of different PEG molecular weights in industrial and scientific applications is mainly based on the required physical properties, chemical stability, and specific application requirements.