Important Properties of Polyethylene Glycols which make Them Important Products for Pharmaceutical Applications
Polyethylene glycols are water soluble linear polymers widely used in pharmaceutical applications. These are synthesized for various applications in industries by a polymerization process where ethylene oxides are made to react with water, mono or di-ethylene glycols under alkaline catalysis. The glycols are good solvents, binders, lubricants, plasticizers and ointment base in various pharmaceutical applications. These are used in tablet coating and liquid oral medications.
The polyethylene glycols are classified into various grades or categories for different applications by the means of their molecular weights. They are represented by the word abbreviated for polyethylene glycols, “PEG” followed by the molecular weight number of the glycol. For example PEG 500 is a polyethylene glycol consisting of polymers with varying molecular weights with an average 500.
The normal range of molecular weights in which polyethylene glycols are available is 200 to 8000. Therefore with so many variants of PEG grades available in the market, the users get a great flexibility in selection of appropriate variant of glycols exhibiting properties to meet specific requirements or applications as desired. As the molecular weights differ, the properties of polyethylene glycols also vary. Therefore glycols of different grades are used in different applications as per their properties and for this reason can be selected as per choicest requirements of the user for applications in a specific industry.
Properties of Polyethylene Glycols
The most important property of polyethylene glycols is their solubility in water. As the molecular weight of the glycols increases, their solubility in water and other solvents decreases. Therefore for higher solubility, glycols with less molecular weight are usually selected. The PEGs up to molecular weight 600 are easily soluble with water in any ratio. These are soluble even in hard water or the aqueous solutions of various salts.
The PEGs 400 are non-volatile liquids at room temperature and in the absence of oxygen. The low volatility of PEGs provides them the thermal stability desired for various applications.
Polyethylene glycols have an excellent property of retaining moisture. PEGs with low molecular weights are hygroscopic in nature and therefore are preferred for various applications due to their moisture retention features.
As the hardness of glycols increases, the melting range goes up to a maximum value which is generally around 60°C. The PEGs 800 to PEGs 2000 are pasty and easy to melt materials with a low melting range.
The polyethylene glycols with low molecular weight have excellent solvent power and for this reason can be used in various formulations for dissolving the substances that are sparingly soluble in water. PEGs 200 to 400 are used in liquid preparations as there are drops, parenterals or fillings for gelatin capsules.
The polyethylene glycols used in pharmaceutical industry have excellent absorping and binding properties and therefore are preferred substances in tablet processing applications in pharma industries. Visit - http://www.rimpro-india.com/polyethylene-glycols.html to know more and get best quality polyethylene glycols.
Conclusion:
Therefore with such valuable properties of polyethylene glycols, they are preferable substances used in a variety of pharmaceutical formulations. They are widely used in tablet processing, as laxatives, excipients, ointment bases, suppositories and ophthalmic demulcents in pharmaceutical processes.
Rimpro-India is one of the leading suppliers of polyethylene glycols offering high quality polyethylene glycols ranging between 200 to 2000 molecular weight range. The polyethylene glycols offered by the supplier are highly valuable products that can be effectively used in a variety of pharmaceutical formulations including parenteral, topical, ophthalmic, oral and rectal preparations.
This article has been written by Govind Patel.
