Case Study: Polyethylene Glycol Purity

By Nigel A Langley and Karen H Chen at Croda Inc

One of the main challenges in the pharmaceutical industry is the ability to produce stable drug formulations. This is especially demanding as many active pharmaceutical ingredients (APIs) respond unstably to oxidation, moisture or pH. Generally, excipients are the major component of any given drug formulation. In the past, pharmaceutical excipients have been viewed as ‘inert' ingredients that played an insignificant role in the stability of formulations containing APIs. This view is now changing as pharmaceutical formulators have gained a greater awareness of the importance of excipient purity. Excipient impurities can accelerate the degradation of the API as well as destabilising emulsions, causing skin and cellular irritation and promoting gelatin cross-linking in both soft gelatin and hard gelatin capsules.