Excipient (pharmacologically inactive substance)
What is it?
Hypromellose, also commonly known as hydroxypropyl methycellulose (HPMC) is a coating agent and film-former used as an inactive ingredient in the pharmaceutical industry. It has also been used as a rate-controlling polymer for sustained-release dose forms.
As a powder, hypromellose is off-white to beige and may be in granules. Hypromellose is considered an inert ingredient. It has a high viscosity and is often used in ophthalmic preparations as artificial tears for dry eyes. In the US, it is available over-the-counter (OTC) in such products as Isopto Tears and Nature’s Tears.
 Dave RH. Overview of pharmaceutical excipients used in tablets and capsules. Drug Topics (online). Advanstar. 10/24/2008 http://drugtopics.modernmedicine.com/drugtopics/Top+News/Overview-of-pharmaceutical-excipients-used-in-tabl/ArticleStandard/Article/detail/561047. Accessed 08/19/2011