Highly purified natural pulp is etherified with methyl chloride or with the combination of methyl chloride and propylene oxide to form a water-soluble, non-ionic cellulose ether. METOLOSE^® can be used as a binder for solid dosage forms such as tablets and granules. It also serves a variety of functions, for example, in enhancing water retention, thickening, acting as a protective colloid due to its surface activity, sustaining release, and film formation. METOLOSE® SR is designed exclusively for a hydrophilic matrix agent. It has tighter specifications compared to the regular METOLOSE® grades. The hydrophilic matrix system is the simplest sustained-release technology for oral dosage forms, consisting essentially of a drug and a water-soluble, highly viscous polymer.