Croscarmellose sodium, or sodium CMC, is a cross-linked polymer of carboxymethylcellulose sodium. It appears as white, fibrous, free-flowing powder, and is used commonly as an FDA-approved disintegrant in pharmaceutical manufacturing. Disintegrants facilitate the breakup of a tablet in the intestinal tract after oral administration. Cross-linking allows enhanced bioavailability of the drug through superior drug dissolution. Without a disintegrant, tablets may not dissolve appropriately and may effect the amount of active ingredient absorbed, thereby decreasing effectiveness.