Near Infrared Spectroscopic Study of the Hydration/Swelling Process of Microcrystalline Cellulose, Starch and Carboxymethylcellulose

Disintegrating agents, such as microcrystalline cellulose (MCC), starch, carboxymethyl cellulose (CMC) and polyvinylpyrrolidone, are often used as drug additives to make the tablet swell and disintegrate in water. Here, we investigated the swelling process of these agents via near infrared and two-dimensional correlation spectroscopic analysis. The traditional agents MCC and starch showed increments of loose hydration prior to strong hydration. However, strong hydration increases were followed by loose hydration for CMC. In conclusion, the distinguishing swelling property of CMC is provided by the first strong hydration of water molecules, which may avoid polymer–polymer interaction and induce water penetration into the drug tablet.