Modified Drug Release From Beads Prepared with Combinations of Two Grades of Microcrystalline Cellulose

In previous work, the use of binary drug diluent mixtures with various grades or types of microcrystalline cellulose were shown to exhibit varying degrees of release from beads prepared by extruder/marumerizer technology.In this work beads of suitable physical appearance were prepared with varying proportions of two grades of microcrystalline cellulose (Avicel PH-101 and Avicel RC-581) and 10% drug. In-vitro dissolution results varied with the proportion and the grade of the microcrystalline cellulose and with the dissolution medium utilized. Microcrystalline cellulose beads remained intact in water or in acid, but beads with the microcrystalline cellulose/carboxymethylcellulose sodium product exhibited gel structures in water and remained as beads in acid. The quantity of gel formation increased with an increasing level of the carboxymethylcellulose sodium product.