Shrinking and swelling properties of pellets containing microcrystalline cellulose and low substituted hydroxypropylcellulose: II. Swelling properties

Abstract

Pellets containing microcrystalline cellulose (MCC) and low substituted hydroxypropylcellulose (L-HPC) are able to swell in contract with an aqueous phase. Swelling is the reverse to shrinking of wet pellets obtained by extrusion/spheronization during drying. This shrinking is only partially reversible. Shrinking and consequently swelling can be almost suppressed using freeze-drying. The pellets studied do not disintegrate during swelling and dissolution. For propyphenazone, caffeine and acetaminophen as model drugs, the dissolution rate is enhanced in the presence of L-HPC in the pellets. The dissolution rates of freeze-dried pellets are greater compared with fluid-bed-dried pellets.