Use of kappa-carrageenan as alternative pelletisation aid to microcrystalline cellulose in extrusion/spheronisation. II. Influence of drug and filler type.

The extrusion/spheronisation process is an established technique to produce pellets for pharmaceutical applications. Microcrystalline cellulose (MCC) is being usually used as a pelletisation excipient in the extrusion process. However, MCC has some disadvantages, e.g. lack of disintegration and prolonged drug dissolution. Therefore, kappa-carrageenan was investigated as a substitute for MCC to overcome such disadvantages. A fixed ratio of kappa-carrageenan (20%) was combined with different fillers (lactose, mannitol, maize starch and dicalciumphosphate dihydrate) and different drugs (acetaminophen, theophylline, mesalamine and hydrochlorothiazide) in several formulations. Some pellet properties (yield, aspect ratio, mean Feret diameter, 10% interval fraction, tensile strength and dissolution profile) were determined. Most formulations resulted in pellets of a sufficient quality with respect to size, size distribution and shape independent of the incorporated fillers and drugs. In contrast to MCC pellets, the release profile of kappa-carrageenan pellets was much less affected by the solubility of the drug. Generally, kappa-carrageenan pellets owned fast disintegration and fast drug release in contrast to MCC pellets.