Single-step granulation/tabletting of different grades of lactose: a comparison with high shear granulation and compression

The influence of the particle size, particle morphology and crystallinity of lactose on the extrusion properties and on the quality of tablets were investigated using single-step granulation/tabletting as a tabletting technique. Results showed that particle size and type of lactose (alpha-lactose monohydrate, anhydrous beta-lactose and spray dried lactose) affected the powder feeding, the process performance as well as the process capacity. Different grades of lactose yielded tablets with similar tensile strength, but significantly different disintegration time. Single-step granulation/tabletting always yielded tablets with a significantly higher tensile strength and similar or significantly lower disintegration time compared to high shear granulation and compression. The tensile strength of a-lactose monohydrate tablets (without and with PVP) did not change during one year of storage at 60% RH-25 degreesC and at 75% RH-40 degreesC, whereas a significant increase in disintegration time was observed. It can be concluded that although the lactose grade affected the performance and the optimal parameters of single-step granulation/tabletting, all lactose grades can be efficiently processed using this technique. (C) 2004 Elsevier B.V. All rights reserved.