REQUIREMENTS FOR THE PRODUCTION OF MICROTABLETS - SUITABILITY OF DIRECT-COMPRESSION EXCIPIENTS ESTIMATED FROM POWDER CHARACTERISTICS AND FLOW-RATES

Eleven direct-compression excipients, namely 3 microcrystalline cellul oses, 4 lactoses, 4 co-processed excipients, and 4 mixtures of lactose s with Avicel PH102 SCG were evaluated for possible use in micro table ting. Powder-technological parameters, namely particle size distributi ons, true and apparent densities, densification behaviour, and mass fl ow rates from a funnel through very narrow orifices, were determined. Flow rates required on modern high-speed rotary tableting machines wer e calculated. Flow rates may be estimated even for very narrow orifice s, and such studies aid in selection of suitable excipients. Mainly sp ray-dried lactose preparations with certain, definite upper limits in size distribution, seem to comply with the prerequisites for the produ ction of micro tablets.