THE RATIONAL DEVELOPMENT AND OPTIMIZATION OF CAPSULE FORMULATIONS WITH AN INSTRUMENTAL DOSATOR CAPSULE FILLING MACHINE .1. INSTRUMENTATION AND INFLUENCE OF THE FILLING MATERIAL AND THE MACHINE PARAMETERS

On a capsule filling machine Zanasi LZ 64 with intermittent operation the dosator was instrumented with strain gauges and the influence on t he quality of the formulation and machine parameters was examined. As model formulations served Avicel PH 101 as visco-elastic material and Lactose anhydrous as brittle material as well as mixtures of various s ieve fractions of Lactose. It was shown that for unproblematic filling with uniform fill weights the good compressibility by reduction of vo lume as well as strength of binding is important. The compressibility by reduction of volume is described by the change of the tapped densit y versus time and this can be linearised by the Kawakita equation. Equ al is the measurement of the precompression force. The compressibility by strength of binding results from the degree of densification, the quotient of the densities between the filling material within the caps ule and in its powder bed. Nevertheless too good flow properties, whic h go beyond the necessary outflow out of the hopper, are not opportune : The better the capsule formulations flow the worser they can be dens ified and the greater are the weight variations. The necessary amount of lubricant is determined by the measurement of the ejection force.