Dynamic measurement of density using terahertz radiation with real-time thickness measurement for process control

摘要

A method of determining a density of a roller compacted ribbon is disclosed. The method comprises compacting dry pharmaceutical powder between press rollers of a roller compactor to produce a compact ribbon. The method also comprises determining a thickness at a point on the compact ribbon in a non-invasive manner after it has rolled out from in between the press rollers. Further, the method comprises passing the compact ribbon through a gap in between the terahertz emitter and the terahertz detector. Next, the method comprises determining a refractive index at the point on the compact ribbon using a measurement value from the terahertz emitter and the terahertz detector and a measured value for the thickness at the point. Finally, the method comprises computing a density of the compact ribbon at the point using a value of the refractive index.

主权项

1. A method of determining a density of a roller compacted ribbon, said method comprising:
compacting dry pharmaceutical powder between press rollers of a roller compactor to produce a compact ribbon; determining a thickness at a point on said compact ribbon in a non-invasive manner after it has rolled out from in between said press rollers; passing said compact ribbon through a gap in between a terahertz emitter and a terahertz detector; determining a refractive index at said point on said compact ribbon using a measurement value from said terahertz emitter and said terahertz detector and a measured value for said thickness at said point; and computing a density of said compact ribbon at said point using a value of said refractive index and a calibration equation.