Abstract: A method of analysing powder formed as a mixture of pharmaceutical ingredients and derived from a bulk preparation of powder by spectrophotometric analysis utilising transmission measurements. A sample powder is removed from the bulk mixture and pressed into a test wafer and spectrophotometrically analysed for the transmitted beam to provide an assay test spectrum of actual absorption characteristics of ingredients in the material of the wafer. These characteristics of the assay test spectrum are compared with predetermined assay standard spectra determined from individual standard wafers for each relevant ingredient in the powder mixture by measuring absorption characteristics of the individual ingredients from the transmitted beam at known wavelengths of the beam to assess acceptability of the homogenity and distribution of the relevant ingredient in the powder of the sample. The wafer is preferably pressed with flat and parallel opposed end faces through which the beam is directed.

Abstract: A method of and apparatus for spectrophotometrically analyzing a tablet by NIR transmission measurements includes a tablet holder 1 having a recess 5 within which a tablet 20 is located. A probe 40 is applied to the tablet 20 to direct an NIR beam 45 to and through the tablet for sensing at a detector 32 from which measurements characteristics of the tablet are analyzed. The recess 5 accommodates the tablet 20 as a close, possibly complementary fit. The tablet is clamped in the recess 5 by a spring loaded rod 8 to ensure that the tablet is located and retained at a predetermined position in the recess 5 relative to an aperture 7 through which the transmitted beam is directed to the detector 32. Preferably the tablet 20 is subjected to clamping forces applied by two spring loaded clamping rods disposed substantially perpendicularly relative to each other in the tablet holder.