METHOD AND APPARATUS FOR RAPID IN SITU ANALYSIS OF PRESELECTED COMPONENTS OF HOMOGENEOUS SOLID COMPOSITIONS, ESPECIALLY PHARMACEUTICAL COMPOSITIONS

摘要

A method and apparatus for rapid in situ spectroscopic analysis of preselected components of homogeneous solid chemical compositions, especially pharmaceutical products. The apparatus comprises a high-power pulsed laser (10) whose beam is focused on the material (18), typically a tablet or the powder prior to compaction into the tablet, which generally consists of an active ingredient (e.g. a drug) and a filler material (cellulose, glucose, lactose, etc.). The pulsed laser beam vaporizes a small volume of the pharmaceutical product and produces a plasma having an elemental composition which is representative of the pharmaceutical product. The atomic composition of the vaporized material is analyzed with an optical spectrometer (24). As the temperature of the plasma is sufficiently elevated to cause dissociation of the molecules of the constituents of the pharmaceutical product, the concentration of the active ingredient is obtained by analyzing the atomic concentration of an element which is present in the active ingredient but not in the matrix or filler material, or whose concentration in the active ingredient is substantially different from the matrix, and acts as a tag on the active material. The technique can also be used to analyze inactive ingredients or the presence of unwanted contaminants which consist of elements not normally present in such pharmaceutical products such as trace metals introduced accidentally during processing.