Nondestructive and on-line monitoring of tablets using light-induced fluorescence technology

A system using light-induced fluorescence (LIF) technology was developed for rapid and nondestructive analysis of active pharmaceutical ingredients on tablet surfaces. Nonhomogeneous tablets with defined layer of active ingredients were made by 3-Dimensional Printing technology to determine penetration depths of the light source and the resultant fluorescence responses. The LIF method of analysis showed penetration to depths of up to 3 mm into tablets. A correlation between LIF signals from analysis of tablet surfaces and the total drug content of the respective tablets was established. This method of surface analysis was verified with UV spectrometric methods for the total drug content of each respective tablet. The results from a small sample population of tablets made from both homogeneous and nonhomogeneous powder mixtures established good correlation between LIF surface monitoring and total tablet content. The use of on-line monitoring of the individual tablet for surface content demonstrated consistent LIF profiles from simulated production rates up to 3000 tablets a minute. The instrument was also field tested successfully on a tablet analyzer.