High throughput in-line content uniformity measurement of tablets based on real-time UV imaging

This paper presents a precursor of a novel, high-throughput, in-line system, which utilizes ultraviolet (UV) imaging in order to predict the active pharmaceutical ingredient (API) content of tablets in real-time, non-destructive manner. Pimobendan, cardiovascular drug used in veterinary medicine was chosen as a fluorescent model API. Two experiments were carried out using different measurement setups, where the tablets were moving at different speeds. The blue colour components of the images were used to predict the pimobendan content of the tablets, and as a reference method, traditional UV spectroscopy was used to measure the API content of the dissolved tablets. In the case of the first, slower experiment (with a conveyor belt speed of 83 mm/s), a second order polynomial was fitted to the calibration tablets containing a nominal dose of 1.25, 5 and 10 mg of pimobendan and it was used to predict the API content. The RMSEP obtained was 0.428 mg for the validation tablets with a relative error as low as 7% for the target level. For the second, faster experiment (1000 mm/s) the same polynomial was used to predict the pimobendan concentration of a different set of tablets, achieving a relative error of 2.03%. Finally, the throughput of both systems was calculated to assess their applicability to meet the requirements of a pharmaceutical manufacturing line. The first system could inspect up to 93375 tablets per hour, while the second was able to process up to 360000 tablets in an hour, making it suitable for industrial application. By using these developed systems, the API content of all produced tablets could be determined non-destructively, which can greatly improve patient safety.