Study on fast prediction of film coating terminal point of Tianshu Tablets by near- infrared spectroscopy / 中草药

ABSTRACT

Objective: To investigate how to rapidly predict coating terminal point in the thin film coating of Tianshu Tablets by near-infrared spectroscopy (NIRS). Methods: Firstly, synergy interval partial least square (siPLS) was used to optimize the modeling intervals and the pretreatment methods were screened. Secondly, according to the optimal modeling parameters, the conformity test and similarity matching were used to establish calibration models based on the established reference spectra library. Subsequently, by comparing the similarities between the test spectra and the reference spectra, the threshold value was set. The relation among the similarities, threshold value and the coating end point was obtained. Finally, the performance of the calibration model was verified by the validation set. Results: During the coating process, the similarities between the test spectra and the reference spectra were gradually increasing until the similarities of continuous test spectra exceeded the threshold, thus, indicating the end point. Conclusion: Conformity test and similarity matching can sensitively monitor the change of similarities among spectra and the corresponding trend. Both models have high performance, which can accurately predict the coating terminal point. It’s of great significance to reduce batch-to-batch variation in film coating and the loss of coating materials, and improve the coating efficiency and the quality uniformity of solid preparation.