Article http://dx.doi.org/10.26855/ea.2022.12.012

PAT Monitoring of Coating Pan by NIR - PLS Method Calibration Approach


Andrea Umberto Gelain1,*, Eleonora Mustorgi2, Alice Melocchi3, Emiliano Genorini2, Giuseppe Buratti1

1Freund-Vector Corporation European Laboratory, Via Enrico Mattei 2, Villasanta (MB), Italy. 

2VIAVI Solutions, Via Cernuschi 8, Monza (MB), Italy. 

3Università degli Studi di Milano, Dipartimento di Scienze Farmaceutiche, Via G.Colombo 71, Milano (MI), Italy.

*Corresponding author: Andrea Umberto Gelain

Published: January 12,2023


A process analytical technology (PAT) method relying on near infrared (NIR) diffuse reflectance spectrometry was developed to determine the average coating thickness applied and the weight gained by tablets during coating process. The NIR device was installed inside the pan directly in contact with the cores under processing and relevant spectra were recorded in real time during the entire coating process. The method required principal component analysis (PCA) and partial least squares regression (PLS). The primary methods to calibrate PLS are tablet weight gain and coating thickness, they were carried out using the chemometric methods. The PLS-model was employed as the calibration curve for an online process monitoring and was based on the spectra obtained from the tablets during coating, pretreated with SNV and first derivative, and ordered into one object. This way, the method developed could be advantageously used for in-line PAT monitoring. Additional characterization insights were attained by calibrating the spectra versus the weight gain data obtained from at-line tablet weighing. Overall, the possibility to monitor multiple parameters using just one device and one spectrum was demonstrated.


[1] J.D. Kirsch, J.K. Drennen Appl. Spectrosc. Rev., 30 (1995), pp. 139-174.

[2] Klemen Korasa, FrancVrečer: Overview of PAT process analysers applicable in monitoring of film coating unit operations for manufacturing of solid oral dosage forms, 2017.

[3] L.G. Weyer Appl. Spectrosc. Rev., 21 (1985), pp. 1-43. 

[4] I.M. Mills, in: I. Murray, I.A. Cowe (Eds.), Making Light Work: Advances in Near Infrared Spectrometry, VCH, Weinheim, 1991, pp. 67–80. 

[5] Kim H. Esbensen, Andres D. Roman-Ospino, Adriluz Sanchez, Rodolfo J. Romanach: Adequacy and verifiability of pharma-ceutical mixtures and dose units by variographic analysis (Theory of sampling) – A call for a regulatory paradigm shift, Inter-national journal of pharmaceutics, 2015.

[6] Nada O’Brien, Charles A. Hulse, Donald M. Friderich, Fred J Van Milligen, Marc K.vongunten, Frank Pfeifer, Heinz W Siesler: Miniature Near Infrared (NIR) Spectrometer Engine For Handheld Applications; Proceedings of SPIE – The International Society for Optical Engineering, 2012.

[7] M.Anderssona, M.Josefson, F.W.Langkilde, K.-G.Wahlund. (1999). Monitoring of a film coating process for tablets using near infrared reflectance spectrometry. Journal of Pharmaceutical and Biomedical Analysis, 20, 27-37.

How to cite this paper

PAT Monitoring of Coating Pan by NIR - PLS Method Calibration Approach

How to cite this paper: Andrea Umberto Gelain, Eleonora Mustorgi, Alice Melocchi, Emiliano Genorini, Giuseppe Buratti. (2022). PAT Monitoring of Coating Pan by NIR - PLS Method Calibration Approach. Engineering Advances2(2), 201-210.

DOI: http://dx.doi.org/10.26855/ea.2022.12.012