Quantifying Pharmaceutical Film Coating with Optical Coherence Tomography and Terahertz Pulsed Imaging: An Evaluation.
Spectral domain optical coherence tomography (OCT) has recently attracted a lot of interest in the pharmaceutical industry as a fast and non-destructive modality for quantification of thin film coatings that cannot easily be resolved with other techniques. Because of the relative infancy of this technique, much of the research to date has focused on developing the in-line measurement technique for assessing film coating thickness. To better assess OCT for pharmaceutical coating quantification, this paper evaluates tablets with a range of film coating thickness measured using OCT and terahertz pulsed imaging (TPI) in an off-line setting. In order to facilitate automated coating quantification for film coating thickness in the range of 30-200 μm, an algorithm that uses wavelet denoising and a tailored peak finding method is proposed to analyse each of the acquired A-scan. Results obtained from running the algorithm reveal an increasing disparity between the TPI and OCT measured intra-tablet variability when film coating thickness exceeds 100 μm. The finding further confirms that OCT is a suitable modality for characterising pharmaceutical dosage forms with thin film coatings, whereas TPI is well suited for thick coatings.
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB2 3RA, UK.
Hungyen
H
Lin
Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK.
Yue
Y
Dong
Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK.
Yaochun
Y
Shen
Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB2 3RA, UK.
J Axel
JA
Zeitler
D000465:Algorithms; D002626:Chemistry, Pharmaceutical; D003627:Data Interpretation, Statistical; D004339:Drug Compounding; D015203:Reproducibility of Results; D013499:Surface Properties; D013608:Tablets, Enteric-Coated / Q000737:chemistry*; D055069:Terahertz Imaging; D041623:Tomography, Optical Coherence; D035501:Uncertainty; D058067:Wavelet Analysis
D013608:Tablets, Enteric-Coated
Processing; coating; imaging methods; physical characterization; process analytical technology (PAT); tablet