Visualization and quantification of citalopram hydrobromide within highly porous drug products by near-infrared chemical imaging

A novel method for the fabrication of flexible and precise doses of an antidepressant, citalopram hydrobromide (CHB), utilizing two approaches of incorporating CHB into the dosage form, was introduced in an earlier study. This method, called tunable modular design (TMD), employs CHB-preloaded modules done by freeze-drying together with inkjet printing of CHB-containing ink onto the modules. In this study, near-infrared chemical imaging (NIR-CI) was utilized to visualize the distribution of CHB both on the printed surface of the samples as well as through imaging the cross-section of these samples. Furthermore, as the TMD samples are to be optimally produced at the point of care, it is crucial to understand the factors affecting the development of fast, non-destructive, quantitative models for dose verification to ensure the delivery of high-quality drug products to patients. A state-of-the-art pushbroom NIR-CI instrument was utilized for this purpose. Industry-standard partial least squares (PLS) and support vector machine (SVR) models were implemented for data analysis. Furthermore, multivariate curve resolution was explored as both qualitative and quantitative modeling tools. The obtained prediction models were accurate, having the root mean square error of prediction of the quantitative SVR models as low as 0.21. Additionally, NIR-CI could detect the printed drug in the samples along the cross-section and on the surface, thus making it a potent tool for the troubleshooting and quality control of TMD samples.