Raman-based real-time dissolution prediction using a deterministic permeation model.

The purpose of this study was to develop a deterministic permeation model (DPM) that predicts the in vitro release profile of an active ingredient (API) embedded in hydroxypropyl-methylcellulose (HPMC) matrix tablets based on Raman spectra. So far in the literature, such mechanistic models were utilized only for formulation optimization (off-line dissolution prediction), while the real-time prediction of dissolution profiles based on Process Analytical Technology (PAT) data was performed by empirical methods such as Partial Least Squares (PLS) regression. Our work represents a novel conceptual approach that utilizes a mechanistic model to predict dissolution profiles based on data yielded by PAT tools. Tablets containing various API- and HPMC-amounts were produced using different compression pressures according to a 3 full factorial design, their Raman spectra were recorded before dissolution testing. The DPM was constructed using one-third of the measured dissolution profiles and is presented as a system of differential equations together with its analytical solution. The parameters of DPM were estimated by the training data set containing the spectroscopically determined API- and HPMC- amounts and the tableting pressures used, then the release profiles of the remaining two-thirds of the tablets were predicted. The Raman spectra-based predictions of DPM were compared with predictions of an Artificial Neural Network (ANN). It was found that the two methods yield similar results, however, the mechanistic approach has the benefit of requiring a lower amount of training samples. Although the model is based on a remarkable simplification of reality, it facilitates a deeper understanding of the behavior of the formulation. The DPM could improve our understanding of the effect of HPMC and tableting pressures on the release kinetics of the HPMC matrix tablets and participate in the development of PAT-based new surrogate dissolution methods for Real-Time Release testing (RTRt).