New advances in the characterization of lyophilised orally disintegrating tablets

Orally disintegrating tablets (ODTs) produced by lyophilisation have a unique porous structure which leads to a favorable orodispersable functionality. They possess ultra-fast disintegration kinetics, have acceptable mechanical strength and give a smooth mouth texture. Only limited literature is available on the characterization of ODTs and even fewer on lyophilised tablets. The suitability of a broad range of characterization methods for lyophilised tablets was evaluated since they possess other mechanical properties compared to compressed tablets. Four ODTs with diverse properties were carefully selected and thoroughly analysed using various characterization techniques leading to a multitude of descriptors. The functionality of these four lyophilised tablets was examined and the relation between the different descriptors was evaluated using a Principal Component Analysis (PCA). Furthermore, μCT images of two ODTs were acquired to study the internal structure and active pharmaceutical ingredient (API) distribution inside the tablets. The important descriptors, disintegration and mechanical strength, interacted inversely indicating the importance of a well-balanced ODT formulation to achieve favorable properties. μCT data can improve the process knowledge as it yields very diverse descriptors. Ultimately, the different tablets were ranked at their performance.