Quantitative Assessment of the in vivo Dissolution Rate to Establish a Modified IVIVC for Isosorbide Mononitrate...

A modified in vitro-in vivo correlation (IVIVC) of the oral solid dosage forms has been proposed as a linear correlation between in vitro and in vivo dissolution. Nevertheless, the analysis of in vivo dissolution is limited by the lack of available methods. In this proof-of-concept study, a novel pharmacokinetic (PK) model containing the in vivo dissolution process and its quantification was presented to directly estimate the in vivo dissolution rate constant (k_d). The new model was validated with a hypothetical oral solution (k_d → +∞). The accuracy of the new method was clarified by comparing with the relatively true value of k_d from the literature. Isosorbide mononitrate (ISMN) was used as a model drug to explore the practicability of the novel method. The dissolution capacities of ISMN reference and test tablets were discriminated by an improved in vitro dissolution method. Following the human PK studies, the k_d values and corresponding in vivo dissolution profiles of two formulations were obtained using the novel method. Finally, a modified level A IVIVC between in vitro and in vivo dissolution of ISMN tablets was established, which is expected to guide the optimization of the tablet formulation containing ISMN.