Quantification of free/loaded drug fractions and release kinetics from colloidal-based formulations

The correlation between in vivo and in vitro (IVIVC) is yet not sufficiently optimized to allow a significant reduction and replacement of animal testing in pharmaceutical development. One of the main reasons for this lies in the poor comprehension and interpretation of physical mechanism allowing enabling formulations to deploy the drug. For instance, it is currently very complicated/impossible to empirically assess the fraction of freely dissolved drug even from “simple” enabling formulations (such as liposome/ cyclodextrin dispersions/solutions). The precise and real-time quantification of free drug fraction of enabling formulations is crucial for modern pharmaceutics as, according to the most accepted dissolution/permeation theory, it is THE driving force for drug permeation/absorption1.