Examination of a Shannon entropy-like figure of merit for controlled release of drugs and other molecules

We propose a figure of merit, based on temporal entropy, to evaluate the degree to which a controlled drug release system is able to adhere to its target release pattern. This criterion can be used, for example, to design multilayered drug release systems whose release flux optimally tracks the target pattern. Such multilayered systems are produced by sequential polymerization, sequential spraying, 3D printing, and other additive manufacturing techniques. After calculating this figure of merit for certain canonical controlled release mechanisms, with zero-order release as the target pattern, we optimize the pattern of initial drug concentrations in a multilayer system with respect to the figure of merit.