Synchronization of Cocrystal Dissolution and Drug Precipitation to Sustain Drug Supersaturation.

A graphical analysis of both drug and coformer concentrations contributed by dissolving cocrystals is presented in the context of a simplified cocrystal phase diagram. The conceptual basis and analysis identify parameters that control cocrystal dissolution-drug supersaturation-precipitation (DSP) behavior. The important effects of coformer concentration, cocrystal dose, and cocrystal solubility on drug supersaturation levels are demonstrated and quantified by the DSPindex. While the studies presented rely on high and nonstoichiometric coformer concentrations contributed by the dissolving cocrystals, the concepts and findings can answer the question of whether and how much coformer should be added to cocrystal dissolution media or formulations.

Cocrystals to facilitate delivery of poorly soluble compounds beyond-rule-of-5.

Besides enhancing aqueous solubilities, cocrystals have the ability to fine-tune solubility advantage over drug, supersaturation index, and bioavailability. This review presents important facts about cocrystals that set them apart from other solid-state forms of drugs, and a quantitative set of rules for the selection of additives and solution/formulation conditions that predict cocrystal solubility, supersaturation index, and transition points. Cocrystal eutectic constants are shown to be the most important cocrystal property that can be measured once a cocrystal is discovered, and simple relationships are presented that allow for prediction of cocrystal behavior as a function of pH and drug solubilizing agents. Cocrystal eutectic constant is a stability or supersatuation index that: (a) reflects how close or far from equilibrium a cocrystal is, (b) establishes transition points, and (c) provides a quantitative scale of cocrystal true solubility changes over drug. The benefit of this strategy is that a single measurement, that requires little material and time, provides a principled basis to tailor cocrystal supersaturation index by the rational selection of cocrystal formulation, dissolution, and processing conditions.