Stimulus-responsive antioxidant crystals and method for their preparation

Compositions comprising an active oxygen-responsive antioxidant crystal, methods of making them, and methods for controlling the dissolution rate and/or altering the crystallization behavior of an antioxidant are disclosed. The crystals comprise an antioxidant and a disulfide- or diselenide-crosslinked polymer that is adsorbed onto a surface of the antioxidant. Upon exposure to an active-oxygen stimulus, the polymer de-crosslinks to release the antioxidant from the composition in an amount effective to counteract the stimulus. While prior approaches to altering dissolution rates have relied on passive zero- or first-order kinetics that are independent of ROS levels, the inventive compositions actively respond by releasing antioxidant in an amount proportional to the concentration of active-oxygen species present. The crystallization methods are simple and scalable. The antioxidant balances ROS concentration and allows formulators of nutritional supplements, drug therapies, and other applications to more effectively use antioxidants while avoiding undesirable levels of antioxidative stress.