Delivery of Both Active Enzyme and Bleach from Water-in-Silicone Oil (D4) Emulsions

Advanced cleaning formulations, such as liquid laundry packages, consist of many components that require a complex mixture of interfacial actives including silicones for foam control, bleach for brightening, and enzymes for stain removal. Many of these ingredients are mutually incompatible, particularly in liquid formulations where they can be in intimate contact over extended periods of time. Solid dispersions of a prototypical bleach, NaBO3, in silicone polyether surfactants were shown to be very stable over time, even in the presence of water-in-silicone (D(4)) emulsions containing the enzyme alpha-chymotrypsin. Normally, perborates undergo rapid decomposition on contact with water. The rate of denaturation of the enzyme in the emulsion was similarly unaffected by the presence of the bleach until the emulsion was broken, unlike the case where the polyether surfactant was not present. The polyether surfactant thus protects the perborate from hydration and the enzyme from denaturing on contact with silicone oil until excess water and high shear are applied to the emulsion; protective mechanisms are discussed.