Storage-stable solid peroxymonosulfate composition

A storage-stable solid composition consisting of:

• a tooth whitening effective amount of potassium peroxymonosulfate;
• and
• a particulated drying agent comprising tetrapotassium pyrophosphate salt present in an amount of about 1% to about 10% by weight of the total composition, a buffering agent, optionally an additional drying agent selected from phosphates, polyphosphates, orthophosphates, metaphosphates, and polymetaphosphates, less than 4% water by weight of the composition, and optionally one or more of an effervescent acid and base, one or more lubricants, one or more fillers, one or more surfactants, one or more flavor agents, one or more color agents,
• wherein the potassium peroxymonosulfate agent is the only peroxide whitening agent in the composition, and wherein the composition is an oral care formulation formulated as a tablet, powder, or granule, and wherein the buffering agent is selected from sodium carbonate, sodium bicarbonate, monopotassium phosphate, monopotassium biphosphate, and citrates;
• wherein the potassium peroxymonosulfate is present in an amount of about 0.5% to about 7.5% by weight of the total composition.