Patent ID: 8425940

Claim:
Substantially leachless, transparent, agent-encapsulating sol-gel particles having a spherical shape, an average particle size that ranges between 0.05 micron and 5 microns in diameter or a surface area that ranges between 0.01 m 2 /gram and 5 m 2 /gram, being prepared by a method of preparing substantially leachless, agent-encapsulating sol gel particles, the method comprising: emulsifying an inner phase containing at least one agent and at least one first sol-gel precursor in an outer phase containing a dispersing medium for obtaining initial sol-gel particles encapsulating said at least one agent; and reacting said initial sol-gel particles with at least one second sol-gel precursor, thereby obtaining said substantially leachless, agent-encapsulating sol-gel particles; wherein said substantially leachless agent-encapsulating sol-gel particles are characterized by leaching of no more than 2 weight percentages of said at least one agent from therein upon mixing and agitating said sol gel particles with an extraction medium for at least 7 days at 40° C.