Patent ID: 8025892

Claim:
A method of preparing a gel delivery system comprising gel particles for topical application of at least one active agent, said method comprising: (a) forming an aqueous solution of a polymeric gelling agent, said aqueous solution being maintained at a first temperature above the gelling point of said polymeric gelling agent, the solution being gellable at a lower temperature below the solution temperature, said aqueous solution forming a gelling agent solution further comprising, dispersed therein, said at least one active and a restraining polymer; (b) discharging the gelling agent solution through a discharge orifice into a moving stream of hydrophobic liquid and forming droplets of said gelling agent solution, said hydrophobic liquid being at a second temperature below the gelling point of said gelling agent solution, the hydrophobic liquid being immiscible with the gelling agent solution; wherein the gel particles coalesce from the gelling agent solution in the hydrophobic liquid stream through the gelling of said droplets with said active and said restraining polymer entrapped therein, and wherein the restraining polymer has sufficient molecular weight to prevent egress of the restraining polymer from the gel particles, and wherein said restraining polymer is bonded to the at least one active agent in the gelling agent solution so as to retain the at least one active agent in the gel particles; wherein the restraining polymer includes at least one quaternary ammonium group or includes a complex comprising a water-soluble or hydrolyzed protein and a quaternary amine salt; wherein the active is a dermally active or dermally effective substance having biological or cosmetic activity.