Advanced Polymer Systems, Inc.

Diamond Shamrock Corporation

Richard Won

Martin A Katz

Sergio Nacht

Michael Froix

Tai Chun Cheng

Robert P Eury

Christine Jy Liau

Chung H Cheng

Robert P Zajac

Retinoic acid compositions intended for topical application are incorporated in novel formulations in which they are retained as impregnants inside the pores of porous solid particles or microspheres. The pores form a continuous network open to the exterior of the particles, permitting outward diffusion of the retinoic acid impregnant at a controlled rate depending on the pore size. The impregnated particles are prepared by impregnation of preformed particles with the retinoic acid.

Methods and compositions for topical delivery of retinoic acid

Ionic compositions comprise an active ingredient absorbed within a network of internal pores defined by a plurality of polymeric particles. The particles are preferably crosslinked polymeric beads having a diameter in the range from about 5 to 100 microns and a surface charge density from about 0.1 to 10 meq/qm hydrogen ion capacity. The active ingredients are released from the ionic polymer beads over time when orally administered, applied to a keratinic material, typically human skin or hair or otherwise delivered to a target environment. The use of a cationic charge promotes adhesion of the beads to the keratinic material.

Ionic beads useful for controlled release and adsorption

Ionic beads for controlled release and adsorption

Active substances intended for topical application are incorporated in novel formulations in which they are retained as impregnants inside the pores of porous solid particles or microspheres. The pores form a continuous network open to the exterior of the particles, permitting outward diffusion of the impregnants at a controlled rate depending on the pore size. The impregnated particles are prepared by impregnation of preformed particles with the active substance.

Two step method for preparation of controlled release formulations

Delivery vehicles comprised of a polymeric bead having a network of pores with an active ingredient held within the network are provided for use in a method to provide controlled release of the active ingredient. The network of pores is substantially non-collapsible upon removal of the active ingredient and the delivery vehicles are polymerized by a process in which the active ingredient also comprises the porogen during formation of the network of pores.

Method for delivering an active ingredient by controlled time release

A method for preparing macroporous aminotriazine-aldehyde resins by reaction in the presence of an acid catalyst and a miscible porogen. The resin product has high surface area and porosity and displays excellent sorption capacity.

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Palo Alto, CA, United States of America

Richard Won