Rhone-poulenc Chimie

Rafael Jorda

Daniel Desmonceau

Hugues Porte

Ghislaine Torres

Polyester/silicon co-crosslinked polymer substrates at least partially degradable by hydrolysis, well adopted as matrices for the controlled release of a wide variety of active agents therefrom, are prepared by controlledly co-crosslinking (a) at least one diorganopolysiloxane having at least two hydroxyl groups per molecule and (b) an oligomeric polylactic and/or polyglycolic polyester .alpha.,.omega.-diol, with an effective co-crosslinking amount of (c) an organic polyisocyanate.

Hydrolytically degradable polyester/silicon co-crosslinked matrices

Non-agglomerating elastomeric organopolysiloxane particulates having a mean particle size ranging from 50 .mu.m to 3 mm, uniformly coated with silica powder on the face surfaces thereof and well adapted as a soft filler material for natural or synthetic polymers or as a controlled release dosage form, are produced by (a) forming an oil-in-water emulsion of .alpha.,.omega.-dihydroxydiorganopolysiloxane oils, silica powder, a platinum curing catalyst and, optionally, an active principle such as a medicament or an agrochemical, and then (b) breaking and polycondensation crosslinking such emulsion into the desired particles by heating it to a temperature ranging from 40.degree. to 100.degree. C.

Non-agglomerating elastomeric organopolysiloxane particulates produced

Non-agglomerating elastomeric organopolysiloxane particulates having a mean particle size ranging from 50 .mu.m to 3 mm, uniformly coated with silica powder on the face surfaces thereof and well adapted as a soft filler material for natural or synthetic polymers or as a controlled release dosage form, are produced by (a) forming an oil-in-water emulsion of silicone oils, silica powder, a platinum curing catalyst and, optionally, an active principle such as a medicament or an agrochemical, and then (b) breaking and polyaddition crosslinking such emulsion into the desired particles by heating it to a temperature ranging from 40.degree. to 100.degree. C.

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Sainte Foy Les Lyon, France

Rafael Jorda