04861627 is referenced by 212 patents and cites 9 patents.

A single step method for preparation of multi-layer polymeric delivery systems. Any two or three different degradable or non-degradable polymers which are not soluble in each other at a particular concentration, as dictated by their phase diagram, can be used. The multi-layer microcapsules produced by the method are distinguished by extremely uniform dimensioned layers of polymer and actual incorporation of the substance to be delivered into the polymer layers.

In the preferred embodiment of the method, two polymers are dissolved in a volatile organic solvent, the substance to be encapsulated is dispersed or dissolved in the polymer solution, the mixture is suspended in an aqueous solution and stirred, and the solvent is slowly evaporated, creating microspheres with an inner core formed by one polymer and an outer layer formed by the second polymer. In another embodiment one polymer may be formed within a layer of the other polymer by increasing the rate of evaporation of the volatile solvent.

Title
Preparation of multiwall polymeric microcapsules
Application Number
7/45840
Publication Number
4861627
Application Date
May 1, 1987
Publication Date
August 29, 1989
Inventor
Robert S Langer
Somerville
MA, US
Edith Mathiowitz
Brookline
MA, US
Agent
Kilpatrick & Cody
Assignee
Massachusetts Institute of Technology
MA, US
IPC
B01J 13/02
A61K 9/58
A61K 9/56
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