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US 4,460,563 AGranted
Process for preparing microcapsules in a liquid vehicle
AssigneeEurand, Inc.
InventorMassimo Calanchi
Life of this patent
Estimating the term…
Abstract
The invention relates to a process for preparing microcapsules in a liquid vehicle, allowing to microencapsulate both water soluble and water insoluble substances, using either ionic or non-ionic systems, in which the membrane enclosing the core of the microcapsules is formed by a polymer selected from the group of the phthalates, and more particularly by hydroxypropylmethylcellulose phthalate.
Claims16
A process for preparing microcapsules in a liquid vehicle, comprising the following steps:
- (1) dissolution of a membrane-forming cellulosic polymer in a solvent which is the microencapsulation vehicle;
- (2) addition of cores of a substance to be microencapsulated to said solution;
- (3) formation of a coacervate by adding a substance adapted to cause phase separation;
- (4) deposition of the coacervate, forming a continuous coating of polymer around the cores of the substance;
- and
- (5) solidification of the polymer;
- the improvement comprising the fact that the membrane-forming cellulosic polymer is a cellulose phthalate having the following chemical structure:
- ##STR2## wherein R is hydrogen or a methyl, hydroxypropyl, carboxybenzoyl, 2-(2-carboxybenzoyl)propyl, or acetyl group, at least one R being always carboxybenzoyl, that the polymer is dissolved in aqueous or buffer solution, and that the phase separator is a substance causing phase separation of the cellulose phthalate from aqueous solution at a pH.gtoreq.5.
5 more elements
Dependencies are inferred from the claim text.