Microencapsulation process

Claim 3

The method of claim 1, wherein said microcapsules formed in step (c) are separated from said continuous-phase processing medium prior to complete solvent removal in step (d).

Claim 4

The method of claim 1, wherein said continuous-phase processing medium is water, xylene, toluene, a synthetic oil or a natural oil.

Claim 5

The method of claim 3, wherein said continuous-phase processing medium further comprises a surfactant.

Claim 6

The method of claim 4, wherein said continuous-phase processing medium is water containing from 1 to 10% polyvinylalcohol.

Claim 7

The method of claim 1, wherein the fluid product of step (b) is a stable water-in-oil or oil-in-water emulsion.

Claim 8

The method of claim 1, wherein said solvent is a substance selected from the group consisting of halogenated aliphatic compounds, halogenated aromatic hydrocarbon compounds, aromatic hydrocarbon compounds, cyclic ethers, alcohols, water and acetone.

Claim 9

The method of claim 7, wherein said solvent is methylene chloride.

Claim 10

The method of claim 1, wherein solvent is evaporated from said dispersion by reducing the pressure over said dispersion.

Claim 11

The method of claim 1, wherein residual solvent is removed from said microcapsules in step (d) by washing said microcapsules with water containing a surfactant by vacuum filtration.

Claim 12

The method of claim 10, wherein said washed microcapsules are dried by subjecting said microcapsules to a vacuum followed by sieving the microcapsules.

Claim 13

The method of claim 1, wherein said wall forming material is polystyrene, ethylcellulose, cellulose acetate, hydroxy propylmethylcellulose phthalate, dibutylaminohydroxypropyl ether, polyvinyl butyral, polyvinyl formal, poly(meth)acrylic acid ester, polyvinylacetaldiethylamino acetate, 2-methyl-5-vinylpyridine methacrylate-methacrylic acid copolymer, polycarbonate, a polyester, polypropylene, a vinylchloride-vinylacetate copolymer, a polysaccharide and glycerol distearate.

Claim 14

The method of claim 12, wherein said polyester is polylactide, polyglycolide or polycaprolactone or copolymers thereof.

Claim 15

The method of claim 1, wherein said active agent is a biologically active agent selected from the group consisting of estrogens, progestins, gastrointestinal therapeutic agents, non-steriodal anti-fertility agents, parasympathomimetic agents, psychotherapeutic agents, major tranquilizers, minor tranquilizers, rhinological decongestants, sedative-hypnotics, non-estrogenic and non-progestational steroids, sulfonamides, sympathomimetic agents, vaccines, vitamins, nutrients, anti-malarial compounds, anti-migraine agents, anti-Parkinson agents, antispasmodics and anticholinergic agents, antitussives, bronchodilators, cardiovascular agents, electrolyte replacements, ergot alkaloids, analgetics, non-narcotics, antibiotics, anti-cancer agents, anti-convulsants, anti-emetics, anti-histamines, anti-inflammatory agents, prostaglandins, cytotoxic drugs, antigens and antibodies and enzymes.

Claim 16

The method of claim 1, wherein from 5 to 30 wt% of said active agent is dissolved or dispersed in said solvent.

Claim 17

The method of claim 1, wherein from 5 to 35 wt% of said wall forming material is dissolved in said solvent.

Claim 18

The method of claim 1, wherein the weight ratio of said active agent to said wall forming material in said solvent ranges up to about 80 wt% active agent to 20 wt% wall forming material.