DE1184323B - Process for the production of very small particles containing a liquid emulsified in oil inside by coacervation - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Kl .: BOIg

Number:
File number:
Registration date:
Display day:

German KL: 12c-3

1 184 323
U6729IVc / 12c
December 11, 1959
December 31, 1964

It is already known, very small, oil-containing particles inside by coacervation of a Mixture consisting of an aqueous gelatin sol and an oil-in-water emulsion. Other substances can also be dissolved or dispersed in the oil.

It has been found that very small particles that are inside an emulsion of a hydrophilic liquid Contained in oil, can be produced by coacervation if, according to the invention, the emulsion added a stabilizer, and this in the presence of an aqueous dispersion of a styrene-maleic acid or a styrene-maleic acid amide copolymer or a carbohydrate acetate phthalate in a known manner Way is coacervated.

The properties of the thus encapsulated product can be improved by adding a known one To achieve thickener for the hydrophilic phase.

The obtained particles gradually let the solute in the hydrophilic liquid pass through. For example, fertilizers, plant growth hormones and pesticides, such as fungicides, nematocides, bactericides or viricides. Similarly, you can Vitamins, especially combinations of water- and oil-soluble vitamins, which are only found in animals Body released to be enclosed in such capsules. Next can be cosmetic or pharmaceutically active substances are encapsulated in this way.

The method can also be used to encapsulate particles already from a Coacervate membrane are enclosed.

The choice of oil is not critical; it depends on the function to be performed by the oil, d. H. if the oil as a solvent or suspending agent or simply as the outer phase of a further emulsion serves, from. Virtually any animal, vegetable, synthetic or mineral oil that contains the desired physical properties can be used for this purpose. examples for such oils are lanolin, corn oil, soybean oil, castor oil, cod liver oil, and mineral oil. In making the The usual emulsifiers such as the esters of polyhydric alcohols and sorbitol derivatives are usually used as emulsions and polyoxyethylene derivatives are used.

The thickeners used must not dissolve in the oil phase. They are only intended to increase the viscosity of the hydrophilic liquid. Suitable means for this purpose are e.g. B. acacia and tragacanth gum, methylcellulose ^ arboxymethyl process for the production of very small
Particles that emulsified in oil inside
Contained fluid due to coacervation

Applicant:

The National Cash Register Company,

Dayton, Ohio (V. St. A.)

Representative:

Dipl.-Chem. Dr. jur. W. Beil, A. Hoeppener
and Dr. HJ Wolff, lawyers,
Frankfurt / M.- Höchst, Antoniterstr. 36

Named as inventor:

Everett Nelson Hiestand;

Erik Hugo Jensen;

Peter Dietrich Meister, Kalamazoo, Mich.

(V. St. A.)

Claimed priority:
V. St. v. America December 22, 1958
(781 921)

cellulose, magnesium aluminum silicate, polyglycols, glycerine or syrup.

Surfactants such. B. Sorbitol fatty acid esters and the polyoxyethylene sorbitol fatty acid esters or preferably nonionic and thickening agents, such as natural and synthetic Waxes, solid fats and stearins are used, oil thickeners are for example beeswax, Carnauba wax, paraffin wax, saturated fatty acid esters, sitosterect, cholesterol, stigmasterol and hydrogenated Castor oil.

The polymers to be used according to the invention contain both lipophilic and hydrophilic ones Units, d. i.e., the recurring monomeric group is essentially lipophilic Character and derives from styrene, alkyl-substituted styrene or by ether grappling, ester groups or halogen-substituted styrene, while the other periodically occurring unit is essentially has a hydrophilic character and z. B. derived from maleic acid uad maleic acid amide. Mixed These are lipophilic and polymerized

409 760/269

hydrophilic groups represent the majority of the units present in the polymer.

The copolymers include the hydrolyzed styrene-maleic anhydride and styrene-maleic acid amide copolymers, Carbohydrate acetate phthalates, e.g. B. starch acetate phthalate, cellulose acetate phthalate and amylose acetate phthalate.

Hydrolyzed styrene-maleic anhydride mixed polymers are preferred, whose anhydride groups are at least 50% hydrolyzed, used.

As the solubility of the polymers to be used in various hydrophilic liquids is different, known solubilizers can be used. For carboxylic acid polymers are as solubilizing agents polysaccharides, z. B. alginates, pectins, methyl cellulose, carboxymethyl cellulose, suitable. The galactose polysaccharides are particularly valuable, e.g. B. that of Irish Moss (carrageenan) derived. For example, the solubility of fully hydrolyzed styrene-maleic anhydride interpolymer can be reduced in water with relatively small amounts of this polysaccharide increased from about 2% to about 7 to 10% will.

Between a pH of 1 and 2.5 (the pH that normally occurs in the stomach) a styrene-maleic acid copolymer dissociates only up to 1% and therefore within this pH range not soluble, so that the polymer is used as a coating for agents that act on the intestine can be.

example 1

10 cc of water, are dissolved in the 20 g of urea are containing at 8O ⁰ C in 25 cc of corn oil, 0.25 g hydrogenated castor oil, emulsified. From 10.0 g of a styrene-maleic acid copolymer of the formula

ι styrene-maleic acid copolymers of the formula

CH ₂ - / ITT -ι 1 FCH O / TT ι 0.890 CH
I. I.
C =
I. I. λ OH I.
C = O OH

J ™

With a molecular weight of approximately 120,000, a sol is produced with 500 ecm of water. 20 g of sodium sulfate are dissolved in 80 ecm of water and diluted to 100 ecm with water. The emulsion and .the Sol be heated to 8O ⁰ C and slowly added together into the heated also to 80 ° C solution of sodium sulfate with vigorous stirring.

After coacervation and phase separation, the temperature of the mixture is reduced to 5 ° C. in order to solidify the coacervate. Then 5 ecm of glacial acetic acid are added to harden and the mixture is left to stand at 5 ° C. for 4 hours. The particles are then spun down, washed and spray dried at 8O ⁰ C.

Example 2

A water-in-oil emulsion is thereby prepared by at 8O ⁰ cyanine green Alizarin-F and 0.2 g of magnesium aluminum silicate contains C 33 cc of water containing 0.5 g emulsified in 33 cc of mineral oil Contained 0.33 g of sorbitol monooleate. A sol of 8.0 g

wherein the average molecular weight of a polymer unit 234.5 is, in 400 cc of water a likewise heated to 80 ° C 20% sodium phosphate solution is added heated to 8O ⁰ C, mixed with the emulsion and slow ecm to 125th The sodium phosphate solution is vigorously stirred during the addition. Then 15 ml of 10% hydrochloric acid solution are added to harden the coacervate. The hardened coacervate is then filtered off, washed and dried.

The coacervate prepared above is impermeable to acid and neutral solutions, which through the small amount of dye that is displayed when stored in test liquids for a long period of time is delivered.

Example 3

A glycerin-in-oil emulsion is prepared by emulsifying at 8O ⁰ C in 100 cc of glycerol, peanut oil, containing 1 g of hydrogenated castor oil. A sol of the used in Example 1, styrene-maleic acid copolymers obtained by heating 100 g of the polymer in 5000 cc of water to 8O ⁰ C. The sol is mixed with the emulsion and the resulting mixture ecm slowly to 1200 of a 20% igen sodium sulfate solution, which is also heated to 80 ° C, given. The sodium sulfate solution is vigorously stirred throughout the addition. To the coacervate obtained, 200 ecm of 38% acetic acid are added to harden the coacervate shell. The hardened coacervate is then filtered off and dried.

Claims (3)

Patent claims: 1. Method of making very small particles having inside an emulsified in oil contain hydrophilic liquid by coacervation, characterized in that a stabilizer is added to the emulsion and this in the presence of an aqueous dispersion of a styrene-maleic acid or styrene-maleic acid amide copolymer or a carbohydrate acetate phthalate is coacervated in a known manner will. 2. The method according to claim 1, characterized in that hydrogenated as a stabilizer Castor oil is used. 3. The method according to claim 1 and 2, characterized in that an emulsion is used is that in the hydrophilic liquid phase a known thickener, z. B. methyl cellulose, contains. References considered: U.S. Patents Nos. 2,800,457, 2,800,458; Jürgensens - Straumanis, "Kurzes Lehrbuch der Kolloidchemie", 1949, p. 238 ff. 409 760/269 12.64 © Bundesdruckerei Berlin