| 摘要 |
Capsular units, each consisting of a cluster of individual capsules surrounded by an outer capsular wall and each capsule consisting of a substantially water-insoluble core surrounded by its own capsular wall, are prepared by dispersing discrete entities of the core material in an aqueous sol of a plurality of film-forming polymers having fractions of different molecular weights which are capable of undergoing coacervation under two sets of conditions, adjusting the condition of the sol-dispersion to one of the said sets of conditions to cause a part of the polymer materials to deposit as liquid walls around each of the core entities whilst the sol-dispersion is continuously agitated until clusters of the liquid walled entities form, thereafter changing the conditions to the second set of conditions to cause the remaining polymer material to deposit by coacervation around individual clusters and thereafter solidifying and optionally hardening the liquid wall materials around both the individual capsules and clusters thereof. Specified film-forming materials are: gelatine, gum arabic, chondrus, zein, soya bean protein, polyethyleneimine, polyvinyl methyl ether-maleic anhydride and polyethylene-maleic anhydride copolymers. Coacervation may be induced by the successive alteration of the pH of the aqueous sol to values within two suitable pH ranges or by the similar alteration of solubility conditions. The core material may be a vegetable, animal, mineral or synthetic oil with or without additional dissolved or dispersed material or substantially water-insoluble solids. By mixing dispersions in which different core materials have been formed into individual capsules and subsequently causing the second coacervation to occur, products containing a plurality of differing individual capsules within a single outer mantle may be formed. A wide variety of materials which may be encapsulated are mentioned in addition to the above-mentioned oils, e.g. pharmaceuticals such as salicylamide, tetracycline hydrochloride and phosphate, phenaglycodol, cholorotrianisine, cholesterol, meprobamate, erythromycin propionate, benzathine penicillin G, Vitamins A-palmitate, B2 and K; flavours, aromatics and perfumes, e.g. cocoa-butter, coffee oil, musk, citronella, spearmint and palm oils; solids, e.g. magnetic iron oxide, calcium carbonate, zinc sulphide, carbon black, solid catalysts and polymer materials, bentonite and titanium dioxide. Specification 751,600 is referred to. |
