Patent GB-762700-A (GB)
Title: Improvements in or relating to encapsulation
Inventor: MERTON ROBERT RALPH
IPC: A61J3/07
Filed: 1954-05-17
Abstract: 762,700. Processes of encapsulation. ALGINATE INDUSTRIES, Ltd: May 17, 1955 [May 17, 1954; July 20, 1954], Nos. 14465/54 and 21190/54. Class 81(1) A process of encapsulation comprises the steps of forming around a discrete portion of the material to be encapsuled a film of liquid encapsulating medium e.g. a solution of an alginate, and causing the embryo capsule so produced to pass through an intermediate layer of liquid, which is immiscible and non-reactive with the encapsulating medium, into a gelling liquid which acts on the film of liquid encapsulating medium to gell it. The intermediate layer of liquid may be lighter than the gelling liquid the embryo capsules being allowed to fall through the intermediate layer into the gelling liquid, or heavier, in which case the capsules are produced below the surface of the intermediate liquid allowed to float upwardly therethrough into the gelling liquid, which floats above the intermediate liquid. As shown, encapsulating liquid, i.e. a solution of sodium alginate, is fed to the annular space between the tubes 13, 14 through a feed pipe 19 of a capsule-forming nozzle 12 situated above a tank 11 containing the intermediate liquid 27 i.e. a mixture of petroleum ether and carbon tetrachloride, floating on the gelling liquid 26 i.e. a solution of calcium chloride and at the bottom of these tubes it is directed inwardly through the annular gap 16. The material to be encapsulated is fed into a third co-axial inner tube 20 which stops short of the lower edges of the tubes 13, 14 and is held in place by a cap 21 threaded over the upper ends of the tube 14, and is allowed to fall a drop at a time inside the tube 14 and from the end of the tube 20 on to a film 23 of the encapsulating liquid emerging from the space between the ends of tubes 13, 14 which film becomes gradually distended and when sufficient of the liquid to be encapsulated has dropped to form a globule 29 the film necks in at 23, seals and the capsule breaks off and falls into the tank 11 and through the intermediate layer 27 to the gelling liquid whilst the film reforms ready for the next globule. In a modification wherein the capsules e.g. cod liver oil capsules are lighter than the gelling medium an apparatus shown in Figs. 7, 8 is employed which comprises a tank 33 containing a layer of heavy inert liquid 34 which may consist of a mixture of carbon tetrachloride and petroleum ether in such proportions that the liquid is heavier than the gelling liquid 135 which forms a supernatant layer above it, and having a nozzle 35 provided with a lateral inlet pipe 36 to which sodium alginate solution is admitted from a pump 37 in periodic doses and in the centre of which is an upwardly directed nozzle 137 for the supply of cod liver oil from an inlet pipe 38 supplied by a pump 39, the sodium alginate solution being pumped upwards into the liquid 34 through the annular space between the pipes 35, 137 and after an upward bulge of such material has begun to form at the upper lip 40, cod liver oil to be encapsulated is injected into it by the inner nozzle 137. Each delivery stroke of the pumps forms and detaches a capsule complete with its covering skin in the liquid 34, through which it rises into the gelling liquid 135 and after rising to the surface thereof may be removed