Abstract: A temperature- and/or polar fluid-sensitive device which comprises a mechanically strained semi-crystalline hydrophilic polymer.

Abstract: The invention provides a method of plant growing in which method one or more plants are grown in a growing medium comprising hydrogel particles charged with aqueous nutrient solution for the plant and plants, the growing medium being housed in a substantially water-impermeable container and the plants extending out of the container, and, when the water content within the hydrogel particles falls below a predetermined level, introducing further nutrient solution into the container.

Abstract: Control valves are known which incorporate moisture sensitive material to control the flow of fluid through the valve. Described herein is control valve (1) which incorporates a moisture sensitive material (4) in contact with and responsive to increasing environment moisture levels. The material (4) acts on a moisture impermeable flexible film (5) to shut off a fluid flow connection between an inlet (6) and an outlet (7), the material (4) being sealed from the inlet (6) and outlet (7) by the film (5). Also the invention provides a method of plant growing in which method one or more plants are grown in a growing medium comprising hydrogel particles charge with aqueous nutrient solution for the plant or plants, the growing medium being housed in a substantially water-impermeable container and the plants extending out of container, and, when the water content within the hydrogel particles falls below a predetermined level, introducing further nutrient solution into the container.

Abstract: Linear chain extended poly(alkylene oxides) having at least a portion of hydrophobic hydrogen bonding chain extending groups are soluble in at least one solvent and swellable in water. The chain extending groups preferably comprise a urea linkage and can be produced by the reaction of an amine with an isocyanate. The extended polymers and their solutions may readily be fabricated into controlled release compositions, e.g. for the release of pharmaceuticals.

Abstract: An envelope having flexible water-permeable or porous walls contains a quantity of particulate water-insoluble hydrogel. The quantity of hydrogel in the envelope is such that, when the hydrogel is fully swollen at 20.degree. C., its volume is at least 66%, preferably at least 100%, of the maximum non-stretched internal volume of the envelope. Thus, the envelope according to the invention is limp and floppy under dry conditions but in a wet environment the hydrogel absorbs water and swells accordingly causing the envelope to swell and take on a more rigid configuration. The envelope is particularly useful for the administration of sustained release pharmaceutically or veterinarily active ingredients. Thus the limp dry envelope may for example be rolled up for introduction through the throat but will swell up and therefore be retained in the stomach for sustained release of the active ingredient therein.

Abstract: A non-crosslinked derivative formable by reacting at least one substituted or unsubstituted, saturated or unsaturated, mono-, di- or poly-carboxy, hydroxy or mercapto hydrocarbon with at least one cyclic unsaturated (thio)ether.

Abstract: A controlled release composition comprising an active substance other than a prostaglandin and a polymeric carrier therefor comprising residues having a ratio of number average molecular weight to functionality greater than 1000 which comprises polyethylene oxide and are cross-linked through urethane groups.

Abstract: A process for the preparation of a controlled release composition comprising a prostaglandin and a polymeric carrier therefor comprising residues having a ratio of number average molecular weight to functionality greater than 1,000 which comprise polyethylene oxide and are cross-linked through urethane groups.

Abstract: A device for the sustained release of active substance comprises a wall defining a cavity for the reception of active substance, the wall being of impermeable material and having one or more ports therethrough. Sections of hydrogel material are within the cavity, the hydrogel, in use, being swollen to cover the ports in the cavity wall. Active ingredient is released from the container only through the hydrogel covering the ports. In this way sustained and controlled release of the active substance from the device is obtained.

Abstract: A controlled release composition comprising a prostaglandin and a polymeric carrier therefor comprising residues having a ratio of number average molecular weight to functionality greater than 1,000 which comprise polyethylene oxide and are cross-linked through urethane groups.

Abstract: A controlled release composition comprising an active substance other than a prostaglandin and a polymeric carrier therefor comprising residues having a ratio of number average molecular weight to functionality greater than 1000 which comprises polyethylene oxide and are cross-linked through urethane groups.

Abstract: A composition which comprises at least one solid or liquid particle comprising at least one active substance, the or a plurality of such particles being encapsulated by the in situ cationic (co)polymerization there on of at least on cationically polymerizable monomer or prepolymer.

Abstract: A controlled release device which comprises:(i) a hydrogel; and incorporated therewith(ii) an active substance,at least part of at least one surface of the device comprising(iii) a layer which is impermeable to aqueous media.

Abstract: A hydrogel which comprises polymerized moieties derivable from (i) at least one polymerizable cyclic (thio)ether and (ii) at least one hydrophilic homo- or copolymer.

Abstract: A process for the preparation of a particulate gel, which process comprises (i) contacting the gel with a swelling agent and (ii) subjecting the swollen gel to shear stress such that the swollen gel is comminuted to particles.

Abstract: A hydrogel which comprises polymerized moieties derivable from (i) at least one polymerizable cyclic (thio)ether and (ii) at least one hydrophilic homo- or copolymer.

Abstract: A hydrogel which comprises polymerized moieties derivable from (i) at least one polymerizable cyclic (thio)ether and (ii) at least one hydrophilic homo- or copolymer.

Abstract: A polymeric composition which is capable of being shaped and which preferably is in the form of a sheet, the composition being formed by partially reacting a mixture of(a) the precursors of a polyurethane comprising at least one polyfunctional compound capable of reacting with isocyanate groups and at least one polyisocyanate, and,(b) the precursors of a cured polyester resin comprising at least one ethylenically unsaturated polyester and at least one ethylenically unsaturated monomer copolymerizable therewith,and the composition containing at least one alpha, alpha diketone as a photosensitive catalyst.

Abstract: A pharmaceutical composition of prolonged effect in the treating of Tropical Diseases comprises an organic nitrogen base drug which is effective against diseases such as malaria, dispersed in a polymeric matrix of a copolymer of the compound ##STR1## and a comonomer which contains more than one functional group selected from hydroxy and carboxy groups.

Abstract: A medicinal composition comprising a steroid compound entrapped within a polymeric matrix composed of a copolymer of a compound containing two or more groups selected from the group consisting of OH and --COOH groups and a bisdihydropyron of the general ##STR1## wherein R is an organic bridging group which is unreactive to the OH or --COOH groups.The most preferred bridging group is one which contains one or more ester groups. Any bridge which is non-reactive to the comonomer containing the --OH or --COOH groups can be used. Another preferred compound is the product of the added condensation of 2-formyl-3, 4-dihydro-2H-pyron.