Particles
AssigneeCiba Specialty Chemicals Water Treatments Ltd.
InventorsKishor Kumar Mistry, Janine Andrea Preston, Kenneth Charles Symes
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Abstract
A particulate composition comprising particles having a core comprising a hydrophobic polymer within a shell, characterised in that the shell comprises a semi-permeable membrane. Particulate composition can be used for making a stable dispersion of particles uniformly distributed throughout a first hydrophobic liquid, wherein the particles comprise a core within a shell and the core comprises a hydrophobic polymer into has been imbibed a second hydrophobic liquid, Compositions can be used to encapsulate active substances and may be used in sustained release mechanisms.
Claims40
A particulate composition comprising particles having a core within a shell, in which the core comprises a hydrophobic polymer, characterised in that the shell comprises a semi-permeable membrane.
A process for making particles having a core comprising hydrophobic polymer within a shell, by the steps,
- a) dispersing an aqueous emulsion of hydrophobic polymer into a water immiscible liquid containing an emulsifier to form a reverse phase emulsion comprising of an aqueous dispersed phase which contains the hydrophobic polymer,
- b) inducing interfacial polycondensation of at least one interfacial polycondensation reactant to form a polymeric shell around the hydrophobic polymer, to form a dispersion of the particles,
- c) optionally subjecting the dispersion of particles to dehydration to remove any residual water from the particles, characterised in that the shell comprises a semi-permeable membrane,
A stable dispersion of particles uniformly distributed throughout a first hydrophobic liquid, wherein the particles comprise a core within a shell and the core comprises a hydrophobic polymer into has been imbibed a second hydrophobic liquid, characterised in that the shell comprises a semi-permeable membrane.
A method of making a stable dispersion of particles that are uniformly distributed throughout a first hydrophobic liquid, comprising the steps of,
- (a) forming a particulate composition comprising particles which have a core that comprises hydrophobic polymer within a shell;
- (b) dispersing the particles into a second hydrophobic liquid, in which the hydrophobic polymer is soluble or swellable and which has approximately the same density as the first hydrophobic liquid;
- (c) allowing sufficient time for the second hydrophobic liquid to be imbibed by the hydrophobic polymer in the core;
- (d) transferring the particles comprising the second hydrophobic liquid formed in step (c) into the first hydrophobic liquid;
- characterised in that the shell comprises a semi-permeable membrane.
A method of controlling the release of an active substance comprising by placing into a substrate or environment into which the active substance is to be released a particulate composition comprising particles which have a core comprising a hydrophobic polymer within a shell, said hydrophobic core material comprising the active substance, characterised in that the shell comprises a semi-permeable membrane.
Dependencies are inferred from the claim text.