Abstract: Ultrasound contrast agents comprising microbubbles of biocompatible gas, e.g. a sulphur halide or a perfluorocarbon, stabilized by opsonisable amphiphilic material, e.g. a membrane-forming lipid such as a phospholipid, especially a negatively charged phospholipid such as a phosphatidylserine, may exhibit prolonged contrast-generating residence time in the liver following intravenous administration.

Abstract: The present invention relates to a method of imaging of an animate human or non-human animal body, which method comprises: administering parenterally to said body a particulate material comprising a matrix or membrane material and at least one contrast generating species, which matrix or membrane material is responsive to a pre-selected physiological parameter whereby to alter the contrast efficacy of said species in response to a change in the value of said parameter; generating image data of at least part of said body in which said species is present; and generating therefrom a signal indicative of the value or variation of said parameter in said part of said body. The invention also relates to contrast media for imaging a physiological parameter.

Abstract: Microbubble dispersions stabilised by phospholipids predominantly comprising molecules which individually have an overall net charge exhibit advantageous stability, rendering them useful as efficacious contrast agents. An improved process for preparing microbubble-containing contrast agents is also disclosed, this comprising lyophilising an aqueous dispersion of gas microbubbles stabilised by one or more membrane-forming lipids to yield a dried product which may be reconstituted in an injectable carrier liquid to generate a microbubble-containing contrast agent.

Abstract: The present invention relates to a method of imaging of an animate human or non-human animal body, which method comprises: administering parenterally to said body a particulate material comprising a matrix or membrane material and at least one contrast generating species, which matrix or membrane material is responsive to a pre-selected physiological parameter whereby to alter the contrast efficacy of said species in response to a change in the value of said parameter; generating image data of at least part of said body in which said species is present; and generating therefrom a signal indicative of the value or variation of said parameter in said part of said body. The invention also relates to contrast media for imaging a physioloogical parameter.

Abstract: The invention relates to pH-sensitive liposome systems, compositions comprising said pH sensitive liposome systems and the use of such compositions as contrast agents and medicaments.

Abstract: Ultrasonic visualisation of a subject, particularly of perfusion in the myocardium and other tissues, is performed using novel gas-containing contrast agent preparations which provide controllable and temporary growth of the gas phase in vitro following administration and can therefore act as deposited perfusion tracers. The preparations comprise an injectable aqueous gas dispersion and an administrable substance or substances capable of destabilising the dispersed gas to provide temporary growth thereof. In cardiac perfusion imaging the preparations may advantageously be coadministered with vasodilator drugs such as adenosine in order to enhance the differences between return signal intensity from normal and hypoperfused myocardial tissue respectively.

Abstract: Ultrasonic visualisation of a subject, particularly of perfusion in the myocardium and other tissues, is performed using novel gas-containing contrast agent preparations which promote controllable and temporary growth of the gas phase in vivo following administration and can therefore act as deposited perfusion tracers. The preparations comprise an injectable aqueous medium comprising dispersed gas and an injectable oil-in-water emulsion in which the oil phase comprises a diffusible component capable of diffusion in vivo into the dispersed gas to promote temporary growth thereof, such that material present at the surfaces of the dispersed gas phase and material present at the surfaces of the dispersed oil phase have affinity for each other, e.g. as a result of having opposite charges.

Abstract: Ultrasound contrast agents of the phase shift colloid type, comprising emulsions of volatile oils in water, are provided with gas-containing nucleation sites associated with (e.g. within) droplets of the dispersed oil phase, in order to enhance efficacy and control of the liquid-to-gas phase transition.

Abstract: Microbubble dispersions stabilised by phospholipids predominantly comprising molecules which individually have an overall net charge exhibit advantageous stability, rendering them useful as efficacious contrast agents. An improved process for preparing microbubble-containing contrast agents is also disclosed, this comprising lyophilising an aqueous dispersion of gas microbubbles stabilised by one or more membrane-forming lipids to yield a dried product which may be reconstituted in an injectable carrier liquid to generate a microbubble-containing contrast agent.

Abstract: Ultrasound contrast agents comprising microbubbles of biocompatible gas, e.g. a sulphur halide or a perfluorocarbon, stabilized by opsonisable amphiphilic material, e.g. a membrane-forming lipid such as a phospholipid, especially a negatively charged phospholipid such as a phosphatidylserine, may exhibit prolonged contrast-generating residence time in the liver following intravenous administration.

Abstract: The stability of phospholipid compositions is enhanced by the inclusion of a buffer system comprising ammonia or a water soluble amine having a pH at 15° C. of less than or equal to 9.5.

Abstract: Microparticulate contrast agents comprising gas or a gas precursor encapsulated by a non-polymeric and non-polymerisable wall-forming material are readily characterisable materials exhibiting surprising structural integrity and stability.

Abstract: Microbubble dispersions stabilized by phospholipids predominantly comprising molecules which individually have an overall net charge exhibit advantageous stability, rendering them useful as efficacious contrast agents. An improved process for preparing microbubble-containing contrast agents is also disclosed, this comprising lyophilising an aqueous dispersion of gas microbubbles stabilized by one or more membrane-forming lipids to yield a dried product which may be reconstituted in an injectable carrier liquid to generate a microbubble-containing contrast agent.

Abstract: Microbubble dispersions stabilised by phospholipids predominantly comprising molecules which individually have an overall net charge exhibit advantageous stability, rendering them useful as efficacious contrast agents. An improved process for preparing microbubble-containing contrast agents is also disclosed, this comprising lyophilising an aqueous dispersion of gas microbubbles stabilised by one or more membrane-forming lipids to yield a dried product which may be reconstituted in an injectable carrier liquid to generate a microbubble-containing contrast agent.

Abstract: Microbubble dispersions stabilised by phospholipids predominantly comprising molecules which individually have an overall net charge exhibit advantageous stability, rendering them useful both as efficacious contrast agents per se and as intermediates in the preparation of contrast agents wherein the phospholipids are crosslinked or polymerised. An improved process for preparing microbubble-containing contrast agents is also disclosed, this comprising lyophilising an aqueous dispersion of gas microbubbles stabilised by one or more membrane-forming lipids to yield a dried product which may be reconstituted in an injectable carrier liquid to generate a microbubble-containing contrast agent.

Abstract: A contrast agent for use in diagnostic studies, particularly ultrasound imaging, comprising a dispersion in an injectable aqueous medium of a biocompatible azeotropic mixture which is in gaseous form at 37° C., at least one component of said mixture being a halocarbon having a molecular weight of at least 100.

Abstract: Ultrasound contrast agents having microbubbles of gas or a gas precursor encapsulated by non-proteinaceous crosslinked or polymerised amphiphilic moieties, e.g. in the form of micelles, exhibit good stability in vivo upon administration and may if desired incorporate biodegradable linkages so as to possess particular desired levels of biodegradability.

Abstract: Novel extended polymer surfactants comprising a methoxy-terminated polyethylene glycol hydrophilic block acylated with a hydrophobic moiety comprising a chain of at least two fatty acid units, e.g. an acyloxyacyl group such as 16-hexadecanoyloxyhexadecanoyl, are useful in the preparation of polymer-based gas-containing contrast agents by emulsion techniques.

Abstract: The present invention relates to polymer-based gas-containing contrast agents in which microbubbles of gas are encapsulated by non-polymerizable wall-forming block or graft copolymer surfactants. The polymer surfactants are preferably biodegradable and include block and graft copolymers containing linkages of formula (I):--(O).sub.m --CO--O--C(R.sup.1 R.sup.2)--O--CO--(O).sub.n --(I)where R.sup.1 and R.sup.2 each represent a hydrogen atom or a carbon-attached monovalent organic group, or R.sup.1 and R.sup.2 together form a carbon-attached divalent organic group and m and n are each zero or 1.