Polymeric surfactant-encapsulated microbubbles and their use in
申请人:Nycomed Imaging AS
公开号:US05919434A1
公开(公告)日:1999-07-06
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.
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. 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.