Daiichi Pharmaceutical Co., Ltd.

Nof Corporation

Nycomed Imaging As

Nomura Micro Science Co., Ltd.

Kiyoto Yachi

Hiroshi Kikuchi

Sadao Hirota

Jo Klaveness

Norio Suzuki

Arne Berg

Pal Rongved

Hitoshi Yamauchi

Thorfinn Ege

Hiromi Morita

Trond Vegard Jacobsen

Takazo Hirose

Akinori Hoshio

Hiroshi Honda

A liposomal aqueous dispersion and method of making the liposomal aqueous dispersion is useful for encapsulation of drugs. The liposomal aqueous dispersion comprises: an aqueous suspension medium; multilamellar liposomes comprising an anionic phospholipid and cholesterol as essential components; neutral phospholipid in a mole ratio of 0 to 40% based on the total amount of said multilamellar liposomes; and a cation moiety-containing water-soluble drug, wherein the electrolyte concentration of said aqueous suspension medium is not more than 40 mM.

Liposomal products

The invention provides a diagnostic composition for administration to human or animal subjects, the composition containing multilamellar liposomes, optionally together with unilamellar liposomes, the liposomes containing at least one imaging agent and being suspended in an aqueous medium containing said imaging agent, wherein the liposomes comprise a neutral phospholipid and a charged phospholipid, the average particle diameter of the liposomes is 50-3000 nm and the concentration of imaging agent in any aqueous phase filling the interior of the liposomes is substantially the same as that in the aqueous medium in which the liposomes are suspended. The contrast agents concerned are typically X-ray, MRI or ultrasound contrast agents.

Liposomes

A filter unit comprises a metallic supporting plate possessed of stepped through holes opening with a larger diameter in one main surface and with a smaller diameter in the other main surface (wherein the diameter ratio of larger-diameter openings to smaller-diameter openings is desired to be in the range of 1:0.01 to 1:0.5) or a pressureproof supporting plate having in one surface thereof inclined liquid flow grooves arranged in a radial pattern and concentric circular liquid flow grooves adapted to intersect the radially arranged liquid flow grooves and a membrane filter disposed on the surface of the supporting plate containing larger-diameter openings or liquid flow grooves. This filter unit is ideally used for finely dividing and uniformly sizing suspended lipid particles assuming a definite average particle size and a specific particle size distribution. The high-pressure sizing apparatus and the method for production of suspended lipid particles utilize the filter unit constructed as described above and rely essentially for their operation on effecting fine division of lipid particles in the suspension by supplying the suspension of lipid particles from the membrane filter side under pressure and causing the suspension to pass through the membrane filter. Thus, they constitute themselves effective measures for pharmacological products and cosmetic products which are in need of lipid particles assuming a definite average particle size and a specific particle size distribution.

Filter unit and high-pressure sizing apparatus

A method of producing liposomal products which comprises treating a positively or negatively charged, freeze- or spray-dried liposomal preparation with an aqueous solution of a drug charged oppositely to the charge of the liposomes.

Method of producing liposomal products from freeze or spray-dried

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Tokyo, Japan

Kiyoto Yachi