Methods of making liposomes containing hydro-monobenzoporphyrin photosensitizer
AssigneeQLT PhotoTherapeutics, Inc.
InventorRon Liu
Life of this patent
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Abstract
Liposomal compositions containing green porphyrins as photosensitizers are improved by enhancing the ratio of phospholipid to photosensitizer and by conducting the hydration an sizing of the liposomes in the composition at low temperature.
Claims24
A method for making a pharmaceutical composition containing liposomes, said liposomes comprising a therapeutically acceptable amount of a hydro-monobenzoporphyrin photosensitizer and a mixture of phospholipids comprising egg phosphatidyl glycerol ("EPG") and dimyristoyl phosphatidyl choline ("DMPC"), wherein said method comprises the steps of:
- a. combining the photosensitizer and the phospholipids in a molar ratio of 1:7.0 or more phospholipid in the presence of an organic solvent;
- b. removing said organic solvent to form a photosensitizer:phospholipid complex;
- c. hydrating said photosensitizer:phospholipid complex with an aqueous solution at a temperature below the glass transition temperature of the photosensitizer:phospholipid complex to form coarse liposomes containing said photosensitizer-phospholipid complex;
- and
- d. homogenizing or reducing the particle size of said coarse liposomes to a particle size range of below about 300 nm at a temperature below the glass transition temperature of the photosensitizer:phospholipid complex.
A pharmaceutical composition containing liposomes in the particle size range of about 150 to 300 nm, wherein said liposomes comprise:
- a. a therapeutically acceptable amount of a photosensitizer and
- b. a mixture of phospholipids comprising:
- (1) egg phosphatidyl glycerol ("EPG") and
- (2) dimyristoyl phosphatidyl choline ("DMPC"),
- wherein the molar ratio of said photosensitizer and said mixture of phospholipids is about 1:7.0 or more phospholipid.
Dependencies are inferred from the claim text.