| abstract |
This invention relates to benzoporphyrin containing vesicles which are suitable for pharmaceutical application. In particular, the present invention relates to a liposomal preparation of benzoporphyrin (BPD) incorporated into vesicles comprising a liposome forming lipid such as EPC or DMPC at a drug to lipid ratio of greater than 100 mu g/umole lipid which will allow adequate drug dosing with relatively low lipid concentration. In an additional aspect of the present invention, sized liposomes are described which are storage stable. Certain sized BPD-containing vesicles (no greater than about 120 nm in diameter) permit sterilization by terminal filtration. Further, a lyophilized preparation of the BPD-lipid mixture can be obtained from aqueous buffer under conditions which do not result in vesicle fusion/aggregation or BPD precipitation. Liposomes according to the present invention are able to accommodate surprisingly large amounts of BPD within the bilayer of the liposome, rather than in the encapsulated buffer. The advantages of this surprising aspect of the present invention includes the ease of manufacture and the cost savings associated with an efficient use of BPD are also presented. |