Liposome formation method polymerization

The procedure chosen for the preparation of lipid complexes of AmB was nanoprecipitation. This procedure has been developed in our laboratory for a number of years and can be applied to the formulation of a number of different colloidal systems liposomes, microemulsions, polymeric nanoparticles (nanospheres and nanocapsules), complexes, and pure drug particles (14-16). Briefly, the substances of interest are dissolved in a solvent A and this solution is poured into a nonsolvent B of the substance that is miscible with the solvent A. As the solvent diffuses, the dissolved material is stranded as small particles, typically 100 to 400 nm in diameter. The solvent is usually an alcohol, acetone, or tetrahydrofuran and the nonsolvent A is usually water or aqueous buffer, with or without a hydrophilic surfactant to improve colloid stability after formation. Solvent A can be removed by evaporation under vacuum, which can also be used to concentrate the suspension. The concentration of the substance of interest in the organic solvent and the proportions of the two solvents are the main parameters influencing the final size of the particles. For liposomes, this method is similar to the ethanol injection technique proposed by Batzii and Korn in 1973 (17), which is however limited to 40 mM of lipids in ethanol and 10% of ethanol in final aqueous suspension. 

Another possible form of administration that is under study is through the use of nanoparticles with diameters in the range of 200-400 nm, obtained through the formation of nanocrystals or by creating nanoscale structures that capture the biomolecules. Depending on the materials employed and the preparation method, distinct particles can be used nanoparticles, liposomes, polymeric micelles, ceramic nanoparticles, and dendrimers. 

Polymerized liposomes are being actively investigated for their use in controlled release applications such as drug delivery and biosensors.(24) At present, in order to obtain liposomes which have the release characteristics required for a specific need, the amphiphiles used to construct the liposome as well as the precise mixture of amphiphiles required must be designed and synthesized from start each time. This is a time consuming and expensive process. One of our main objectives in this research is to design a series of liposomes constructed from diacetylenic and short chain spacer lipids with predictable leak rates which could be utilized in controlled release applications. In order to accomplish this goal, it was necessary to characterize both the effect of spacer lipid on microstructure formation properties and to determine the methods that could be used to... 

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