Critical fluid liposomes

Preparations of liposomes via SCF processing are designated as critical fluid liposomes (CFLs). CFLs have successfully encapsulated hydrophobic drugs such as taxoids, camptothecins, doxorubicin, vincristine, and cisplatin. In addition, stable paclitaxel liposomes with a size of 150-250 nm were obtained. Aphios Co. s patent (US Patent 5,776,486) on Super-Fluids CFL describes a method that is useful for the nanoencapsulation of paclitaxel and campothecin in aqueous liposomal formulations called Taxosomes and Camposomes , respectively. 

In summary, the above studies and processes show the versatility in utilizing critical fluid media for modifying a target nutraceutical for functional food use. In the case of PPLs, the above studies illustrate how they could be prepared for rapid dissolution in food formulations or to encapsulate them for sustained delivery rates, or, alternatively, to use PPL-based liposomes and so on to encapsulate nutraceutical ingredients. Obvious extensions to other target nutraceuticals follow, and application of the technology outside of its traditional niche in the pharmaceutical industry seemed assured. 

A new approach in the 1990s was to use supercritical fluid technology to produce uniform particles to replace crystallization. Even though super critical fluids were discovered over 100 years ago, and the commercial plant was built over 20 years ago in the United States, it is only now that the technology is used for a number of pharmaceutical applications (2-5), so as to produce aspirin, caffeine, ibuprofen, acetaminophen, etc. One of the major areas on which the research and development of supercritical fluids is focused is particle design. There are different concepts such as rapid expansion of supercritical solution, gas antisolvent recrystallization, and supercritical antisolvent to generate particles, microspheres, microcapsules, liposomes, or other dispersed materials. 

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