Aphios said that the invention entails methods of purifying protein-containing polymeric microspheres/nanospheres from unused polymer and an apparatus therefore.
Aphios claimed that the uniformity and integrity as well as processing time and the cost associated with preparation of biodegradable polymer microspheres containing therapeutic products are greatly reduced by using supercritical fluids, critical or near-critical fluids with or without polar cosolvents (SuperFluids).
Aphios stated that in the process, a biodegradable polymer such as PLGA is dissolved in SuperFluids and mixed with the target therapeutic in solution or as a slurry of nanoparticles at operating pressures.
Further, the mixture is decompressed through a nozzle into an aqueous solution, liquid nitrogen or an empty vessel (spray dryer). Polymer nanospheres are formed encapsulating the protein therapeutics.
Alternatively, the polymer-enriched SuperFluids stream can be decompressed into an aqueous solution containing the target therapeutic agent. In addition to reduction or elimination of organic solvent usage, use of SuperFluids for making nanospheres imparts advantages of no residual toxic organic solvent and pathogen safety.
Aphios said that SuperFluids polymer nanospheres (PNS) process can be utilised to encapsulate therapeutic proteins and other molecules without utilising organic solvents as is traditionally done.
Further by changing nozzle design and process parameters, the process can also be utilised to manufacture polymer microspheres.
SuperFluids PNS is a single-step process that is readily scalable. SuperFluids PNS can be utilised for improving the oral bioavailability of peptides and proteins, depot delivery of peptides and proteins for sustained, controlled release and the subcutaneous and/or oral delivery of sensitive vaccine antigens.