Supercritical fluids sterilization

Supercritical fluids can be used to extract substances from natural products, as solvents or as anti-solvents to micronize drugs and biodegradable polymers, encapsulate drugs in polymeric matrices, resolve racemic mixtures of pharmacologically active compounds, fractionate mixtures of polymer and proteins, and sterilize bacterial organisms. 

In the last few years, an increasing trend towards new high pressure applications could be observed in R D, all of them in a certain way taking advantage of the remarkable properties of fluids at near critical or supercritical conditions. At the same time the demand for high pressure pilot units for these new" applications like Supercritical Fluid Reactions, HP-Micronization, HP-Spray Drying and HP-Sterilization increased. In order to also supply customized... 

Supercritical fluid CO2 was also investigated for sterilization of dry-powder animal blood plasma containing both living micro-organisms and bacterial endospores (56). The initial water content of the plasma powder was 6.8%. No apparent inactivation of the microbes was achieved at 35°C and 20 MPa in a 2-h treatment. However, with the addition of water (initial water content of 16.7%) and/or the use of cosolvents (ethanol or acetic acid), 2-5 log reductions in living cells could be achieved. The need for water to achieve sterilization of the powders is consistent with previous investigations of sterilization at low water content. 

Although very important research and development (R D) means are dedicated to applications of supercritical fluids (SCFs) in the pharmaceutical industry, a very limited number of commercial plants are now operating or under construction and few companies have acquired some know-how in process scale-up, especially in SCF formulation and particle design, in compliance with the constraints imposed in this industry [traceability and General Manufacturing Processes (GMP), sterility, etc]. 

Drying techniques have been explored for pharmaceutical biopolymer formulations drying with the aid of a supercritical fluid is especially attractive for reasons of mild process conditions, cost-effectiveness, possible sterilizing properties of supercritical carbon dioxide, capability of producing microparticulate protein powders, and feasibility of scaling up. 

In addition to supercritical fluid extraction and supercritical fluid chromatography, supercritical and near-critical fluids are of increasing interest for other applications. These include their use as processing fluids for dyeing of fibers, production of finely dispersed particles (RESS, PGSS, SAS, GAS, etc.), as promising solvents for syntheses and kinetic studies, for the destructive oxidation of wastes with supercritical water (SCWO), for the purification of filters, catalysts, contaminated soils, for drying and sterilization processes, and others [13,19,20]. 

Another way of applying the technology of supercritical fluid against pain supercritical CO2 is used for sterilizing steroids powdered drugs in relation to vegetative bacteria [71]. 

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