Water decomposition conventional processes

Steckel et al. (105) used the ASES process to micronize several steroids and particles with the required size were obtained. No chemical decomposition was observed. The wettability of the active products was improved upon addition of a physiological surfactant to the initial solution. This is advantageous for suspensions of the drug particles in water, hydrophilic solvents, or propellants. Some modifications were brought to the conventional process. First, once the organic solution spraying has been done, the antisolvent injection is stopped and a sedimentation phase is allowed to take place this phase is claimed to increase the yield. Second, the removal of the residual... 

This process, frequently called lyophilisation, is necessary when water is to be removed from solutions containing heat-labile materials so that conventional distillation, even under reduced pressure, would cause extensive losses by decomposition. Examples are to be found in the removal of water from aqueous solutions of enzymes, polysaccharides, peptides, etc. In principle the aqueous solution is frozen in a suitable solid carbon dioxide freezing mixture (see Section 2.12), and the ice is sublimed off to leave a dry residue.42... 

Secondly, the mixture produced is thermoformed in a hot-plates press at 80 °C for 5 min using a pressure of 1 ton with the aim of obtaining circular samples. The thermoformed sample of activated NR was then introduced into a circular mould. The mould was also placed in the hot-plates press where the vulcanization and foaming process were performed simultaneously. The reason for choosing a hot-plates press instead of a conventional oven was that the heat transfer is faster in a press than in an oven, which consequently allows a reduction in the production time. Nevertheless, no pressure was applied to the material. The plates of the press were only in contact with the upper and lower surfaces of the mould. Temperature and time were set up respectively to 160 °C and 30 min. During this time, NR was crossUnked and expanded due to the decomposition of azodicarbonamide in gases, mainly N2 and CO, allowing NR to fill the mould completely. Finally, the mould was water cooled and the foam was removed from it. 

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