Current issues relating to anti-solvent micronisation techniques and their extension to industrial scales

Realisation of the potential of dense gas anti-solvent precipitation for commercially viable processing of fine chemicals is hindered by our inability to fully exploit the advantages afforded to dense gases. The feasibility of producing dry uniformly sized micronised material using dense gas technology has been well established on a bench scale. However, translating these advantages to an industrial scale remains a challenge for engineers. In this paper, issues specific to the process scale up of dense gas anti-solvent precipitation are discussed. Anti-solvent precipitation is essentially a mixing process and any predictable increase in production rate is impossible without a thorough understanding of the dominant controlling factors. In this paper the dominant process variables, issues such as safety, cleaning, residual solvent concerns, precipitate sizing and product handling are addressed.