Solvent properties, desirable safety

Estimate key physical properties and review desirable solvent properties. Give careful consideration to safety, industrial hygiene, and environmental requirements. Use this preliminary information to trim the list of candidate solvents to a manageable size. (See Desirable Solvent Properties. )... 

Of these molecular variants, one is the desired product with the desired properties with respect to biological activity and efficacy. Some structurally related variants (referred to as product related ) exhibit similar properties to the desired product and are therefore not considered as impurities. However, there may also be structurally related variants with altered properties with respect to biological activity, efficacy and/ or safety, which must be considered as impurities. In addition to the molecular variants of the protein (or protein-like) product, additional process-related substances may be part of a biotechnological drug substance, e.g., cell culture media, host cell proteins, DNA residuals, solvents, bacteria and/or viruses. This suggests that the determination of purity of these products (which is referred to as purity estimation rather than purity determination ) is a complex analytical issue. A purity estimation consists of both the definition of the heterogeneity of the protein (or proteinlike) product, and the identification and quantitation of product- and process-re-... 

Inflammability. Low inflammability is of course desirable for reasons of safety, and the flash point is frequently used as a numerical indication of the property. If the solvent can be burned, it should have a high flash point and close concentration limits for explosive mixtures with air. 

The strategy for the selection of the CSP—eluent combination for enantioseparations using SMB technology has been described in numerous publications [11,47—50]. The basic requirements for the mobile phase include selectivity, safety, recycling ability, and cost. One property, which is less important in analytical-scale operations but of crucial importance in SMB, is the solubility of the sample in the mobile phase. The last requirement means that it is desirable for the CSP to be stable and exhibit sufficient (enantio)selectivity in the solvent, where the maximum amount of a sample can be dissolved. Together with the productivity of the process, this is required for running the system under equilibrium conditions. It is almost impossible to automate an SMB separation before it reaches steady-state conditions. 

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