Polymeric bridging agents

Removal of particles from liquids, as in the formation of pellet-like floes from clay in water by the use of polymeric bridging agents. 

Fractionation of particle of clays in water using polymeric bridging agents selective oil agglomeration... 

A typical application for these filter aids is the filtration of solids from antibiotic fermentation broths, where the average particle size is 1-2 microns and solids concentration are 5-10%. Being hard to filter and often slimy, fermentation broths can also be charged with polymeric bridging agents to agglomerate the solids, thereby reducing the quantities of filter aid required. 

Fig. 4.1. Some general methods of introducing covalent cross-links into a polymeric system, (a) Bridging agents (b) cross-linking initiators (c) catalytic cross-linking agents (d) active site generators.

More recently, and based on the same concept, O Neill and coworkers have prepared a series of related systems (80a-c) based on Vennerstrom s adamantyl trioxolane unit". These derivatives, which are synthesized in only three steps from adamantan-2-one, have activity in the low nanomolar region (<3 nM versus K1 P. falciparum). Like the prototypes synthesized by the groups of Meunier" and Singh", these compounds can be formulated as water-soluble salts and it is anticipated that these agents may have the capacity to hit the parasite by two distinctive mechanisms. Indeed, any chemical or metabolic degradation of the endoperoxide bridge in these compounds will result in metabolites that may still have the ability to function as inhibitors of heme polymerization provided that they do not become covalently attached to proteins in the bioactivation process. 

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