Synthesis and evaluation of fully (5-amidoisophthalic acid)-functionalised polyacrylamides as selective inhibitors of the beta crystal polymorph of l-glutamic acid

Poly-N-5-acrylamidoisophthalic acid (4), poly-N-(5-(N′-(3,5-dicarboxyphenyl)carbamoyl)pentyl)acrylamide (10a) and poly-N-(11-(N′-(3,5-dicarboxyphenyl)carbamoyl)undecyl)acrylamide (10b) were prepared and assessed as polymorph-selective crystallization inhibitors of the stable β form of l-glutamic acid. Polymerization was carried out as the final step in the preparation of 10a and 10b to ensure the preparation of fully functionalized polymers. Polymers 4, 10a and 10b were effective as complete inhibitors of the stable β form of l-glutamic acid in quantities of 0.5% w/w or greater, whereas the corresponding ‘monomeric’ additives 2 and 11 required quantities of 3% or greater to completely inhibit the β form, demonstrating a cooperative binding effect by the polymeric additives. Within the series of polymers 4, 10a and 10b, polymer 10a, which features a short tethering chain, was the most effective.