In vitro studies on stability of L-p-boronophenylalanine-fructose complex (BPA-F)

Boron neutron capture therapy (bnct) is an experimental drug-targeted treatment combining tumour-seeking boronated drug(s) and subsequent 10b activation by neutrons. synthetic amino acid,l-p-boronophenylalanine (bpa),administered as a fructose complex (bpa-f) is used in bnct trials. we tested the in vitro biological and structural stability of the bpa-f as a function of time (11 days). the bpa-f samples were analyzed using biological bacterial endotoxin and sterility tests. visual tests were clarity,degree of opalescence and coloration according to european pharmacopoeia. the structural stability of the bpa-f was monitored via 1h nmr signal intensity of the aromatic protons of the bpa-f samples. a slight change of bpa-f samples in coloration was observed during storage. bpa-fructose complex remained sterile and bacterial endotoxin tests were negative. in the end of study period,relative intensity of the 1h nmr signals of the bpa-f sample was ≥90% of the initial relative intensity. the biological properties of the bpa-fructose complex and chemical structure of the complex remained the same during the test period. visually the solutions stayed clear,but there was a slight change in colour. the tests indicate that the prepared batch of bpa-f complex can be used for the patient infusion at least for a week.