Optimization and validation of RP-HPLC method for evaluation of pyrrole -containing hydrazones in isolated rat synaptosomes

In the current study, RP-HPLC method for evaluation of 2 pyrrol-based hydrazones in isolated rat synaptosomes was optimized and validated according to ICH guidelines. The synaptosomes were obtained by multiple centrifugations with Percoll reagent and the selected 2 N-pyrollyl hydrazide-hydrazones were incubated for 2 hours at 37 °C. Subsequently, the purified fraction through protein precipitation was analyzed by an UltiMateDionex 3000 DAD system with Purospher STAR C18 (4.6 x 12.5 cm, 5 µm) column. The mobile phase, consisting of acetonitrile: phosphate buffer pH 3.5: methanol in ratio 42/36/22 (v/v/v), was eluted isocratically with 0.8 mL/min flow rate. Afterwards, the novel and rapid method was applied effectively for identification of biotransformation in isolated rat brain synaptosomes. The analysis results indicated an absence of new peaks and persistent sample concentration which determined the stability of the analyzed ethyl 5-(4-bromophenyl)-1-(2-(2-(2-hydroxybenzylidene) hydrazinyl)-2- oxoethyl)-2-methyl- 1H-pyrrole-3-carboxylate ( 11b ) and ethyl 5-(4-bromophenyl)-1-(3-(2-(2-hydroxybenzylidene)hydrazinyl)-3-oxopropyl)-2-methyl-1H-pyrrole-3-carboxylate ( 12b ) and pointed these structures as promising.