A critical quality parameter in quantitative fused-core chromatography： The injection volume

As part of the method development,the injection volume as a critical quality attribute in fast fused-core chromatography was evaluated.Spilanthol,a pharmaceutically interesting Nalkylamide currently under investigation in our laboratory,was chosen as the model compound.Spilanthol was dissolved in both PBS and MeOH/H2O(70/30,v/v)and subsequently analyzed using a fused-core system hereby selecting fve chromatographic characteristics(retention time,area,height,theoretical plates and symmetry factor)as responses.We demonstrated that the injection volume signifcantly influenced both the qualitative and quantitative performance of fused-core chromatography,a phenomenon which is confounded with the nature of the used sample solvent.From 2 mL up to 100 mL injection volume with PBS as solvent,the symmetry factor decreased favorably by 20%.Moreover,the theoretical plates and the quantitative parameters(area and height)increased up to 30%.On the contrary,in this injection volume range,the theoretical plates for the methanol-based samples decreased by more than 60%,while the symmetry factor increased and the height decreased,both by 30%.The injection volume is thus a critical and often overlooked parameter in fused-core method description and validation.