amlodipine besylate adsorption on filter

[formulator694]

adsorption of amlodipine besylate on filter after dissolution ask if any another method to exclude filtration after dissolution with put onto consideration centrifuge perform the same problem on dissolution results can i take sample as it is for injection on HPLC ???

[tom jupille]

Several comments here:
1. Have you tried different filter media to find something less adsorptive?
2. Centrifugation should work. However if you find evidence of adsorption on the pellet (i.e. incomplete recovery from a spiked matrix blank), then you really have to revisit your formulation, because that suggests that you will get poor availability in vivo
3. Direct injection into the HPLC may be possible if the volume injected is small enough, but I would *definitely* use an in-line filter and/or a guard cartridge -- and be prepared to change them frequently.

[formulator694]

centrifuge perform the same problem can i take sample as it is from dissolution vessel to inject it to HPLC direct ???