Gel Viscosity:

[thambo1]

Hi:
We are making a gel finished product. Syringe is used for administration. It has povidone and other exciepients. The viscosity of this product in syringe is significanltly changed. bulk is fine. I am an HPLC guy so I was wondering if there is a method for assaying povidone K-90 by HPLC. Is molecular wt changes are detectible? Any help is appreciated.

[Uwe Neue]

My first thought was to look at the molecular weight distribution via SEC, maybe in 50/50 methanol water on an aqueous SEC column. My second though is that you might be able to do this also with a water/acetonitrile gradient at 210 nm. For the moment, you only care if you see something, and if the stuff in the syringe is different from before. You can worry about an interpretation later.

[Furry_dice]

The following should help.



M. P. Tarazona, E. Saiz, "Combination of SEC/MALS experimental procedures and theoretical analysis for studying the solution properties of macromolecules", Journal of Biochemical and Biophysical Methods. 56, 95-116 (2003).


That has a description of a method used for PVP.


Have fun!