Dear Vijay, could you be more specific in terms of the expected molecular weight and content of each grade of HPMC present in the tablet and your SEC setup?

Michal

Without any of the details Michal has enquired after, you probably need to look at the SE column you are using and find one capable of separating materials of those sizes.

To add a bit to the complexity, HPMC (and other cellulosic derivatives) are by and large linear polymers, while the exclusion limits of SEC supports and size exclusion membranes are quoted for globular proteins. That means a suitable mobile phase (probably non-aqueous) might need to be used to keep the HPMC coiling and loosening at bay.

@Colin - This is not the first and probably not the last question with insufficient details and the author not responding.

Dear Dr Colin and Dr. Michal thanks for your reply. i am adding some details below.

one grade molecular weight is 90000 while other grade mol. wt. is around 1300000. The SEC is tried along with RI Detector but the both grades are coeluting at same RT. Both grades have different mol. wt. and different viscosity. But when these two are in tablet how to separate and quantify.

@ Dr. Colin: As per your suggestion i am enquiring the SEC column appropriate for the given mol. weight. i am also planning to try HPLC- ELSD.

i will appreciate further suggestions.

Dear Vijay, you may start your search at biocompare.com, discuss your application with application engineers from the suppliers found and then eventually looking for more suppliers of the same type of column. At the first glance I'd go for the Waters BioSuite High Resolution SEC Column, 450Å, 8 µm, 7.8 mm X 300 mm, 20K - 7M, which seems to cover your range of molecular weights. RI detector should be perfectly OK for SEC, unless you have access to Multiple Angle Scattering detector. That would of course be ideal.