I have tried to analyse a sample of prednisolone according to the specifications described in its monograph of The European Pharmacopeia 4th edition. However I was not able to meet the system suitability criteria set for "Related substances": resolution was below 2. If anyone has carried out this analysis successfully please let me know which column did you use and what adjustments (if any)have you made to the mobile phase composition.

Thanks a lot in advance.

I'm afraid I don't have the details you probably need.
But, I did once run into a similar problem with a
prednisolone assay (extracted from plasma). On
reversed phase, I couldn't get baseline resolution from
related steroids (some of which only differ by the
location of a double bond). I ended up using one of
the normal phase methods from the literature.
Interactions between the polar stationary phase and
analytes promised to be more specific than the
reversed phase sep. It was true.

It was my first experience with normal phase, and not
as frustrating as I expected. I was careful to presaturate
the organics with H2O, which makes the system less
sensitive to small changes in water content of the
mobile phase. I no longer have the reference, but I
remember there being many normal phase methods
described for steroids in the literature.

Dear sl, I just received a brand new application for standard Methylprednisolone formulation in tablets, separation and detection of degradation products 0,1% limit during stability testing. If this application would be of interesst for you, just e-mail me to g.kratz@tosohbiosep.de and I will send you that application. Otherwise it will be published next week on a flyer, but I'm not sure if you are on our mailing list. Gerhard