Dear Forum members,
I am having difficulty analysing (dex)panthenol by RP-LC. This molecule has no real chromophore, that's why I am trying low wavelength UV, ESI MS and MS/MS as detection modes. Problem is how to retain this molecule with a MS-friendly buffer. Even at 2% methanol, it is not really retained (acidic pH). Did a literature search, but only found some old papers analysing at 200 nm in nice clean matrices. My sample is a dermatological cream at 5 mg/g dexpanthenol.
Any hints ?
Jan

If you can't retain it in reversed-phase, it is likely to work well in HILIC (e.g. on a HILIC silica column). The advantage is also a higher sensitivity in MS (if you care).

Have you tried some scouting with different pH's?
I know its possible with RP LC, my previous company has one, but I dont remember the mobile phase (detection was UV 205 nm)

Dear Jan,

Quite recently I performed a separation of panthenol from a commercial "vitamin Beverage" using HILIC mode and UV detection at 210 nm, and it worked out really well. If you are interested I can send you a pdf that illustrates the separation.

Patrik

We've used GC after trimethylsilyl derivatization, even GCMS if there is co-elution issue with cetyl alcohol.

Update on panthenol by LC :
What we did yesterday was sticking to LC on C18 (I'm very conservative ;-)) and lowering the acetonitrile to as few as 1%. Panthenol elutes at 2 min whereas solvent front is at 0.7 min. Luckily no interference was seen when analysing the cosmetic cream, you just need a steep gradient to elute cream excipients. We quantitated at 210 nm as well as MS full scan and MS/MS mode. Results were comparable although UV signal was more reproducible and more linear (we use ion trap MS).
I think in this particular sample we were lucky no interference was seen from the cream matrix, next time we might need to use HILIC to have better retention.
Thanks for everybody's help
Jan

Do anybody know what main degradation product that may be expected from panthenol? Is it more or less hydrophilic?

Does anyone know how to extract panthenol from skin creams??
Thanks

Panthenol is fairly soluble in water, methanol, ethanol,...
How to extract it from your cream depends on the nature or you cream. If you can solubilize your cream in methanol or a methanol/water mixture, I'd stick with that. It your cream is to "fatty", try adding some THF first to dissolve it, than add methanol.
Good luck
Jan

Thanks Jan
I have different types of creams, so IŽll try it with these solvents