I need to analysis something in gel. How to get rid off gel

[Jady Wang]

I need to analysis methylparaben in gel product by HPLC
I tried to extract methylparaben from gel by methanol, dissolved gel by methanol, the stored at -20 C, centrifuged at 15,800 RPM for 30. I would not get rid off the gel .
Does anybody have experience to precipitate gel? thanks.

[Consumer Products Guy]

We assay gel samples frequently here, usually blend with organic solvent, then filter through HPLC sample membrane filters.

If you heat/stir to dissolve, it will likely re-gel.

[Bryan Evans]

There is an opportunity to do direct injection of gelatin matrix samples with either:

Cadenza HS-C18 (hydrophopic / hydrophillic hybrid ODS)
http://www.imtaktusa.com/site_media/fil ... TI387E.pdf

OR

Presto FF-C18 (2um non-porous C18):
http://www.imtaktusa.com/site_media/fil ... TI567E.pdf
.

[shaun78]

depending upon the product excipients, you may be better off simply extracting in MeOH over a steam bath...

[Jady Wang]

Thanks everyone. It really help!!!!!!!
Jady

[MestizoJoe]

Jady I'm curious, which way worked for you?

[zdravkam]

Hi everybody
Please help...
I am new here and completely freshly new in HPLC.
My expertise is formulation, not so much analytical techniques
My problem is similar to Jadys.
I have some drugs (poorly water solubles, like indomethacin) in gelatin and I should analyze them by HPLC.
So how exactly to get rid of the gelatin? I taught of precipitating and filtering it. But which solvent to use?
And at which temperature to heat?
I have this column : LiChrospher® 60 RP-select (5 µm)
Could I use it, since I am not sure we could buy new one, like Bryan suggested: Cadenza HS-C18 (hydrophopic / hydrophillic hybrid ODS) ?

Thank you all for help

[Consumer Products Guy]

Blend with solvent that your active is soluble in. Filter. Simple is usually best.

[cody84]

Hey, I'm having a similar issue. Developing method for CHG related compounds in a gel product. The problem is I need to dilute the gel 50% to get the correct concentrations I'm looking for. I need to be able to inject a preparation that has 2mg/ml.
I don't have much experience in sample prep development beyond dilution in diluent, etc.
The gel is extremely viscous, so when mixing 50:50 with diluent....not all that much happens.
Any suggestions for how I should go about this?

Sorry to hijack the thread, but same problem I guess.

[Consumer Products Guy]

Hey, I'm having a similar issue. Sorry to hijack the thread, but same problem I guess.

We assay gel samples frequently here, usually blend with organic solvent, then filter through HPLC sample membrane filters. If you heat/stir to dissolve, it will likely re-gel.

What I posted above. Twice.

[cody84]

yea, that's not working..

[Consumer Products Guy]

yea, that's not working..

Then it's time to hit the bench and earn your keep !!!

[cody84]

haha, I'm hittin the computer to do the Reseach part of my job, just exhausting all possibilities before I hit the bench

[cody84]

when mixing 50:50 with diluent....not all that much happens.

And FYI ^^^ As you can see from my first post I already tried what you suggested. Twice.

[Consumer Products Guy]

Have you tried freezing the sample then pulverizing?

Have you tried different solvents and mixtures?