How to analyze drug dissolved in Castor Oil?

[californiachemist]

Hi,

I like to know if anyone has experience analyzing a drug in castor oil by HPLC. I like to avoid using Normal Phase HPLC or GC. The drug has very poor aqueous solubility, excellent solubility in Acetonitrile, that's all I know so far. I need to find a way to dissolve the drug in castor oil and some other solvent, then inject it onto HPLC to get solubiltiy data for now, eventually I will need to have the method validated. I'm thinking about trying IPA or Methanol in Castor oil, I don't know how it will go, also does anyone know if I can make a final dilution in acetonitrile, is IPA/ACN or Methanol/ACN miscible?

What about impurities in Castor Oil, it is NF grade, what else do I need to look for or keep in mind when developping the method?

Thanks so much!

[Alexandre]

Some generic protocol may be

Take X g of oil drug preparation
Add 10X of ACN, extract
Analyze ACN by LC.

Tricks and tips.

ISTD is beneficial. Protocol is generic and may need adjustment depending of preliminary results. Matrix calibration is better. If any problem with calibration try std additions.