[PharmaStud.]

Hello,

For an assignment, I have to work on the determination of 5-fluorouracil and its impurities. I found an HPLC method in the pharmacopeia to assay all impurities except urea. I'm a bit lost, I don't know what parameters I need to change to be able to include urea in this HPLC method. What should I pay attention to? Should i do derivatization of urea ?

The impurities measured by this method are:
- Barbituric acid
- Isobarbituric acid
- 5-methoxyuracil
- 5-chlorouracil
- 2-ethoxy-5-fluorouracil

Column :
– dimensions: l = 0.25 m, Ø = 4.6 mm,
– stationary phase: octadecylsilyl silica gel for R chromatography (5 μm).
Mobile phase: R monopotassium phosphate solution at 6.805 g/L adjusted to pH 5.7 ± 0.1 with a 5 M potassium hydroxide solution prepared with potassium hydroxide R.
Flow rate: 1.0mL/min.
Detection: spectrophotometer at 266 nm.
Injection: 20 μL.
Ambient temperature.
Record: 3 times the retention time of fluorouracil.

Thanks

[MOTOBALL]

The fact that this method, which is good for 5 imps, but does not mention urea suggests that it cannot be used for urea.

Suggest that you check the Pharmacopeia's for HPLC methods for urea, preferably without derivatization.

You may well need any combo of different column/mobile phase/pH etc....

ALWAYS avoid derivatization, if at all possible!!

Regards,
Motoball

[PharmaStud.]

Thank for your response ! I'll check the pharmacopeia for Urea