By leek on Wednesday, October 23, 2002 - 11:53 am:
Hi
can guide me toward studies or information regarding various exipients(povidone, magnesium stearate, etc.) in the HPLC analysis of pharmaceutical formulations?
thanks
By Mel on Wednesday, October 23, 2002 - 11:58 am:
The USP will have assays and ID tests for pharmaceutical excipients that have been used forever.
Melissa
By leek on Thursday, October 24, 2002 - 07:46 am:
Thanks,
But I should state what I am really looking for. I want information regarding common problems, appropriate mobile phase composition, and wash procedures when assays are preformed in the presence of these excipients. I am having problems with reproducibility when assaying granulations (peaks broadening and tailing). The active only assay does not present these difficulties.
By Anonymous on Thursday, October 24, 2002 - 10:04 am:
Do you filter your samples before injecting them?
By Daren on Thursday, October 24, 2002 - 01:10 pm:
sometimes your excipients can act as ion pairing (competing) agents with your actice. This can cause peak tailing, broadening, even full splitting of your active peak. I have solved this problem in the past by incorporating salts into my mobile phase (sodium sulfate, sodium chloride, lithium chloride)to compete. your may want to sceen different salts at various concentrations and see what works best at blocking this ion-pairing. Also make sure your column can handle it and that the salt doesn't crash out in your organic. Hope this helps