I coated the metal surface with a mixture of PLLA and sirolimus and i want to study the drug release in human plasma. The loading amount was 125 ug per sample. For the drug release, i immersed the sample in 1 ml of plasma solution and after predetermined time 1d, 3d, 5d, ....... i can't measure the amount of the released sirolimus. could you please inform me how to extract the sirolimus from the plasma solution or any other way?
Thank you in advance
Dear Tarek,
since we do not have the complete picture, it is a bit difficult to give advice.
Did you check that the concentration you expect can be detected by your analysis, i.e. did you inject the amount that would correspond to ~10 % release as a standard and see a signal?
Did you repeat this with analyte in matrix (plasma) and still see a signal?
If so please give more details on the sample composition, expected concentrations, cleanup procedure and analytical system. If you don't see the analyte in the two suggested settings, I would like to know more about the UV spectrum of the analyte in your HPLC solvent, the HPLC column etc.
Hope that helps!
Best regards
Holger
Holger has good advice. Also, is it possible that the compound has not released into the plasma? Are you able to measure the amount remaining on the surface?
Hi,
May be your extraction procedure or analytical procedure is not appropriate for the study.
HI,
you can go through following link too,
http://onlinelibrary.wiley.com/doi/10.1111/j.1432-2277.2004.00066.x/pdf
Thank you all of your advice
After searching, i found that the sirolimus is not stable in human plasma solution as the half-life time of sirolimus is only 6 hrs.
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