By Sumate on Monday, August 18, 2003 - 11:22 pm:
Hello,i'm new in this forum.
Could SPE technique deproteinate bound form of drug in plasma? And which is the suitable sample preparation for high (>90%) protein binding drug?
By Anonymous on Thursday, August 28, 2003 - 12:55 am:
Dear Sumate,
there are many aspects you will have to take into account. One thing is, that any dilution during operation will change the equilibrium of the binding of your drug to protein. So if you bind your protein to your SPE matrix and elute with excess buffer this might allow you to isolate most of your drug in a large volume of buffer/organic phase. But this depends on the specific interaction between the protein and your drug and must be checked. This is the same process happening during dialysis.
Another possibility is to use a SPE matrix with high affinity for your drug and maybe a preincubation phase with sample applied to the SPE modules, in order to reverse actual protein binding. In this case the affinity of your drug for the SPE must be very high and the protein concentration in your sample low enough to get reproducibly high yield of your drug.