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Analysis of drugs in
plasma samples has traditionally required a range of sample
pretreatments before HPLC. Direct injection of plasma and
serum samples onto reversed phase HPLC columns causes column
clogging and rapid loss of efficiency due to adsorption
and accumulation of proteins in the stationary phase. Hence,
lengthy deproteinization steps are necessary prior to sample
injection on standard reverse-phase columns.
BIOPTIC® is the result of new bonded phase technology
which allows the hydrophobic inner surface of a spherical
silica bead to be shielded from proteins by a permanently
bonded hydrophilic outer Avidin layer. Injected serum proteins
are prevented from interacting with the hydrophobic inner
layer by the hydrophilic avidin outer layer, and are not
retained by the column. The protein elutes as a large void
volume peak. Smaller drug analytes, however, diffuse through
the outer avidin layer into the hydrophobic inner layer
where typical reverse-phase interactions occur. Uniquely,
drug analytes also interact with the optically active Avidin
outer layer and undergo chiral resolution.
BIOPTIC® columns allow reverse phase and chiral
resolution of drug analytes directly from plasma samples
without deproteinization. BIOPTIC® is the only
column of its type available. |
