Bioptic

Bioptic^® HPLC columns are designed for the simple analysis of bioactive substances (e.g. drugs or metabolites) from plasma samples. The base material is a spherical silica gel modified with avidin molecules via a special alkyl spacer linkage. Bioptic AV columns allow the inner hydrophobic surface of the silica to be shielded by a permanently bonded hydrophilic avidin layer. Large molecules like plasma proteins are excluded from interacting with the hydrophobic inner surface by the avidin layer, and elute by size-exclusion mechanisms in the void volume. Smaller compounds, such as drugs and drug metabolites, pass through the avidin layer and interact with the hydrophobic inner layer by a reverse-phase mechanism.

Bioptic AV-1 contains non-denatured avidin and a chiral center, allowing separation of chiral drugs and their metabolites. Bioptic AV-2 contains a denatured form of avidin and lacks the chiral separating ability of AV-1, but offers different selectivity.