Enhanced microdialysis recovery of some non-steroidal anti-Inflammatory drugs (NSAIDs) and their metabolites using covalent organic frameworks

by Olubanjo, Kehinde Adedeji; Almansaf, Zainab; Stenken, Julie Ann

Microdialysis sampling is a versatile and widely used tool used for the sampling of analytes from the extracellular space of tissue. It was initially and primarily employed in neurosciences, and then spread to the pharmaceutical sciences. Despite its versatility, a major drawback associated with the technique is its inability to sample hydrophobic analytes, as they tend to exhibit non-specific adsorption with the probe materials thereby resulting in significantly reduced relative recovery. To overcome this shortcoming, an affinity agent (AA) is added to the perfusion fluid in the MD probe a thereby providing addnl. mass transport driving force for analyte to pass through the dialysis membrane and thus increases the relative recovery (RR). For the first time Covalent Organic Frameworks (COFs) were employed as affinity agents in microdialysis for the extraction of three types of hydrophobic drugs and two of their metabolites. COFs exhibit some useful properties as affinity agents such as high surface area, large pore volumes, thermal stability, reusability, solvent stability and good porosity. In this study three different types of imine-based COFs were employed as AAs in enhanced microdialysis of three NSAIDs - flurbiprofen, naproxen, fenbufen and two metabolites - 4-hydroxyflurbiprofen, 4-biphenyl acetic acid. The preliminary results indicate relative recovery was enhanced by 2 to 13-fold (statistically significant, p < 0.05) for the NSAIDs studied and their metabolites under investigation. In conclusion, this study highlights the potential of COFs as a tool for the enhancement of relative recovery of hydrophobic drugs using microdialysis technique.