Performance evaluation of a MIP for the MISPE-LC determination of p-[18F]MPPF and a potential metabolite in human plasma.

Within the family of serotonin (5-HT) receptors, the 5-HT1A subtype is particularly interesting as it may be involved in various physiological processes or psychological disorders. The p-[18F]MPPF, a highly selective 5-HT1A antagonist, is used for in vivo studies in human or animal by means of positron emission tomography (PET) [1]. In order to selectively extract p-[18F]MPPF and its main metabolites from plasma, molecularly imprinted polymer (MIP) was prepared against these compounds by using the p-MPPF as template. For the control of the selectivity, non-imprinted polymer (NIP) was also synthesized without template. The MIP sorbent, packed in disposable extraction cartridges (DECs), was then evaluated as molecularly imprinted solid-phase extraction (MISPE) prior to the LC determination. The conditions of extraction were evaluated in order to obtain the highest selective retention of the p-[18F]MPPF and its metabolites on this MIP. The MIP selectivity was exploited in the loading and washing steps by adjusting the pH of plasma samples at a suitable value and by selecting mixtures for the washing step to limit the contribution of non-specific interactions. Other important parameters involved in the conditioning and elution steps were also studied. Finally, a pre-validation was carried out with optimal extraction conditions to demonstrate the performance of this MISPE-LC method as a generic method in the context of evaluation of new MISPE for p-[18F]MPPF and its potential for metabolites extraction from human plasma.