Adapting Fabric Phase Sorptive Extraction as an Innovative Multitool for Sample Transfer and Extraction in Pharmacokinetic Analysis Followed by LC-MS Determination of Levofloxacin in Plasma Samples

Fabric phase sorptive extraction (FPSE) is a simple microextraction technique that allows analytes to be rescued from matrix components while using a small volume of samples to analyze complex biological systems. This study used FPSE as a microextraction tool and a sample storage and transfer device. Levofloxacin as a model molecule was applied intravenously (IV) to New Zealand male rabbits. The samples were simultaneously extracted by using FPSE and protein precipitation methods. The final solutions were analyzed using LC-MS equipped with an ACE C18 LC Column (150 mm x 4.6 mm, 5 mu m) at 25 degree celsius employed in isocratic elution mode using solution A (0.1% formic acid in water)/solution B (0.1% formic acid in acetonitrile) (80:20, v/v). The total analysis time was less than 15 min. The developed method was validated using the ICH M10 bioanalytical method validation and study sample analysis guidelines. The results obtained using FPSE were statistically identical to those obtained using protein precipitation. The plasma samples applied onto FPSE (10 mu L onto 1.0 cm x 1.0 cm Biofluid Sampler) were stored in three different temperatures [refrigerator (2-8 degree celsius), at ambient temperature (20 +/- 5 degree celsius), and in the stability cabinet (40 degree celsius, 75% humidity)] and three different storage conditions (Eppendorf tubes, plastic containers, and straw paper envelopes). Levofloxacin in plasma samples adsorbed by FPSE biofluid sampler remained stable at 2-8 degree celsius in Eppendorf tubes for at least 1 week. This study showed that FPSE could be used as a sample storage and transfer device for pharmacokinetic applications that need to work with small sample volumes and discard aggressive cold chains to store and transfer the plasma samples.