Development of a magnetic solid phase extraction method for gemcitabine from rat plasma by using magnetic graphene oxide calix[6]arene composite and its application to pharmacokinetics

A highly accurate and precise HPLC-UV method was developed for identification and quantification of gemcitabine anti-cancer drug in rat plasma. A new magnetic graphene oxide-based calixarene composite was developed and used as a solid phase for extraction of gemcitabine from rat plasma. Extraction efficiency has been studied by varying different experimental variables (eluent type, sorbent amount, extraction time and eluent volume etc.) and these were evaluated and optimized. Magnetic solid phase extraction (MSPE) conditions such as amount of solid phase, extraction solvents and their amounts, and adsorption and desorption times were optimized for getting better recoveries. Under the optimized conditions, linearity was evaluated with good correlation coefficient value R-2 (0.9993). Limit of detection (2.0 ng/mL) and limit of quantification (13.0 ng/mL) was assessed using signal-to-noise ratio method. Intraday precision RSD values of gemcitabine (GEM) were found to be less than 4.6% and interday precision values are less than 6.8%. The results obtained during the robustness study were RSD values between 1.2 and 4.6%; these results indicate that the method has effective performance and reliability. The recovery percentages of gemcitabine at three QC level concentrations were obtained in the range from 97.6 to 100.2%.