Optimization of Extraction and Pre-Concentration of Rizatriptan in Biological Samples Using Solvent Bar and Chemometrics Design

Introduction: The acute treatment of migraine headaches is one of the major fields in which rizatriptan is used. Materials and Methods: To determine rizatriptan in biological fluids, many analytical approaches have been reported based on Liquid Chromatography/ Tandem Mass Spectrometry (LC-MS/MS), High- Performance Liquid Chromatography (HPLC), Reversed Phase Liquid Chromatography with Diode Array Detection (RP-LC-DAD), and High-Performance Thin-Layer Chromatography (HPTLC). In this work, for the first time, Solvent Bar Microextraction (SBME) technique followed by HPLC with Ultraviolet (UV) was used to extract, detect, and determine rizatriptan in biological samples. The chemometric method was applied to optimize effects of various parameters affecting the extraction efficiency of the proposed method. Next, the extraction parameters including organic membrane solvent, extraction time, pH of donor and acceptor phases, salt addition, stirring rate, and sample solution temperature were optimized. The organic liquid membrane consisted of 1-Octanol immobilized in hollow fiber wall pores. A pH gradient was applied to migrate analytes from alkaline sample solution having a pH of 9.0, through the organic liquid membrane, into a solution of acidic acceptor having a pH of 2.9, existing inside the lumen of the hollow fiber. Having optimized the experimental conditions, extraction recoveries above 86% were achieved in various biological matrices. Result: As a result, pre-concentration factors above 127, acceptable Relative Standard Deviations (RSD%) with intra-day being 3.1% and inter-day being 4.6% were observed. The method showed decent linearity with estimation of coefficient above 0.999. Ultimately, it was used to detect and determine rizatriptan in human plasma and urine sample.