ABSTRACT:
Rizatriptan benzoate (RBZ), a member of the triptan class, is frequently prescribed in migraine therapy due to its high selectivity towards 5-hydroxytryptamine (5-HT1B, 5-HT1D) receptors. Despite its efficacy, the therapeutic dose (typically 5–10 mg) results in relatively low plasma concentrations. Such nanogram-level concentrations require highly sensitive analytical methods for accurate detection in biological matrices. A simple, cost-effective and sensitive ‘high-performance liquid chromatography’ (HPLC) method was thus, developed and validated for the quantification of RBZ in rat plasma. The chromatographic separation was accomplished using an isocratic mobile phase of 10 mM anhydrous dipotassium hydrogen orthophosphate (K2HPO4) pH 3.5 and methanol (MeOH) in the ratio of 80:20 (v/v), with ultra-violet (UV) detection at 225 nm. The developed method was validated in accordance with the ‘International Council for Harmonisation’ (ICH) M10 guidelines, which included examining specificity, linearity, recovery, accuracy, precision, limit of detection (LOD) and quantification (LOQ), robustness as well as stability. This validated method was applied in the pharmacokinetic investigation of Rizatriptan benzoate (5 mg/kg) in Sprague-Dawley rats after single oral administration. The method demonstrated excellent linearity (5–1500 ng/mL, R² = 0.99), with retention-time (Rt) of 6 minutes. Methanol was identified as the most effective extraction solvent, offering 95.81% recovery. This validated, developed HPLC method was robust, reliable and sensitive, making it apt for routine study of RBZ in preclinical studies emphasizing its translational relevance.