Bioanalytical HPLC Method for Quantification of Benidipine in Rat Plasma: Stability and Application to Pharmacokinetic Study.

Benidipine is a dihydropyridine calcium channel blocker widely used in management of hypertension, and its pharmacokinetic evaluation requires reliable quantification in plasma. Even though liquid chromatography-mass spectrometry methods are available, simple and cost-effective HPLC approaches for determining benidipine in rat plasma remain limited. To address this gap, a reversed-phase high-performance liquid chromatographic (HPLC) method was developed and validated to assess the presence of benidipine in rat plasma. Acetonitrile was used as the extracting solvent for the liquid-liquid extraction of the plasma's analytes, followed by separation on an HPLC column. Benidipine's retention time was found to be 8.134 min. The limit of detection and the limit of quantification were determined to be, respectively, 0.016 μg/mL and 0.047 μg/mL. The method was validated over a liner (R2 = 0.9995) concentration range of 0.05 to 10 μg/mL. The level of precision and accuracy were found to be within acceptable limits. Benidipine was found to be stable under freeze-thaw and short-term conditions. Benidipine's pharmacokinetic parameters were suitably assessed in Sprague-Dawley rats after a single oral dosage (0.822 mg/kg). The findings demonstrated the suitability and applicability of the developed bioanalytical HPLC approach as a tool for the pharmacokinetic analysis of benidipine.