Preclinical Pharmacokinetic Assessment of a Promising Vasorelaxant, Analgesic, and Anti-Inflammatory Prototype 5-[1-(4-Fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole (LQFM020) Through Selective Bioanalytical HPLC-PDA-Based Method.

A simple and selective high-performance liquid chromatography bioanalytical method was developed and validated to determine the pharmacokinetic parameters of 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole (LQFM020) with promising vasorelaxant, anti-inflammatory, and antinociceptive properties while verifying its potential hepatic enzyme induction or inhibition. Chromatographic separation was achieved using a reversed-phase C18 column (ACE, 150 × 4.6 mm, 5 μm) with isocratic elution of a solvent mixture comprising acetonitrile and 0.2% formic acid (30:70, v/v). Detection of LQFM020 and the internal standard, piroxicam, was performed using a photodiode array detector. The method demonstrated excellent linearity (r > 0.998), with precision and accuracy within acceptable limits [intraday precision: 6.1%, interday precision: 9.3%; intraday accuracy: 113.2%, interday accuracy: 107.3%]. Pharmacokinetic studies revealed rapid oral absorption of LQFM020 at doses of 9, 18, and 36 mg/kg, as well as following a single intravenous dose (10 mg/kg). LQFM020 exhibited an absolute bioavailability of 46%, a relatively low apparent volume of distribution, and moderate elimination rates, suggesting extensive plasma protein binding. Additionally, LQFM020 showed no significant effect on the biotransformation of compounds mediated by the cytochrome P450 CYP3A4 enzyme. In conclusion, this new bioanalytical method supports preclinical studies and provides a basis for the utility of LQFM020 as a potential drug candidate.