The pharmacokinetics and Concentration-QTc analysis of a new etomidate analog ET-26-HCl: a phase I trial in healthy Chinese subjects

Methoxetamine hydrochloride (ET-26-HCl) is a novel short-acting intravenous general anesthetic that retains the advantages of etomidate while minimizing its impact on adrenal cortical function. A single-center, randomized, open-label, placebo-controlled clinical trial was conducted using concentration-QTc (C-QTc) model analysis to evaluate the pharmacokinetics, clinical sedative effect, safety, and potential risk of QT interval prolongation of ET-26-HCl at doses of 0.8 mg/kg (the clinical dosage) and 2.8 mg/kg. In the 0.8 mg/kg group, the mean peak concentration ( C max ) of ET-26 was 1,510 ng/mL with upper limits of the 90% confidence interval (CI) for QTcF interval corrected by baseline and placebo (ΔΔQTcF) falling within an acceptable range, not exceeding ±10 ms (−1.543 ms to +2.788 ms). The 2.8 mg/kg group exhibited a higher C max value for ET-26, along with corresponding mean ΔΔQTcF values that remained below the ±10 ms threshold limit. Based on the established C-QTc model analysis, it is predicted that the upper limit of 90% CI for the mean ΔΔQTcF corresponding to ET-26 at twice the C max of 0.8 mg/kg is ≤ ±10 ms. The study findings in conjunction with the C-QTc model demonstrated the rapid onset and recovery properties of ET-26. Furthermore, increased exposure and dose-dependent sedative/hypnotic effects were observed, with no risk of QT prolongation for this investigational drug, thereby ensuring patient safety and minimizing potential risks in its clinical application. Clinical Trials Registration Number ClinicalTrials.gov CTR20233230.