The preclinical pharmacological study of a novel intravenous anesthetic, ET-26 hydrochloride, in aged rats

PeerJ. 2022 Sep 29:10:e13995. doi: 10.7717/peerj.13995. eCollection 2022.

Abstract

Background: ET-26 hydrochloride (ET-26HCl) is a novel analogue of etomidate approved for clinical trials. However, all results from recent studies were accomplished in young adult animals. The objective of this study was to evaluate the efficacy and safety of ET-26HCl in aged rats.

Methods: Aged Sprague-Dawley rats were randomly divided into three groups (three males and three females in each group) were given dose of two-fold of median effective dose (ED50) of ET-26HCl, etomidate and propofol: the measurements of loss of the righting reflex (LORR) and cardiovascular and respiratory function after injection at the two-fold dose of the median effective dose were used for evaluation of effectiveness and safety, and the modified adrenocorticotropic hormone-stimulation experiment was used to evaluate the inhibition effect of the drugs on the synthesis of adrenal cortical hormones.

Results: There was no significant difference in the onset time among propofol, etomidate and ET-26HCl. The duration of propofol (850.5 ± 77.4 s) was significantly longer than that caused by etomidate (489.8 ± 77.0 s, p = 0.007) and ET-26HCl (347.3 ± 49.0 s, p = 0.0004). No significant difference was observed in the time to stand and normal activity among drugs. A total of 66.7% of rats in the ET-26HCl group were evaluated to have mild hematuria. Then, etomidate and ET-26HCl had a milder blood pressure inhibition effect than propofol. Apnea was observed in all rats administered propofol and the duration for this side effect was 45.0 ± 9.0 s. For etomidate and ET-26HCl, no apnea was observed. No other clinical signs of side-effect were observed, and no rats died. No significant difference was observed in corticosterone concentrations between ET-26HCl and solvent group. However, rats administered etomidate had lower corticosterone concentrations than those administered ET-26HCl at 15, 30, and 60 min.

Conclusions: Our results indicate ET-26HCl in aged rats is an effective sedative-hypnotic with stable myocardial and respiratory performance and also have mild adrenocortical suppression. Thus, these findings increase the potential for the clinical use of ET-26HCl in the elderly population.

Keywords: Aged rats; ET-26 hydrochloride; Etomidate analogue; Intravenous anesthetic; Pharmacological study.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Anesthetics, Intravenous / pharmacology
  • Animals
  • Corticosterone
  • Etomidate* / pharmacology
  • Female
  • Humans
  • Male
  • Propofol* / pharmacology
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Etomidate
  • Propofol
  • Corticosterone
  • Anesthetics, Intravenous

Grants and funding

This work was supported by a grant from National Science and Technology Major Project, Ministry of Science and Technology of the People’s Republic of China (No. 2014ZX09101001), Beijing, China; the Science and Technology Department of Sichuan Province, China (No. 20YYJC3881, 2018sz0236); and the Science and Technology Department of Chengdu City, China (No. 2021-YF05-00855-SN). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.