BACKGROUNDBrozopentyl Sodium (BZP), a novel agent for ischemic stroke, has shown promising results in preclinical pharmacological studies, prompting the initiation of the first-in-human investigation.PURPOSEThis study aimed to assess the safety, tolerability, and pharmacokinetic (PK) characteristics of BZP in Chinese healthy volunteers.METHODSThe study consisted of two parts. Part I was a single-center, randomized, single-blinded, placebo-controlled, single-ascending study with six BZP dose cohorts (SAD: 25, 50, 100, 200, 300, and 400 mg). Part II was a single-center, randomized, single-blinded, placebo-controlled, multi-dose- and dose-elevated study with three BZP dose cohorts (MAD: 50, 100, and 200 mg). Doses were administered once daily on days 1 and 7 and twice daily on days 2-6. The PK properties of BZP and its bioactive metabolites, BNBP, were assessed. Safety and tolerability evaluations were also conducted.RESULTSIn the SAD study, BZP reached peak plasma concentrations (Tmax) at the end of administration, with median Tmax values ranging from 1 to 1.03 h, while BNBP reached Tmax between 1.25 to 1.38 h. The terminal half-lives (T1/2) were approximately 8 h for BZP and 15 h for BNBP. In the MAD study, steady-state plasma concentrations of BZP were reached by day 5. There was minimal accumulation of both BZP and BNBP after 7 days of administration. The area under the plasma concentration-time curve from 0 to time of the last measurable concentration (AUC0-t) and maximum plasma drug concentration (Cmax) showed dose-proportional increases for BZP but not for BNBP in both study parts. Single and multiple doses of BZP demonstrated a good safety profile and were well-tolerated.CONCLUSIONBZP displayed safety, good tolerability and predictable PK characteristics following both single and multiple ascending intravenous administrations. These findings provide a basis for further clinical development of BZP for ischemic stroke patients.