This study shows that age, weight and the VKORC1 and CYP2C9 polymorphism affect warfarin dose requirements in our sample of Chinese patients receiving long-term therapy and showing stable control of anticoagulation. It is anticipated that the use of dosing regimens modified by taking into account the contribution of age, weight, and the CYP2C9 and VKORC1 genotypes has the potential to improve the safety of warfarin therapy.

Aims This trial (NCT03751956) investigated the mass balance, pharmacokinetics and pharmacodynamics of HSK3486, a novel anaesthetic, in healthy subjects. Methods A single dose of 0.4 mg/kg [14C]HSK3486 was administered to six healthy subjects. Blood, urine and faecal samples were collected, analysed for radioactivity, unchanged HSK3486 and profiled for metabolites. The Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale and vital signs were closely monitored during the study. Results The mean recovery of total radioactivity in excreta was 87.3% in 240 h, including 84.6% in urine and 2.65% in faeces. The exposure (AUC0‐t) of total radioactivity was much higher than that of unchanged HSK3486 in plasma, indicating there were circulating metabolites in plasma. The glucuronide conjugate of HSK3486 (M4) was found as the only major circulating metabolite in plasma (79.3%), while unchanged HSK3486 accounted for only 3.97% of the total radiation exposure. M4 also resulted in a longer estimated elimination half‐life (t1/2) of total radioactivity than that of unchanged HSK3486 in plasma. Fortunately, the metabolite was detected to be not specific to red blood cells and was suggested to be nonhypnotic and nontoxic. All the subjects were quickly anaesthetized (2 min) after drug administration and woke up smoothly after a short time (5.5–14.1 min) with few residual effects. The only adverse event in the study was mild (grade 1) and consisted of hypotension. Conclusion HSK3486 is a promising anaesthetic candidate with rapid onset of action and clear absorption, distribution, metabolism, excretion (ADME) processes. HSK3486 showed favourable pharmacokinetic characteristics, pharmacodynamic responses and safety at the study dose.

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A theory-based PKPD model describes warfarin concentrations and clinical response. Expected PK and PD genotype effects were confirmed. The role of predicted fat free mass with theory-based allometric scaling of PK parameters was identified. R-warfarin had a minor effect compared with S-warfarin on PCA synthesis. INR is predictable from 1/PCA in vivo.