Zhejiang Xianju Pharmaceutical Co., Ltd.

Steroid drugs play a pivotal role in clinical therapeutics, with androsta-1,4-diene-3,17-dione (ADD) serving as a critical intermediate whose efficient biosynthesis relies on the catalytic activity of 3-ketosteroid-Δ1-dehydrogenase (KstD). Building upon the previously engineered KstD₂^ep variant, this study employed semi-rational design strategies to enhance KstD₂'s high-substrate-loading adaptability. Key residues (V332, L334, G534) were systematically identified through homology modeling and molecular docking, followed by constructing a combinatorial mutant library. Through alanine scanning and iterative screening of single/multiple-site mutations, the optimal mutant KstD₂^ep (V332E/L334T/G534V) demonstrated a 1.1-fold enhancement in catalytic efficiency compared to the KstD₂^ep. Molecular dynamics simulations confirmed significantly enhanced structural stability in the mutant. Whole-cell catalytic optimization revealed expanded operational tolerance to temperature fluctuations, pH variations, and co-solvent exposure. Implementing high-density fermentation coupled with fed-batch substrate supplementation, the process achieved a 1.5-fold increase in substrate conversion efficiency, yielding 117.75 g/L ADD. These advancements position the engineered variant as a high-potential candidate for scalable steroid biotransformation, addressing key barriers to enzymatic stability and process efficiency for enzyme-driven biosynthesis of steroidal pharmaceutical intermediates.

CZ1S injection is a novel, extended-release local anaesthetic formulation of ropivacaine, classified as a type 2.2 new drug, with potential for post-operative analgesia by subcutaneous infiltration and peripheral nerve blockade. This study aimed to validate the superior properties of CZ1S over ropivacaine hydrochloride injection and to evaluate the safety, tolerability, pharmacokinetic (PK) and pharmacodynamic (PD) profiles of a single dose of brachial plexus block with CZ1S in healthy Chinese adults. The tolerability and PK profile of CZ1S were investigated following a unilateral brachial plexus injection in 24 healthy adults. Safety assessments were performed throughout the study and the PD effects of CZ1S injection for unilateral brachial plexus block were also evaluated. The results showed that CZ1S was slowly absorbed after a single injection in healthy subjects, with PK parameters of ropivacaine (including C_max, AUC_t and AUC_∞) increasing with the CZ1S doses. CZ1S demonstrated a prolonged and non-constant release profile compared to a single 75 mg injection of ropivacaine hydrochloride, resulting in a smooth and sustained blood concentration. CZ1S significantly prolonged the duration of sensory and motor blockade, and further analysis revealed a correlation between PK and sensory nerve block. The PK profile of CZ1S was enhanced compared to that of ropivacaine injection, and it was deemed safe and well tolerated in healthy Chinese adults, suggesting its potential application in postoperative analgesia. CLINICAL TRIAL REGISTRATION: Chinadrugtrials.org.cn: CTR20231295 (registration date: 26 April 2023).

As our ongoing chemical investigation, two new pregnane steroidal glycosides, cynataihosides G (1), with a new aglycone, and H (2) were isolated from the 95% ethanol extract of Cynanchum taihangense. Their structures were elucidated on the basis of 1 D and 2 D NMR spectral data, HR-ESI-MS analysis and qualitative chemical methods. The compounds were subjected to detect the cytotoxicity against three human tumor cell lines (HL-60, THP-1 and PC-3). The compounds displayed no significant cytotoxicity.Supplemental data for this article can be accessed at https://doi-org.libproxy1.nus.edu.sg/10.1080/14786419.2019.1672682.