M-031

Chuanwang Xiaoyan (CWXY) capsule is primarily used to treat a variety of acute and chronic inflammations, including acute and chronic pharyngitis and tonsillitis. However, a systematic study of its chemical constituents is still not available. This study evaluated the chemical constituents in vitro and metabolite profiles in vivo of CWXY using ultra‐high‐performance liquid chromatography (UHPLC) coupled with Q‐Exactive Orbitrap mass spectrometry, and the pharmacokinetic behaviors of the nine main components in rats were detected using ultra‐high‐performance liquid chromatography‐triple quadrupole‐mass spectrometry (UPLC‐QQQ‐MS/MS). A total of 92 chemical constituents in CWXY were preliminarily identified in vitro. After oral administration to rats, 56 prototype components and 128 metabolites of CWXY were detected in the biological samples of rat plasma, urine, bile, and feces. Of these prototype components and metabolites, seven new compounds, namely M15, M16, M25, M30, M31, M71, and M128, were detected for the first time. The quantitation method of nine components in rat plasma was developed using a pharmacokinetic study. To the best of our knowledge, this study was the first to investigate the pharmacokinetic behavior of triumbelletin.

Arginine deiminase (ADI) is a therapeutic protein for cancer therapy of arginine‐auxotrophic tumors. However, its application as anticancer drug is hampered by its poor stability under physiological conditions in the bloodstream. Commonly, random PEGylation is being used for increasing the stability of ADI and in turn the improved half‐life. However, the traditional random PEGylation usually leads to poor PEGylation efficiency due to the limited number of Lys on the protein surface. To boost the PEGylation efficiency and enhance the stability of ADI further, surface engineering of PpADI (an ADI from Pseudomonas plecoglossicida) to increase the suitable PEGylation sites was carried out. A new in silico approach for increasing the PEGylation sites was developed. The validation of this approach was performed on previously identified PpADI variant M31 to increase potential PEGylation sites. Four Arg residues on the surface of PpADI M31 were selected through three criteria and subsequently substituted to Lys, aiming for providing primary amines for PEGylation. Two out of the four substitutions (R299K and R382K) enhanced the stability of PEGylated PpADI in human serum. The average numbers of PEGylation sites were increased from ~12 (tetrameric PpADI M31, starting point) to ~20 (tetrameric PpADI M36, final variant). Importantly, the PEGylated PpADI M36 after PEGylation exhibited significantly improved Tm values (M31: 40°C; M36: 40°C; polyethylene glycol [PEG]‐M31: 54°C; PEG‐M36: 64°C) and half‐life in human serum (M31: 1.9 days; M36: 2.0 days; PEG‐M31: 3.2 days; PEG‐M36: 4.8 days). These proved that surface engineering is an effective approach to increase the PEGylation efficiency which therefore enhances the stability of therapeutic enzymes. Furthermore, the PEGylated PpADI M36 represents a highly attractive candidate for the treatment of arginine‐auxotrophic tumors.