Systematic screening and structural characterization of dipeptides using offline 2D LC-LTQ-Orbitrap MS:A case study of Cordyceps sinensis / 药物分析学报

Cordyceps sinensis(C.sinensis)is a widely used and highly valuable traditional Chinese medicine.Several dipeptides have been detected in C.sinensis,but current scientific knowledge of its chemical makeup remains limited.In this study,an improved approach that integrates offline two-dimensional liquid chromatography(2D LC)separation,precursor ion list,library screening,and diagnostic ion filtering was established to systematically screen and characterize dipeptides in C.sinensis.Offline 2D LC integrating hydrophilic interaction LC and reverse phase separations was established to eliminate interference and identify the target dipeptides.A library containing the potential 400 dipeptides was created,and a precursor ion list with all theoretical precursor ions was adopted to trigger the MS/MS scan with high sensitivity.To identify dipeptides,the type and connection sequence of amino acids were determined according to the product ions.Ile and Leu residues were differentiated for the first time according to the characteristic ion at m/z 69.07.Ultimately,170 dipeptides were identified or tentatively characterized from C.sinensis,and most are reported for the first time in this species herein.In addition,the identified dipeptides were also applied for discrimination among the three Cordyceps species,and 11 markers were identified.The obtained results provide a deeper understanding of the chemical basis of C.sinensis.

Forming Technology Optimization of Zuojin Concentrated Pills by Orthogonal Test / 中国药师

Objective:To optimize the forming technology of Zuojin concentrated pills. Methods: Single factor test was used to optimize the types of excipients and wetting agents with the shaping result as the index. Orthogonal test was used to optimize the forming technology taking the dissolution time,shaping rate and appearance quality as the evaluation indices,and the proportion of excipients, the rate of drugs to excipients and wetting agent amount as the investigation factors. Results: The best forming technology of Zuojin concentrated pills was as follows:MCC and PVP-K30 were used as the excipients with the ratio of 3:1,the ratio of drugs to excipients was 1:1,5% water was used as the wetting agent to obtain the damp mass,and then Zuojin concentrated pills were prepared in a pill machine. Conclusion:The optimized forming technology is stable with good reproducibility,and the pills are round and smooth with u-niform color,whose quality meets the requirements described in Chinese Pharmacopoeia(2015 edition,partⅣ,page 0108 for concen-trated pills). The study provides reference for the further study.