1.Research on the transformation of diisopropyl azodicarboxylate (DIAD) in gas chromatography and the development of its residual determination method
Shuai CHEN ; Junliang YAO ; Daquan YIN
Journal of China Pharmaceutical University 2026;57(4):460-465
For the first time, an intriguing phenomenon was observed in which diisopropyl azodicarboxylate (DIAD) was converted into diisopropyl hydrazine-1,2-dicarboxylate (DIHD) during gas chromatography (GC) analysis. Subsequently, a GC method with pre-column derivatization was developed and validated for the determination of residual DIAD, using triphenylphosphine (TPP) as the derivatization reagent. The method was performed on a gas chromatograph equipped with a flame ionization detector (FID), using direct injection, an Agilent DB-5 capillary column, and a programmed temperature profile. Method validation demonstrated a good linear response for DIAD in the range of 1.057-10.57 µg/mL, with a detection limit of 0.528 µg/mL and a quantification limit of 1.057 µg/mL. The established method allows DIAD and DIHD to be determined collectively as a single analyte, both of which may be introduced during the manufacturing process. It exhibits high accuracy, sensitivity, excellent repeatability and stability, as well as a simple and rapid derivatization procedure. This method is expected to be applicable as a general approach for detecting DIAD and its structural analogues.
2.Preparation and characterization of multi-functional targeting nano-carrier based on pH-redox tumor microenvironment
Jingfang SUN ; Chunjing GUO ; Yunduan ZHANG ; Xiaoyan SONG ; Jiantao LYU ; Jungang YIN ; Daquan CHEN
Journal of China Pharmaceutical University 2017;48(3):305-310
In order to construct a novel multifunctional targeting nano-carrier based on pH-redox characteristics of tumor microenvironment,ketone bonds and disulfide bonds were bonded to the oligomeric hyaluronic acid (oHA) being sensitive to pH and the reduction environment.The chemical structure of oligomeric hyaluronic acid-8-mercaptomenthone 1,2-glycerolketal (oHMST) was characterized by 1H NMR,IR and ESI-MS.Curcuminloaded micelles were prepared by dialysis.The single factor investigation was carried out on the dosage form.Some properties,including particle size zeta potential,the morphology of micelles,and pH-sensitivity were studied.The materials were synthesized successfully.The micelles were spheric with a diameter of about 100 nm.The Zeta potential of the micelles was-(21.97 ± 1.08) mV.The in vitro test showed that oHMST carriers have good pH-sensitivity and redox-sensitivity.

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