Pan Zhang,Yanxi Ji,Wenya Li,Lihua Xu,Lemeng Wang,Dong Fu
The viscosities of N -(2-aminoethyl)ethanolamine (AEEA), 1,4-butanediamine (BDA) and N-methyl- 1,3-propane- diamine (MAPA) activated 2- diethylaminoethanol (DEAE) aqueous solutions were measured at temperatures ( T ) from 303.2 K to 323.2 K, respectively. The DEAE mass fractions ( w DEAE ) and the other three amines ( w AEEA / w BDA / w MAPA ) are 0.300 to 0.500 and 0.050 to 0.150 respectively. The Weiland equation was used to calculate the viscosity of these three solutions, and the calculation results were satisfied with data of the experimental results. With the aid of experimentally determined viscosity data, the activation energy ( E a) of these three solutions was predicted through the Arrhenius formula. With the help of the viscosity data and the diffusion coefficient model of CO 2 in water, the CO 2 diffusion coefficient ( D CO2 ) in these three solutions was calculated. The quantitative relationship between the calculated values (viscosity, activation energy and diffusion coefficient) and the operation conditions (solution mass fraction and temperature) was analyzed. Our results show that the DEAE-BDA absorbent has better application potential due to its lower viscosity, higher CO 2 diffusion coefficient and lower activation energy.
A specific, sensitive, rapid, precise, and reliable UPLC–MS/MS-based method was designed for the first time for the simultaneous determination of 1-deoxynojirimycin (DNJ) and N-methyl-1-deoxynojirimycin (N-CH 3 -DNJ) in rat plasma. Miglitol was served as the internal standard (IS). An MN-NUCLEODUR HILIC column was assessed to separate the two compounds by isocratic elution using acetonitrile : water with 0.05% formic acid and 6.5 mM ammonium acetate (72:28, v/v) at a flow rate of 0.4 mL/min. A triple quadrupole mass spectrometer was operated in the positive ionization mode using multiple reaction monitoring (MRM), and it was employed to determine transitions of m / z 164.1 → 110.1, 178.1 → 100.1, and 208.1 → 146.1 for DNJ, N-CH 3 -DNJ, and IS, respectively. The method of the two constituents was validated and the results were acceptable. The absolute bioavailability of DNJ and N-CH 3 -DNJ in rats was 50 ± 9% and 62 ± 24%, respectively. The method was then successfully used for the first time to study the pharmacokinetic behavior and absolute bioavailability of DNJ and N-CH 3 -DNJ in rats after intravenous (10 mg/kg) and oral administration (80 mg/kg). The results of this study might provide more information on preclinical pharmacokinetics and a solid basis for assessing the clinical efficacy of DNJ and N-CH 3 -DNJ.
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