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One-sixth of the currently known natural products contain α, β-unsaturated carbonyl groups. Our previous studies reported a rare C-sulfonate metabolic pathway. Sulfonate groups were linked to the β-carbon of α, β-unsaturated carbonyl-based natural compounds through this pathway. However, the mechanism of this type of metabolism is still not fully understood, especially whether it is formed through enzyme-mediated biotransformation or direct sulfite addition. In this work, the enzyme-mediated and non-enzymatic pathways were studied. First, the sulfite content in rat intestine was determined by LC-MS/MS. The results showed that the amount of sulfite in rat intestinal contents was from 41.5 to 383 μg·g
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Abstract We discuss recent results on decay of exotic proton rich nuclei at the proton drip line with Z<50, that are of great importance for nuclear astrophysics models.
Resumen Discutimos los resultados recientes sobre la desintegración de los núcleos exóticos ricos en protones en la línea de goteo de protones con Z <50, que son de gran importancia para los modelos de astrofísica nuclear.
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Based on the fact that chromogenic reaction of blue complex, a reaction product which can be dissolved in organic solvents, can be realized by polyethoxy and ammonium thiocyanate in tween 80, a rapid and accurate way for the determination for tween 80 in pharmaceutical adjuvant was established in this study, providing reliable technical means for quality control of traditional Chinese medicine injections. Based on the study of reaction kinetics, chromogenic reaction temperature and time, as well as extraction of organic solvents and other key conditions were optimized, and Kumu injection was used as the test material for method validation and applicability investigation. It was finally determined that 3 mL ammonium thiocyanate solution was added in the sample solution, and the reaction was carried out in a boiling water bath for 2 h. After cooling to room temperature, 5 mL of dichloromethane was added to extract the chromogenic product. The absorbance value was measured at the wavelength of 623 nm to calculate the tween 80 content in the sample. Under optimized conditions, tween 80 solution showed a good linear relationship with the absorbance in the range from 0.8 mg to 3.0 mg. The linear regression equation was ＝0.258-0.047. The correlation coefficient was 0.999 6. Under the experimental conditions, the average recovery was 99.66%, and the precision RSD was less than 2.0%. The results showed that this method can quickly and accurately determine the content of tween 80 in Kumu injection, and it could be applicable to the quality control of traditional Chinese medicine injections.
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Adyuvantes Farmacéuticos , Química , Medicina Tradicional China , Polisorbatos , Química , Control de Calidad , Solventes , TemperaturaRESUMEN
Objective To investigate the reaction kinetics between the stone-dissolving solution and the urinary stone in a model simulating the condition of a kidney for further clinical administration. Methods An artificial upper urinary tract was made by silica gel. Lactic acid prepared in the preliminary study was used to react with artificial stone in the model. The concentration of reaction product in the effluent was measured to identify the reaction velocity. Relationships between the efficiency and dissolution rate or stone surface was investigated. Results The highest utilization rate of dissolution was 100 ~ 150 mL/h. Dissolution efficiency is in positive rela-tion with stone surface. The efficiency correlates with the stone surface and infusion speed in the range of 50~400 mL/h. Conclusions Before dissolution treatment ,the stone should be shattered as deeply as possible to in-crease the surface of reaction. If possible ,the irrigating speed should be as high as possible to eliminate the stone sooner.
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Objective: To investigate the stability of aqueous solution of scutellarin at different pH values, temperature, ionic strengths, and initial concentration under the condition of dynamic characteristics of the degradation reaction according to ICH guidelines. Methods: The content of scutellarin change with time in different conditions was studied using HPLC method. Based on the chemical reaction kinetics, the parameters of degradation kinetics were calculated under different conditions. The activation energy and half-time (t1/2) were evaluted. Results: The degradation of scutellarin in different conditions followed the first-order kinetics process. The most stable enviroment was in aqueous solutions of pH 7 at 25℃, the half-life period was 203.87 h and the reaction activation energy was 97.9 kJ/mol. But with the temperature increased, the degradation reaction rate greatly accelerated. Under any condition, the stability is higher than the monomer. The initial concentration and ionic strength of Na+ and Cl- had no influence for its degradation. Conclusion: The degradation of scutellarin in different conditions follows the first-order kinetics process and is greatly influenced by the environment of high temperature, strong acid, and weak alkaline. The injection with five kinds of commonly used infusion compatibility is unstable.
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Objective: To study the enzymatic reaction kinetics of dl- tetrahydropalmatine (TET) in total alkaloid (TA) of Corydali Rhizoma in rat liver microsomes and to investigate the compatible effects of the effective components such as coumarin (Cou) and volatile oil (VO) in Angelicae Dahuricae Radix with TA in Corydali Rhizoma on enzymatic reaction kinetics of TET. Methods: Rat liver microsomes were prepared by ultracentrifugation and the TET concentration in incubation medium was determined by HPLC. Comparative study on the enzymatic reaction kinetics of TET in each group of TA, TA-Cou, TA-VO, and TA-Cou-VO to deduce the michaelis constant (Km) and maximum reaction rate (Vmax) of TET in each group and calculate the clearance rate (CLint) of TET in each group. Results: The Km, V max, and CLint in TA group were 0.12 μmol/ (L·min·mg), 5.40 μmol/L, and 0.022 L/(min·mg), respectively; In TA-Cou group they were 0.27 μmol/(L·min·mg), 40.18 μmol/L, and 0.006 L/(min·mg), respectively; In TA-VO group they were 0.57 μmol/(L·min·mg), 22.60 μmol/L, and 0.025 L/(min·mg), respectively; In TA-Cou-VO they were 0.84 μmol/(L·min·mg), 23.25 μmol/L, and 0.036 L/(min·mg), respectively. Conclusion: The effective components of TA in Corydali Rhizoma with Cou and VO in Angelicae Dahuricae Radix could decrease CLint of TET in TA of liver.
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Using Isopropyl amine (0.003 mol/L), p-methyl-phenol (0.03 mol/L) and methanol (1 mol/L) for simulating amino groups, phenol groups and hydroxyl groups in silk fibroin respectively, the reaction rate of different nucleophilic groups in silk with monochlorotriazine reactive dye was studied at various temperature and pH by high performance liquid chromatography. It was found that the overall reaction rate of dyes′ phenolysis was by far higher than that of ammonolysis and alcoholysis on the conditions of 70-95 ℃ and pH=8-10. The phenolysis overall reaction rates of C.I. reactive red 24 and C.I. reactive orange 2 were 8.5 and 12.5 times of their ammonolysis′, and 23 and 50 times of their alcoholysis′ in the term of pH 9 and 95 ℃. The phenolysis efficiencies of those two dyes were 47.4 and 96.3, the ammonolysis efficiencies were 4.6 and 6.9, and the isopropyl amine, p-methyl-phenol and methanol to simulate the silk fibroin, the reaction selectivity between the monochlorotriazine reactive dyes and nucleophilic groups in silk fibroin was investigated. It was deduced that monochlorotriazine reactive dyes are suitable for dyeing silk on the conditions of about 85 ℃ and pH=8-9, and under this condition, phenol groups are the major groups in silk dyeing with monochlorotriazine reactive dyes, amino groups are the minor groups, and the contributions of hydroxyl groups can be neglected.
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ABSTRACT The nuclear shell model predicts that the next doubly magic shell-closure beyond 208Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical ‘SuperHeavy Elements’ (SHEs). Experimental methods are described, which allowed for the identification of elements produced on a cross-section level of about 1 pb. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission, not fission. Decay properties as well as reaction cross-sections are compared with results of theoretical investigations.
El modelo nuclear de capas predice que el próximo nivel doblemente mágico más allá de 208Pb ocurre para un número atómico Z = 114, 120 o 126 y para un número de neutrones N = 172 o 184. El objetivo más importante de estos experimentos es la exploración de la región de elementos superpesados esféricos. En el trabajo se describen los métodos experimentales que permitieron identificar los elementos producidos para un valor de la sección eficaz de aproximadamente 1 pb. Los datos de decaimiento revelan que para los elementos más pesados el modo dominante es la emisión alfa y no la fisión. Las propiedades de decaimiento así como las secciones eficaces se comparan con resultados de estudios teóricos.