Proposal of a non-linear model to adjust in vitro gas production at different incubation times

This work aims to propose a new model named Gompertz-Von Bertalanffy bicompartmental (GVB), a combination of the models Gompertz and Von Bertalanffy. The GVB models is applied to fit the kinetic curve of cumulative gas production (CGP) of four foods (SS ­ sunflower silage; CS ­ corn silage; and the mixtures 340SS ­ 660 gkg-1 of corn silage and 340 gkg-1 of sunflower silage; and 660SS ­ 340 gkg-1 of corn silage and 660 gkg-1 of sunflower silage). The GVB fit is compared to models Logistic-Von Bertalanffy bicompartmental (LVB) and bicompartmental logistic (BL). All the process studied employed the semi-automatic "in vitro" technique of producing gases used in ruminant nutrition. The gas production readout was performed at times 2, 4, 6, 8, 10, 12, 15, 19, 24, 30, 48, 72, and 96 h. The data generated were used to estimate the models' parameters by the least squared method with the iterative Gauss-Newton process. The data fit quality of the models was verified using the adjusted coefficient of determination criterion (), mean residual square (MRS), Akaike information criterion (AIC), and mean absolute deviation (MAD). Among the analyzed models, the LVB model presented the best quality of fit evaluators for CS. In contrast, the GVB model showed better quality of fit to describe CGP over time for 340SS, 660SS, and SS, presenting the highest values of () and the lowest values of MSR, AIC, and MAD.

Use of microalgal biomass as functional ingredient for preparation of cereal based extrudates: impact of processing on amino acid concentrations and colour degradation kinetics

Abstract Suitability of developing Spirulina incorporated cereal based low cost nutritious extrudates was analysed against extrusion processing parameters. Most significant extrusion processing parameters considered for present study were feed moisture (20-25%), die temperature (100-120 °C) and screw speed (50-100 rpm). Different extrusion conditions were used to obtain most acceptable rice: Spirulina blend extrudates. In present study before extrusion processing different additives (citric acid and sodium bicarbonate) were added in rice: Spirulina blend and checked its effect on colour degradation kinetics at varied packaging and storage conditions. Higher screw speed (100 rpm) indicating less residence time of feed material inside the barrel resulted in higher colour retention of rice: Spirulina (97:03) blend extrudates. Kinetics for rice: Spirulina (97:03) blend extrudates indicates faster rate of colour degradation in terms of lightness (half-life of 4 days) when packed in metalized polyethylene at 50°C with 65% relative humidity. Increased concentration of Spirulina (1-3%) in raw formulations resulted in increase in concentration of all amino acids. Impact of extrusion processing has shown non-significant (p ≤ 0.05) effect on amino acid concentrations of rice: Spirulina blend extrudates. Also, all the spirulina added samples showed good consumer acceptability with the score of 6.7

Caracterización y estabilidad de un extracto rico en antocianinas a partir de corteza de gulupa / Characterization and stability of an extract rich in anthocyanins from passion purple fruit peel / Caracterização e estabilidade de um extrato rico em antocianinas de cortez de fruta roxa da paixão

Resumen La gulupa es una fruta originaria de la región amazónica, cuyo epicarpio es un subproducto con alto potencial en antioxidantes como las antocianinas. Por lo anterior, los objetivos de este estudio fueron realizar una extracción por solvente, a partir del epicarpio, para obtener un extracto rico en antocianinas; caracterizar su capacidad antioxidante y realizar la cinética de degradación de antocianinas monoméricas durante el almacenamiento a tres temperaturas (-14 ± 2 °C, 5 ± 1 °C y 21 ± 0,7 °C). En consecuencia, se obtuvo un extracto con un contenido de antocianinas de 165 ±9 mg cianidina-3-O-glucosido/L. La capacidad antioxidante fue de 464 ± 19 y 366 ± 7 μmol Trolox/100 g de extracto, según los ensayos FRAP y DPPH respectivamente, y un contenido de vitamina C de 2,07 ± 0,04 mg ácido ascórbico/100 g de extracto. La cinética de degradación se definió por el orden uno con las siguientes constantes: 2, 1·10-3, 8, 6·10-3 y 2,7·10-2 días-1 para -14 ± 2 °C, 5 ± 1 °C y 21 ± 0,7 °C respectivamente, generando una energía de activación de 46, 0·103 J/mo'l. Por consiguiente, se concluyó que es posible obtener, a partir del epicarpio de gulupa, extractos ricos en compuestos de alto valor como las antocianinas, los cuales son afectados por la temperatura de almacenamiento, siendo este un factor para considerar durante su aplicación en matrices alimentarias.

Abstract Purple passion fruit is a fruit from the Amazon region whose epicarp is a by-product with high potential as a source of anthocyanins. The objective of this investigation was to do a solvent extraction from the epicarp to obtain an extract rich in anthocyanins, and then, to characterize its antioxidant capacity, and evaluate the anthocyanin kinetic degradation during storage at three temperatures (-14 ± 2 °C, 5 ± 1 °C and 21 ± 0,7 °C). In consequence, an extract was obtained with an anthocyanin content of 165 ± 9 mg cyanidin-3-O-glucoside/L, an antioxidant capacity of 464 ± 19 and 366 ± 7 μmol Trolox/100 g extract according to FRAP and DPPH assays respectively, and a vitamin C content of 2.07 ± 0.04 mg ascorbic acid/100 g extract. The degradation kinetics was defined by order one with the following degradation constants: 2,1·10-3, 8,6·10-3 and 2,7·10-2 days-1 for -14 ± 2 °C, 5 ± 1 °C and 21 ± 0,7 °C, respectively, which corresponds to an activation energy of 46.0·10-3 J/mol. Therefore, it is concluded that is possible to obtain, from purple passion fruit epicarp, high-value compounds extract rich, such as anthocyanin, that is affected by storage temperature, which is an important factor during its use in food matrices.

Resumo O maracujá roxo é uma fruta nativa da região amazónica cujo epicarpo é um subproduto com alto potencial em antioxidantes como as antocianinas. Por conseguinte, o objectivo deste estudo foi a extracção por solventes a partir de epicarpo para se obter um extracto rico em antocianinas, caracterizar a sua capacidade antioxidante e executar a cinética de degradação de antocianinas monoméricas durante o armazenamento a três temperaturas (-14 ± 2 °C, 5 ± 1 °C e 21 ± 0,7 °C). Portanto, obteve-se um extracto contendo antocianina 165 ± 9 mg de cianidina-3-glucósido ou/L, a capacidade antioxidante de 464 ± 19 e 366 ± 7 micromol Trolox/100 g de extrato de acordo com o ensaio de FRAP e DPPH, e vitamina C de 2,07 ± 0,04 mg de ácido ascórbico/100 g de extrato. A cinética de degradação foi definida por ordem um com as seguintes constantes: 2,1·10-3, 8,6·10-3 e 2,7·10-2 dias-1 para -14 ± 2 °C, 5 ± 1 °C e 21 ± 0,7 °C respectivamente, gerando uma energia de ativação de 46,0·103 J/mol. Portanto, conclui-se que é possível obter, a partir de gulupa epicarpo, extrai rico em compostos de alto valor, tais como as antocianinas, as quais são afectadas por temperatura de armazenamento, sendo este um factor para ter em conta a sua aplicação em matrizes alimentares.

Preformulation of a liquid dosage formulation of captopril for pediatric use: drug-excipient compatibility and stability studies

Currently, medications used in children are typically modified from pharmaceutical dosage forms designed for adults. Captopril is widely adapted to liquid formulations for use in hospitals. Its stability in the aqueous medium is reduced since it undergoes oxidation producing captopril disulfide (its main metabolite). The aim of this formulation study was to suggest favorable conditions for the development of a stable captopril formulation. The compatibility between the drug and excipients was evaluated by differential scanning calorimetry analysis (DSC). For studies in solution, different formulations were prepared according to a factorial design varying EDTA concentration, water purity and pH. The resultant formulations were stored at 60°C and analyzed over a twelve-day period using HPLC. The DSC curves obtained suggested, although not conclusive to elucidation, interactions of captopril with citric acid and sucralose. The stability study of these solutions revealed that the variables significantly influenced captopril content, which degraded at zero order kinetics and rates differing by a factor of up to 7 times, where pH proved the most influential factor. Interactions between variables were observed. Therefore, development of a stable captopril formulation is feasible provided EDTA and a buffering agent is used at suitable concentrations (0.08% and pH 3.85).

Study on degradation kinetics of epalrestat in aqueous solutions and characterization of its major degradation products under stress degradation conditions by UHPLC-PDA-MS/MS / 药物分析学报

Drug stability is closely related to drug safety and needs to be considered in the process of drug production, package and storage. To investigate the stability of epalrestat, a carboxylic acid derivative, a reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed in this study and applied to analyzing the degradation kinetics of epalrestat in aqueous solutions in various conditions, such as dif-ferent pH, temperatures, ionic strengths, oxidation and irradiation. The calibration curve was A=1.6 × 105C–1.3 × 103 (r=0.999) with the liner range of 0.5–24 μg/mL, the intra-day and inter-day precision was less than 2.0%, as was the repeatibility. The average accuracy for different concentrations was more than 98.5%, indicating that perfect recoveries were achieved. Degradation kinetic parameters such as degradation rate constants (k), activation energy (Ea) and shelf life (t0.9) under different conditions were calculated and discussed. The results indicated that the degradation behavior of epalrestat was pH-dependent and the stability of epalrestat decreased with the rised irradiation and ionic strength;however, it was more stable in neutral and alkaline conditions as well as lower temperatures. The results showed that the degradation kinetics of epalrestat followed first-order reaction kinetics. Furthermore, the degradation products of epalrestat under stress conditions were identified by UHPLC-PDA-MS/MS, with seven degradation products being detected and four of them being tentatively identified.

Effect of Phospholipid Complex on the Degradation of Geniposide by Rat Intestinal Flora in Vitro / 中国药学杂志

OBJECTIVE: To investigate the effect of geniposide phospholipid complex on the degradation of geniposide by intestinal microflora, which provides the rationale for the design of an appropriate geniposide dosage form.METHODS: The intestinal flora was collected from fresh rat feces. The geniposide and geniposide physical mixtures and their complexes were incubated with the rat intestinal flora in anaerobic conditions, respectively. Samples were taken at 0,2, 4, 6, 8 and 12 h. The content of geniposide was determined by HPLC. The preparative geniposide phospholipid complexes were characterized by DSC and X-ray diffraction.RESULTS: In the physical mixture of geniposide and geniposide phospholipids, geniposide continuously decreased in the first 2 h, while the degradation accelerated at 2 to 4 h and completely degraded at 4 h. In the phospholipid complex group, the content of geniposide was decreased by 67.2% within 6 h, and it was completely degraded at 8 h.CONCLUSION: The geniposide can be completely degraded in the gut microbiota of male SD rats in vitro. After the preparation of the phospholipid complex, the degradation rate of geniposide was slowed down. In the physical mixture group, the presence of phospholipids does not delay the degradation of jasminoidin.

Degradation kinetics of larotaxel and identification of its degradation products in alkaline condition / 药物分析学报

Larotaxel, a new taxane compound prepared by partial synthesis from 10-deacetyl baccatin Ⅲ, is active against tumors. In this research, a selective LC–MS method was developed and validated for the study of degradation kinetics of larotaxel, which was carried out in aqueous solutions with different pH (1.5, 3.0, 5.0, 6.5, 7.4, 9.0, 10 and 11.0) and temperature (0, 25, 37 and 45 °C). The linear range was 0.5–25μg/mL, the intra-and inter-day precisions were less than 7.0%, and accuracy ranged from 97.4–104.5% for each analyte. The observed rate obtained by measuring the remaining intact larotaxel was shown to follow first-order kinetics. The activation energies for degradation were 126.7 and 87.01 kJ/mol at pH 1.5 and 11, respectively. Although larotaxel was stable in pH 5, 6.5 and 7.4 buffers at 37 °C for 24 h during our study, increasing or decreasing the pH of the solutions would decrease its stabilities. Moreover, three main degradation products in alkaline condition were separated by HPLC and identified by Q–TOF–MS. The three degradation products were confirmed as 10-deacetyl larotaxel, 7, 8-cyclopropyl baccatin Ⅲ and 10-deacetyl-7, 8-cyclopropyl baccatin Ⅲ.

Chemical degradation kinetics of fibrates: bezafibrate, ciprofibrate and fenofibrate

ABSTRACT Fibrates are drugs used for the treatment of hypertriglyceridemia and for the prevention of atherosclerosis. Three drugs in the fibrate class, ciprofibrate, fenofibrate and bezafibrate, were chosen for this study because their raw materials are readily available and because scientific publications on these compounds is limited. To evaluate their intrinsic stability, the drugs were exposed to a test condition (temperature, oxidation, UV light exposure, hydrolysis at different pH values and metal ions in solution) and then were subjected to analysis by HPLC. The samples were run on a C18 column, with a flow rate of 1.0 mL min-1 in a mobile phase consisting of methanol: 0.01 % phosphoric acid v/v (80:20), with variable detection wavelengths in the UV spectra. The analysis methodology showed satisfactory performance parameters. The three drugs were very unstable, degrading in each of the conditions evaluated. The test conditions of acid and basic hydrolysis showed the most significant degradation. The results demonstrated that the drugs in this class are unstable. Based on these experimentally determined degradation kinetics, it is easy to understand and emphasize the importance of the lack of liquid dosage forms on the market for fibrates because of their instability.

Estabilidad de antocianinas durante el almacenamiento de jugos de arándanos / Anthocyanins stability during storage of blueberries juice

Antecedentes: Los arándanos y productos de arándano tienen alto valor nutricional, especialmente por su alto contenido de antocianinas. Estas son potentes antioxidantes y poseen alta capacidad de secuestrar radicales libres. Así, los arándanos y productos de arándanos han resultado atractivos para los consumidores interesados en alimentos funcionales. Sin embargo, los tratamientos térmicos y posterior almacenamiento de productos alimenticios influyen en el contenido de antocianinas. La cinética de degradación de las antocianinas puede ser evaluada desde una perspectiva termodinámica, basada en funciones como energía libre, entalpía, entropía y energía de activación. Objetivos: Se estudió el efecto de la pasteurización y la estabilidad de antocianinas presentes en jugos de arándanos, sin pasteurizar y pasteurizados, durante el almacenamiento. Métodos: Jugos de arándanos sin pasteurizar y pasteurizados fueron almacenados a -18, 0, 5 y 10°C durante 148 días. A intervalos de tiempos se cuantificó la concentración de antocianinas monoméricas totales. Se realizó un Análisis de Componentes Principales y los resultados experimentales se ajustaron a modelos cinéticos de orden cero y uno, y a los modelos de Arrhenius y Eyring. Resultados: La pasteurización provocó disminución del 28,5% en la concentración inicial de antocianinas monoméricas totales, mientras que para todas las temperaturas estudiadas, la disminución de antocianinas en función del tiempo de almacenamiento siguió una cinética de primer orden. En el jugo sin pasteurizar, la constante de velocidad de degradación varió entre 0,0080 - 0,0084 días-1 y el tiempo de vida media, entre 75 - 87 días. En el jugo pasteurizado, la constante de velocidad de degradación varió entre 0,0023 - 0,0060 días-1 y el tiempo de vida media, entre 116-301 días. En éste la energía de activación, la energía libre de Gibbs, entalpía y entropía de activación fueron 44,66 kJ/mol, 83,80 kJ/mol, 42,35 kJ/mol y -139,09 J/mol.K, respectivamente". Conclusiones: El tratamiento de pasteurización provocó disminución del 28,5% en la concentración de antocianinas monoméricas totales iniciales de los jugos de arándano. La estabilidad de las antocianinas durante el almacenamiento fue mayor en los jugos pasteurizados, siendo mayor cuando se almacenaron a 0°C; mientras que en los jugos pasteurizados almacenados a -18°C las antocianinas mostraron menor estabilidad.

Background: The blueberries and blueberry products has great nutritional value, primarily because it has high anthocyanin content. Anthocyanins are potent antioxidants and have high radical-scavenging activities. Thus, the blueberry and blueberry products has become very appealing to consumers interested in functional foods. However, the anthocyanins content is affected by heat treatment and subsequent storage. The kinetics degradation of anthocyanins can be evaluated from a thermodynamic perspective, based on activation functions such as free energy, enthalpy, entropy and activation energy. Objectives: pasteurization effect and anthocyanins stability were studied during storage of pasteurized and nonpasteurized blueberries juices. Methods: Pasteurized and non-pasteurized blueberries juices were store at -18, 0, 5 and 10°C during 148 days. Total monomeric anthocyanins concentration was quantified at different times. Principal Components Analysis was performed and experimental results were adjusted to zero and first-order kinetic models as well as to Arrhenius and Eyring ones. Results: A decrease in total monomeric anthocyanins original concentration was 28.5 % due to pasteurization while for all temperatures studied, the reduction followed a first-order kinetic during storage. Degradation rate constant varied between 0.0080 - 0.0084 days-1 and half-life, 75 - 87 days for non-pasteurized juices, whereas these parameters were among 0.0023 - 0.0060 days-1 and 116 - 301 days, respectively for pasteurized ones. Activation energy was 44.66 kJ/mol while Gibbs free energy, enthalpy and entropy were 83.80 kJ/ mol, 42.35 kJ/mol and -139.09 J/mol. K respectively, for the latter juices. Conclusions: Pasteurization caused in a 28.5 % loss of initial total monomeric anthocyanins. Anthocyanins stability was higher in pasteurized blueberries juices and resulted even bigger when store at 0°C, while in pasteurized juices stored -18 ° C were less stable anthocyanins.

Preparation and in vitro evaluation of albumin nanoparticles produced by thermal driven self-assembly / 中国药科大学学报

@#The aim of this study was to prepare albumin nanoparticles by thermal driven self-assembly, and to investigate the formation mechanism, cellular uptake, the kinetics of cellular uptake and intracellular degradation, etc. By measuring the concentrations of thiol, amino and carboxyl groups, the formation mechanism of albumin nanoparticles was revealed. CCK-8 assay was performed to detect the cytotoxicity; inverted fluorescence microscope was used to observe the cellular uptake of the nanoparticles; while the fluorescence resonance energy transfer(FRET)method was applied to investigate the cellular uptake and intracellular degradation kinetics. The drug-loading capacity was investigated using paclitaxel(PTX)as the model drug. The results showed that the albumin nanoparticles produced by thermal driven self-assembly were safe, nontoxic, biodegradable and stabilized by intermolecular disulfide and amide bonds. The drug-loading study indicates that PTX can be highly encapsulated in the nanoparticles. Hence, thermal driven self-assembly method is green and easy to operate, and the albumin nanoparticles can be applied as a new delivery platform for anticancer drugs.

Studies on scutellarin and its degradation kinetics in Dengzhanhuasu Injection / 中草药

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.

Degradation kinetics of chlorogenic acid, cryptochlorogenic acid, and neochlorogenic acid at neutral and alkaline pH values / 药学学报

The degradation kinetics of chlorogenic acid (5-CQA), cryptochlorogenic acid (4-CQA), and neochlorogenic acid (3-CQA) in aqueous solution at 37 ℃ and different pH values (7.05, 7.96, 9.25) were investigated in the present work. The results indicated that 3-, 4- and 5-CQA tended to remain stable in acidic pH circumstance, and unstable in neutral and alkaline pH circumstance. With the increase of the alkalinity, the degradation of 3-, 4- and 5-CQA was increased leading to a less amount of total CQA and was satisfactorily described by the Weibull equation. Meanwhile, caffeic acid was not detected after the degradation of CQA. Moreover, the degradation of 3-CQA and 5-CQA tended to be converted to 4-CQA, and the degradation of 4-CQA tended to be converted to 3-CQA rather than 5-CQA. The comparison of the degradation kinetics parameters of 3-, 4- and 5-CQA at neutral and alkaline pH values showed that the orders of the rate constant (k) values were 4-CQA > 3-CQA > 5-CQA, while the orders of the degradation half life (t1/2) values were 4-CQA < 3-CQA < 5-CQA, indicating the orders of the stabilities of 3-, 4- and 5-CQA at 37 ℃ and neutral and alkaline pH values were 4-CQA < 3-CQA <5-CQA.

Assessment by HPLC of the degradation behavior of acitretin under hydrolytic, oxidative, photolytic and thermal stress conditions

Acitretin is a photosensitive oral retinoid with very limited data available on its degradation. The official HPLC method for acitretin determination was insufficient to resolve the degradation products generated during stability studies. Therefore, an isocratic RP-HPLC-UV method was developed for the determination of acitretin in the presence of its related impurities and degradation products. Efficient chromatographic separation was achieved on a Thermo beta-basic column C18 (100 mm×4.6 mm, 5 μm) with mobile phase containing 0.3% (v/v) glacial acetic acid with acetonitrile (ACN) and isopropyl alcohol (IPA) in an isocratic ratio of 70:30 at a flow rate of 1.0 mL/min with the eluent monitored at 360 nm. The method was validated for specificity, linearity, precision, accuracy and robustness. The calibration plot was linear over the concentration range of 50-150 μg/mL with a correlation coefficient (r (2)) of 0.999. The proposed method was used to investigate the degradation kinetics of acitretin under the different degradative conditions. The degradation rate constant (K), half-life (t 1/2), and t 90 were calculated. Degradation of acitretin followed pseudo-first-order kinetics. The drug was found to be less stable under acidic and photolytic degradation conditions: the photolytic degradation constants for acitretin in sunlight and UV light were 0.002698% and 0.0008402% min(-1), respectively. The LOD for acitretin and the known impurities were at a level below 0.02%. The method shows consistent recoveries for ACTR (99.8%-101.2%) and also for its known impurities (97.2-101.3%). The method was found to be accurate, precise, linear, specific, sensitive, rugged, robust, and useful for characterizing the stability of this chemical.

Studies on degradation kinetics of paeoniflorin-6-O’- benzenesulfonate in vitro / 安徽医科大学学报

Objective To investigate the degradation kinetics of paeoniflorin-6-O’- benzenesulfonate ( CP-25 ) in vitro. Methods The homogenates of liver and intestine were prepared in vitro, and concentrations of CP-25 in ho-mogenates were detected by HPLC. Results CP-25 was obviously degradable in liver and intestine homogenates, and half life of degradation was decreased when levels of homogenates increased;the metabolisms of CP-25 in dif-ferent homogenates of intestine were diverse, the metabolic actions in duodenum and colon were weaker than those of jejunum and ileum. Conclusion Oral administration of CP-25 suffers first pass elimination from intestine and liver, which suggests the absorption of CP-25 could be further improved by appropriate pharmaceutical preparations.

Degradation kinetics of methylnaltrexone bromide aqueous solution / 中国药学杂志

OBJECTIVE: To investigate the degradation kinetic characteristics of methylnaltrexone bromide aqueous solution and to study the factors that influence methylnaltrexone bromide degradation, thus to provide necessary data for the pharmaceutical research. METHODS: Classical isothermal method was employed to evaluate the degradation kinetic profile of methylnaltrexone bromide under different temperatures, pH values, illumination and concentrations of Fe3+. The activation energy and shelf life were predicted with Arrhenius equation. RESULTS: The degradation of methylnaltrexone bromide aqueous solution complied with first order kinetics. The aqueous solution was stable in an environment of pH 3.51, the higher the temperature was, the larger the degradation kinetic rate constant was. The shelf-life of the aqueous solution was 145 d at room temperature; and the illumination, as well as the existence of Fe3+ could both facilitate the degradation of methylnaltrexone bromide. CONCLUSION: The degradation of methylnaltrexone bromide follows apparent first-order kinetics, and the degradation kinetic rate is affected by Fe3+ and illumination. Moreover, its degradation remarkably and positively correlates with temperature. pH also has an effect on the degradation rate. The kinetic profile provides basis for the investigation of the degradation mechanism and necessary experimental data for the future pharmaceutical research.

Isolation,Identification and Degradation Characteristics of a DMP-degrading Strain / 微生物学通报

A bacterial strain which could grow well on the substrate of PAEs as the sole source of carbon and energy was isolated from contaminated sludge in the river of WeiFang in ShangDong province and it was designated as JDC-3. Based on the morphology,biophysical and biochemical properties as well as molecular characteristics,this isolate was preliminarily identified as Delftia sp.. A fragment of phthalate dioxygenase gene was successfully amplified from the genus of Delftia for the first time using a set of degenerate primers. Meanwhile,the degradation capability of JDC-3 was determined by HPLC using DMP as test substrate. The results showed that the optimal pH and temperature were at 7.0～8.0 and 30?C～35?C respectively. The degradation kinetics of JDC-3 was studied in different initial DMP concentration under optimal conditions. The results indicated that the degradation dynamic equation was ln C =-0.06837 t + A when DMP concentration was lower than 300 mg/L,with half life of 12.48 h. The degradation rate decreased and half life of JDC-3 prolonged as the initial concentration kept on increasing.

Degradation Kinetics of Sinomenine Hydrochloride Aqueous Solution / 中国药房

OBJECTIVE:To investigate the degradation kinetic characteristics of Sinomenine hydrochloride aqueous solution.METHODS:The colorimetric method was used to determine the degradation kinetic parameters of Sinomenine hydrochloride aqueous solution under various pH solutions,various ionic strength and various dielectric constant conditions.RESULTS:With comparative regression analysis of linear fitting,the degradation kinetic order of Sinomenine hydrochloride aqueous solution was determined as n=1.The higher the pH in Sinomenine hydrochloride aqueous solution was,the higher the degradation kinetic rate constant was.The Sinomenine hydrochloride aqueous solution degraded slowly at the field of lower pH(pH5).The higher the ionic strength of Sinomenine hydrochloride aqueous solution was,the higher the degradation kinetic rate constant was.As the dielectric constant of solution increased,so did the degradation kinetic rate constant.CONCLUSION:It was found that the degradation of Sinomenine hydrochloride followed apparent first-order kinetics.The degradation kinetic rate was affected by pH remarkably and positively correlated with ionic strength and dielectric constant.

DEGRADATION KINETICS OF ACONITINE IN THE SAMPLE OF RABBITS / 西安交通大学学报(医学版)

A high performance liquid chromatography (HPLC)has been used to determine aconitine in the sample of rabbits. Kinetics of degradation of aconitine in vitro was studied. The degradation of aconite from the poisoned specimens (coagulated blood, liver) treated differently in vitro was characterized by pseudo-secondorder kinetics. The K. of aconitine in these samples was the biggest in the fixed section of 4% aqueous solution of formaldehyde (1.5619, O.7728?g/d), bigger in the fixed section of 95% alcohol(0.4891, 0.07536?g/d) and the smallest in the refrigerator at 4℃ (0.06372, 0.03903 ?g/d), respectively. That is, aconitine in the poisoned samples was decomposed slowly in the refrigerator and secondly in the fixative of alcohol. Amount of aconitine might be extrapolated from the result of examination of specimens taken from the subject after poisoning or killing by the poison, using the kinetics equation.