植物胶水溶性影响因素的研究

针对植物胶的水溶性，从物理改性和配液方法两个方面，研究了原料、水合、增粘、粉碎、配液对瓜尔胶粘度和水不溶物的影响，确定了比较理想的工艺参数、技术路线和配液方法。     

Aqueous solubility of poorly water-soluble drugs: Prediction using similarity and quantitative structure-property relationship models

The aqueous solubility of poorly water-soluble drugs is an important property of many factors affecting their bioavailability such as the solubility and rate of dissolution in water. The quantitative structure-property relationship approach using genetic algorithm was applied to make models for predicting some poorly water-soluble drugs such as ursodeoxycholic acid, diphenyl hydrantoin and biphenyl dimethyl dicarboxylate. The experimental solubility data of 3518 chemical structures were collected from the web and used to build a model. Three data sets of 50 compounds were extracted according to their structural similarity with each drug. A fast and predictive similarity based approach was developed and validated with conventional method. This can be used to predict the aqueous solubility for drugs by using a small set of compounds, especially for poorly water-soluble compounds. Moreover, the estimation values of various sets were further compared with fine grinding experiment data.     

Enhancing the solubility and bioavailability of isoflavone by particle size reduction using a supercritical carbon dioxide-based precipitation process

Isoflavones are a group of small molecular compounds found in many plants. Genistein is the most well studied isoflavones because of its beneficial effects in reducing menopausal symptoms, anti-oxidant and anti-cancer. The major difficulty in developing isoflavone-based healthcare products is their low water solubility. In this study, the solubility and oral bioavailability of genistein were increased by reducing its particle size using supercritical CO₂ as an antisolvent in the precipitation process. The effects of various process parameters including type of solvent, pressure of precipitation, and concentration of genistein solution on particle formation were evaluated. We found that under optimized conditions: dissolving 4 mg/mL genistein in acetone and precipitating them with supercritical CO₂ under 100 bar at 40 °C, the size of genistein particles was reduced from its original width of 10–50 μm to ∼254 nm. The reduction of genistein particle size not only increased its water solubility by 2 fold but more importantly increased its 24 h-plasma concentration by 2.6 fold after orally administrated to rats. These results proof the concept of using supercritical CO₂ as an antisolvent in the precipitation process to reduce particle size of water insoluble compounds such as genistein and to improve its oral bioavailability.     

A novel chemometric method for the prediction of human oral bioavailability

Orally administered drugs must overcome several barriers before reaching their target site. Such barriers depend largely upon specific membrane transport systems and intracellular drug-metabolizing enzymes. For the first time, the P-glycoprotein (P-gp) and cytochrome P450s, the main line of defense by limiting the oral bioavailability (OB) of drugs, were brought into construction of QSAR modeling for human OB based on 805 structurally diverse drug and drug-like molecules. The linear (multiple linear regression: MLR, and partial least squares regression: PLS) and nonlinear (support-vector machine regression: SVR) methods are used to construct the models with their predictivity verified with five-fold cross-validation and independent external tests. The performance of SVR is slightly better than that of MLR and PLS, as indicated by its determination coefficient (R(2)) of 0.80 and standard error of estimate (SEE) of 0.31 for test sets. For the MLR and PLS, they are relatively weak, showing prediction abilities of 0.60 and 0.64 for the training set with SEE of 0.40 and 0.31, respectively. Our study indicates that the MLR, PLS and SVR-based in silico models have good potential in facilitating the prediction of oral bioavailability and can be applied in future drug design.     

Multiobjective optimization of an industrial grinding operation using elitist nondominated sorting genetic algorithm

The elitist version of nondominated sorting genetic algorithm (NSGA II) has been adapted to optimize the industrial grinding operation of a lead-zinc ore beneficiation plant. Two objective functions have been identified in this study: (i) throughput of the grinding operation is maximized to maximize productivity and (ii) percent passing of one of the most important size fractions is maximized to ensure smooth flotation operation following the grinding circuit. Simultaneously, it is also ensured that the grinding product meets all other quality requirements, to ensure least possible disturbance in the following flotation circuit, by keeping two other size classes and percent solid of the grinding product and recirculation load of the grinding circuit within the user specified bounds (constraints). Three decision variables used in this study are the solid ore flowrate and two water flowrates at two sumps, primary and secondary, each of them present in each of the two stage classification units. Nondominating (equally competitive) optimal solutions (Pareto sets) have been found out due to conflicting requirements between the two objectives without violating any of the constraints considered for this problem. Constraints are handled using a technique based on tournament selection operator of genetic algorithm which makes the process get rid of arbitrary tuning requirement of penalty parameters appearing in the popular penalty function based approaches for handling constraints. One of the Pareto points, along with some more higher level information, can be used as set points for the previously mentioned two objectives for optimal control of the grinding circuit. Implementation of the proposed technology shows huge industrial benefits.     

Solubility of celecoxib in N-methyl-2-pyrrolidone+water mixtures at various temperatures: Experimental data and thermodynamic analysis

Solubility is one of the most significant physicochemical properties of drugs, and improving the solubility of drugs is still a challenging subject in pharmaceutical sciences due to requirements of enhancing their bioavailability. Celecoxib, according to the biopharmaceutics classification system (BCS), is a class 2 drug, possessing low water solubility (<5 μg·mL^?1) and high permeability. Increasing the solubility of this group can lead to improved bioavailability, dose reduction and subsequently, increased efficiency and reduced side effects. In this study, celecoxib solubility was determined in binary mixtures of N-methyl-2-pyrrolidone (NMP)+water at 293.2, 298.2, 303.2, 308.2 and 313.2 K. The solubility of celecoxib is increased with the addition of NMP to the aqueous solutions and reaches a maximum value in neat NMP. In addition, increased temperature leads to enhanced solubility of celecoxib in a given solvent composition. The solubility data of celecoxib in NMP+water at different temperatures were correlated using different mathematical models including, the Jouyban-Acree model and a combination of the Jouyban-Acree and van’t Hoff models. Thermodynamic parameters, Gibbs energy, enthalpy and entropy of dissolution processes were performed based on Gibbs and van’t Hoff equations. Thermodynamic analysis allowed observing two main entropy or enthalpy-driven dissolution mechanisms, varying according to the composition of aqueous mixtures. Moreover, preferential solvation of celecoxib by water is observed in water-rich mixtures but preferential solvation by NMP was seen in mixtures with similar composition and also in NMP-rich mixtures.     

Effect of oxic state on nonpolar organic contaminant distribution,mobility, and bioavailability in estuarine sediments

Dissolved and particle-associated natural organic matter plays an important role in nonpolar organic chemical distribution, mobility, and bio-availability in sediment environments. We investigated the influence of oxic state on the association of a model hydrophobic organic chemical (HOC), 2,2',4,4'-tetrachlorobiphenyl (TeCB), with dissolved and particle-associated organic matter in estuarine sediments. Site-specific distribution data were used to model the effect of oxic state on diffusive flux of TeCB across the sediment-water interface. Additional experiments examined the role of oxic state in TeCB bioavailability to a deposit-feeding epibenthic echinoderm. Aeration of estuarine sediment pore waters induced a negligible change to greater than an order of magnitude decrease in the dissolved organic carbon (DOC)–water distribution coefficient, K_pwdoc, in all but one system examined. Correspondingly, oxidation of sediment solids effected a negligible to 0.5 log unit decrease in the particle associated organic carbon-water distribution coefficient, K_oc. These results indicate that aeration of anoxic estuarine sediments induced by dredging, bioturbation, or storm events may result in release of HOCs from particle-associated and dissolved organic matter, increasing the concentration of the truly dissolved compound. Model simulations indicated that oxygenation of anoxic sediments would result in a 34–100% increase in TeCB diffusive flux. Pore water dissolved organic matter (DOM)facilitated TeCB transport across the sediment-water interface and increased diffusive flux by up to a factor of 1.7. A sensitivity analysis indicated that facilitation of diffusive transport by DOM would be significant in the systems under investigation when log K_pwdoc exceeded approximately 5.7. Therefore, disturbing anoxic sediments can mobilize HOCs. In bioaccumulation assays using sea urchins, TeCB bioavailability temporarily increased after anoxic sediments were disturbed and aerated, but long-term bioavailability remained unaltered when sediment reduction potential returned to the level of the unaerated control.     

助磨剂工程应用的试验与评价

总结了助磨剂影响粉磨过程和水泥性能的因果层次递进关系和多重作用,在此基础上,根据国内外水泥厂应用助磨剂的实际经验,提出基于工程应用要求的助磨剂试验与评价方法。认为：助磨剂试验应谨慎地使用化验室统一试验小磨制样;助磨剂对水泥与减水剂相客性的影响应该作为助磨剂的主要评价内容之一;应以性能指标的性价比评价助磨剂的经济性,并作为选择助磨剂的主要依据。     

Enhancement of bioactivity and bioavailability of curcumin with chitosan based materials

Curcumin (CUR) has been investigated for its poor accessibility to a site of action or absorption and rapid metabolism to cope with the limited medication and cure applications. This article reviews numerous approaches, such as encapsulated surfactant/polymeric micelles, liposomes, micro/nano-spheres, nano-suspensions/composites, nanocomplex, films, and hydrogels for effective transfer of CUR to target sites. Chitosan (CS), and chitosan derivatives have been found to enhance therapeutic efficacy of CUR. CS/modified-CS based alginate, cyclodextrin, starch, dextran sulfate, ZnO, phytosomes, and poly(butyl) cyanoacrylate drug delivery matrices improved bioavailability, prolonged drug loading and permeability, sustained release rate, improved solubility and stability (prevent metabolic degradation) of CUR, consequently promoting various clinical applications. CS based polysaccharide, protein, and metal oxide drug delivery nano formulations advantageously participated to improve biological activities of CUR. We have attempted to summarize these delivery approaches, and reviewed future trends/strategies to permit the introduction of CUR as practical therapeutic drug.     

Zinc bioavailability in the regional diet of S?o Paulo

Zinc bioavailability in the diet of the population of S?o Paulo area, with income lower than two minimum salaries, was studied in Wistar rats, recently weaned, with an average weight of 47.0 g. Three groups formed the experimental protocol: for 60 days. The experimental groups was fed ad libitum with a diet based on the diet of S?o Paulo (DRSP), control 1-"pair feeding" and control 2, ad libitum, with a diet of casein supplemented with methionine (CA). The diets contained 11% protein and 11 mg of zinc per kg of diet. To investigate zinc bioavailability, the apparent zinc absorption index and zinc content in the carcass, were used. Zinc bioavailability in the DRSP diet is low in comparison to the control diet CA. A significantly positive correlation between zinc intake and zinc level in the carcass, was observed.     

钙基添加剂对污水污泥在水热炭化过程中磷形态及生物有效性的影响

在污泥的热处置过程中,添加剂的存在会改变污泥中的磷形态从而对后续磷的回收利用产生重大影响。本文综合利用化学连续提取（SMT方法）、SEM-EDS、XRD和ICP-MS等分析测试方法,系统研究了CaCl₂在水热炭化过程中对污泥中磷形态及其生物有效性的影响。研究结果表明,水热炭化可以使污泥中有机磷（OP）向无机磷（IP）转化,同时促进污泥中非磷灰石无机磷（NAIP）向磷灰石无机磷（AP）的转化,CaCl₂的适量添加可以促进上述转化过程。经过水热炭化处理后,污泥水热炭中IP和AP的浓度分别提升了35.6%和63.4%,当添加质量分数为20%的CaCl₂时,污泥水热炭中IP和AP的浓度同时达到最大值,分别为79.62mg/g和75.61mg/g。此时污泥水热炭中可溶性磷在2%CA溶液中的溶解度也达到最大的57.02mg/g,在此条件下,污泥水热炭中磷的生物有效性也达到最高。     

The preparation of soy products with different levels of native phytate for zinc bioavailability studies

Soy products with low, intermediate and normal phytate levels were prepared in the pilot plant for subsequent rat-feeding experiments to evaluate zinc bioavailability. The low level (0.29%) phytate product was made by precipitation of the protein curd at pH 5.5, whereas the normal level (1.05%) phytate product was produced by a similar process except that the phytate previously isolated from the whey fraction was added back to the original curd as native phytate. The intermediate level (0.73%) phytate product was also produced by acid precipitation, but at pH 4.5. The pH 5.5 precipitation process yielded a large quantity of whey in which the ratio of water content to phytate was over 1,000 parts to 1. However, ca. 75% of the water was subsequently removed by reverse osmosis (RO), which increased the concentration of phytate in the whey fraction and facilitated its isolation. Protein was first removed from the whey by precipitation with trichloracetic acid, then phytate was precipitated in the supernatant with ferric chloride. Another series of experiments was run to find optimal conditions to convert ferric phytate to the more soluble sodium phytate form, using a minimal amount of sodium hydroxide so that the phytate could be recycled back to the curd without causing a large increase in sodium content of the product. There were only minor differences in the protein, lipid and mineral contents of the three products.     

表面活性剂在花岗岩研磨中的物理化学作用

花岗岩研磨过程中添加含不同类型表面活性剂的磨削液。测量添加不同表面活性剂及不同浓度的磨削液时花岗岩的磨削比 ,分析比较磨削液浓度及表面活性剂对花岗岩研磨效率的影响。通过测量磨削液的表面张力、磨削液作用后的花岗岩表面电位等参数 ,研究了表面活性剂对花岗岩研磨过程的物理化学作用机理。实验结果表明 :与水比较 ,表面活性剂磨削液能明显提高花岗岩研磨效率 ;阳离子型表面活性剂的磨削液对研磨效率的提高效果优于阴离子型和非离子型的表面活性剂磨削液 ;研磨盘的粒度越细 ,表面活性剂的作用效果越明显。     

Controlled drug release by polymer dissolution. I. Partial esters of maleic anhydride copolymers—properties and theory

The kinetics of drug release from a series of partial esters of vinyl acetate–maleic anhydride has been investigated. These polymers in their un-ionized forms are hydrophobic and water insoluble, but in their ionized forms they are water soluble. Polymer dissolution is pH sensitive, and different half-esters have a characteristic pH range above which they are soluble and below which they are insoluble. When films are placed in buffered media, they erode at a constant rate that depends on the pH of dissolution of the polymer and on the pH of the buffered medium. Dissolution of the polymer is limited to the polymer–buffer medium interface, and drugs dissolved or uniformly dispersed in the polymer are released by zero-order kinetics. A detailed model has been developed that successfully correlates dissolution behavior and various experimental parameters.     

Degradation and bioavailability of dried alginate hydrocolloid capsules in simulated soil system

Hydrocolloid capsules are common chemical carriers used in many types of applications in foods, biotechnology, and agriculture. Alginate microbeads and macrobeads are some of the more prevalent types of hydrocolloid capsules. Most studies to date have focused on alginate carrier applications but only a few have looked at their bioavailability after use. In this study, alginate carriers were subjected to simulated field conditions and their biodegradation in the soil was evaluated by respiration measurements, visualization, and volatile solids reduction. Using respiration rate, the degradation rate was calculated at 32 ± 3.1% (w/w) after 2 months. The visually estimated volume and volatile solids reduction gave degradation rates of 40 ± 8.6% (v/v) and 22.5 ± 2.5% (w/w), respectively. Moreover, water-loss calculations suggested that the carriers can serve as a stand-alone soil amendment for water retention. These findings emphasize the importance of studying hydrocolloid bioavailability in the soil and alginate carrier suitability for future applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48142.     

有助磨作用的陶瓷添加剂

对具有助磨作用的陶瓷添加剂进行了探讨。包括试样的制备、球磨、粒度测定、助磨机理的解释等。通过多次实验确定，十二烷基磺酸钠、柠檬酸钠＋水玻璃等瓷石有较好的助磨效果；木质素磺酸钠、油酸等对石英砂有较好的助磨效果。     

Chemistry and pharmacokinetics of gallium maltolate, a compound with high oral gallium bioavailability

Gallium maltolate, tris(3-hydroxy-2-methyl-4H-pyran-4-onato)gallium (GaM), is an orally active gallium compound for therapeutic use. It is moderately soluble in water (10.7 +/- 0.9 mg/mL at 25 composite functionC) with an octanol partition coefficient of 0.41+/-0.08. The molecule is electrically neutral in aqueous solution at neutral pH; a dilute aqueous solution (2.5 x10-(-5) M) showed little dissociation at pH 5.5-8.0. Single crystal X-ray diffraction analysis found the GaM molecule to consist of three maltolate ligands bidentately bound to a central gallium atom in a propeller-like arrangement, with one of the ligands disordered in two possible orientations. The compound is orthorhombic, space group Pbca, unit cell a = 16.675(3), b = 12.034(2), c = 18.435(2) A at 158K. GaM was administered to healthy human volunteers at single doses of 100, 200, 300, and 500 mg (three subjects per dose). GaM was very well tolerated. Oral absorption of Ga into plasma was fairly rapid (absorption half life = 0.8-2.0h), with a central compartment excretion half life of 17-21h. Absorption appeared dose proportional over the dosage range studied. Estimated oral gallium bioavailability was approximately 25-57%, based on comparison with published data on intravenous gallium nitrate. Urinary Ga excretion following oral GaM administration was approximately 2% of the administered dose over 72h, in contrast to 49-94% urinary Ga excretion over 24h following i.v. gallium nitrate administration. We suggest that oral administration of GaM results in nearly all plasma gallium being bound to transferrin, whereas i.v. administration of gallium nitrate results in formation of considerable plasma gallate [Ga(OH)(4) (-)], which is rapidly excreted in the urine. These data support the continued investigation of GaM as an orally active therapeutic gallium compound.