痤疮凝胶剂的研制与质量评价

目的 研制克林霉素与维甲酸凝胶剂的制备工艺与质量评价。方法 用卡波姆 - 940作基质 ,三乙醇胺为中和剂 ,加入克林霉素、维甲酸制成凝胶剂 ;采用紫外双波长法直接测定凝胶剂中克林霉素 ,维甲酸的含量。结果 制备的复方克林霉素、维甲酸凝胶剂 ,细腻、光洁透明、稳定性好、释放药物快 ,且含量测定简单易行。结论 该凝胶剂配方合理 ,符合中国药典2 0 0 0版的规定 。

氟哌酸锌凝胶剂的制备及质量控制

目的:研制一种局部应用治疗小儿湿疹的制剂。方法:按凝胶剂制备工艺制备了诺氟沙星锌凝胶剂;建立了性状、鉴别、酸碱度、含量测定等质控方法,并进行了体外抑菌实验。结果:以紫外分光光度法测定诺氟沙星锌凝胶剂的含量,平均回收率为100.03%,RSD为1.67%;稳定性良好。结论:该制剂制备工艺可行,性质稳定,质控方法简单可靠。

Preparation of Cationic Chitosan-Polyacrylamide Flocculant and Its Properties in Wastewater Treatment

Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide （AM） and methacrylatoethyl trimethyl ammonium chloride （DMC） as raw materials and ceric ammonium nitrate （CAN） as initiator. The flocculation ability of the resulting polymer （PCAD） was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of ehitosan and DMC content on PCAD＇s flocculation ability were studied. Floeculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the ehitosan＇s content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD＇s flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD＇s dosage was 8mg-Lk Compared with cationic polymer （the copolymer of AM and DMC, PAD）, PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.

Preparation of a Novel Coal Gangue–Polyacrylamide Hybrid Flocculant and Its Flocculation Performance

A novel flocculant based on hybrid coal gangue-polyacrylamide （HCGPAM） has been prepared by using modified coal gangue and polyacrylamide. Factors related to the preparation such as reaction time, temperature, concentration of the polymer monomer and ratio of initiators are investigated. The product is characterized by infrared spectra （FTIR）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, as well as viscometry. The flocculating tests on oiffield drilling wastewater show that the removal efficiency is 85.5% and the light transmittance is 53.6%. The results indicate that the coal gangue could be used for the preparation of inorganic-organic hybrid flocculant and the removal efficiency is much higher than that of commercial polyacrylamide （PAM） or PAM/ coal gangue blend.

Study on the sedimentation capability of bauxite flotation concentrate

The sedimentation behaviors of bauxite flotation concentrates were investigated at different pH values and floceulant dosages. The effects of three types of flocculants （ cationic, anionic and non-ionic polyacrylamide floceulants） as well as the molecular weight of anionic flocculants on the sedimentation of concentrate were studied. It is shown from the experimental results that at the pH 7.0, best sedimentation capability is reached when anionic polyacrylamide flocculant （molecular weight 14 million） is added and the optimal dosage is 30 g/t.

THE MECHANISM STUDY OF EFFECT OF CALCIUM AND ALUMINIUM IONS ON FLOCCULATING PROCESS OF KAOLIN

The effects of Ca(2+) and Al(3+)ions on flocculating process of kaolin using plogycrylamide as flocculant was studied. Mechanism of the effects was investigated and discussed through molecularorbit(MO) theory , solution chemistry calculation and electronic probe examination in this article.

Crosslink Polymerization Kinetics and Mechanism of Hydrogels Composed of Acrylic Acid and 2-Acrylamido-2-methylpropane Sulfonic Acid

Crosslink polymerization kinetics of poly（acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid）,AA/AMPS hydrogels,was investigated by using dilatometry in the presence of sodium persulfate as initiator and N,N＇-methylene bis（acrylamide） as crosslinker.It was found that the reaction for the crosslink polymerization of AA/AMPS hydrogels had orders of 0.58,1.14,and 0.86 with respect to the initiator,AMPS,and AA,respectively.From the Arrhenius plots,the activation energy of the crosslink polymerization was found to be about 140 and 89 kJ·mol-1 in the presence and absence of the crosslinker,respectively,in the temperature range from 45 to 65 °C.It was noted that the crosslinker had effects on the reaction order of the initiator and the activation energy due to the formation of cross-linked networks,which was verified by Fourier transfer infrared （FTIR） spectrum.To further confirm the influences of the cross-linked network structure on kinetic parameters of the crosslink polymerization,a mechanism was proposed,which highlights the different termination routes between free radical polymerization and crosslink polymerization.These results suggest that dilatometry provides a convenient tool for crosslink polymeri-zation study,and confirm that the cross-linked networks are formed in the crosslink polymerization.

Green and efficient cycloaddition of CO2 toward epoxides over thiamine derivatives/GO aerogels under mild and solvent-free conditions

Thiamine derivatives that are cheap, readily available, non-toxic and green are used as heterogeneous catalyst for the generation of cyclic carbonates through cycloaddition of CO_2 to epoxides without the need of co-catalyst and solvent. The interaction between thiamine hydrochloride(VB_1-Cl) and substrates(CO_2 and propylene oxide) was proven by ultraviolet-visible spectroscopy and ~1H nuclear magnetic resonance analysis, and it is deduced that the synergistic action among multi-functional groups(hydroxyl, halide anion and amine) is a favorable factor for cycloaddition reaction. A series of VB_1/GO aerogels were facilely prepared through the addition of aqueous VB_1 derivatives to a suspension of GO in ethanol at room temperature. It was found that the aerogel generated through the interaction of VB_1-Cl with GO shows catalytic activity and stability higher than those of VB_1-Cl. It is because the electrostatic interaction between GO and VB_1-Cl enhances the nucleophilicity and leaving ability of anion. The effects of reaction temperature, catalyst loading, CO_2 pressure and reaction time on CO_2 cycloaddition to propylene oxide were thoroughly studied.