相转移催化合成2,4-二氯苯氧乙酸新工艺研究

以2,4-二氯苯酚和氯乙酸为原料,在碳酸钾作用下筛选相转移催化剂(四丁基溴化铵、四乙基溴化铵和PEG-600)进行醚化反应,制备2,4-二氯苯氧乙酸。所获得的最佳工艺条件是:催化剂选PEG-600/KI为最佳,二氯苯酚和氯乙酸原料物质的量比1∶2,相转移催化剂PEG-600用量为二氯苯酚的6%,KI用量为二氯苯酚量的10%。在此合成条件下,2,4-二氯苯氧乙酸收率达94.2%。     

Adsorption characteristics of 2,4-dichlorophenoxyacetic acid and 2,4-dinitrophenol in a fixed bed adsorber

The influence of temperature and initial pH of aqueous solution on adsorption has been discussed in detail using the Sips equation. Single-component adsorption equilibria of 2,4-D and 2,4-DNP dissolved in water have been measured for three kinds of GACs (F400, SLS103, and WWL). For 2,4-D, the magnitude of adsorption capacity was in the order of F400>SLS103>WWL, and that for 2,4-DNP was SLS103>F400>WWL. These results may come from the effects of the pore size distribution, surface area, surface properties, and difference in adsorption affinity. Kinetic parameters were measured in a batch adsorber to analyze the adsorption rates of 2,4-D and 2,4-DNP. The internal diffusion coefficients were determined by comparing the experimental concentration curves with those predicted from surface diffusion model (SDM) and pore diffusion model (PDM). The linear driving force approximation (LDFA) model was used to simulate isothermal adsorption behavior in a fixed bed adsorber and successfully simulated experimental adsorption breakthrough behavior under various operation conditions. Efficiency of desorption for 2,4-D and 2,4-DNP was about 80% using distilled water at pH of 6.     

抗紫外聚多巴胺香料纳米胶囊缓释体系的研究

利用多巴胺(DA)在碱性溶液中的自氧化和聚合,在香料乳液液滴表面涂覆聚多巴胺(PDA)层制备香料PDA纳米胶囊,比较了PDA对不同香料的包覆性能和缓释效果。结果发现苯乙醛和香茅醛因与多巴胺(DA)发生Maillard反应而不能被包覆,苯乙醇、香茅醇、乙酸苯乙酯和乙酸香茅酯则能被包覆在纳米胶囊内部,扫描电子显微镜(SEM)和动态激光光散射(DLS)结果显示:香料纳米胶囊基本呈球形,分布较均匀,香料种类对粒径影响大,可由88 nm(乙酸香茅酯)变化到556 nm(苯乙醇)。对香茅醇的包埋率最高,可达到19. 8%,在常温下保存50 d后香料保留率可保持69. 39%以上,具有良好的缓释性能,同时由于PDA对紫外及可见光有一定的吸收,因此可以为光敏性或光毒性香料的应用提供进一步的光屏蔽作用。     

Photodegradation of 2,4-dichlorophenoxyacetic acid using ZnAlFe layered double hydroxides as photocatalysts

ZnAlFe layered double hydroxides (LDHs) with different Zn:Al:Fe ratio were obtained by the co-precipitation method and tested as photocatalysts for 2,4-dichlorophenoxyacetic acid (2,4-D) degradation. High specific surface areas (138–70 m²/g) as well as semiconductor properties (band gap values of 2.59–2.00 eV) were obtained in the samples calcined at 673 K. When calcined samples were put in contact with as solution containing 300 ppm of 2,4-D, the reconstruction of the LDHs (memory effect) and an unexpected high capacity of 2,4-D adsorption were observed. The photodegradation in aqueous phase after saturation of the LDHs with 2,4-D showed that the confined (adsorbed) 2,4-D can be successfully degraded with ZnAlFe LDH photocatalysts.     

2,4-D/CMC接枝物纳米粒子的制备与缓释性能研究

以羧甲基纤维素钠（CMC）为基材，甲基丙烯酸甲酯（MMA）和二甲基二烯丙基氯化铵（DMDAAC）为改性单体，通过乳液聚合制备了CMC-g-P(MMA-DMDAAC)共聚物，采用自组装方法负载2,4-二氯苯氧乙酸（2,4-D）得到2,4-D/CMC-g-P(MMA-DMDAAC)纳米药物缓释体系。利用傅里叶红外光谱（FTIR）、差示扫描量热法（DSC）、热重分析（TGA）、扫描电镜（SEM）、粒度分析仪对其结构和形貌进行表征，并探究其载药性能和缓释性能。结果表明，2,4-D/CMC-g-P(MMA-DMDAAC)载药粒子呈笼状结构，粒度分布为160～425 nm；其载药率随着CMC∶MMA∶DMDAAC的摩尔比增大而提高，最高可达40.8%；其药物累计释放率随CMC∶MMA∶DMDAAC的摩尔比增大而降低，其释放行为符合Weibull模型，遵循Fick扩散机理。     

壳聚糖胶囊材料的制备及其缓释性能

采用壳聚糖为基材、果胶为交联剂制备了薄膜材料,考察了卡拉胶和淀粉为添加剂对该薄膜材料力学性能的影响。结果显示,不加卡拉胶、淀粉的果胶-壳聚糖复合聚合物薄膜材料由于不溶于模拟胃液和模拟肠液,不适合单独作为缓释胶囊材料。当加入卡拉胶和淀粉后,不仅可进一步增加薄膜材料的柔韧性、凝胶性、透明度和力学性能,还增加其在模拟肠液和胃液中的溶解性。果胶-壳聚糖、卡拉胶、淀粉的质量比为2∶1∶1,得到的薄膜材料不仅具有良好的成型性和弹性,也具有适中的胃液和肠液溶解性。将该材料制备成胶囊,在模拟胃液和模拟肠液环境考察其破壁缓释效果,结果显示,胶囊在模拟胃液和肠液中的溶解是一个缓慢过程,浸泡6h后,胶囊药物的缓释率大致为93%。     

低CMC纳米载体PEGMA-b-PLLA-b-PCL的制备及其药物缓释性能

以ε-己内酯（ε-CL）为疏水原料，聚乙二醇甲醚甲基丙烯酸酯（PEGMA）为亲水原料，通过引入亲疏水性过渡原料L-丙交酯（LLA），利用可逆加成-断裂链转移法（RAFT）制备了超低临界胶束浓度（CMC）的聚乙二醇甲醚甲基丙烯酸酯-聚丙交酯-聚己内酯（PEGMA-b-PLLA-b-PCL）。通过FTIR、1HNMR、GPC、DLS和SEM对聚合物的结构、相对分子质量（简称分子量）及粒径进行测定，用界面张力法测得PEGMA-b-PLLA-b-PCL 胶束溶液的CMC，用溶剂挥发法负载姜黄素（CUR）制备载药胶束溶液，并计算其载药量和包封率，进一步考察载药胶束溶液在不同环境下的释药能力。结果表明，聚合物相对分子质量（简称分子量）为1220~8782，粒径为28~180 nm，且最低CMC为0.62 μg/mL（pH=7.4）。载药胶束的载药量和包封率最高可达12.6%和78 .0% (pH=7.4)，且药物释放可在15 d内完成，在pH=5环境下释放量最高可达45.53%。     

甲壳素及其衍生物在缓释药物中的应用

介绍了甲壳素及其衍生物制备缓释药物的常见方法以及影响药物释放速率的主要因素     

医用多孔支架材料的制备及缓释性能分析

采用溶液浇铸法制备了聚己内酯⁃姜黄素（PCL⁃CUR）多孔支架,通过冷场发射扫描电子显微镜（SEM）和热重分析仪（TG）等对支架材料的孔隙率、载药量及缓释性等进行了表征,并分析了其体外释药模型。结果表明,CUR在支架材料中含量为2 %（质量分数,下同）,PCL在醋酸中浓度为10 %,壳聚糖在支架材料中含量为2.86 %时,其释药模型符合1级方程,支架材料的孔隙率达95 %以上,载药量达到1.63 %,在PBS缓冲液中90 h内CUR累计释放率为76.2 %;其他配方的支架材料孔隙率均为95 %以上,90 h内CUR累计缓释率在60 %~87 %之间,表明制得的支架材料具有较理想的孔隙率和明显的CUR药物缓释作用,在组织工程领域有较好的应用前景。     

类氨基酸基载药水凝胶敷料的制备与性能

为制备一种具有良好生物相容性、可控缓释的物理交联的水凝胶敷料,选用类氨基酸单体N-丙烯酰基甘氨酰胺（NAGA）与生物发酵产物衣康酸（IA）为单体,在紫外光条件下,通过自由基聚合,在不需要外加任何交联剂条件下即可形成水凝胶聚（N-丙烯酰基甘氨酰胺-衣康酸）（P(NAGA-IA)）。所得水凝胶具有溶胶-凝胶转变温度（UCST）、较高的水溶胀率（40倍）及力学性能（压缩模量最高540 kPa）、较优的药物负载性和缓释性,这是因为NAGA单元提供分子间多重氢键作用,进而赋予了水凝胶较优的综合性能;而IA单元赋予了聚合物的pH刺激响应性,从而可诱导药物的释放。因此,所得P (NAGA-IA)水凝胶可作敷料用于创伤治疗。     

盐酸米托蒽醌多囊脂质体的制备工艺优化及性能

采用均匀设计优化并制备了平均粒径为58.75 μm的载盐酸米托蒽醌多囊脂质体。该多囊脂质体粒度分布较窄,球形度好。Zeta电位、相变温度及稳定性考察均表明该体系稳定性强,适于药物的释放体系。渗漏率结果表明相对于室温（37 ℃）,冰箱（4 ℃）更有利于载药多囊脂质体的保存。盐酸米托蒽醌平均包封率为90.13%,考察了胆固醇及三油酸甘油酯用量对多囊脂质体药物释放的影响,药物释放符合《药典》规定,无突释效应,且具有较好的体外缓释性能。     

Adsorption equilibrium characteristics of 2,4-Dichlorophenoxyacetic acid and 2,4-Dinitrophenol on granular activated carbons

Adsorption characteristics of 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2,4-Dinitrophenol (2,4-DNP) onto granular activated carbon (GAC) were studied to obtain basic information on their removal from aqueous solution. Single component adsorption equilibria of 2,4-D and 2,4-DNP dissolved in water have been measured for three kinds of GACs (F400, SLS103, and WWL). In case of 2,4-D, the magnitude of adsorption capacity was in the order of F400> SLS103>WWL, and that for 2,4-DNP was SLS103> F400> WWL. The influence of temperature and initial pH of aqueous solution on adsorption has been discussed in detail by using the Sips equation.     

Copolymers of acrylic acid with 2‐acryloyloxyethyl 2,4‐dichlorophenoxyacetate: Synthesis and herbicide release

Free‐radical copolymerization of acrylic acid with 2‐acryloyloxyethyl 2,4‐dichlorophenoxyacetate using 1.0 mol/L 1,4‐dioxane solution and 1.5 × 10^?2 mol/L of 2,2′ azobisisobutyronitrile as initiator has been carried out at 50°C. In addition to low conversion solution experiments performed to estimate the monomer reactivity ratios, three different copolymerizations over the whole range of conversions have been made. Theoretical values of cumulative copolymer composition, determined by the Mayo‐Lewis terminal model, have been correlated with those experimentally obtained. Finally, the herbicide release in three different aqueous pH buffer solutions has been evaluated in heterogeneous phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4238–4244, 2006     

CTX/淀粉接枝PLA共聚物微球的制备及药物释放行为

采用乳化-溶剂挥发法,以头孢噻肟钠(CTX)为模型药物,以自制两亲性聚合物淀粉聚乳酸接枝共聚物(ST-g-PLA)为药物载体,制备了CTX/ST-g-PLA载药微球。考察了乳化剂PVA浓度、油水体积比、ST-g-PLA浓度及搅拌速度对微球粒径、载药量及包裹率的影响,采用IR,DSC和SEM等技术对微球结构进行了表征,研究了微球在4种不同介质中的降解性及体外释药性能。结果表明,当PVA浓度为2%,Vo/Vw=1∶6,共聚物浓度为30%时,制备的微球外型规则,分散性好,载药率为8.2%,包载率为49.2%;微球在不同环境中降解速率不同:肠液>碱液>PBS>酸液;较PLA微球,CTX/ST-g-PLA微球有良好的缓释性。     

CS／PLLA／TPP纳米微胶囊的制备及体外释放

主要考察负载雷帕霉素（Rapaymcin,RAPA）的壳聚糖（Chitosan,CS）微球在加入左旋聚乳酸（L—polylactic acid,PLLA）时的载药量,包封率及在不同溶剂中的缓释性能。采用三聚磷酸钠（Sodium tripolyphosphate,TPP）作为离子交联剂,应用离子凝聚法制备CS／PLLA／TPP纳米微胶囊,用透射电镜和粒径分析仪进行了表征。结果表明：离子凝胶法可以得到粒径约300—400nm均匀分散的壳聚糖纳米微胶囊;微胶囊包封率可达84．25％,微胶囊载药量可达30．22％,雷帕霉素在不同溶剂中的缓释性能有很大不同。     

改性聚乳酸载药微球的制备及性能

以尼莫地平为模型药物,聚乳酸(PLA)为载体材料,采用溶剂蒸发萃取法制备了N-乙烯基吡咯烷酮(NVP)接枝聚乳酸共聚物(PLA-g-PVP)微球,考察了聚乳酸质量分数、乳化剂质量分数、转速和投药质量比对微球的影响。采用红外光谱、差式扫描量热分析表征药物与载体的相互作用,扫描电镜观察微球表面形态,对不同接枝率共聚物微球的粒径、载药量、包封率及体外释放性能进行研究。结果表明,当w(PLA)=4%,w(乳化剂)=3%,转速9 000 r/min,投药质量比为2∶3时,不同接枝率改性聚乳酸微球形态圆整,平均粒径小于10μm,粒径分布窄,微球可连续释放14 d以上,释放速率随着接枝率增大而增大。     

Preparation of drug‐loaded microspheres of linear and star‐shaped poly(D,L‐lactide)s and their drug release behaviors

Linear (1‐arm) and star‐shaped (4‐, 6‐, and 16‐arm) poly(D,L ‐lactide)s (PDLLs) were synthesized by ring‐opening polymerization in bulk of D,L ‐lactide monomer. Hydroxyl end‐group compounds and stannous octoate were used as the initiator and catalyst, respectively. The intrinsic viscosity and glass transition temperature (T_g) of the PDLLs decreased steadily as the branch arm number increased for similar molecular weights. However, the intrinsic viscosity and T_g values of the linear PDLL were less than the star‐shaped PDLL for similar each PDLL arm lengths. Ibuprofen, a poorly water soluble model drug was entrapped in the PDLL microspheres. All drug‐loaded PDLL microspheres were prepared by the oil‐in‐water emulsion solvent evaporation method, were spherical in shape, and had a smooth surface with fine dispersibility. In vitro drug release behaviors indicated that the drug release from the microspheres with higher branch arm number was faster than from those with lower branch arm number. Moreover, the drug release from the star‐shaped PDLL microspheres was slower than that of the linear PDLL microspheres for similar PDLL arm lengths. The drug release behavior could be adjusted through both the branch arm number and arm length of PDLL. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

滴丁·乙-脲醛微囊悬浮剂的制备与表征

以原位聚合脲醛树脂的方法制备了滴丁·乙-微囊悬浮剂。利用UV,激光粒度仪,光学显微镜,SEM,FT-IR等对制剂进行表征,结果表明:所制备的微囊悬浮剂中,2,4-D丁酯和乙草胺的包封率分别为85%和89.9%,微囊平均粒径为3.79μm,粒度分布较窄,表面光滑致密,红外光谱分析表明微囊由脲醛树脂壁材与滴丁·乙芯材所组成。     

缓释型农药的制备与性能研究

缓释型农药是使用物理、化学或物理化学结合的方式把农药包裹起来,以降低接触的毒性,控制其释放速度,增大了稳定性,延长残效期,减弱了农药对环境的污染,是安全、经济、合理使用农药的理想剂型。选取农药吡虫啉为研究对象,通过三聚氰胺-甲醛预聚体对吡虫啉进行了包覆,并对制备过程当中的主要影响因素及其释放性能进行了研究。主要通过对比包覆前后农药的红外谱图判定包覆是否成功。利用紫外分光光度计分析在制备过程中影响缓释性能的因素。