基于静电纺丝技术的农药传递体系的制备与性能

为获得一种新型高载药率、易分散型农药制剂，基于药物传递理论，以阿维菌素（AVM）为农药模型、乙基纤维素（EC）为主要农药载体、卡波姆（CB）为改性材料，利用静电纺丝技术构建了一种具有微纳结构的农药传递体系。考察了复配比例、溶解参数及纺丝条件对农药传递体系性能的影响，采用SEM、XRD及FTIR对其进行了表征，对农药传递体系的载药率、利用率与光解率、释药率、释药动力学与药物释放机制及水分散性进行了测试。结果表明，采用N,N-二甲基乙酰胺与无水乙醇以体积比3∶1的混合液对载体EC与CB分别进行溶解，EC（质量浓度60 g/L）与CB（质量浓度30 g/L）溶液的体积均为3.9 m L时，农药传递体系的载药率可达35.7%,AVM利用率可达100%，耐光解性大幅提升。并且，该农药传递体系的水分散性非常优异，具有长效释药性。     

N,N-双十二烷基-3,6-O-磺丙基壳聚糖对紫杉醇的增溶作用

合成高取代度的N,N-双十二烷基-3,6-O-磺丙基壳聚糖（SPDLCS）双亲性衍生物,通过透析法制备了SPDLCS载紫杉醇（PTX）胶束,考察了投料比对载药量、包封率、胶束粒径和Zeta电位的影响,并对胶束形态及其稳定性进行了研究。结果表明,紫杉醇以无定形态包载于胶束的疏水内核中,最优投料比为SPDLCS∶PTX=1∶1.1,载药量为50.36 %,包封率为92.2 %,对紫杉醇的增溶能力达6.08 mg/mL。载药胶束呈现分散性良好的球形颗粒,平均粒径为141.1 nm,Zeta电位为?34.1 mV。稳定性实验表明SPDLCS载紫杉醇胶束具有良好的稳定性,SPDLCS是潜在的疏水药物高增溶载体材料。     

不同生物农药和化学农药对核桃枝枯病的防治试验

[目的]研究农药对核桃枝枯病菌的防治效果。[方法]采用菌丝生长抑制法,对13种农药进行初筛及EC50值的测定,将效果较好的生物农药和化学农药进行复配,测定复配剂的毒力。并测定效果较好的化学农药、生物农药及其复配的田间防效。[结果]单剂中梧宁霉素和咪鲜胺的毒力最强,EC50值分别为0.0402、0.0006 mg/L。当梧宁霉素与咪鲜胺以2∶1比例复配时具有增效作用,且当以2∶1质量比配合时,其田间防效为62.62%。[结论]梧宁霉素和咪鲜胺的防治效果较好,梧宁霉素与咪鲜胺按2∶1比例复配时能增加对核桃枝枯病的防治效果。     

基于磷氮协同阻燃体系的抗静电PBT材料的性能研究

采用聚对苯二甲酸丁二醇酯（PBT）作为基体树脂、二乙基次磷酸铝（AlPi）和三聚氰胺次磷酸盐（MPP）以质量比2∶1的配比作为协效阻燃剂、炭黑（CB）作为抗静电填料,制备了阻燃抗静电PBT材料。通过极限氧指数、UL 94垂直燃烧实验、热重分析和扫描电子显微镜分别研究了PBT复合材料的燃烧性能、热稳定性、抗静电性能并测试了其体积电阻率。结果表明,复合材料的阻燃级别达到UL 94 V-0级,极限氧指数为31 %;CB的阈值为12份（质量份,下同）,CB加入量为20份时的体积电阻率达到104 Ω·cm;复配阻燃剂和CB对材料的热稳定性有一定程度的改善,复合材料燃烧后表面形成多孔连续的炭层,获得了优良的阻燃效果。     

聚苯胺/聚乙烯复合电极的制备及性能测定

以低密度聚乙烯（PE）为基体材料,乙烯-醋酸乙烯共聚物（EVA）为增韧剂,聚苯胺（PAn）和炭黑（CB）为导电添加剂制备复合电极板,探讨了原料配比对物理力学性能、电学性能的影响。结果表明,原料配比PE∶EVA∶CB=75%∶5%∶20%时,电极的电阻最小,但是其韧性不佳;当原料配比PE∶EVA∶（CB＋PAn）=85%∶5%∶10%时,复合电极板具有最好的韧性能。     

RDP与葫芦脲协同阻燃聚碳酸酯的研究

采用间苯二酚二苯基磷酸酯（RDP）复配大环分子葫芦［6］脲（CB［6］）对聚碳酸酯（PC）进行无卤阻燃改性。通过极限氧指数仪、锥形量热仪、热失重分析仪及扫描电子显微镜测试分析了阻燃体系的阻燃性能、热性能及燃烧炭层的微观形貌。结果表明,RDP与CB［6］复配质量比为6∶2时阻燃效果最好,材料的极限氧指数达到32.5 %,通过UL 94 V-0级,热释放速率峰值(PHRR)降低至266 kW/m2;复配阻燃体系的加入改善了PC热稳定性,提高了阻燃复合材料的残炭率;复配阻燃体系能促进形成连续致密的膨胀炭层。     

苦杏仁苷明胶微球的制备及其工艺优化

对苦杏仁苷明胶微球的制备工艺及特性进行初步研究.以生物降解材料明胶为载体,采用乳化化学交联法制备含苦杏仁苷的明胶微球,并进行验证试验和微球的体外溶出试验以及微球稳定性和胃黏膜刺激性实验.优化最佳处方为明胶质量分数15%,苦杏仁苷与明胶质量比1∶10,液体石蜡与明胶溶液体积比4∶1;制备的苦杏仁苷明胶微球外形圆整,稳定且刺激性小,平均载药量为7.5%,包封率为25.12%.     

介孔二氧化硅-阿维菌素缓释体系的制备与性能研究

以正硅酸乙酯(TEOS)为硅源,氨水为碱性催化剂,采用无模板法制备介孔二氧化硅和中空介孔二氧化硅,选用持效期较短的阿维菌素作为模型药物构成缓释体系,通过扫描电镜(SEM)、透射电镜(TEM)、比表面仪(BET)、傅里叶红外光谱仪(FTIR)和紫外分光光度计(UV)对二氧化硅材料的形貌、粒径、载药量进行表征和测定,同时测试其缓释性能。探讨了溶剂蒸发法和超声浸渍法两种不同载药方法对缓释性能的影响。结果表明,两种农药缓释载体均呈球形,平均粒径500 nm,其中中空介孔二氧化硅载体具有独特的中空介孔复合结构,超声浸渍法载药效果较好,两种载体的载药量分别为48. 89%和52. 58%,中空介孔二氧化硅-阿维菌素缓释体系的缓释区间较大,缓释效果较好,31 h才基本达到平衡。     

DIDOPO与POSS/EG协同阻燃环氧树脂泡沫及机理研究

以对苯乙基桥链9,10⁃二氢⁃9⁃氧杂⁃10⁃磷杂菲⁃10⁃氧化物（DIDOPO）、聚甲基倍半硅氧烷（POSS）、膨胀石墨 （EG）为复配阻燃剂对环氧树脂（EP）泡沫进行阻燃改性,研究了复配阻燃剂对EP泡沫材料的阻燃效果和阻燃机理。结果表明,当DIDOPO/POSS=3∶1（质量比,下同）、DIDOPO/EG=1∶3时,复配阻燃体系的阻燃效果最佳;添加20 %（质量分数,下同） DIDOPO/POSS复配阻燃剂的加入可以使EP泡沫的UL 94测试达到V⁃0级; 添加20 %的 DIDOPO/EG复配体系可以使EP泡沫的极限氧指数（LOI）提高至30.8 %,UL 94测试达到V⁃0级;阻燃体系具有一定的抑烟效果。     

载药聚乳酸纤维膜的制备及释药性能研究

将药物——消炎痛和聚乳酸(PLA)同时溶解在三氯甲烷∶丙酮(体积比2∶1)的混合溶液中,制得均匀的纺丝液,通过静电纺丝制备载药PLA纤维膜。通过扫描电镜(SEM)观察其形貌结构;通过紫外分光光度计检测其释放在磷酸缓冲溶液(PBS)中药物的吸光度,并计算其释药速率。结果表明:纤维的平均直径随着含药量的增加而减小,随着PLA质量分数的增加而增加;释药速率随着纤维直径的减小而加快;与纯药粉的释药速率相比,载药PLA纤维膜有明显的缓释性,提高了药物的利用率及安全性。     

羧甲基纤维素-大豆分离蛋白农药缓释颗粒的制备及性能

为提高农药利用率、精确控制农药释放,设计了一种pH响应型缓释颗粒。以3-氨丙基三乙氧基硅烷（APTES）为桥连接羧甲基纤维素（CMC）与大豆分离蛋白（SP）得到羧甲基纤维素-大豆分离蛋白（CMC-SP）,然后利用分子自组装法负载阿维菌素（AVM）形成载药颗粒（CMC-SP@AVM）。采用红外光谱（FTIR）、扫描电镜（SEM）、热重分析（TGA）等手段对改性产物结构和形貌进行表征,并对CMC-SP@AVM的载药性能、缓释性能、抗紫外性能、杀虫活性进行了探究。结果表明,CMC-SP@AVM具有近似椭圆形的结构,CMC-SP@AVM的平均粒径为104nm;对AVM的包封率达41.9%,并赋予AVM优异的抗紫外光分解性能,强紫外光照射120h后,CMC-SP@AVM中AVM的残留率比未包封的AVM高117%,其药物释放具有pH响应特性,pH越大,释放速率越快;药物释放过程符合Elovich模型。在相同AVM浓度下CMC-SP@AVM的杀虫活性与原药无显著差异。     

Avermectin/polyacrylate nanoparticles: preparation,characterization, anti-UV and sustained release properties

In an effort to reduce the dose of drugs and in order to improve drug efficacy, avermectin (AVM) was encapsulated by amphipathic polyacrylic ester (PAE) via self-assembly. The experimental results indicated that the AVM/PAE nanoparticles were spherical in shape, homogeneous dispersion, and had a core-shell structure, the particle size ranged from 172.7?nm to 337.8?nm, the highest encapsulation efficiency and loading capacity were 62.11 and 25.65%. The anti-UV property has been significantly improved. Consistent with the Korsmeyer–Peppas model, the release rate was observed to be higher upon decreasing Tg and increasing the core-shell ratio.     

羧甲基壳聚糖-蓖麻油基聚氨酯农药缓释微球的制备及性能

以羧甲基壳聚糖（CMCS）、蓖麻油（CO）和异佛尔酮二异氰酸酯（IPDI）为原料,自乳化法制备了羧甲基壳聚糖-蓖麻油基聚氨酯微球（CO-CMCS-PU）,通过分子自组装法负载阿维菌素（AVM）得到载药微球（CO-CMCS-PU@AVM）。采用FTIR、1HNMR、SEM、TGA等对产品结构及形貌进行表征,并探究了不同药量载药微球的包封率、缓释性能、抗紫外性能、叶面接触角和黏附性能。结果表明,相比AVM分散液,紫外照射后载药微球中AVM的保留率提高到43%,说明CO-CMCS-PU载体的抗紫外性能良好;载药微球比AVM分散液在黄瓜叶面上的接触角降低了20%以上,滞留量提高了40%以上,说明其在叶面上有较好的黏附性和润湿性;载药微球包封率可达80%以上,具有良好的缓释和pH响应释放性能,释药行为符合First-order动力学模型,药物释放受Fickian扩散控制。     

聚乳酸-羟基乙酸聚合物载入羟基喜树碱载药纳米粒子的制备及表征

以抗癌药物羟基喜树碱作为模型药物,可降解材料聚乳酸-羟基乙酸(PLGA)为药物负载体,采用溶剂-抗溶剂沉淀法制备聚乳酸-羟基乙酸/羟基喜树碱的载药纳米微球,考察不同溶剂-反溶剂体系对载药包封效果的影响。结果表明,以丙酮-水为溶剂体系制备的载药微球性能较好,形貌外观呈圆球形,球表面圆润光滑,粒度均一,分散效果良好,平均粒径为160 nm,载药微球包封率随着载药量的增加而减小,实测载药量为7.83%的PLGA载药微球,其载药包封率为87.68%,在28 d后溶出累计量约50%,可见以聚乳酸-羟基乙酸为载体制备的羟基喜树碱剂型,缓释作用良好。     

β‐cyclodextrin‐conjugated hyaluronan hydrogel as a potential drug sustained delivery carrier for wound healing

In order to develop a potential drug sustained delivery carrier suitable for wound healing, a series of β‐cyclodextrin conjugated hyaluronan hydrogels (β‐CD‐HA) with adjustable crosslink densities were synthesized and characterized, meanwhile the delivery kinetics and mechanism of diclofenac as a model anti‐inflammatory drug from these hydrogels were investigated. By controlling the feeding molar ratio of β‐CD/HA, a β‐CD substitution degree of 4.65% was obtained by ¹H‐NMR analysis. The incorporation of β‐CD modification had little effect on the internal porous structure, water swelling ratio, and rheological property of HA hydrogel, which however were influenced by the crosslink density. Although the crosslink density had an influence on the drug loading and release profile by altering the water swelling property, the interaction between β‐CD and drug was the primary factor for the high loading capacity and long‐term sustained delivery of diclofenac. The semiempirical equation fit showed that the release of diclofenac from HA‐based hydrogels followed a pseudo‐Fickian diffusion mechanism. By the aid of β‐CD and controlled crosslink density, a β‐CD‐HA hydrogel with a diclofenac sustained delivery period of over 28 days and desirable physicochemical properties was achieved, which will be a promising drug sustained delivery carrier for wound healing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43072.     

Study on the gelation and sustained release effect of the thermosensitive material TPGS1000

Polyethylene glycol 1000 vitamin E succinate (TPSG₁₀₀₀) was commonly used as absorption promoter, solubilizer, and emulsifier in drug delivery systems. In addition, TPGS₁₀₀₀ possessed thermosensitivity and gelling property that were not extensively studied. Hence, TPGS₁₀₀₀ was synthesized by Collnot method, characterized, evaluated for gelling property, and applied as the thermosensitive carrier in the study. Thin-layer chromatography, Fourier transform infrared spectroscopy, and high-performance liquid chromatography methods proved that the TPGS₁₀₀₀ was successfully synthesized. Under the condition of 4.5% sodium sulfate, 12% TPGS₁₀₀₀ could rapidly form stable hydrogels at 37°C. In addition, the gelling time tends to shorten with temperature increasing. It is worth noting that TPGS₁₀₀₀ as the carrier for loading doxorubicin displayed significant sustained release behavior. In conclusion, the study laid foundation for the application and further research of TPGS₁₀₀₀ in thermosensitive gel drug delivery system and provides a novel material for thermosensitive gel preparations.     

Synthesis of pH-responsive isolated soy protein/carboxymethyl chitosan microspheres for sustained pesticide release

In order to improve the utilization rate of avermectin (AVM), a complex was prepared by electrostatic self-assembly using isolated soy protein (ISP) and carboxymethyl chitosan (CMCS) for loading AVM to obtain ISP/CMCS@AVM microspheres. The encapsulation efficiency (EE), sustained release property, ultraviolet (UV) protective ability, and toxicity of the microspheres were evaluated, and the release kinetics of AVM from the microsphere at different pHs were investigated. The results demonstrated that the average particle size of ISP/CMCS@AVM was 283.95 nm, and the EE reached 88.42% for AVM after denaturation. After 70 h of exposure to UV light, the residual rate of AVM in ISP/CMCS@AVM was 78.12%, which was significantly higher than 35.18% in the AVM emulsion. Moreover, the formulation imparted pH sensitivity and sustained-release property to AVM and was consistent with the Korsmeyer–Peppas model, controlled by Fick diffusion. Finally, the insecticidal toxicity of ISP/CMCS@AVM did not differ significantly from that of unmodified AVM. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48358.     

Melt spinning of β‐phase poly(vinylidene fluoride) yarns with and without a conductive core

When poly(vinylidene fluoride) (PVDF) is to be used as a piezoelectric material, the processing must include the formation of polar β‐phase crystallites, as well as the application of electrically conducting charge collectors, that is, electrodes. In this article, results from the melt spinning of PVDF yarns and a novel bicomponent PVDF‐yarn with a conductive carbon black/polypropylene (CB/PP) core are presented. Melt spinning has been done under conditions typical for industrial large‐scale fiber production. The effects on the resulting crystalline structure of varying the spinning velocity, draw rate, and draw temperature are discussed. The results show that, for maximum α‐to‐β phase transformation, cold drawing should take place at a temperature between 70 and 90°C, and both the draw ratio and the draw rate should be as high as possible. It was observed that the cold drawing necessary to form β‐phase crystallinity simultaneously leads to a decrease in the core conductivity of the bicomponent yarns. In this work, the melt spinning of bicomponent fibers with high‐β‐phase PVDF in the sheath and a CB/PP core was successfully accomplished. The core material remained electrically conductive, paving the way for the use of a CB‐polymer compound as inner electrode in the melt spinning of piezoelectric bicomponent fibers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Functionalized chitosan with super paramagnetic hybrid nanocarrier for targeted drug delivery of curcumin

Recently, hydrophobically functionalized polymers have been deployed as carriers to improve the encapsulation of hydrophobic drugs. The metal nanocomposites are extensively used to improve the biocompatibility of the formulation and target the drug to the specialized site. In our current study, naphthalene acetate (NAA) was incorporated into the amine group of chitosan to form a hydrophobically functionalized chitosan–NAA drug delivery carrier. The calcium ferrite nanoparticles (CFNP) were embedded in the chitosan–NAA matrix to form a super paramagnetic hybrid nanocarrier for controlled curcumin drug delivery. Various analytical techniques were performed to ensure the functional group modifications, thermal stability, surface nature and morphological behavior of synthesized hybrid carriers. The maximum encapsulation efficiency of 93.6% was obtained under the optimized conditions of drug to chitosan–NAA at 0.1, CFNP to chitosan–NAA at 0.75 and TPP to chitosan–NAA at 1.0 (w/w) ratios, respectively, by adapting Taguchi method. Drug release studies were conducted to determine the effect of pH, drug loading concentrations and magnetic field responses. The drug release data were fitted to various kinetic release models to understand the drug release mechanism. The biocompatibility of the hybrid material was tested using L929 mouse fibroblast cells. The cytotoxicity test against breast cancer cells (MCF-7) was also performed to study the anticancer property of the hybrid paramagnetic material. The prepared curcumin-loaded chitosan–NAA/CFNP was very active against cancer cells in comparison to the normal cells. The results confirmed the applicability of the hybrid nanocarriers in cancer cell-targeted drug delivery.     

Preparation a novel pH‐sensitive blend hydrogel based on polyaspartic acid and ethylcellulose for controlled release of naproxen sodium

Hydrogels based on pH‐sensitive polymers are of great interest as potential biomaterials for the controlled delivery of drug molecules. In this study, a novel, pH‐sensitive hydrogel was synthesized by poly(aspartic acid) (PASP) crosslinked with 1,6‐hexanediamine and reinforced with ethylcellulose (EC). The loading and release characteristics of naproxen sodium (NS) were studied. The PASP–EC blend hydrogels had pH‐sensitive characteristics and were strongly dependent on the pH value. The release kinetics for NS from the PASP–EC blend hydrogels and PASP hydrogel were evaluated in simulated gastric fluid (pH = 1.05) and simulated intestinal fluid (pH = 6.8) at 37°C. The results showed that the drug‐loaded hydrogels were resistant to simulated gastric fluid, and hence, they could be useful for oral drug delivery. Compared with the PASP hydrogel, the PASP–EC blend hydrogels showed a lower release rate of NS in the same pH conditions. It was evident that the presence of hydrophobic groups (EC) retarded the release of NS and led to sustained release. The kinetics of NS release from the drug‐loaded hydrogels conformed to the Korsmeyer–Peppas model. The release exponent of the model was 0.7291, which indicated multiple drug release. The PASP–EC blend hydrogels were biodegradable and pH sensitive; there would be a wide range of applications for them in controlled drug‐delivery systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009