蓝藻为载体的阿维菌素抗紫外缓释剂的制备及其性能

以滇池蓝藻为载体,利用其抗紫外特性,用卡波姆树脂包裹蓝藻-阿维菌素(Avermectin, Av)粉,制成阿维菌素抗紫外缓释剂,利用FT-IR, SEM和HPLC等对蓝藻和缓释剂进行表征,研究其吸附与释放行为. 结果表明,Av在异丙醇中的饱和吸附量为160.81 mg/g,包裹10%卡波姆树脂的抗紫外缓释剂具有很好的缓释功能,在乙醇/水(4:1, j)中释放20 d,累计释放率为51.8%,释放机制是Fick扩散和骨架溶蚀的双重机制. 经4 h紫外光照射,含蓝藻的制剂中Av残留量为61%,不含蓝藻的制剂中Av残留量为39%.     

DSP-PELA/SiO2微球的制备及其体外释药研究

采用自制的聚乳酸-聚乙二醇-聚乳酸/SiO2 PELA/SiO2)材料作为药物载体,通过溶剂挥发法制备了地塞米松磷酸钠(DSP)微球,并对微球的粒径、载药量以及体外缓释性能进行了研究.微球电镜图片显示其粒径大小分布在8μm左右,符合缓释制剂要求.体外缓释研究结果显示,PELMSiO2微球具有明显的缓释作用.     

阿司匹林聚乳酸／SiO2微球的制备及其体外缓释研究

应用自制的聚乳酸／SiO2材料为药物载体通过溶剂挥发法制备了阿司匹林微球，并对该微球的粒径、包封率、载药量以及体外缓释性能进行了研究。微球电镜图片显示粒径大小分布在15μm左右，符合缓释制剂要求。体外缓释研究所得Higuchi方程为Q=0．3598＋0．03t^1/2，相关系数P=0．9961，该结果显示所得微球具有明显缓释作用。     

木质素季铵盐-海藻酸钠聚合物负载阿维菌素粉体的制备及抗紫外光性能分析

以三甲基木质素季铵盐-海藻酸钠(QL-SA)为载体,用物理混合法制备了阿维菌素缓释聚合物(AVM-QL-SA),利用FT-IR对其结构进行了表征,探讨了交联剂用量、药物加入量、体系pH值等因素对载药量和包封率的影响,并对其缓释性能和抗紫外光降解进行了研究。结果表明:阿维菌素(AVM)均匀的混合在QL-SA载体中,主要以物理混合为主;最佳制备条件为:戊二醛为5%(以单体质量分数计)、药物加入量为1%(以单体质量分数计)、体系pH值为8.5,载药量和包封率分别达到1.36%和73.36%;阿维菌素缓释聚合物粒径符合正态分布,平均粒径为83.90 μm;阿维菌素缓释聚合物具有很好的缓释性能,在乙醇/水(体积比1:1)中释放30 h,累计释放率为88.97%;经8 h紫外光照射,阿维菌素原药中AVM残留量为6.24%,阿维菌素缓释聚合物中AVM残留量为37.75%,具有良好的抗紫外分解性能。     

纳米SiO2对聚羧酸减水剂的吸附作用研究

采用红外光谱、紫外-可见分光光度计研究了纳米SiO2对聚羧酸减水剂的吸附作用,并利用纳米粒度zeta电位仪、旋转粘度计研究了纳米SiO2吸附减水剂后对其分散性以及新拌水泥浆体流动性的影响.研究结果表明,纳米SiO2对聚羧酸减水剂存在吸附作用,吸附量随减水剂浓度的增大而增加,当减水剂浓度增加到5g/L时,吸附量趋近饱和.纳米SiO2对聚羧酸减水剂的吸附作用,使其团聚粒径增大,粒径分布曲线整体向大颗粒方向偏移,分散性大大降低.将纳米SiO2溶于拌和水中,先加入水泥搅拌,然后再加入减水剂搅拌,可减小纳米SiO2对减水剂的吸附,增大减水剂的利用效率,提高水泥浆体的流动性.     

以微囊藻为载体制备戊唑醇缓释剂

利用天然藻为载体,采用喷雾干燥的方法得到了微囊藻的微球,在其表面吸附杀菌剂戊唑醇,加入适量成膜剂制备新型环保的农药缓释剂型。对藻的吸附能力及其在特定溶剂的释放行为进行分析表明：该载体藻类具有较高的吸附能力,吸附量最大可达到18000mg/kg;缓释剂型有较好的缓释效果,最长可达200h,最终释放量为80%。该方法既经济又环保,具有较好的应用前景。     

甲氨基阿维菌素苯甲酸盐微囊藻缓释剂的制备及性能

以微囊藻为吸附载体、卡波树脂为包衣剂,研制了甲氨基阿维菌素苯甲酸盐农药缓释剂,对微囊藻组成及形貌进行了表征,研究了微囊藻对甲维盐的吸附动力学和制剂的释放动力学. 结果表明,微囊藻的平均粒径为3.5 mm,表面存在大量的微孔和功能性基团,说明其具有很好的吸附作用;30℃下在1:1(j)乙醇水溶液中微囊藻对甲维盐的最大吸附量为70.78 mg/g,平均每个微囊藻吸附1.1×109个甲维盐分子;在3:7(j)乙醇水溶液中不含成膜剂的甲维盐-微囊藻缓释颗粒在24和72 h时的累积释放率分别为52.9%和65.3%,说明微囊藻具有对甲维盐的缓释应用前景.     

超细SiO2颗粒的制备及其对α-淀粉酶的吸附固定化

采用Triton X-100反胶团体系法和Stber法分别制备粒径为50 nm及1μm的SiO2颗粒,用二氯二甲基硅烷(DDS)对其进行表面疏水性修饰,用于α-淀粉酶的固定化.结果表明,经DDS修饰的SiO2颗粒对α-淀粉酶的吸附能力明显提高,且有效提高了吸附稳定性,经6次洗涤后酶活仅损失30%;1μm SiO2颗粒比50 nm SiO2颗粒对α-淀粉酶的吸附量大,SiO2颗粒载体固定的α-淀粉酶的活性为50 nm SiO2>1μm SiO2>50 nm修饰后SiO2>1μm修饰后SiO2.     

超细SiO2颗粒的制备及其对α-淀粉酶的吸附固定化

采用TritonX-100反胶团体系法和St(o)ber法分别制备粒径为50 nm及1μm的SiO2颗粒,用二氯二甲基硅烷(DDS)对其进行表面疏水性修饰,用于α-淀粉酶的固定化.结果表明,经DDS修饰的SiO2颗粒对α-淀粉酶的吸附能力明显提高,且有效提高了吸附稳定性,经6次洗涤后酶活仅损失30％;1μm SiO2颗粒比50 nm SiO2颗粒对α-淀粉酶的吸附量大,SiO2颗粒载体固定的α-淀粉酶的活性为50 nm SiO2＞1 μm SiO2＞50 nm修饰后SiO2＞1 μm修饰后SiO2.     

纳米SiO2粒子静电吸附引发剂及引发甲基丙烯酸甲酯乳液聚合

对纳米SiO2粒子静电吸附2,2′-偶氮(2-脒基丙烷)二氯化氢(AIBA)引发剂,进而在其表面引发甲基丙烯酸甲酯乳液聚合而制备聚甲基丙烯酸甲酯(PMMA)/纳米SiO2复合粒子进行了研究.发现当介质pH值高于SiO2粒子等电势点时,纳米SiO2能与AIBA发生静电吸附而锚固上引发剂.使用高速离心分离/紫外分光光度计分析,证明引发剂吸附存在一个稳定上限,在pH=10时为0.067g·(g·SiO2)-1.随着纳米SiO2粒子锚固AIBA量的增加,聚合速率增加,PMMA/纳米SiO2复合粒子的平均粒径变小;乳化剂OP-10用量过大时,复合粒子的胶体稳定性降低.原位乳液聚合得到的PMMA/纳米SiO2复合粒子的典型形态为"草莓"型核壳结构.     

刺激响应型农药控释剂研发与应用进展

农药的长期低效使用增加了农业生产成本,造成大量农药流失,威胁食品安全与生态环境。利用农药缓控释技术对现有农药剂型进行改进是提高农药利用率的有效措施。刺激响应聚合物作为新兴载体,可以感受周边环境变化,从而响应并靶向控制释放有效成分。在医药领域,这类材料作为药物运载体的研究已相当广泛,在癌症的靶向治疗方面更是颇具成效。在农药控释领域的相关应用则处于基础研究阶段,仍然有一系列的因素限制着这类材料在农药控释领域的发展,比如载体成本、药物负载性能、体系稳定性、加工工艺的普适性及应用等。本文综述了刺激响应性聚合物应用于农药控释领域的研发现状,并对该类农药控释剂的应用前景进行了展望。     

Lignins as formulating agents for controlled release in agriculture

The use of naturally-occurring polymers, and in particular, kraft lignin, for controlled release pesticide formulations is reviewed. A matrix of kraft lignin containing polar pesticides can be prepared in granular form and the release rates of the active ingredient from this formulation are described. Successful applications of this type of formulation include herbicides for weed control in conifer plantation and insecticides in tropical flooded rice.     

NCs-Delivered Pesticides: A Promising Candidate in Smart Agriculture

Pesticides have been used extensively in the field of plant protection to maximize crop yields. However, the long-term, unmanaged application of pesticides has posed severe challenges such as pesticide resistance, environmental contamination, risk in human health, soil degradation, and other important global issues. Recently, the combination of nanotechnology with plant protection strategies has offered new perspectives to mitigate these global issues, which has promoted a rapid development of NCs-based pesticides. Unlike certain conventional pesticides that have been applied inefficiently and lacked targeted control, pesticides delivered by nanocarriers (NCs) have optimized formulations, controlled release rate, and minimized or site-specific application. They are receiving increasing attention and are considered as an important part in sustainable and smart agriculture. This review discussed the limitation of traditional pesticides or conventional application mode, focused on the sustainable features of NCs-based pesticides such as improved formulation, enhanced stability under harsh condition, and controlled release/degradation. The perspectives of NCs-based pesticides and their risk assessment were also suggested in this view for a better use of NCs-based pesticides to facilitate sustainable, smart agriculture in the future.     

浅谈农药剂型的研究现状

国内外农药的剂型正朝着水基性、颗粒化、缓释、多功能及省力化的方向发展.论述了农药剂型的研究现状,并介绍了剂型的开发与改进,对农药剂型的发展做了大体的展望.     

化学型农药缓释剂

介绍了控制释放技术及其在农药生产中的应用,论述了农药控制释放剂型在减轻环境污染,减少农药使用量以及提高农药施用安全性的作用,并详细论述了化学型农药缓释剂的原理,制备技术和活性物质释放的影响因素。天然的,可生物降解的高分子化合物用于控制释放越来越为人们重视,正成为农药制剂研究的发展方向。     

界面聚合法制备农药微胶囊剂的研究

选取杀螟硫磷作为有效成分,介绍了界面聚合法制备农药微胶囊剂的改进方法,将多异氰酸酯预处理后再进行聚合反应,并与农药微胶囊剂的传统制备方法进行了对比,发现方法改进后,微胶囊的囊皮特性得到很好改善,微胶囊的包药率提高约一倍,达到95％以上,热贮稳定性有很大程度提高,分解率从15％降低到2％左右,释放速度更加缓慢,而且可以通过不同的条件控制释放速度,说明改进后方法制得的微胶囊剂能更好地提高农药的持效性,可以减少施药量一文中还着重研究了多种反应条件对农药微胶囊化的影响,测定了农药微胶囊在水中的释放速度,实验表明：释放速度可以通过界面聚合反应的时间、微胶囊剂粒子的大小、农药与囊材的不同用量比、两种水相单体的不同用量比等因素进行控制和调节,以获得适合实际要求的微胶囊：     

A novel one-step microemulsion method for preparation of quercetin encapsulated poly(methyl methacrylate) nanoparticles

A series of drug-loaded poly(methyl methacrylate) (PMMA) nanoparticles were prepared and studied as controlled release carrier of quercetin drug using a simple one-step differential microemulsion method. The polymer carriers were prepared in different monomer/surfactant ratios. The encapsulated PMMA nanoparticles were characterized by Fourier transform infrared spectroscopy, dynamic light scattering and transmission electron microscopy analysis. The particle size was obtained below 10 nm with spherical shape and narrow size distribution. In vitro drug release studies were performed using a dissolution medium such as sodium phosphate buffer saline simulating body fluids. Based on a full factorial 3² experimental design, nine formulations for quercetin-loaded PMMA nanoparticles were prepared and the molar ratio of monomer/surfactant and amount of initiator were considered as independent variables, while the encapsulation efficiency, solid content and drug release were taken into account as responses. Based on ANOVA analysis, with desirability factor of 0.952, the software F3 was suggested as an optimized formulation. This formulation was composed using a monomer/surfactant molar ratio of 3 and initiator amount of 0.02 g as independent variables, while the amounts of 71.10, 25.34, and 61.54%, in the order given, for encapsulation efficiency, solid content and drug release, were obtained as responses. To estimate release mechanism, the obtained cumulative release data were fitted to zero-order, first-order, Higuchi and Korsmeyer-Peppas kinetic models. In vitro release experiments in all cases revealed that the controlled release behavior followed from Korsmeyer-Peppas kinetic model exhibited non-Fickian diffusion mechanism. Consequently, this research offers useful pharmaceutical carriers with the purpose of providing prolonged release for targeting delivery.     

Preparation of acetamiprid-loaded polymeric microcapsules: Influence of preparation parameter in emulsion system on microcapsule characteristics

Microencapsulation of pesticides is a promising technique for avoiding high initial doses and multiple applications of the chemicals to agricultural land which cause environmental pollution. It is because the formulation is possible to improve the stability of the chemicals against environmental degradation and control the release rate. In the present study, polymeric microcapsules prepared by the solvent evaporation method via water-in-oil-in-water (W/O/W) emulsion were used as immobilization supports of acetamiprid, a water-soluble pesticide. The pesticide was loaded in the microcapsules by impregnating the polymeric supports with acetamiprid dissolved in an organic solvent. Increased volume ratio (ϕ) of inner aqueous phase to oil phase in the emulsion system contributed to more pores in the microcapsules and increase in the content of acetamiprid in the polymeric supports. Release rate of acetamiprid from the microcapsules could be controlled by changing ϕ.     

Controlled release study of carbaryl insecticide from calcium alginate and nickel alginate hydrogel beads

In this study, controlled release formulations for reducing environmental impact of pesticides have been produced by encapsulating as a model pesticide carbaryl (Carb) in the alginate beads. The various hydrogel bead formulations were prepared by the ionotropic crosslinking of sodium alginate (NaAlg) with calcium and nickel ions. The surface morphology of prepared beads was characterized with scanning electron microscopy (SEM). SEM confirmed the spherical nature and surface morphology of the particles. Bead characteristics, such as carbaryl entrapment efficiency, particle size, equilibrium swelling degree, and carbaryl release kinetics, were determined. The effects of the bead preparation conditions such as crosslinker concentration and type, carbaryl/sodium alginate (Carb/NaAlg) ratio and percentage of NaAlg on the carbaryl release from the calcium alginate (Ca‐Alg) and nickel alginate (Ni‐Alg) beads were investigated in distilled water at 25°C. It was observed that carbaryl release from the Ca‐Alg beads was slower than that of Ni‐Alg beads. The release results indicated that carbaryl release from both of the Ca‐Alg and Ni‐Alg beads decreases with the increasing crosslinker concentration, Carb/NaAlg ratio and percentage of NaAlg. The highest carbaryl release was found to be 100% for the Ni‐Alg beads at 3 days whereas the lowest carbaryl release was found to be 67% for the Ca‐Alg beads at 21 days. The swelling measurements of the beads were also in consistent with the carbaryl release results. The carbaryl release from most of the bead formulations followed Case II transport. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007