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以壳聚糖-海藻酸钠为囊材,采用乳化-外部凝胶法制备猪脾脏转移因子壳聚糖-海藻酸钠微囊,并研究了其粒径、载药量、包封率、体外释药等性质. 结果表明,经优化工艺所制微囊球形度良好,平均粒径11.05 mm,平均载药量11.60 mg/g,平均包封率60.8%,在磷酸缓冲液(pH=7.4)中的释药曲线方程为ln(1-Q)=-0.0692t-0.6449 (R2=0.9876),符合一级动力学方程. 该制备工艺简单,所制猪脾脏转移因子微囊具有良好的溶胀性能和缓释性能. 相似文献
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采用固体分散技术结合泡腾技术制备硫酸头孢喹肟脂质体,考察了减压旋转蒸发温度、氯仿用量、大豆卵磷脂/胆固醇质量比、吐温-80用量、药/脂质量比、柠檬酸与NaHCO3用量对脂质体外观形态和包封率的影响. 通过正交实验优化制备条件,并探讨了脂质体的形成机制. 结果表明,制备硫酸头孢喹肟脂质体的优化条件为:大豆卵磷脂/胆固醇/吐温-80/柠檬酸/NaHCO3的质量比为37:18:5:33:7,药/脂质量比1:10. 该条件下所制脂质体外观形态良好,粒径分布均匀,平均粒径为(203±5) nm,平均包封率为55.17%±0.44%,平均载药量为5.04%±0.02%. 相似文献
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采用锐孔/聚合法制备了平均粒径为1.89 mm、负载5-氨基水杨酸(5-ASA)的纤维素硫酸钠(NaCS)-壳聚糖微胶囊,采用Box-Behnken响应面法进行实验设计和分析,考察了内、外水相pH值和NaCS浓度、多聚磷酸钠(PPS)浓度对微胶囊载药量和包封率的影响. 结果表明,内水相pH值对负载5-ASA微胶囊的载药量和包封率起关键作用. 最佳制备条件为内水相pH 4.25,外水相pH 6.0,NaCS浓度14 g/L, PPS浓度5 g/L,该条件下所制微胶囊最大载药量为59.02%,最大包封率为89.96%.. 相似文献
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采用薄膜水化法制备载阿奇霉素-鼠李糖脂(AZI-RHL)胶束,以包封率、载药量为评价指标,通过单因素试验和正交试验优化制备工艺,并考察其理化性质。制备载药胶束前先测定RHL水溶液的临界胶束浓度(CMC)。结果表明,RHL水溶液的CMC值约为0.25 mg/mL。优化后的最佳制备工艺条件为:RHL投料量100 mg,甲醇用量12 mL,搅拌时长20 min。在此条件下制备的AZI-RHL胶束呈球形,水动力学直径为136.3±68.5 nm,Zeta电位为-23.1±6.8 mV,包封率为80.34%±0.60%,载药量为19.42%±0.48%。红外光谱证明AZI包埋在胶束中。体外释放试验表明AZI-RHL胶束具有一定的缓释作用,其体外累计释放曲线符合Ritger-Peppas方程,释放药物以Fick扩散为主。综上所述,AZI-RHL胶束的制备工艺稳定可靠,胶束粒径小,且包封率、载药量高,是一种有潜力的新型制剂。 相似文献
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《化学与生物工程》2017,(5)
以苄达赖氨酸、大豆卵磷脂、胆固醇为原料制备了苄达赖氨酸脂质体。以包封率为主要指标,选取药脂比、超声时间、水相pH值和孵育温度4个因素进行正交实验优化制备工艺,用紫外分光光度计测定包封率,用粒度和Zeta电位分析仪测定所制备脂质体的粒径分布及Zeta电位。确定最佳制备工艺条件为:药脂比1∶5(g∶g)、超声时间15min、水相pH值5、孵育温度60℃,在该条件下所制得的3批苄达赖氨酸脂质体的平均包封率为81.54%,平均粒径为(99.85±9.60)nm,平均Zeta电位为(-30.6±1.8)mV,体外释放实验证明释放速度慢于市售制剂。表明所制备的苄达赖氨酸脂质体包封率高、稳定性好。 相似文献
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目的:研制洛伐他汀长循环脂质体,考察其制备的影响因素,优化处方工艺,并对其理化性质和释放行为进行表征。方法:以PEG2000作为表面修饰剂,采用薄膜分散法制备了洛伐他汀长循环脂质体。采用微柱离心法测定包封率并结合粒径,在单因素考察的基础上,通过正交设计对处方和工艺进行优化,确定了洛伐他汀长循环脂质体的最佳处方及制备工艺。结果:制得的洛伐他汀长循环脂质体外观圆整,大小均一,可清晰看到指纹状结构,较普通脂质体更为不规则,平均粒径为(115.6±0.3 nm),Zeta电位为(-14.41±0.57 m V),载药量为(100±2.9 g/m L),包封率80%以上。用透析法考察了洛伐他汀长循环脂质体的体外释药行为,结果表明洛伐他汀长循环脂质体释放稍快于普通脂质体。 相似文献
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以平均粒径、载药量、包封率及总评归一值为评价指标,运用星点设计考察芯材比、油水相比、壳聚糖浓度对微球制备的影响,对结果进行二项式拟合,效应面法选取最佳工艺条件并进行预测分析。结果显示,最佳工艺条件为:油水相比为4.2∶1,壳聚糖浓度为2%,交联时间为3.5 h。在此条件下,制得的微球粒径均一,球形圆整,平均粒径为7.21μm,包封率为61.34%,载药量为70.12%。体外释放行为符合Higuchi方程,2 h和24 h时累积释放率分别为32%和84%。 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively.
There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized.
High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without
the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of
fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to
achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic
SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve
F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender
particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing,
and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing
or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually
preserves suspension stability during freezing.
Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago,
IL. Tied for first place in The John A. Gordon Best Paper Competition. 相似文献
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Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US
In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae
and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted
in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures
(release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species
(Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species
to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were
exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of
separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles
from the southeastern region of the US. 相似文献
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Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed. 相似文献
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍. 相似文献
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。 相似文献