苄达赖氨酸脂质体的制备

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。     

二甲基姜黄素脂质体的制备及性能研究

以乙醇为溶剂,采用薄膜分散法制备二甲基姜黄素(ASC-J9)脂质体。通过单因素试验和正交试验优化得到最佳制备工艺:磷脂与胆固醇的质量比为10∶1、磷脂与ASC-J9的质量比为1 000∶10、水化温度为60℃以及磷脂质量浓度为6. 67 mg/mL。最佳条件下制备的ASC-J9脂质体的包封率为97. 99%,平均粒径为145. 7 nm,其粒径分布较窄且在水中分散较好。4℃下ASC-J9脂质体的稳定性较好,且脂质体可以较好地保护包载的ASC-J9。该制备工艺具有绿色环保、操作简便、产品性能好等特点,所制ASC-J9脂质体可以有效改善ASC-J9的热稳定性和水溶性。     

复方石杉碱甲-虾青素脂质体的制备及评价

采用薄膜分散-探头超声法制备复方石杉碱甲-虾青素脂质体,高效液相色谱法分别测定石杉碱甲、虾青素的含量,葡聚糖凝胶柱色谱法分离脂质体与未包封的游离药,以包封率为指标,采用单因素考察和正交试验法优化脂质体制备工艺,并对其粒径、多分散系数(PDI)和形态进行综合评价。结果显示工艺验证复方脂质体中石杉碱甲平均包封率为65.35%±1.30%,虾青素平均包封率为50.42%±2.77%。粒径(156.22±3.71)nm, PDI为0.24±0.02,脂质体的粒径均一﹑包封率高﹑稳定性良好。     

正交设计优化尼莫地平脂质体的制备工艺

优化了尼莫地平脂质体的制备工艺。利用乙醇注入法制备尼莫地平脂质体,以包封率为评价指标,采用正交试验优化制备工艺,并考察脂质体形态、粒径、Zeta电位和包封率。结果表明:优化工艺条件为药物-磷脂的质量比1∶20,胆固醇-磷脂的质量比1∶10,脱氧胆酸钠-磷脂的质量比1∶10,磷脂浓度1%;尼莫地平脂质体外观接近球形,平均粒径(122.8±5.3)nm,平均Zeta电位(-23.69±1.24)m V,包封率84.27%±0.58%。结论:优选得到的尼莫地平脂质体制备工艺合理,为尼莫地平新制剂的研发提供依据。     

抗坏血酸脂质体的制备与稳定性研究

以磷脂和胆固醇为膜材,采用薄膜分散-高压均质法制备抗坏血酸脂质体。通过对制得的脂质体进行表征考察后发现,平均粒径为90.8 nm,多分散指数(PDI)为0.231,包封率可达60%以上。将脂质体在室温和4°C条件下放置存储,以抗坏血酸脂质体的粒径和包封率变化为指标考察其稳定性。结果表明,4°C条件保存的脂质体粒径和包封率无明显变化,抗坏血酸脂质体稳定性良好。     

包封维生素E脂质体的研究

采用超声法制备包封维生素E的脂质体,以包封率和粒径为衡量标准,通过单因素实验确定较优的实验条件为:m(大豆卵磷脂)∶m(维生素E)∶m(胆固醇)∶m(聚乙烯醇)=6∶3∶3∶2,V(氯仿)∶V(水)=1∶3,且体系中维生素E的质量分数为8.8%,超声2 min。此条件下包封率可达86.8%,平均粒径为62.9 nm;所得脂质体呈圆球状,储存在4℃下较适宜。     

芦丁脂质体的制备与药物包封率的测定

采用薄膜分散法,制备包封率高、粒径均匀、稳定性好的芦丁脂质体,并建立芦丁脂质体中芦丁含量和包封率的测定方法。以包封率为主要指标,通过正交设计优化芦丁脂质体的制备工艺,同时采用反相高效液相色谱法进行芦丁含量和包封率测定。结果表明,薄膜分散法制备的脂质体平均包封率为66.50%,外观均匀、稳定性良好。建立的反相高效液相色谱法能将芦丁与辅料分离良好,芦丁浓度在4～40μg/L范围内与峰面积呈现良好的线性关系（r=0.999 2,n=5）,平均回收率为99.0%,可用于测定芦丁脂质体的药物含量与包封率。     

脂质体载药性能与卵磷脂的关系

探讨了卵磷脂对脂质体载药性能的影响。用逆相蒸发法制备阿糖胞苷脂质体,通过测定脂质体的包封率、平均粒径和药物渗漏量,考察了蛋黄卵磷脂、大豆卵磷脂及猪脑卵磷脂对脂质体载药性能的影响。实验结果表明,在n(PC)∶n(CHOL)=1∶1的条件下,蛋黄卵磷脂脂质体的平均粒径为2.59μm,包封率为(17.02±0.21)%,在37℃经40 h温育后,平均粒径增加0.53μm,药物渗漏量为(0.18±0.01)mg/h。平均粒径和包封率均高于大豆卵磷脂脂质体及猪脑卵磷脂脂质体,平均粒径增加值低于大豆卵磷脂脂质体及猪脑卵磷脂脂质体,渗漏速度高于猪脑卵磷脂脂质体,但低于大豆卵磷脂脂质体。对比实验证明,蛋黄卵磷脂脂质体的载药性能较好。     

南极冰藻DNA光修复酶脂质体的制备及其质量评价

以包封率为评价指标,氯仿-乙醚混合溶剂(2∶3,体积比)为有机相,固态大豆卵磷脂和胆固醇为膜材,采用逆向蒸发法制备南极冰藻DNA光修复酶脂质体。经单因素实验和正交实验确定光修复酶脂质体的最佳制备工艺条件为:膜材比3∶1、药脂比1∶10、油相与水相体积比4∶1、超声时间6min,在此条件下,光修复酶脂质体的平均包封率达到(44.13±2.90)%。所制得的光修复酶脂质体呈圆形或椭圆形,平均粒径为(490.9±2.3)nm,Zeta电位在-30~-60mV范围内,制剂的质量标准符合中国药典(2015版)要求,为DNA光修复酶在日用防晒品中的应用提供了可靠的理论依据。     

薄膜分散法制备SN-38脂质体及质量评价

为了制备7-乙基-10-羟基喜树碱（SN-38）脂质体并进行相关制剂学评价，采用薄膜分散法制备SN-38脂质体，以包封率为评价指标，用高效液相色谱法进行测定，通过单因素实验考察优化SN-38脂质体的制备工艺并进行质量评价。结果表明：制备工艺中，磷脂浓度3%，药脂比为1∶20，胆固醇与磷脂比为1∶6，水化温度为50℃，包封率平均值为92.0%，选择质量分数为10%的甘露醇为冻干保护剂，制备SN-38脂质体的冻干品；质量评价方面，SN-38脂质体的外观澄清带有蓝色乳光，平均粒径为147 nm。选用载体成膜法制备SN-38脂质体的工艺操作简便、合理可行。     

Insect antifeedant properties of anthranoids from the genusVismia

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.