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1.
用转动包衣造粒法研制一种新剂型的生物杀线虫剂-0.5%阿维菌素颗粒剂。初步研究了黏结剂、吸附剂、分散剂、包衣时间及筒体充填度等因素对产品制备工艺的影响,确立了最佳配方并测定了其质量技术指标。田间药效试验表明,该颗粒剂对胡椒根结线虫具有较好的防治效果,用量75kg/hm^2时,药后60d,防效能保持在95%以上。  相似文献   

2.
复合基质型经皮给药控释系统体外释放的传质规律   总被引:1,自引:0,他引:1  
为研究和改进基质中药物的体外释放特性 ,以雌二醇为模型药物 ,制备了具有储库层的复合基质型经皮给药控释系统 ,进行了体外释放实验 ,测定了释放曲线 ,建立了复合基质型药物控释系统在体外分层释放的数学模型。模型计算结果与实验结果基本吻合 ,表明模型较好地反映了复合基质型经皮给药制剂的体外释放特征。药物的初始释放速率和传统经皮给药控释系统相近 ,释药量与储库层药物含量无关 ;但平均释放速率大于后者。复合系统的控释作用优于传统的单层系统  相似文献   

3.
为实现药物的长期稳定释放并提高药物利用率,提出了一种以聚乳酸-聚羟基乙酸(PLGA)为载药基体的新型植入式药物控释系统。该药物控释系统可埋植在病灶附近进行长期释药,在药物释放结束后药物载体自然降解。为研究该药物控释系统的释药性能,建立其药物释放模型、模拟释药过程是有效方法之一,但在建立药物释放模型过程中,不断降解的PLGA材料特性难以量化。文中提出了一种使用扩散系数来表征PLGA材料的降解溶蚀程度的方法,在37℃下使用生理盐水模拟体液,对50/50、65/35及75/25三种单体比例的PLGA材料进行吸水实验和降解实验,并制备全封装药物控释系统进行了体外释药实验。通过实验结果的对比并基于物质守恒与传递定理,推导了封装药物在PLGA载药基体中释放时扩散系数的分段表达函数。基于该扩散系数表达函数,建立了药物通过该给药系统释放的有限元模型;使用有限元模型模拟药物的释放过程,并将有限元模拟结果与该药物控释系统体外释药实验结果进行了对比。结果表明,药物控释系统累积释药量呈线性变化,有限元模型模拟结果与体外释药实验结果基本吻合,验证了药物在PLGA材料中扩散系数分段表达式及有限元释药模型的正确性。该研究为后期建立药物释放的解析模型提供了一定的理论基础。  相似文献   

4.
为研究口服药物控释微球的制备及其体外释药性质,以格列吡嗪为模型药物,采用喷雾干燥法制备具有恒速释药性质的微球.通过考察微球的收率、包封率以及体外释放特性,研究了载体材料、材料与药物比例以及药物释放环境对格列吡嗪控释微球释药性质的影响.结果表明,采用醋酸纤维素为载体材料,选用合适的配方,可制得具有零级释药动力学的格列吡嗪控释微球制剂,并且该制剂可以根据需要的条件在12 h或24 h内释放完毕.不同条件下微球的药物释放曲线线性拟合的相关系数在0.981~0.999之间.  相似文献   

5.
己酮可可碱渗透泵控释片的研制   总被引:1,自引:1,他引:0       下载免费PDF全文
应用正交设计优化渗透泵控释片片芯处方,通过单因素考察,确定包衣液处方及包衣增重;通过以不同渗透压的溶液作为释放介质,考察其释放机理。制备的3批己酮可可碱渗透泵控释片呈现良好的零级释放特征,体外控释效果好,所制己酮可可碱渗透泵控释片遵从以渗透压差为释药动力的渗透泵式释药模式,工艺稳定。  相似文献   

6.
用硅酸酯水解法制备了孔径为3 nm的MCM-41作为烯效唑载体,采用负压浸渍法载药.用XRD、BET、TEM、SEM、TG等仪器对包覆体系进行了表征分析.用低平均分子量γ-PGA(M.W.≈9180 Da)包覆负载药物的纳米粒子,形成控释体系.在不同乙醇-PBSaq溶液中,对不同控释体系的控释效应进行了探究.通过零级释放、一级释放、Higuchi和Rigter-Peppas释放动力学模型的拟合探究控释体系的药物控释机理.分析结果表明:烯效唑在MCM-41外表面及孔道内均有吸附,负压浸渍法能有效促使烯效唑分子进入3 nm孔道内部,以单分子层的吸附为主;在聚乙烯亚胺作用下,制得包覆壳层厚度均一、分散性较好的MCM-41@γ-PGA纳米控释体系;未包覆的载药体系的药物释放不满足零级释放、一级释放和Higuchi模型,但满足Rigter-Peppas释放动力学模型,遵循Fick扩散机理.  相似文献   

7.
为了制备西咪替丁控制微丸并研究其释药机理,用单因素实验方法考察包衣液中溶媒系统的组成、膜材的浓度、包衣膜厚度对药物释放的影响,用分光光度法测定微丸释放出的药物浓度.结果表明:制作的微丸,包衣液中的溶媒系统的组成、膜材浓度及包衣膜厚度共同决定衣膜的控释能力.体外释放表表明制备的微丸属于包衣骨架控释微丸,随包衣厚度的改变释放机理有所不同.  相似文献   

8.
通过单一及复合使用哈茨木霉菌与蜡样芽孢杆菌,调查不同处理对大田番茄根结线虫的预防和防治效果。田间试验结果表明,连续施用两次生防菌后,两种微生物菌剂的复合使用比单一菌株对根结线虫表现出明显的预防和防治效果。45 d后两种微生物菌剂复合使用对番茄根结线虫的预防和防治效果分别达到70.2%、48.4%,根际土壤根结线虫减退率分别达到61.4%、54.9%,番茄根中根结线虫减退率分别达到75.9%、60.7%,显著高于单一菌株对根结线虫的预防和防治效果(P<0.05),研究结果为下一步研发微生物菌剂的复合使用防治番茄根结线虫提供了参考依据。  相似文献   

9.
以钠基蒙脱石为原料,用十六烷基三甲基氯化铵(CTAC)进行有机改性制备季铵盐改性蒙脱石(CMMT),之后吸附五氟尿嘧啶(5-FU),再用海藻酸钠(SA)进行包衣,最后测定该载药凝胶球的释药性能.考察p H值和释放时间等因素对载药凝胶球体外释放5-FU的影响规律,通过三种体外释放模型对其释药数据进行拟合,探讨了凝胶球中5-FU的释放机理,说明了季铵盐改性蒙脱石作为5-FU治疗结肠癌控释载体材料的可行性.结果表明:CMMT/SA对5-FU的载药量远大于MMT/SA,其载药量可达到0.6827 g/g;而载药凝胶球中5-FU的体外释放能力主要受释放介质p H值的影响,当p H 7.4时,5-FU/CMMT/SA中5-FU的累积释放率最大,可达到77.10%,在p H 1.5时的结果最小;一级动力学模型能比Korsmeyer-Peppas模型和Higuchi模型更好地拟合5-FU在不同p H下的体外释放情况.  相似文献   

10.
为提高蜡样芽胞杆菌BCJB01粉剂对蔬菜根结线虫病的田间防治效果,采用添加营养基质、有机肥等方式,进行了蜡样芽胞杆菌BCJB01防治番茄根结线虫病的田间技术研究。结果表明,在整地时同时添加有机肥和营养基质的处理对番茄根结线虫的防治效果最好,防效为77.45%,优于对照药剂10%噻唑膦颗粒剂对番茄根结线虫的防治效果。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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