Description
MethoxyPEGAceticAcid withsuperiorqualityspecificationof ≥95%Substitution.
MethoxyPEG AceticAcid fromJenKemTechnologyisan AminePEGylationreagentreactivetowards theaminogroupoflysine(s)atpH7-8. MethoxyPEG AceticAcid ismorestablethanM-PEG-SCM. JenKemTechnologyoffersMethoxyPEG AceticAcid withMW5000(M-CM-5000),MW10000(M-CM-10K)andMW20000 (M-CM-20K),in1gand10gpackingsizes.
DifferentMWofMethoxyPEG AceticAcid productsmaybeavailablebycustomsynthesis,pleaseemailus attech@jenkemusa.comfordetailsoncustomPEGs. JenKemTechnology providesrepackagingservicesforanadditionalfee,pleasecontactusifyourequireadifferentpackagesizethanourcatalogselection.
BulkPEGsandGMPgradePEGsaremade-to-order.Pleasecontactus forbulkpricing.
ClickheretodownloadtheMSDS
Note:StartingJuly2016,Methoxy PEGAceticAcidisthenewnameoftheproductMethoxy PEGCarboxyl(MW5000(M-COOH-5000),MW10000(M-COOH-10K)andMW20000 (M-COOH-20K)).JenKemTechnologyhasrevisedthenameoftheproducttobetterreflectthechemical structure,asmanyotherPEGderivativeswithaCOOHgroup areofferedinourcatalog.
References:
1. Javanmardi,S.,etal.,Redox-Sensitive,PEG-ShieldedCarboxymethylPEINanogelsSilencingMicroRNA-21,SensitizesResistantOvarianCancerCellstoCisplatin,AsianJournalofPharmaceuticalSciences,2018.
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10.Li,Y.,etal.,Agraphenequantumdot(GQD)nanosystemwithredox-triggeredcleavablePEGshellfacilitatingselectiveactivationofthephotosensitiserforphotodynamictherapy, RSCAdv.,2016,6,6516-6522.
11. Jones,S.K,etal.,FolateReceptorTargetedDeliveryofsiRNAandPaclitaxeltoOvarianCancerCellsviaFolateConjugatedTrIBLockCopolymertoOvercomeTLR4DrivenChemotherapyResistance, Biomacromolecules,2016,17(1),76-87.
12. Chaudhary,R.,etal., Engineeredatherosclerosis-specificzincferritenanocomplex-basedMRIcontrastagents.JournalofNanobiotechnology,2016,14(1):1-7.
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14. Brinkman,A.M.,etal.,Aminoflavone-loadedEGFR-targetedunimolecularmicellenanoparticlesexhibitanti-cancereffectsintriplenegativebreastcancer.Biomaterials,2016,101:20-31.
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Foundedin2001byexpertsinPEGsynthesisandPEGylation,JenKemTechnologyspecializesexclusivelyinthedevelopmentandmanufacturingofhighqualitypolyethyleneglycol(PEG)productsandderivatives,andrelatedcustomsynthesisandPEGylationservices.JenKemTechnologyisISO9001andISO13485certified,andadherestoICHQ7AguidelinesforGMPmanufacture.TheproductionofJenKem®PEGsisback-integratedtoin-housepolymerizationdirectlyfromethyleneoxide,enablingfaciletraceabilityforregulatedcustomers.JenKemTechnologycaterstothePEGylationneedsofthepharmaceutical,biotechnology,medicaldeviceanddiagnostics,andemergingchemicalspecialtymarkets,fromlaboratoryscalethroughlargecommercialscale.
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我想提取中药中的有效成分,好像目前醇提取的比较多,中药有比如黄柏,桑白皮这些。有谁知道醇提取步骤吗?能不能帮帮忙,万分感激
求助战友们:
有做过中药醇提取,但是在收醇的时候,当浓缩至醇浓度约20%的时候,有析出现象,析出的还是我的有效成分,怎么才能解决这个问题呢?如果在未析出时停止浓缩,药液太稀,无法干燥呢?
问题1:我该如何浓缩定参数?
问题2:如果在未析出时放液,由于药液太稀,我该如何选择干燥方式?
求助站里的大侠们,谢谢!
补充:
一般使用浓硫酸作催化剂,使醇类脱去羟基生成含双键的有机物。应注意的是醇发生消去反应时的温度控制,温度较低(140℃)时会生成副产物醚类,温度达到一定范围(170℃)时才会发生消去反应。消去反应的本质是羟基与β位上的一个H原子共同脱去生成H2O的反应,因而能发生消去反应的醇类必须要有β-H原子。
如果羟基相连接的碳的邻位碳有多个,且都有氢原子,则消去有氢原子较少的邻位碳上的氢原子。 示例:
乙醇发生消去反应的方程式
CH3CH2OH→CH2=CH2+H2O (条件为浓硫酸 170摄氏度)
用蛋黄卵磷脂制备的“脂质体”粒径50-60nm,而文献中一般都是100多纳米,现在担心形成的不是脂质体,而是胶束,两者有什么方法可以鉴别吗?
甲磺酸与低级醇形成的甲磺酸烷基酯,具有潜在基因毒性。那么,几个碳的低级醇形成的甲磺酸烷基酯按照基因毒性杂质控制?(C<5?)上述结构化合物是否也需按照基因毒性杂质进行研究?
若是,按照此类杂质总和小于TTC(1.5ug/天)来控制,是否合适?
PS:一起始原料中引入此中间体,采用甲磺酰氯与对应醇反应所得,合成路线其他步骤也同时用到甲醇,会引入甲磺酸甲酯。
(二)连接回流冷凝管时,冷凝管连接水不会对浸出物造成影响吗?
请求大神指点,不胜感激!
本人目前在做一个中药提取方法的研究,水提醇沉,醇沉浓度分别为50%、60%和70%,检验结果,得率分别为21.99%、23.85%和25.55%,但含量分别是33.48mg/g、16.60mg/g和19.42mg/g。理论上是醇沉浓度越高,去除的杂质越多,得率越低吗?含量是不是也应该是醇沉浓度越高含量越高?我的试验有什么问题,求各位大虾指点!
各位老师好,有做环黄芪醇的吗?其对心血管效果怎么样?使用剂量范围是不是很窄,我看文献,有报道,黄芪提取物对血管的作有是双向的,会不会在低剂量时对身体是有害的
在本例中,溴处在间位,因此不参与反应。
而氯恰好处于对位,因而能发生反应,被甲氧基取代。
因此产物是4-硝基-2-溴苯甲醚。
完全醇水溶液如长期存放,会出现粘度增加甚至凝胶化的现象,聚合度和粘度越高,储存温度越低,越容易出现这种想象。可以采取以下措施:
(1)将聚乙烯醇水溶液重新加热搅拌即可恢复原来的流动性。
(2)添加硫氰盐酸盐(如钙、钠、铵等盐类)、苯酚、丁醇、山梨酸等可以有效防止凝胶化,添加量为5~10%。部分醇解型PVA长期存放不易产生粘度增加的情况。同时要注意长期存放容易发生发霉、腐化现象,需添加防霉、防腐剂。建议配置好水溶液后即时使用。
小弟有一中药处方,需要水煮醇沉处理,问下具体该怎么做,给我方子的老师去世了
告诉我中药先水煮,在用水煮醇沉法外敷治疗
给电话我直接问液可以