甲基丙烯酸异冰片酯与甲基丙烯酸甲酯共聚合及聚合物表观性能

研究了甲基丙烯酸异冰片酯与甲基丙烯酸甲酯在 BPO 引发下的共聚合。竞聚率 r_1和 r_2分别为0.91±0.02和0.46±0.01。测试了不同组成共聚物的热、光、力学等性能。     

丙烯酸异冰片酯(IBA)-苯乙烯(St)共聚合物的合成及其性能的测定

共聚合反应中 M_1为 IBA,M_2为 St,其竞聚率γ_1=0.35±0.05,γ_2=0.54±0.02;共聚物具有良好的光学性能,折光指数随苯乙烯链段增加而提高,n~(20)_D 1.50—1.60,对于可见光透光率可达100%;共聚物的熔融指数较高,随苯乙烯链段含量增加而下降,共聚物的 T_g 在85—95℃之间;共聚物硬度较高,布氏硬度值在20℃测定是18—19kg/mm~2;共聚物分子量增加,压缩与拉伸强度提高。     

SYNTHESIS AND PROPERTIES OF COPOLYMERS OF ISOBORNYL ACRYLATE(IBA)-STYRENE(St)

共聚合反应中M_1为IBA,M_2为St,其竞聚率γ_1=0.35±0.05,γ_2=0.54±0.02;共聚物具有良好的光学性能,折光指数随苯乙烯链段增加而提高,n~(20)_D 1.50—1.60,对于可见光透光率可达100%;共聚物的熔融指数较高,随苯乙烯链段含量增加而下降,共聚物的T_g 在85—95℃之间;共聚物硬度较高,布氏硬度值在20℃测定是18—19kg/mm~2;共聚物分子量增加,压缩与拉伸强度提高。     

H2O/DMSO混合溶剂对丙烯腈与N-乙烯基吡咯烷酮共聚反应的影响

为得到高性能的聚丙烯腈原丝,采用H2O DMSO(二甲基亚砜)混合溶剂工艺合成了丙烯腈(AN)与N 乙烯基吡咯烷酮(NVP)共聚物。探讨了H2O DMSO混合溶剂对丙烯腈(AN)与N 乙烯基吡咯烷酮(NVP)共聚反应动力学的影响,计算了聚合反应表观活化能,并对共聚物进行了GPC元素分析、IR分析。结果表明:随混合溶剂中DMSO含量的增多,聚合反应速率降低,分子量降低且分布变宽,聚合物立构规整性变差;利用Kelen Tudos法测定出单体竞聚率:rAN=0.656±0.015,rNVP=2.11±0.18。在H2O DMSO=80 20(质量比),t=60℃条件下可得到适合纺丝的共聚物。     

甲基丙烯酸三苯基锡酯及三乙基锡酯与甲基丙烯酸特丁酯共聚参数的测定

本文使用FTIR法测定了60℃下在苯溶液中,AIBN为引发剂,甲基丙烯酸三苯基锡酯和甲基丙烯酸三乙基锡酯分别与甲基丙烯酸特丁酯进行自由基共聚反应的竞聚率,结果分别为: r_1(TPTM)=0.11,r_2(tBMA)=3.28;r_1(TETM)=0.073,r_2(tBMA)=0.069。实验结果表明,不饱和有机锡酯单体中锡原子上有机取代基团的不同,对其共聚反应的行为有较大的影响。     

不同聚合方法下p(AM/NaAMPS)聚合物微观结构的研究

采用溶液聚合和反相微乳液聚合方法对丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸钠(NaAMPS)在较低单体浓度下进行共聚。计算得出两种方法中单体AM、NaAMPS的竞聚率;溶液中r_(AM)=0.30,r_(MADQUAT)=1.31;微乳液中r_(AM)=0.63,r_(MADQUAT)=1.12。并用测得的竞聚率数据,通过计算机程序计算共聚物的瞬时组成、平均组成,研究在溶液和反相微乳液中合成共聚物的组成及序列分布的不同,研究结果表明微乳液聚合得到的聚合物的平均组成更均一     

微波辐射下均聚和共聚反应机理

研究了微波辐射下单体均聚和共聚反应机理。利用溶剂N，N—二甲基甲酰胺(DMF)或乙醇中的自由基捕捉剂1，1—二苯基—2—三硝基苯肼(DPPH)捕捉自由基，验证反应是否为自由基历程。研究了一些单体体系如烯丙基硫脲(AT)和马来酸二丁基锡(DBTM)或单体与载体(A12O3或SiO2)混合存在下的体系。同样，共聚反应如DBTM—AT和DBTM—硬脂酸乙烯酯(SAVE)也进行了相似的聚合实验。结果表明微波辐射可以引发共聚反应，且符合自由基机理。载体可以促进自由基的生成。     

对特丁基苯酚保护间异丙烯基枯基异氰酸酯与丙烯酸丁酯的共聚合

用间异丙烯基枯基异氰酸酯(TMI)与对特丁基苯酚反应合成出保护的α-甲基苯乙烯型单体(BTMI),并且研究了其与丙烯酸丁酯(BA)的共聚合,考察了单体配比、反应时间等因素对共聚反应的影响。求出了共聚合的竞聚率rBTMI=0．13,rBA=0．22以及共聚物中的构型参数σ=0．33,并计算了共聚物的组成分布和序列分布长度．实验表明,BTMI的反应活性较BA低．     

两亲性丙烯酸酯共聚合的动力学研究

利用过氧化苯甲酰 (BPO)为引发剂探讨了甲基丙烯酸 β-羟乙酯 (HEMA)和丙烯酸十六烷基酯(RA)的自由基共聚合。重点讨论了该共聚反应的动力学方程 ,求出了这两种单体的竞聚率。并用 IR、13 C- NMR等手段对共聚物进行了表征     

DBTM—St—BA三元共聚竞聚率的测定

根据改进的欧拉公式,解得Alfrey-Goldfinger微分方程的数值积分,将单纯形调优法与数值积分法相结合,建立数学模型并编写微机程序。采用红外光谱法测定不同转化率下DBTM(顺丁烯二酸二丁基锡酯)-St(苯乙烯)-BA(丙烯酸丁酯)三元共聚体系共聚物的组成。根据三元共聚体系的起始组成、和不同转化率下共聚物的组成,应用所编制的程序,计算该三元共聚体系单体的竞聚率。     

桐油基环氧增塑剂的合成及在聚氯乙烯中的应用

将合成的目标产物环氧桐马甲酯二异辛酯(EDOMEM)与邻苯二甲酸二辛酯(DOP)复配使用增塑聚氯乙烯(PVC)。采用红外光谱对EDOMEM结构进行表征,采用热重分析、热重-红外、热重-质谱、转矩流变仪、万能拉力等测试对共混试样进行了分析。结果表明,相比于试样F0,F4的T_i、T_(10)、T_(50)分别提高了5.6℃、12.6℃和25.4℃;TGA-FT-IR和TGA-MS说明PVC共混物热降解过程中的主要气体为H_2O、CO、HCl、CO_2和C_6H_6;当EDOMEM的含量由0%增加到33.3%(占增塑剂总质量百分比)时,断裂伸长率提高了9%,使得体系柔韧性得以改善;动态热稳定性由原来的12.1min延长至40.2min,加工稳定性能更好;此外,随着EDOMEM含量增加,挥发性和抽出性损失降低,增塑剂在塑料制品中的稳定性得以改善。因此,EDOMEM可以作为PVC的一种良好的辅助增塑剂使用。     

可降解聚碳酸亚丙酯马来酸酯载药微球的制备

采用阴离子配位聚合方法,合成了二氧化碳(CO2),环氧丙烷(PO)与马来酸酐(MA)的三元共聚物,聚碳酸亚丙酯马来酸酯 (PPCMA).采用复相乳液(W/O/W)溶剂挥发法制备了包裹水溶性模型药物葡萄糖(glucose)的可降解微球,并研究了壁材与囊心的比例、稳定剂明胶浓度、搅拌速率等因素对微球性能的影响.当v(PPCMA)∶v(glucose)=1∶2,gelatin质量分数为0.2%,第1次乳化搅拌速率为400r/min,第2次乳化搅拌速率为500r/min时,得到粒径较小、载药量和包封率分别为26.1%和76.1%的载药微球.     

溶剂热合成法制备顺丁烯二酸二丁酯接枝POE

利用新的接枝方法——溶剂热合成的方法制备了顺丁烯二酸二丁酯(DBM)接枝乙烯-辛烯共聚物(POE)。经傅立叶红外光谱(FT-IR)分析,证明DBM成功地接枝到了POE上,并用-C=O-和-CH2-吸收峰面积的比值来确定相对接枝量的大小。研究了单体DBM含量、引发剂过氧化二异丙苯(DCP)含量和反应温度对接枝反应的影响,找到了合适的反应配比和反应条件,得到了较高接枝率的接枝共聚物。结果表明,溶剂热合成法是将DBM接枝到POE上的一种好方法。     

溶剂极性对马来酸氢十六烷酯(HHM)晶体生长的影响

选用几种极性不同的有机溶剂，采用恒温蒸发法进行了马来酸氢十六烷酯（HHM）晶体在溶剂中的结晶性实验和晶体生长实验，结果发现溶剂极性对HHM晶体生长影响很大，采用极性低的溶剂HHM能呈现很好的结晶性并能生长出质量优良的晶体，极性大的溶剂则表现出相反的结果，并讨论了HHM在溶液中分子缔合情况和HHM晶体生长面对溶剂的吸附现象。     

徐放型聚羧酸系减水剂的合成研究

通过合成的聚乙二醇马来酸半酯大单体(PMAn)取代部分烯丙基聚氧乙烯醚(XPEG)进行共聚反应,得到了徐放型聚羧酸系高性能减水剂。合成影响因素的研究结果表明,当PMAn分子量为750且PMAn取代XPEG的比例为20%时,减水剂的减水率和保坍能力最好。红外光谱分析结果表明,合成的减水剂未聚合的单体残留很少;采用合成的减水剂配制的混凝土具有突出的坍落度保持能力。     

Effect of lyophilized grapefruit juice on P-glycoprotein-mediated drug transport in-vitro and in-vivo

The administration of grapefruit juice (GFJ) has been postulated to inhibit the activity of P-glycoprotein (P-gp) transport system and thus can enhance the uptake of substrate drugs. However, for various reasons, the results obtained have been always swaying between confirmation and refutation. This study aims at re-evaluating the effect of lyophilized freshly-prepared grapefruit juice (LGFJ) prepared from the whole peeled fruit on P-gp activity using the model drug doxorubicin (DOX) in-vitro and timolol maleate (TM) in-vivo. Human uterine sarcoma MES-SA/DX5v cells, grown under nanomolar concentration of DOX and highly expressing P-gp, were used as model cells for in-vitro studies whereas white New Zealand male rabbits were used for in-vivo studies. Results showed that the accumulation of DOX in MES-SA/DX5v cells was increased by 18.3?±?2.0% in presence of LGFJ compared to control experiments. Results from in-vivo absorption studies showed that the relative oral bioavailability of TM ingested with LGFJ was significantly higher by 70% and 43% compared to the oral bioavailability of TM ingested with saline and a commercial GFJ, respectively. This study as such confirms the inhibitory effects of LGFJ on P-gp efflux proteins and highlights the superiority of using lyophilized freshly prepared juices over the commercially available juices in research studies. Also, the results call for further studies to assess the possibility of co-administrating LGFJ with anti-cancer agents to modulate multidrug resistance in their cellular environment or incorporating LGFJ in solid dosage forms to improve oral bioavailability of drugs.     

In Vitro and Ex Vivo Permeation Studies of Chlorpheniramine Maleate Gels Prepared by Carbomer Derivatives

The antihistaminic chlorpheniramine maleate (CPM) is used for symptomatic relief of hypersensitivity reactions and in pruritic skin disorders. At present, the drug is marketed in tablet, capsule, syrup, cream, and injectable dosage forms. Chlorpheniramine maleate has some side effects when taken orally. Due to its first pass effect, only 25%–45% of the orally administered dose reaches the blood circulation. To bypass these disadvantages, we aimed to investigate percutaneous absorption of CPM from gel formulations prepared with different carbomer derivatives (Carbopol 934, 940, 941, 2984, 980, and 981; main differences are related to presence of a comonomer and cross‐link density). Cellulose membrane was used as the diffusion barrier for all the formulations' drug‐release studies. The release of active substance from carbopol derivatives, which have the least cross‐linking density (Carbopol 941 and 981) was found to be numerically higher than the others. The formulation (F8; 1% Carbopol 941) that exhibited the maximum drug release through the cellulose membrane was further studied for drug release by using polyurethane membrane, excised rat skin, and human skin. The penetration of the active substance through different diffusion barriers was found to be statistically different (p?<?0.05) when compared. Of all the different diffusion barriers, rat skin gave the closest results to human skin. Thus topical application of CPM in the carbomer gel may be of potential use for local activity. The type and concentration of carbomers can affect drug release. The synthetic membranes are useful in assessments of formulations in quality assurance but they do not give definite indication of how a formulation will behave when it is used on skin.     

甲基丙烯酰氧基-顺丁烯二酸单异丙酯酰氧基-异丙氧基铝的合成及其均聚物研究

合成了甲基丙烯酰氧基-顺丁烯二酸单异丙酯酰氧基-异丙氧基铝(MMPA),通过自由基溶液聚合获得其均聚物。研究了单体与聚合物的红外光谱、核磁共振谱、X射线光电子能谱、热性能、荧光性能及抗溶剂性。     

Development and validation of spectrophotometric and HPTLC methods for simultaneous determination of rosiglitazone maleate and metformin hydrochloride in the presence of interfering matrix excipients

Two simple methods have been developed and validated for the simultaneous determination of rosiglitazone maleate (ROS) and metformin hydrochloride (MET) in synthetic mixtures and coated tablets in a ratio of 1:250 (ROS:MET). The first method was a spectrophotometric one. The minor component, ROS was determined by measuring the values of absorbance at λ_max 312?nm and the D₁ amplitudes at 331?nm where MET shows no absorption contribution. However, absorbance interferences from tablet excipients were successfully corrected by D₁ at 331?nm zero-crossing technique. Study of spectral interference from tablet excipients was included in the text. Standard curves for A_max and D₁ methods were in the concentration range 20.0–80.0?μg?mL^?1. The major component, MET was determined both in binary mixtures and tablets by measuring its A_max at 236?nm. Extensive dilution eliminated any absorption contribution from the coexisting ROS or tablet matrix. Standard curves showed linearity in the concentration range 4.0–12.8?μg?mL^?1. The second method was based on high performance thin layer chromatography (HPTLC) separation of the two drugs followed by densitometric measurements of their spots at 230?nm. The separation was carried out on Merck HPTLC aluminium sheets of silica gel 60 F254 using methanol:water:NH₄Cl 1% w/v (5:4:1 v/v/v) as the mobile phase. Linear calibration graphs of peak area values were obtained versus concentrations in the range of 0.4–2.0?μg?band^?1 and 20.0–100.0?μg?band^?1 for ROS and MET, respectively. According to International Conference on Harmonisation (ICH) guidelines, different validation parameters were verified for the two methods and presented.