温敏性PNIPAAm水凝胶对布洛芬的控制释放

采用自由基聚合法在水溶液中制备了温敏水凝胶聚N-异丙基丙烯酰胺(PNIPAAm),以非水溶性药物布洛芬(IBU)为模型药物分子,研究了该水凝胶的温敏性能及与药物IBU的相互作用,考察了不同温度下(25 ℃和37 ℃)IBU在磷酸盐缓冲溶液(PBS,pH=7.4)中的释放行为.研究结果表明:该水凝胶的最低临界溶解温度(L...     

新型羧甲基壳聚糖水凝胶的合成与表征

通过1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐(EDC)/N-羟基琥珀酰亚胺(NHS)催化体系使羧甲基壳聚糖(CMCS)交联,制备了新型羧甲基壳聚糖水凝胶.探讨了EDC用量和EDC/NHS质量比对水凝胶特性的影响.CMCS水凝胶具有pH响应特性,在等电位点溶胀率最小.降解实验结果表明,水凝胶浸泡在磷酸盐缓冲溶液中,10 d失重率在15%~45%之间,主要是未交联部分溶解所致.而浸泡在含有0.2 mg/mL溶菌酶的磷酸盐缓冲溶液中,低交联度水凝胶80 h基本降解,高交联度水凝胶不易降解.初步研究了CMCS水凝胶包埋牛血清白蛋白(BSA)的释放行为.     

干燥方式对含直链淀粉半互穿网络水凝胶溶胀和降解的影响

以4,4′-二甲基丙烯酰胺基偶氮苯(BMAAB)为交联剂,制备了丙烯酸-丙烯酰胺-甲基丙烯酸酯共聚物和直链淀粉半互穿网络水凝胶.以冷冻干燥和空气干燥两种方式,研究了干凝胶在pH2.2和pH7.4时的溶胀和降解性能.结果表明采用两种干燥方式的凝胶在不同pH的介质中都遵循二级溶胀动力学.凝胶内部水的扩散均为非Fickian机理,即扩散和链松弛协同作用的机理.但经历冷冻干燥的凝胶其扩散机制占优势.在pH=7.4的介质中,冷冻干燥凝胶的平衡溶胀比(SR)显著增大,而在pH=2.2时则无明显变化.扫描电镜(SEM)和降解实验发现,在结肠内容物的作用下,冷冻干燥凝胶在5天内降解率可达35.3%,而空气干燥凝胶的降解率为28.1%,表明冷冻干燥的方式可在一定程度上促进凝胶在结肠环境下的降解.     

结肠位点药物传载凝胶的溶胀动力学研究

合成了带不同疏水侧基的甲基丙烯酸酯、甲基丙烯酰胺及丙烯酸与 4,4′ 二 (甲基丙烯酰胺基 )偶氮苯交联共聚的凝胶 .主要研究了这类凝胶在pH =2 .2至pH =7.4的缓冲溶液的溶胀特性 .其溶胀过程遵循二级溶胀动力学 ,影响这类凝胶溶胀行为的因素包括交联程度、疏水基链的长度、pH值等 .通过调节这些因素是完全可以控制凝胶在小肠内的溶胀程度 ,进而避免凝胶内部的药物被提前释放     

含5-氟尿嘧啶的羧甲基纤维素钠/聚(N-异丙基丙烯酰胺)半互穿网络水凝胶的药物释放性能

以5-氟尿嘧啶(5-FU)为模型药物,对羧甲基纤维素钠/聚(N-异丙基丙烯酰胺)半互穿网络水凝胶(CMC/PNIPA semi-IPN)的药物释放性能进行了研究。结果表明:在37℃、pH=7.4时,药物的释放速率以及释放量都随着凝胶中羧甲基纤维素钠含量的增加而增大。在25℃时,pH对药物释放速率的影响较小;而在37℃时,药物释放速率受pH的影响较大。该凝胶体系用做5-FU的口服释放载体具有较佳的释放性能。     

含有4,4′-双(甲基丙烯酰胺基)偶氮苯水凝胶的合成及其在结肠位药物释放的动物实验

合成了不同链长的甲基丙烯酸酯、甲基丙烯酰胺及丙烯酸与4,4′-双(甲基丙烯酰胺基)偶氮苯交联共聚的功能凝胶.三维网络结构通过压缩弹性模量、有效交联密度及聚合物与溶剂间的相互作用参数进行了表征.主要研究了这类凝胶在pH2.2和pH7.4的缓冲溶液的平衡溶胀特性及其偶氮交联基团在体内的降解行为,并讨论了其降解机制.凝胶在胃部的性能稳定,既不发生溶胀,亦不发生降解;但在盲肠内偶氮交联基因可发生降解.其降解率与凝胶的平衡溶胀程度有一个很好的关联:交联程度、疏水基侧链的长度及含量对凝胶溶胀行为的影响结果与这些因素对偶氮交联基团体内降解的影响结果完全一致.通过调节这些因素不仅可以控制凝胶的溶胀程度,而且可以控制偶氮交联基团在体内的降解行为.     

pH敏感性P(AM-AA-co-C8PhEO10Ac)水凝胶溶胀动力学及其对茶碱的控释

以丙烯酰胺(AM)、丙烯酸(AA)和丙烯酸辛基酚聚氧乙烯醚酯(C8PhEO10Ac)为单体,采用自由基交联共聚法合成了具有pH敏感性的P(AM-AA-co-C8PhEO10Ac)水凝胶.研究了pH、单体配比对凝胶溶胀性能、溶胀动力学和退溶胀动力学的影响.初步探讨了模拟胃液(pH=1.4)、肠液(pH=7.4)中水凝胶对茶碱的控释情况.结果表明:凝胶具有高溶胀、退溶胀速率和良好的pH敏感性等特征;水凝胶的扩散行为在pH=7.4的缓冲溶液中为非Fickian扩散模式;载药凝胶在模拟肠液中对药物的累积释放率明显大于胃液中的累积释放率,其中n(C8PhEO10Ac)∶n(AM)∶n(AA)为1∶20∶30的载药水凝胶对茶碱的累积释放率最大.     

壳聚糖/聚乙二醇/聚丙烯酸复合水凝胶的制备及药物控制释放行为研究

本文以壳聚糖(CS)、聚乙二醇(PEG)和丙烯酸(AA)为原料,制备了复合水凝胶CS/PEG/PAA。研究了负载四种具有不同结构和性质的药物(烟酸、烟酰胺、异烟肼和5-氟尿嘧啶)的复合水凝胶CS/PEG/PAA的药物控制释放行为。结果表明,烟酰胺和异烟肼在pH=1.80的缓冲溶液中的药物累积释放率(R)大于其在pH=6.86的缓冲溶液中的释放率;烟酸却在pH=6.86的缓冲溶液中的药物累积释放率(R)大于其在pH=1.80的缓冲溶液中的释放率。而5-氟尿嘧啶在两种缓冲溶液中的药物累积释放量相当。因此,复合水凝胶CS/PEG/PAA也许可以作为一种新型释放药物的载体。     

聚酰胺-胺(PAMAM)树状大分子对甲氨蝶呤的包合及缓释研究

以甲氨蝶呤(MTX)为模型药物,研究了G5.0PAMAM树状大分子对其包合和释放,并用13^CNMR对PAMAM-MTX包合物进行了表征.UV-Vis研究结果表明,1个G5.0PAMAM树状大分子能包合27个MTX分子,体外释放研究表明,在37℃,pH=7.4的10mmol/LTris-HCl缓冲溶液中G5.0PAMAM树状大分子对MTX具有明显的缓释作用.     

克拉维酸钾及主要原料中大分子蛋白杂质的测定

建立了凝胶排阻色谱对克拉维酸钾及其原料克拉维酸叔辛胺中的残余蛋白进行检测的方法。采用TSK gel G3000 SWXL凝胶色谱柱(5μm,7.8×300 mm),流动相为磷酸盐缓冲溶液,流速为0.8 m L/min,紫外检测波长为220 nm。对照品牛血清白蛋白(BSA)在0.249~49.9μg/m L内线性关系良好(R2=0.9997),平均回收率为101.2%,RSD为0.7%,检测限为0.05μg/m L。方法为同类药物中的大分子蛋白检测提供了有效手段。     

Synthesis and structure of hydroxyisoxazolidines and derivatives of hydroxylamine and alkenals

The reactions of N-substituted hydroxylamines with alkenals serve as a method for the synthesis of the corresponding 2-substituted 3(5)-hydroxyisoxazolidines. The reaction pathway is determined by the nature of the substituent attached to the nitrogen atom. Ring-chain isomerism has been detected in these newly obtained compoundsTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1270–1276, September, 1987.     

Synthesis and characterization of triazenide and triazene complexes of ruthenium and osmium

Triazenide [M(eta2-1,3-ArNNNAr)P4]BPh4 [M = Ru, Os; Ar = Ph, p-tolyl; P = P(OMe)3, P(OEt)3, PPh(OEt)2] complexes were prepared by allowing triflate [M(kappa2-OTf)P4]OTf species to react first with 1,3-ArN=NN(H)Ar triazene and then with an excess of triethylamine. Alternatively, ruthenium triazenide [Ru(eta2-1,3-ArNNNAr)P4]BPh4 derivatives were obtained by reacting hydride [RuH(eta2-H2)P4]+ and RuH(kappa1-OTf)P4 compounds with 1,3-diaryltriazene. The complexes were characterized by spectroscopy and X-ray crystallography of the [Ru(eta2-1,3-PhNNNPh){P(OEt)3}4]BPh4 derivative. Hydride triazene [OsH(eta1-1,3-ArN=NN(H)Ar)P4]BPh4 [P = P(OEt)3, PPh(OEt)2; Ar = Ph, p-tolyl] and [RuH{eta1-1,3-p-tolyl-N=NN(H)-p-tolyl}{PPh(OEt)2}4]BPh4 derivatives were prepared by allowing kappa1-triflate MH(kappa1-OTf)P4 to react with 1,3-diaryltriazene. The [Os(kappa1-OTf){eta1-1,3-PhN=NN(H)Ph}{P(OEt)3}4]BPh4 intermediate was also obtained. Variable-temperature NMR studies were carried out using 15N-labeled triazene complexes prepared from the 1,3-Ph15N=N15N(H)Ph ligand. Osmium dihydrogen [OsH(eta2-H2)P4]BPh4 complexes [P = P(OEt)3, PPh(OEt)2] react with 1,3-ArN=NN(H)Ar triazene to give the hydride-diazene [OsH(ArN=NH)P4]BPh4 derivatives. The X-ray crystal structure determination of the [OsH(PhN=NH){PPh(OEt)2}4]BPh4 complex is reported. A reaction path to explain the formation of the diazene complexes is also reported.     

Mass and NMR spectra of haplophyllidine and perforine and of their derivatives

Conclusions The mass and NMR spectra of haplophyllidine, perforine, and their derivatives have been studied. The influence of the open and cyclic forms of the molecular ion on the nature of the fragmentation has been discussed. The main routes of fragmentation of the compounds considered are due to the presence of substituents at C₈ and C₄.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 4, pp. 273–279, 1969     

Investigation of adhesion and mobility of polyurethane and epoxy-rubber glues and adhesives

The values of activation parameters in uncured and cured epoxy resins, rubbers, and blends thereof are investigated. The dependences of activation energy and adhesion strength of epoxy-rubber compositions on rubber content are determined. The correlation of adhesion and activation energy values for polyurethane rubber and epoxy-rubber compositions is shown.     

Crystal and molecular structure of aroyl- and acetylhydrazones of acet- and benzaldehydes

Aroyl- and acetylhydrazones of acet- (I) and benzaldehydes (IV) and benzoylhydrazones of acet- (II) and benzaldehydes (III) were studied by x-ray structural and quantum-chemical methods in order to establish their structures. Compund (I) was the EEZ structure in the crystal. Calculations and spectral data showed that the EEE form occurs in nonpolar solvents and in the gas phase. According to crystallographic data molecules (I)–(IV) are the E-isomers (relative to the N-N bond) and the hydrazone fragments are planar. Intermolecular N-H...O H-bonds from in the crystals. The data obtained suggest that the majority of acylhydrazones are conformationally rigid on dissolution although exceptions do occur. Apparently the reasons for the difference of acetyl- and benzoylhydrazones in electrocarboxylation reactions are electronic and not steric factors.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 75–81, January, 1991.     

Preparation and characterization of diarylphosphazene and diarylphosphinohydrazide complexes of titanium, tungsten and ruthenium and phosphorylketimido complexes of rhenium

Reaction of the proligand Ph2PN(SiMe3)2 (L1) with WCl6 gives the oligomeric phosphazene complex [WCl4(NPPh2)]n, 1 and subsequent reaction with PMe2Ph or NBu4Cl gives [WCl4(NPPh2)(PMe2Ph)] (2) or [WCl5(NPPh2)][NBu4] (3), respectively. DF calculations on [WCl5(NPPh2)][NBu4] show a W=N double bond (1.756 A) and a P-N bond distance of 1.701 A, which combined with the geometry about the P atom suggests, there is no P-N multiple bonding. Reaction of L1 with [ReOX3(PPh3)2] in MeCN (X = Cl or Br) gives [ReX2(NC(CH3)P(O)Ph2)(MeCN)(PPh3)](X = Cl, 4, X = Br, 5) which contains the new phosphorylketimido ligand. It is bound to the rhenium centre with a virtually linear Re-N-C arrangement (Re-N-C angle = 176.6 degrees, when X = Cl) and there is multiple bonding between Re and N (Re-N = 1.809(7) A when X = Cl). The proligand Ph2PNHNMe2(L2H) reacts with [(C5H5)TiCl3] to give [(C5H5)TiCl2(Me2NNPPh2)] (6). An X-ray crystal structure of the complex shows the ligand (L2) is bound by both nitrogen atoms. Reaction of the proligands Ph2PNHNR2[R2 = Me2 (L2H), -(CH2CH2)2NCH3 (L3H), (CH2CH2)2CH2 (L4H)] with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave [RuCl2(eta6-p-MeC6H4iPr)L] {L = L2H (7), L3H (8), L4H (9)}. The X-ray crystal structures of 7-9 confirmed that the phosphinohydrazine ligand is neutral and bound via the phosphorus only. Reaction of complexes 7-9 with AgBF4 resulted in chloride ion abstraction and the formation of the cationic species [RuCl(6-p-MeC6H4iPr)(L)]+ BF4- {(L = L2H (10), L3H (11), L4H (12)}. Finally, reaction of complex 6 with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave the binuclear species [(eta6-p-MeC6H4iPr)Cl2Ru(mu2,eta3-Ph2PNNMe2)TiCl2(C5H5)], 13.     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。     

Kinetics and mechanisms of chlorine dioxide and chlorite oxidations of cysteine and glutathione

Chlorine dioxide oxidation of cysteine (CSH) is investigated under pseudo-first-order conditions (with excess CSH) in buffered aqueous solutions, p[H+] 2.7-9.5 at 25.0 degrees C. The rates of chlorine dioxide decay are first order in both ClO2 and CSH concentrations and increase rapidly as the pH increases. The proposed mechanism is an electron transfer from CS- to ClO2 (1.03 x 10(8) M(-1) s(-1)) with a subsequent rapid reaction of the CS* radical and a second ClO2 to form a cysteinyl-ClO2 adduct (CSOClO). This highly reactive adduct decays via two pathways. In acidic solutions, it hydrolyzes to give CSO(2)H (sulfinic acid) and HOCl, which in turn rapidly react to form CSO3H (cysteic acid) and Cl-. As the pH increases, the (CSOClO) adduct reacts with CS- by a second pathway to form cystine (CSSC) and chlorite ion (ClO2-). The reaction stoichiometry changes from 6 ClO2:5 CSH at low pH to 2 ClO2:10 CSH at high pH. The ClO2 oxidation of glutathione anion (GS-) is also rapid with a second-order rate constant of 1.40 x 10(8) M(-1) s(-1). The reaction of ClO2 with CSSC is 7 orders of magnitude slower than the corresponding reaction with cysteinyl anion (CS-) at pH 6.7. Chlorite ion reacts with CSH; however, at p[H+] 6.7, the observed rate of this reaction is slower than the ClO2/CSH reaction by 6 orders of magnitude. Chlorite ion oxidizes CSH while being reduced to HOCl, which in turn reacts rapidly with CSH to form Cl-. The reaction products are CSSC and CSO3H with a pH-dependent distribution similar to the ClO2/CSH system.