低分子肝素透皮吸收制剂的研究

 以低抗凝肝素为原料制备了平均分子量为５６００的低分子肝素，测定了理化指标和抗凝效价。分别制备了不合促进剂和含不同促透剂的低分子肝素和肝素Ｏ／ｗ型软膏。体外经皮渗透动力学实验结果表明，软膏中药物的透皮过程符合Ｆｉｃｋ’Ｓ扩散方程，并筛选软膏的最佳处方为：低分子肝素（或肝素）、Ｎ－甲基吡咯烷酮、基质。将该处方软膏敷于家兔背部脱毛皮肤一定时间，可显著延长血液凝固时间和抑制实验性血栓形成。     

人血清白蛋白修饰的尿激酶与天然尿激酶的家兔体内过程比较

家兔静注人血清白蛋白修饰的尿激酶(MUK)和天然尿激酶(NUK)40000IU后,MUK 的体内过程符合零级速率过程,NUK 则符合一级速率过程,血纤溶活性 MUK 持续100min,而 NUK 仅20～25min。在“功能性”去除肝肾的家兔,NUK 血浓度半衰期延长3～4倍,而 MUK 血浓度下降与正常家兔相似。MUK 及 NUK 在去除纤溶抑制物的优球蛋白成份中纤溶活性相似,但在血浆中 NUK 仅存24～35%的纤溶活性,MUK 则保留了64～85%的纤溶活性。提示肝肾的摄取、代谢和消除能力降低及对血浆纤溶抑制物抵抗力增强,是 MUK 血纤溶活性长时间维持高水平的主要原因。     

丁酸氯维地平静脉注射乳剂在大鼠体内的药动学研究

目的研究两种丁酸氯维地平制剂在大鼠体内的药动学特点。方法将24只大鼠随机均分为4组,分别静脉滴注低、中、高剂量的丁酸氯维地平受试制剂及参比制剂,采用HPLC法测定全血中的丁酸氯维地平,计算药动学参数,评价其在大鼠体内的药动学特点。结果丁酸氯维地平低、中、高剂量受试制剂和参比制剂在大鼠血浆中的主要药动学参数为:Cmax分别为46.16±10.65、82.99±9.34、177.80±38.32、80.31±3.04 ng·m L-1;AUC0-t分别为2.309±0.628、4.221±0.988、9.339±1.759、3.968±0.411 min·μg·m L-1;t1/2分别为12.20±4.65、16.74±6.93、15.13±4.81、18.34±4.43 min。结论丁酸氯维地平受试制剂和参比制剂在大鼠体内药动学参数差异无统计学意义,受试制剂在0.36~3.24 mg·kg-1剂量范围内呈非线性动力学特征。     

Acid-Catalyzed Peptide Bond Hydrolysis of Recombinant Human Interleukin 11

Recombinant human interleukin 11 (rhIL-11) is a multispectrum cytokine that plays an important role in megakaryocytopoiesis and platelet production. Probing rhIL-11 chemical reactivity in aqueous solution is an important initial step in developing a dosage form for rhIL-11 clinical trials. This report documents rhIL-11 degradation kinetics at 50°C in solutions adjusted to pH 3.0 to 9.5. Stressed samples were analyzed by reverse-phase HPLC and degradation product peaks were isolated for structural characterization. The results show maximal stability in the region pH 6.5 to 7.0. Degradation product identification shows that the major reaction pathway in acidic solution involves peptide cleavage at aspartate₁₃₃–proline₁₃₄. In alkaline solution, protein disappearance proceeds via nonspecific loss to container surfaces. Degradation products at alkaline pH have not been identified.     

LTA and FAU-X Iron-Enriched Zeolites: Use for Phosphate Removal from Aqueous Medium

Hydrothermally synthesized Linde type A (LTA) and faujasite X (FAU-X) zeolites are low-cost and environmentally benign inorganic carriers for environmental applications. In this study, (oxy)hydroxides were incorporated onto LTA and FAU-X zeolites to promote the phosphate adsorption. The performance of LTA-Fe and FAU-X-Fe was evaluated through batch adsorption assays. A complete evaluation was performed to recover phosphate from synthetic wastewater. The effect of pH, concentration, equilibrium, and kinetic parameters on phosphate adsorption and its further reuse in sorption–desorption cycles were evaluated. LTA-Fe and FAU-X-Fe are effective for adsorption of phosphate at neutral (e.g., pH 7.0 ± 0.2) and in a broad range of phosphate concentrations. Higher ratios of adsorption capacities were obtained by synthetic zeolites enriched with iron in comparison to their parent forms. The phosphate adsorption occurred through hydrogen bonding and complexation reactions between protonated iron hydroxyl groups and phosphate anions. The phosphate monolayer adsorption was followed by diffusion through the internal pores and 80% of the equilibrium adsorption was reached within 50 min. The LTA-Fe and FAU-X-Fe can be used for phosphate recovery from wastewater treatment plants. The use of LTA-Fe and FAU-X-Fe in a tertiary wastewater treatment stage could allow to reduce the phosphate–phosphorous content, reaching the regulatory levels (equal 1 mg L⁻¹ total phosphorous). The phosphate adsorption using LTA-Fe and FAU-X-Fe does not require pH adjustment, and it is endothermic. The reusability of both iron zeolites is limited, and they can be finally disposed for soil amendment applications.     

中药（复方）成分提取动力学数学模型的建立及对六味地黄汤梓醇的验证试验

目的建立封闭体系中药复方成分溶出动力学数学模型，并对六味地黄汤中有效成分梓醇的提取动力学参数进行研究与分析。方法将数学建模方法应用于中药提取过程的研究中，根据提取原理、Fick定律建立中药提取过程的数学模型，对数学模型进行拟合和参数分析。可求得函数表达式，运用该模型研究六味地黄汤中梓醇的动力学参数。结果建立了包舍三项e的指数形式的成分溶出浓度解析厦各参数分析方法。结论封闭可溶中药复方扩散体系的成分溶出符合线性动力学数学模型，各参数可根据溶出浓度表达式关系计算得到。     

氟喹诺酮类药对人肝药酶活性的影响

目的 :观察氟喹诺酮类 (FQs)药物对人肝微粒体药物代谢酶 (细胞色素P 4 5 0 )活性影响的差异。方法 :反应体系中微粒体蛋白终浓度为 0 .33～2 .0 g·L- 1,药物终浓度为 4 0 0mg·L- 1,测定药物代谢酶的活性。对照不加药。并测定不同底物浓度和不同环丙沙星浓度时乙基吗啡N 脱甲基酶的Vm和Km 值 ,求抑制常数Ki。结果 :FQs对酶活性的抑制强度为 :培氟沙星 (PFLX) >环丙沙星 (CPLX)>氧氟沙星 (OFLX) >左氧氟沙星 (LVLX)。FQs对戊巴比妥侧链羟化酶 (PSCH )、苯并芘羟化酶(BPH)、氨基比林N 脱甲基酶 (ADM )、乙基吗啡N 脱甲基酶 (EDM )和NADPH 细胞色素C还原酶的平均被抑制率分别为 :2 9% ,2 6 % ,19% ,17%和2 .3%。CPLX对EDM的抑制为竞争性抑制为主的混合性抑制 ,抑制常数Ki=2 5 0mg·L- 1。结论 :4种FQs对多种肝药酶活性均有不同程度的抑制 ,LVLX的抑制作用相对较弱。 5种肝药酶对药物的敏感性也各不相同。CPLX对EDM的抑制是竞争性抑制为主的混合性抑制。     

Effect ofd-fenfluramine on the indole contents of the rat brain after treatment with different inducers of cytochrome P450 isoenzymes

The effects of pretreatment with inducers of hepatic cytochrome P450 isoenzymes (phenobarbital, dexamethasone and-naphthoflavone) on the metabolism ofd-fenfluramine (d-F) and its acute and long-lasting indole-depleting effects were studied in rats, in an effort to obtain further information on the importance of hepatic drug metabolism in relation to its neurochemical actions. Twenty-four hours after the last dose of each inducer, rats were injected withd-F hydrochloride (5 mg/kg, IP) and killed at various times thereafter for parallel determination of indoles and drug concentrations in plasma and brain. Additional rats were treated as above and killed 1 week afterd-F hydrochloride (5 and 10 mg/kg) to study the recovery of indole in the cortex, a particularly sensitive brain area. Phenobarbital and-naphthoflavone and, to a lesser degree, dexamethasone, stimulated the metabolism ofd-F, as evidenced by a decrease in plasma and brain areas under the curve (AUC) compared to vehicle-treated rats. This indicated that multiple isoenzymes are capable of mediating the drug's metabolism, primarily byN-dealkylation tod-norfenfluramine (d-NF). None of the inducers raised plasma and brain AUC of the nor-derivative, and in fact phenobarbital and particularly-naphthoflavone reduced it. These different effects were even apparent in rats givend-NF (2.5 mg/kg), indicating that both phenobarbital and-naphthoflavone also stimulate the sequential metabolism of the nor-metabolite (byN-deamintaion) which, however, is apparently enhanced most actively by-naphthoflavone-inducible forms of P-450. Total active brain concentrations (d-F+d-NF) after the different pretreatments were in the order of-naphthoflavone < phenobarbital < dexamethasone vehicle. Interestingly,-naphthoflavone rapidly reversed the depletion of brain indoles caused byd-F (andd-NF); phenobarbital provided partial protection and dexamethasone did not appreciably modify either the acute or long-term neurochemical effects of the drug. The fact that phenobarbital affectedd-NF kinetics less than-naphthoflavone, and provided only partial protection against the acute and long-lasting neurochemical effects of high doses ofd-F, further stresses the critical role ofd-NF in the neurochemical outcome of its parent drug. These findings support the view that the degree and duration of the indole-depleting effects are related to critical brain concentrations of the parent compound and its nor-derivative, and provide indirect evidence that hepatic metabolites other thand-NF are unlikely to play any role in the neurochemical effects of high doses ofd-F in rats.     

In vitro metabolism of a novel antithrombotic compound,S002-333, and its enantiomers: quantitative cytochrome P450 phenotyping,metabolic profiling and enzyme kinetic studies

Abstract

1.?S002-333, (2-(4′-methoxy-benzenesulfonyl)-2,3,4,9-tetrahydro-1H-pyrido (3,4-b) indole-3-carboxylic acid amide) is a novel potent antithrombotic molecule currently under development phase. It is the racemic mixture of two enantiomers, namely S004-1032 (R-form) and S007-1558 (S-form).

2.?The contribution of five major isoenzymes, namely CYP2B6, 2C9, 2C19, 2D6 and 3A4 was quantified using recombinant P450s in the phase-I metabolism through relative activity factor approach. CYP2C19 was found to be the major contributor for S002-333 and S007-1558, while CYP3A4 showed greater involvement in S004-1032 metabolism. Chemical inhibition and immunoinhibition studies reconfirmed the results in human liver microsomes (HLM).

3.?Four major phase-I metabolites of S002-333; M-1 and M-3 (oxidative), M-2 (O-demethylated) and M-4 (dehydrogenated) were characterized in HLM. These metabolites constituted 11.2, 11.3 and 21.5% of the parent in comparison with the net phase-I metabolism of 29.9, 31.4 and 38.3% of S002-333, S004-1032 and S007-1558, respectively.

4.?Among CYP2C9, 2C19 and 3A4, the relative contribution of CYP2C9 was found to be maximum during M-1 through M-4 formation. Enzyme kinetic analysis for detected metabolites indicated that M-1 to M-3 followed classical hyperbolic kinetics, whereas M-4 showed evidence of autoactivation. In conclusion, the results suggest prominent role of CYP2C9, 2C19 and 3A4 isoforms for enantioselective disposition of S002-333 in vitro.     

地塞米松磷酸钠温度敏感原位凝胶释药与溶蚀行为的影响因素考察

目的:制备泊洛沙姆温度敏感原位凝胶,考察地塞米松磷酸钠(DSP)在其中的释放行为以及影响释放的因素。方法:以PluronicF127和F68为材料,DSP为模型药物制备温度敏感原位凝胶并测定胶凝温度。采用无膜溶出法和HPLC法测定DSP的释放行为;考察释放介质的接触面积、体积、pH值及振荡频率对DSP释放的影响。测定凝胶的溶蚀行为及其对药物释放的影响。结果:胶凝温度随F127浓度增大而升高,释放介质的接触面积、体积、振荡频率对药物的释放速率有显著影响,释放介质的pH对药物释放速率无显著影响。DSP的释放和凝胶的溶蚀遵循零级动力学方程,释放量随溶蚀量增加而增加,二者间存在线性关系。结论:DSP温度敏感原位凝胶的缓释效果良好,凝胶溶蚀速率、凝胶与释放介质的接触面积是控制药物释放的主要因素。