多巴对映异构体的柱前衍生化HPLC法手性拆分

目的：建立多巴对映异构体的柱前衍生化拆分分析方法。方法：采用柱前衍生化反相高效液相色谱法,以氯甲酸乙酯为酰化剂,L-丙氨酸-β-萘胺（L-Ala-β-NA）为柱前衍生化试剂,在室温反应20 min 后,依利特 Hypersil ODS2（4.6 mm ×250 mm,5μm）为色谱柱;乙腈-0.05%三氟乙酸为流动相,梯度洗脱;流速为1.0 mL·min-1;柱温为25℃;检测波长为280 nm。结果：多巴对映体衍生物获得了基线分离,并确认了R（-）-和S（+）-两个衍生物的色谱峰。结论：该方法经济可行,操作较简便,为多巴的药理学研究和光学异构体纯度测定提供了参考。     

反相HPLC法测定福多司坦胶囊的光学纯度

目的采用反相高效液相色谱法测定福多司坦胶囊的光学纯度。方法采用DiamonsilTM（钻石）C18色谱柱（250mm×4.6mm,5mm）,流动相：硫酸铜D-苯丙氨酸溶液-甲醇（100∶10）,流速为0.8mLomin-1,检测波长270nm,柱温35℃,进样量为20μl。结果福多司坦与光学异构体之间的分离度为4.0,最低检出量约为16.7ng（S/N=3.0）,方法专属性强,灵敏度高。结论此反相HPLC法可用于福多司坦胶囊的光学纯度检查。     

柱前手性衍生化反相高效液相色谱法拆分地佐西平对映异构体的研究

用乙酰葡萄糖异硫氰酸酯(GITC)作柱前手性衍生化试剂,以反相高效液相色谱法成功地拆分了地佐西平对映异构体。在此基础上建立了地佐西平对映异构体纯度和血药浓度测定方法。已用于测定右旋地佐西平的光学纯度和小鼠血药浓度。     

手性衍生化-反相高效液相色谱法测定L-肌肽的光学纯度

目的建立柱前手性衍生化-反相高效液相色谱法(HPLC)测定L-肌肽对映体的纯度。方法以邻苯二甲醛/N-乙酰基-L-半胱氨酸(OPA/NAC)为手性衍生化试剂,反应生成具有荧光吸收的一对非对映异构体衍生物,采用C18色谱柱(250mm×4.6mm,5μm),流速1.0mL·min-1,50mmol·L-1乙酸铵缓冲溶液(pH6.0)-甲醇(70:30,V/V)流动相,柱温35℃,λex=350nm,λem=450nm。结果L-肌肽与其光学异构体分离度大于3,在0.104～2.68mg·L-1范围内,D-肌肽衍生物色谱峰面积与其浓度呈良好线性关系,检测限浓度为0.02mg·L-1。结论建立的L-肌肽光学异构体(杂质)手性衍生化-HPLC拆分检查法方便准确,可用于L-肌肽的光学纯度控制。     

柱前手性衍生化-反相高效液相色谱法拆分布洛芬对映异构体

目的：建立一种柱前手性衍生化-反相高效液相色谱紫外法检测布洛芬的异构体。方法：以N′N-羰基二咪唑（CDI）作为活化剂活化布洛芬的羧基基团,再以（R）-（+）-1-（1-萘基）乙胺（R-NEA）作为手性衍生化试剂进行反应。选用Kromasil C18色谱柱,流速1.0 mL·min-1,柱温30 ℃,以乙腈-0.05%磷酸（68∶32）为流动相,检测波长225 nm。结果：布洛芬的非对映异构体色谱峰的保留时间分别为25.6 min和27.9 min。结论：本方法操作简单,条件温和,衍生化产物稳定,且衍生化试剂价格便宜,更准确地实现了对布洛芬对映异构体的分离检测。     

柱前衍生-手性高效液相色谱法测定R-3-奎宁环醇的光学纯度

目的 建立准确、可靠的测定R-3-奎宁环醇光学纯度的柱前衍生-手性高效液相色谱法。方法 采用苯甲酰氯对(R,S)-3-奎宁环醇进行柱前衍生化,以直链淀粉-三(3,5-二甲苯基氨基甲酸酯)Daicel ChiralpakAD-H手性色谱柱为手性固定相,流动相为正己烷∶乙醇∶二乙胺(80∶20∶0.1,V/V/V),流速为1.0 m L/min,检测波长为232 nm,柱温为25℃。结果 (R,S)-3-奎宁环醇衍生物纯度不低于98%,对映异构体的衍生产物在上述色谱条件下能达到良好分离(R≥4.0)。结论 该方法准确、可靠,可用于测定R-3-奎宁环醇的光学纯度。     

柱前衍生化高效液相色谱法分离分析奥美拉唑对映体

目的 建立柱前衍生化高效液相色谱法分离奥美拉唑对映体.方法 以(S)-(+)-樟脑磺酰氯为柱前手性衍生化试剂,衍生物在Diamonsil C18色谱柱上,以10 mmol·L-1醋酸铵(pH 7.5)-异丙醇(75:25,v/v)为流动相分离,流速为0.5 mL· min-1.结果 奥美拉唑衍生物可达到基线分离,分离度为1.72.结论 采用柱前衍生化高效液相色谱法,在普通C18色谱柱上分离奥分析美拉唑衍生物,为此类手性药物的分离分析提供一个新方法.     

HPLC法测定(1R,2R)-(-)-1,2-环己二胺中S,S对映异构体

目的建立高效液相色谱法测定(1R,2R)-(-)-1,2-环己二胺中S,S对映异构体含量的方法。方法柱前衍生反相高效液相色谱法,利用间甲基苯甲酰氯为衍生化试剂,采用Chiral-AGP(4.0 mm×150 mm)色谱柱,以异丙醇-磷酸盐缓冲液(pH值=6.1)(15∶85)为流动相、流速0.7 mL.min-1、检测波长为214 nm。结果 1,2-环己二胺的R,R与S,S对映异构体衍生物达到基线分离;S,S-对映异构体的定量限为30.1 ng、检测限12.4 ng;S,S-对映异构体在0.015～0.09μg.mL-1浓度范围内线性良好,平均回收率为98.3%,RSD(n=9)为9.36%。结论建立的间甲基苯甲酰氯柱前衍生高效液相色谱法适用于(1R,2R)-(-)-1,2-环己二胺中S,S对映异构体含量的测定。     

用（＋）－FLEC手性试剂自动柱前衍生高效液相色谱法拆分麻黄碱类药物对映体

报道了以（＋）－ＦＬＥＣ作为手性衍生化试剂，用反相高效液相色谱技术分离麻黄碱类药物对映异构体的方法。ｄｌ－麻黄碱、ｄｌ－伪麻黄碱、ｄｌ－去甲麻黄碱、ｄｌ－去甲伪麻黄碱先与（＋）－ＦＬＥＣ形成衍生物后，经过一ＯＤＳＨｙｐｅｒｓｉｌ柱分离，以水和乙腈为流动相梯度洗脱．二极管阵列检测器在２６６ｎｍ检测。该法从样品衍生化到最终报告全部自动完成。上述各对对映体均达到基线分离，分离度Ｒ均大于１．５，方法灵敏度高，最低检出限达１０ｐｍｏ１，保留时间和峰面积的上现性较好，ＲＳＤ分别为１．１／和３．０％。     

左乙拉西坦右旋对映异构体的HPLC测定

建立了手性固定相HPLC法测定左乙拉西坦的对映异构体。采用Daicel CHIRALCEL OD-H色谱柱，流动相为正己烷-异丙醇-三氟乙酸（90：10：0．05），检测波长218nm。左乙拉西坦与右旋对映异构体分离良好，在0．4～1200μg／ml范围内线性关系良好，其检测限为0．15μg／ml。     

Theoretical π-π* absorption and circular dichroic spectra of cyclic dipeptides

The dipole interaction model, treated by the partially dispersive normal mode method, is used to calculate circular dichroic spectra of cyclo(Gly-Gly), cyclo (Ala-Gly), cyclo(Ala-Ala), cyclo(Pro-Gly), cyclo(Pro-Ala), cyclo(Pro-Val), cyclo (Pro-D-Val), and cyclo(Pro-Pro) in the amide π-π* absorption band near 190 nm. Assuming a standard backbone geometry, spectra which are in fair to good agreement wth experiment are obtained for these molecules. The spectra are predicted to be sensitive to conformations of Pro and Val side chains. The effects of dipeptide ring folding on calculated CD spectra are mostly consistent with those found by other workers, except that it is found that a planar ring conformation of cyclo (Ala-Ala) and cyclo (Ala-Gly) gives predicted spectra comparable to experiment. The same model gives theoretical absorption spectra consistent with available experimental data.     

Effects of Nitro-L-Arginine on Blood Pressure and Cardiac Index in Anesthetized Rats: A Pharmacokinetic-Pharmacodynamic Analysis

Purpose. Nitric oxide synthase (NOS) inhibitors such as Nitro-L-arginine (L-NA) are being considered for the management of hypotension observed in septic shock. However, little information is available regarding the pharmacokinetic and pharmacodynamic properties of these agents. Our objective was to examine the relationships between L-NA plasma concentration and various hemodynamic effects such as cardiac index (CI), mean arterial pressure (MAP), and heart rate (HR) elicited by L-NA administration in rats. Methods. L-NA was infused at doses between 2.5 – 20 mg/kg/hr in anesthetized rats over one hour. Hemodynamic effects and plasma L-NA levels were determined. Results. Infusion of L-NA resulted in dose-dependent increases in MAP and systemic vascular resistance (SVR), decreases in CI, and minimal change in HR. The relationships between the hemodynamic effects and plasma L-NA levels were not monotonic, and hysteresis was observed. Using nonparametric analysis, the equilibration half-time (t_1/2,keo) between plasma L-NA and the hypothetical effect site was determined to be 51.5 ± 6.6 min, 42.4 ± 10.1 min, 43.4 ± 9.0 min for MAP, CI, and SVR, respectively (n = 14). The E_max and EC₅₀ values obtained were + 32.5 ± 8.4 and 2.6 ± 1.3 g/ml for MAP and –52.9 ± 15.6 and 3.7 ± 1.8 g/ml for CI, respectively. Conclusions. Although L-NA can bring about beneficial elevation of MAP, such effect is always accompanied by a stronger effect on CI depression. Dose escalation of L-NA may bring about detrimental negative inotropic effect and loss of therapeutic efficacy.     

洛美沙星体内外抗菌活性研究

洛美沙星对革兰氏阴性菌具有强的抑菌活力。对克氏肺炎杆菌的抗菌活性最强,MIC_(50)为0.12mg/L;对痢疾杆菌、产气杆菌、粘质沙雷氏菌、不动杆菌和枸椽酸杆菌的MIC_(50)分别为1和4mg/L。洛美沙星对肠细菌科细菌的活力比诺氟沙星和依诺沙星强2～16倍,明显地比丁胺卡那霉素、庆大霉素强。对金葡球菌MIC_(50)为1mg/L, MRSA对洛美沙星同样敏感。洛美沙星对表葡球菌、链球菌、粪链球菌及肺炎双球菌等的抗菌活性与地氟沙星相似,比诺氟沙星、依诺沙星、丁胺卡那霉素、庆大霉素和头孢三嗪分别强2～4倍。 洛美沙星对小鼠全身感染的疗效优于诺氟沙星。对大肠杆菌、克氏肺炎杆菌和绿脓杆菌感染小鼠iv的ED_(50)分别是0.74、0.13和3.45mg/kg, po的ED_(50)分别是0.94、1.46和6.20mg/kg。     

HPLC法测定丝裂霉素C聚氰基丙烯酸正丁酯纳米粒中丝裂霉素C的含量

目的:建立高效液相色谱法测定丝裂霉素 C 聚氰基丙烯酸正丁酯纳米粒(MMC-PBCA-NP)中药物含量。方法:采用C_(18)柱(4.6 mm×150 mm,5 μm),以混合磷酸盐缓冲液-乙腈(85:15)为流动相,流速为1 mL·min~(-1),紫外检测器,检测波长为365 nm。结果:丝裂霉素 C(MMC)浓度在5～250 μg·mL~(-1)范围内与峰面积呈良好的线性关系,r=0.9998;平均回收率(n=6)为98.15%。结论:本法专属性强,操作简便,结果准确。适用于 MMC-PBCA-NP 的质量控制。     

乙酰吉他霉素临床前药理学研究

乙酰吉他霉素对临床分离的革兰氏阳性球菌有较好的抑菌活力，其对金葡球菌、β－溶血性链球菌、表葡球菌的ＭＩＣ_（５０）分别为１、０．２２和４ｍｇ／Ｌ，对耐红霉素、青霉素的金葡球菌、表葡球菌半数以上较敏感，与吉他霉素相似，但其对革兰氏阴性菌无明显作用。乙酰吉他霉素对小鼠实验性细菌感染有明显保护作用。对金葡球菌、肺炎双球菌感染小鼠口服用药的ＥＤ_（５０）分别为７９．６和２５．１ｍｇ／ｋｇ。其疗效与吉他霉素、麦白霉素、乙酰螺旋霉素相似。乙酰吉他霉素小鼠１次口服的ＬＤ_（５０）＞１５ｇ／ｋｇ，与吉他霉素相比毒性无差异。     

Protective role of exogenous α-lipoic acid (ALA) on hippocampal antioxidant status and memory function in rat pups exposed to sodium arsenite during the early post-natal period

The present work focussed on the effect of exogenous α-lipoic acid (ALA) administration on retention memory and oxidative stress markers in the hippocampus subsequent to early post-natal exposure of rat pups to sodium arsenite (NaAsO₂). Wistar rat pups were divided into the control groups receiving either no treatment (Ia) or distilled water by intraperitoneal route (i.p.) (Ib) and the experimental groups receiving either NaAsO₂ alone (1.5 and 2.0?mg/kg body wt.) (IIa, IIb) or NaAsO₂ (1.5 and 2.0?mg/kg body wt.) followed by ALA (70?mg/kg body wt.) (IIIa, IIIb) (i.p.) from post-natal day (PND) 4–15. The initial and retention transfer latency (ITL and RTL) was determined on PND 14 and 15 using elevated plus maze. The animals were sacrificed by cervical decapitation (PND 16) and the brains were obtained. The dissected out hippocampus was processed for estimation of oxidative stress markers, glutathione (GSH), and superoxide dismutase (SOD). NaAsO₂ exposure resulted in longer RTL in animal groups IIa and IIb, thereby suggestive of arsenic-induced impairment in retention memory. RTL was significantly shorter in animal groups (IIIa, IIIb) receiving ALA following NaAsO₂, thereby suggestive of improvement in retention memory. GSH and SOD levels were significantly decreased in animals receiving NaAsO₂ alone as against group Ib and administration of ALA following NaAsO₂ increased the levels of hippocampal GSH and SOD. These observations are suggestive of the role of exogenous ALA in ameliorating the adverse effects induced by NaAsO₂ exposure of rat pups on retention memory and oxidative stress markers.     

The pathogenesis of,and pharmacological treatment for,Canavan disease

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Dinoflagellate polyether within the yessotoxin, pectenotoxin and okadaic acid toxin groups: Characterization, analysis and human health implications

Diarrhetic Shellfish Poisoning (DSP) is a specific type of food poisoning, characterized by severe gastrointestinal illness due to the ingestion of filter feeding bivalves contaminated with a specific suite of toxins. It is known that the problem is worldwide and three chemically different groups of toxins have been historically associated with DSP syndrome: okadaic acid (OA) and dinophysistoxins (DTXs), pectenotoxins (PTXs) and yessotoxins (YTXs). PTXs and YTXs have been considered as DSP toxins because they can be detected with the bioassays used for the toxins of the okadaic acid group, but diarrhegenic effects have only been proven for OA and DTXs. Whereas, some PTXs causes liver necrosis and YTXs damages cardiac muscle after intraperitoneal injection into mice. On the other hand, azaspiracids (AZAs) have never been included in the DSP group, but they cause diarrhoea in humans. This review summarizes the origin, characterization, structure, activity, mechanism of action, clinical symptoms, method for analysis, potential risk, regulation and perspectives of DSP and associated toxins produced by marine dinoflagellates.     

大鼠溃疡性结肠炎模型的实验研究

目的对不同剂量的三硝基苯磺酸（ＴＮＢＳ）引起的大鼠溃疡性结肠炎（ＵＣ）模型进行观察和评价。方法采用一次性直肠注入大鼠ＴＮＢＳ（２５～１５０ｍｇ·ｋｇ－１）的３０％乙醇溶液，引起慢性炎症性肠疾病（ＩＢＤ），３ｗｋ后外死动物对各剂量下动物结肠的重量、髓过氧化物酶（ＭＰＯ）活性及组织形态学变化进行观察和评价。结果ＴＮＢＳ在１００～１５０ｍｇ·ｋｇ－１剂量下引起的ＵＣ肠壁明显增厚，炎症和溃疡至少维持７ｗｋ时间，ＭＰＯ活性值显著性升高，组织学检查发现粘膜及粘膜下层有大量中性粒细胞及淋巴细胞、巨噬细胞、纤维细胞浸润，肉芽组织及隐窝脓肿形成，５０ｍｇ·ｋｇ－１剂量时有一较轻度的损伤。２５ｍｇ·ｋｇ－１时对结肠的重量、ＭＰＯ活性及损伤指数都没有显著性改变（Ｐ＞０．０５）。结论用ＴＮＢＳ引起大鼠实验性ＵＣ，其溃疡和炎症维持一较长时间，这一病理特征为炎症性疾病防治药物的研究提供了条件；本模型的最佳剂量为１００ｍｇ·ｋｇ－１左右     

Latent role of in vitro Pb exposure in blocking Aβ clearance and triggering epigenetic modifications

Both β-amyloid (Aβ) catabolism and epigenetic regulation play critical roles in the onset of neurodegeneration. The latter also contribute to Pb neurotoxicity. The present study explored the role of epigenetic modifiers and Aβ degradation enzymes in Pb-induced latent effects on Aβ overproduction in vitro. Our results indicated that in SH-SY5Y cells exposed to Pb, the expression of NEP and IDE remained declined during the recovery period, accompanied with abnormal increase of Aβ_1-42 and amyloid oligomer. A disruption of selective global post-translational histone modifiers including the decrease of H3K9ac and H4K12ac and the induction of H3K9me2 and H3K27me2 dose dependently was also showed in recovery cells. Moreover, histone deacetylase inhibitor VPA could attenuate latent Aβ accumulation and HDAC activity induced by Pb, which might be by regulating the expression of NEP and IDE epigenetically. Overall, our results suggest sustained reduction of NEP and IDE expression in response to Pb sensitizes recovery SH-SY5Y cells to Aβ accumulation; however, administration of VPA is demonstrated to be beneficial in modulating Aβ clearance.