HPLC手性色谱柱法测定萘普生与萘普生胶囊中异构体含量

目的探讨萘普生与萘普生胶囊中异构体的含量。方法采用HPLC法,以手性色谱柱为分离柱,测定异构体的含量。结果 L-萘普生峰与D-萘普生峰的分离度良好,溶液在12h内稳定;4批样品的异构体含量为0.5%~0.7%。结论本方法简便、准确性好、灵敏度高,可以有效地测定萘普生与萘普生胶囊中异构体含量。     

高效液相色谱法测定盐酸左旋多巴异戊酯的含量

目的建立测定盐酸左旋多巴异戊酯含量的高效液相色谱法。方法色谱柱采用UltimateTMC18柱（250mm×4．6mm5μm）,流动相为0．05mol／L磷酸二氢钾（磷酸调pH=3．5）-乙腈（70：30）,流速为1．0mL／rain,检测波长为280mm,进样量为20μL,柱温为30℃。结果盐酸左旋多巴异戊酯质量浓度在16．1—322．0μg／mL范围内与峰面积线性关系良好（r=0．9999）,平均回收率为98．41％,RSD为1．85％（n=6）。结论该方法准确、简便,精密度高、专属性强,可用于盐酸左旋多巴异戊酯的含量测定。     

高效液相色谱法测定盐酸左旋多巴正丁酯的含量

目的建立测定盐酸左旋多巴正丁酯含量的高效液相色谱法。方法色谱柱采用WondailTM C18柱(150 mm×4.6 mm,5μm),流动相为0.05 mol/L磷酸二氢钠(用4.3%氢氧化钠溶液调pH至5.0)-甲醇(60:40),流速1.0 mL/min,检测波长280 nm,柱温40℃,进样量20μL。结果盐酸左旋多巴正丁酯质量浓度在25.1～251.0μg/mL范围内与峰面积线性关系良好(r=0.999 9),平均回收率为99.77%,RSD为0.83%(n=9)。结论高效液相色谱法简便、准确、专属性好,可用于盐酸左旋多巴正丁酯的含量测定。     

反相高效液相色谱法测定盐酸左旋多巴正己酯的含量

目的建立测定盐酸左旋多巴正己酯含量的高效液相色谱法。方法采用Ultimate C18色谱柱(250 mm×4.6 mm,5μm),以0.05 mol/L磷酸二氢钾(磷酸调pH至3.5)-乙腈(65∶35,V:V)为流动相,检测波长为280 nm,流速为1.0 mL/min,柱温为25℃。结果盐酸左旋多巴正己酯进样量在0.360～7.200μg范围内与峰面积线性关系良好,回归方程为Y=10 364 X+11 444,r=0.999 9(n=6);平均加样回收率为99.33%,RSD=1.87%(n=6)。结论所建立的方法操作简便,准确度、灵敏度高,可用于盐酸左旋多巴正己酯的含量测定。     

高效液相色谱法测定左旋多巴片的有关物质

目的:采用高效液相色谱法测定左旋多巴片的有关物质。方法:采用依利特Spherisorb C18柱(5μm,150×4.6mm),以0.01mol/L磷酸二氢钾缓冲液(含0.003mol/L辛烷磺酸钠,pH3.0)-甲醇(84:16)为流动相,检测波长280nm,流速1.0ml/min,柱温30℃。结果:降解产物在该色谱条件下与左旋多巴分离良好。结论:本方法用于测定左旋多巴片有关物质,方法简便,快速,结果准确。     

高锰酸钾=左旋多巴化学发光体系测定左旋多巴

发现了高锰酸钾—左旋多巴化学发光体系，建立了利用此体系测定左旋多巴的流动注射化学发光分析新方法．方法的检出限为６．２×１０－５ｇ／Ｌ左旋多巴．左旋多巴浓度在４×１０－４～８×１０－２ｇ／Ｌ范围内与化学发光强度呈良好的线性关系．对４×１０－３ｇ／Ｌ左旋多巴进行１１次测定，ＲＳＤ为１．６％．此方法已用于片剂中左旋多巴的测定，结果与标准方法一致．     

左旋多巴微囊漂浮片的处方优选

摘 要 目的： 优选左旋多巴微囊漂浮片的处方。方法: 高效液相色谱法测定左旋多巴与苄丝肼的含量,以漂浮片释放度得分为指标,采用正交试验优选左旋多巴微囊漂浮片的处方,并对其体外释药特性进行评价。结果: 建立的测定左旋多巴胃内漂浮片中左旋多巴与苄丝肼含量的高效液相色谱法,符合方法学要求。优化的微囊漂浮片处方组成为硬脂酸：主药：丙烯酸树脂：HPMC=2∶5∶2∶1,平均片重为550 mg。验证试验结果表明该微囊漂浮片具有漂浮、缓释、可分剂量使用等特性。结论: 优选出的复方左旋多巴微囊漂浮片处方合理,生产工艺稳定、可行。     

长期应用左旋多巴与美多巴对胃肠道不良反应的比较

目的多巴胺前体物质左旋多巴是目前治疗帕金森病的最有效药物之一,然而,其外周胃肠道不良反应也很严重;而美多巴是左旋多巴和外周多巴脱羧酶抑制剂苄丝肼的混合制剂,美多巴是否也有同样的胃肠道不良反应,本实验即通过长期灌胃给予大鼠左旋多巴与美多巴,来比较观察两药的胃肠道不良反应。方法176只雄性SD大鼠,体重180~220g,随机分为24组,即空白对照组,左旋多巴给药1、2、3、7和14d组,美多巴给药1、2、3、7和14d组。分别采用大鼠小肠运动实验方法和大鼠胃排空实验方法,以大鼠小肠炭沫推进距离和大鼠胃甲基橙残留率为指标,观察长期应用左旋多巴与美多巴对胃肠道有何影响,并比较其不同点。结果给左旋多巴1、2、3、7和14d组均抑制大鼠小肠炭沫推进距离,与对照组比较差异均有统计学意义(P<0.05或P<0.01);而给美多巴各时间段组,对大鼠小肠炭沫推进距离无明显变化;给左旋多巴1、2、3、7和14d组胃甲基橙残留率明显增多,与对照组比较差异有统计学意义(P<0.05或P<0.01),而给美多巴各时间段组,胃甲基橙残留率与对照组比较无明显变化。结论左旋多巴有抑制胃排空和抑制小肠推进的胃肠道不良反应,而美多巴对胃肠道不良反应影响不显著。     

HPLC法测定卡左双多巴缓释片中的有关物质

建立了HPLC法测定卡左双多巴(左旋多巴-卡比多巴)缓释片中的有关物质。采用Waters X-Bridge C₁₈柱(4.6mm×250mm,5μm),以pH1.8的磷酸盐缓冲液为流动相A、pH 1.8的磷酸盐缓冲液和甲醇(体积比250∶750)为流动相B,梯度洗脱。流速为1.0 mL/min,检测波长为280 nm,柱温为25℃,进样量为20μL。结果显示,主峰及各杂质峰均能良好分离,卡比多巴、左旋多巴和7个有关物质的线性关系良好,7个有关物质的平均回收率(n=9)分别为98.97%、100.79%、102.69%、98.13%、102.34%、95.97%、100.80%。强制性降解试验结果显示,该方法可指示各条件下的降解产物。相较于美国药典收录的有关物质检测方法,该方法专属性高、简便耐用,可用于卡左双多巴缓释片的生产控制及稳定性样品测定。     

HPLC法分析左旋多巴及其有关物质

目的：建立高效液相色谱法分析左旋多巴的含量及其有关物质,并对有关物质进行定位。方法：采用Agilent TC-C18色谱柱（150mm×4．6mm,5μm）;以0．1％三氟乙酸溶液-乙腈（96：4）为流动相;流速1．0ml·min^-1;检测波长为280nm;柱温：室温。结果：左旋多巴和L-酪氨酸分别在0．06～0．61mg·ml^-1和5．01～50．12μg·ml^-1范围内线形关系良好,r=0．9999,各杂质均能达到很好的分离。结论：该方法能有效的用于左旋多巴的定量及有关物质的检测。     

左旋多巴对健康老年大鼠的神经毒性

目的研究长期应用左旋多巴对健康老年大鼠多巴胺神经元是否存在毒性作用。方法将24只健康老年大鼠随机分为3组，分别给予大剂量左旋多巴、小剂量左旋多巴、生理盐水共4个月，观察大鼠用药后是否产生运动障碍，以及纹状体部位脑组织匀浆中的还原型谷胱甘肽、谷胱甘肽过氧化物酶、超氧化物歧化酶、丙二醛含量，以免疫组化法检查中脑黑质和纹状体部位酪氨酸羟化酶阳性细胞和纤维的数量。结果没有发现长期应用左旋多巴会引起运动障碍，长期左旋多巴应用引起纹状体部位还原型谷胱甘肽、谷胱甘肽过氧化物酶含量增加，超氧化物歧化酶、丙二醛含量无明显变化；黑质和纹状体部位酪氨酸羟化酶阳性细胞数在各组间无明显差别。结论长期应用左旋多巴对健康老年大鼠无神经毒性作用。     

Preparation and in vitro characterization of gelatin microspheres containing Levodopa for nasal administration

The dissolution properties of twomodel compounds, brilliant blue and tumour necrosis factor (TNF-alpha), from poly(D,L- .lactic-co-glycolic acid) (PLGA) multiphasemicrospheres wereinvestigated. In addition, the invivo releaseof TNF-alpha from the microspheres, in mice, was studied. The microspheres were prepared by an anhydrous multiple emulsion solvent evaporation method. Multiphase microspheres containing brilliant blue exhibited athree phase release profile in vitro, and displayed a significantly lower level of dye released during the initial phase compared to conventional matrix-type microspheres. Slow release of the dye was observed during the second phase, which was followed by a disintegration of the polymer wall during the third phase of the release process. In vitro dissolution profiles of TNF-alpha were calculated by compensation for the simultaneous degradation of the protein in the dissolution medium. The initial burst release of TNF-alpha was significantly reduced with the multiphase microspheres. The three phase release profile, as seen with the dye, was not observed for the microspheres containing the TNF-alpha. The rate of release of the protein from the microspheres was determined in vivo by analysing the residual level of TNF-alpha remaining in the particles following intraperitoneal administration of the microspheres to mice. The release of the protein from the microspheres in vivo was significantly faster than predicted from the results of the in vitro studies. The absence of an initial burst release of TNF-alpha from the multiphase microspheres was reflected in a significant reduction in the plasma level of TNF-alpha when compared to the matrix-type microspheres and a solution of the protein. The controlled release property of the multiphase microspheres is expected to overcome the adverse reactions due to dose dumping that occurs following the local administration of TNF-alpha.     

A comparative clinical investigation of the therapeutic effect of levodopa alone and in combination with a decarboxylase inhibitor (carbidopa) in cases of Parkinson's disease

Summary

The therapeutic effect of the combination of levodopa and carbidopa (‘Sinemet’) was compared with that of levodopa alone in 21 patients with Parkinson's disease. Eighteen parameters of the clinical condition and of functional impairment were determined quantitatively and the results statistically evaluated. Changing over from levodopa to the combination preparation resulted in an average improvement of 51.9% within 2 weeks. No relationship was found to exist between the degree of improvement and the severity or the progression of the disease. By the use of the combination preparation, the daily dosage of levodopa could be reduced by 77 %. Side-effects connected with the gastro-intestinal tract occurred much less frequently, while hyperkinesia increased. No arrhythmogenic effect was found with the combination product. From the clinical standpoint, combination therapy appeared to be qualitatively superior. By selective maintenance of freshly formed dopamine, it should be possible to assure a directed influence on the disturbed equilibrium of the functional systems of the brain.     

Pharmacokinetics of oral entacapone after frequent multiple dosing and effects on levodopa disposition

Objective: Entacapone is a peripherally acting catechol O-methyltransferase (COMT) inhibitor used as an adjunct to each daily levodopa/dopa decarboxylase (DDC) inhibitor dose in the treatment of Parkinson's disease. Parkinsonian patients with advanced disease and motor fluctuations take several doses of levodopa daily, due to the short action of levodopa in this patient population. The present study was conducted in order to evaluate the pharmacokinetics of entacapone after multiple dosing and the pattern of COMT inhibition in erythrocytes during the first day of dosing as well as during steady state. Furthermore, the disposition of plasma levodopa and carbidopa was studied after a single dose of levodopa/carbidopa during the same conditions. Methods: Twelve healthy male volunteers received 200 mg entacapone eight times daily during study day 1 and day 6 at 2-h intervals from 0800 hours to 2200 hours. During days 3, 4 and 5, 200 mg of entacapone was taken ten times daily, from 0800 hours to 0200 hours on the following day. One levodopa/carbidopa tablet (100/25 mg) was taken on study day 1 and day 6 at 1000 hours. Plasma entacapone concentrations and erythrocyte COMT activities were measured frequently on study days 1–2 and 6–7, and twice daily on study days 3–5. Pharmacokinetic parameters calculated from plasma drug concentrations on days 1–2 and 6–7 were compared with each other. Results: There were no differences in maximal plasma concentration (C_max), time to maximal drug concentration in plasma (t_max), elimination half-life (t_1/2) and area under the plasma concentration–time curve (AUC) of entacapone between day 1 and day 6. The mean t_1/2 values of entacapone were 1.3 h and 1.8 h during the first and sixth days, respectively; the difference was not significant. No signs of accumulation of entacapone were noted after the first day. Entacapone reduced erythrocyte COMT activity after the first dose, and this effect was quite stable during frequent dosing. There were no indications of accumulation of COMT inhibition during frequent dosing of entacapone. There were no between-day differences in C_max, t_1/2 (2.4 h on days 1–2 and 2.3 h on days 6–7) or AUC of levodopa, whereas t_max occurred at 0.8 h on day 1 and at 1.2 h on day 6 (P = 0.03). There were no between-day differences in the pharmacokinetic parameters (C_max, t_max and AUC) of carbidopa. Conclusion: Even when dosed frequently, there are neither indications of accumulation of entacapone nor of its COMT inhibiting activity. Received: 28 December 1998 / Accepted in revised form: 29 March 1999     

Tolcapone decreases plasma levels of S-adenosyl-L-homocysteine and homocysteine in treated Parkinson’s disease patients

Background Elevated plasma total homocysteine (tHcy) appeared in levodopa/dopadecarcoxylase inhibitor (DDI) treated patients with Parkinson’s disease (PD). One therapeutic approach for tHcy reduction is vitamine supplementation, since folic acid and cobalamine catalyse and enhance metabolism of tHcy to methionine. A further therapeutic alternative is inhibition of catechol-O-methyltransfrase (COMT) on a regular basis, when levodopa/DDI treatment is performed.Methods We measured the concentrations of S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), tHcy, levodopa and 3-O-methyldopa in plasma of 13 levodopa treated PD patients before first drug intake at 0600 hours. Blood samples were taken before and after 2 days of additional application of the centrally acting catechol-O-methyltransferase inhibitor tolcapone 100 mg t.i.d.Results Plasma levels of SAH [day 1: 48.32±22.52, 23.92–98.25 (mean±SD, range; μmol/l); day 3: 37.72±15.84, 23.4–61.89; p=0.01] and tHcy (day 1: 13.88±5.62, 7.63–24.81; day 3: 11.38±4.44, 5.98–20.45; p=0.04) significantly reduced. Plasma levels of levodopa did not significantly (p=0.17) increase, whereas 3-OMD concentrations significantly (p=0.0002) reduced after additional tolcapone intake. There was no significant change of SAM plasma levels (p=0.22).Conclusion Our prospective trial shows, that COMT inhibition with tolcapone lowers tHcy synthesis. Tolcapone may also possess beside its proven, occasional, hepatotoxic potency also beneficial effects via decrease of SAH and tHcy. This may hypothetically reduce homocysteine mediated progress of neuronal degeneration and the risk for onset of dementia, vascular disease and polyneuropathy in levodopa treated PD patients in the long term.     

Use of an entacapone-containing drug combination and risk of death: Analysis of the FDA AERS (FAERS) database

To assess the signal of death associated with the use of an entacapone-containing drug combination in the FDA Adverse Event Reporting System (FAERS) database.Reports of death events submitted between January 2004 and December 2010 were retrieved and analysed by the reporting odds ratio (ROR). The ROR of case/non-case reports of death associated with an entacapone-containing drug combination was compared with the levodopa/carbidopa combination using the FDA AERS database.Eighty-seven reports linked the entacapone-containing drug combination to death, compared to 27 reports of death linking the levodopa/carbidopa combination. The ROR was statistically significant for the association between deaths with the use of an entacapone-containing drug combination (1.86 [95% CI 1.50–2.31]). In contrast, the ROR of death associated with the combination of levodopa and carbidopa was not statistically significant (0.89 [95% CI 0.61–1.30)].Based on analysing reports in the FAERS database, there is a risk of death with the use of an entacapone-containing drug combination. These results generated a signal of death with the use of this drug. However, epidemiological studies are required to confirm this association.     

An electromyographic analysis of the effect of levodopa on the response time of healthy subjects

Abstract Rationale. Recently, we have shown that oral absorption of levodopa shortens reaction time (RT), measured as the interval between the response signal and the onset of voluntary electromyographic (EMG) activity. The motor time (MT) interval that elapses from the EMG activity to the mechanical response was not analysed. Objective. The purpose of the present study was to analyse the effect of the dose of levodopa administrated in our previous study on the MT. Eight healthy adults (aged 21–28, mean=25), performed a two-choice visual RT task after oral absorption of a single dose of levodopa (200 mg) or a placebo (randomized, double-blind, cross-over design). Results. Like RT, MT was shorter under levodopa than under placebo. Statistical analyses demonstrated that this effect was present for all deciles of the RT and MT distributions. Conclusion. Levodopa shortens not only RT but also MT, which points at the implication of the dopaminergic system in both premotor and motor processes. Electronic Publication     

左旋多巴对脂多糖诱导小胶质细胞产生致炎因子的影响及黄芪保护作用

目的探讨左旋多巴(L-DOPA)对脂多糖(LPS)诱导小胶质细胞产生致炎因子的影响及黄芪多糖(ASP)的保护作用。方法不同浓度LPS(1、5、10ng/ml)和(或)L-DOPA(50、100、500μmol/L)及ASP(20μg/ml)+LPS(10ng/ml)+L-DOPA(50μmol/L)处理小胶质细胞培养液,于0、4、24、48h动态观察一氧化氮(NO)的含量、肿瘤坏死因子-α(TNF-α)的水平及黄芪多糖对上述指标的影响。结果 LPS处理小胶质细胞培养液,当LPS浓度5ng/ml48h、10ng/ml24h、L-DOPA浓度为100μmol/L72h、500μmol/L24h以后、LPS+L-DOPA组各个时间点NO的含量均高于对照组(P<0.05),LPS+L-DOPA组显著高于单独用LPS或L-DOPA处理组(P<0.05)。LPS5ng/ml24h、10ng/ml4h、L-DOPA500μmol/L72h、LPS+L-DOPA组各时间点TNF-α的含量均高于对照组(P<0.05),LPS+L-DOPA组显著高于单独用LPS或L-DOPA处理组(P<0.05),黄芪多糖处理组明显降低NO的含量和TNF-α的水平(P<0.05)。结论 LPS致炎作用有时间剂量依赖性,小剂量L-DOPA无致炎作用,但L-DOPA增强LPS的致炎作用,黄芪多糖通过抑制NO、TNF-α的释放发挥抗炎保护作用。     

苯乙烯对大鼠多巴胺受体1的损害效应及机制

目的观察苯乙烯在不同染毒期限和染毒剂量下对大鼠神经系统多巴胺受体1(DR1)的损伤效应。方法大鼠随机分为5组,每组12只动物,雌雄各半。苯乙烯急性染毒剂量为600 mg/kg,亚急性染毒剂量为150、300和600 mg/kg,恢复组在苯乙烯染毒后正常饲养3周,左旋多巴(L-dopa)组在苯乙烯染毒同时腹腔注射600 mg/kg的L-dopa。测定神经行为学指标和DR1的结合密度及亲和力。结果苯乙烯使大鼠的水平运动和垂直运动显著减少,大鼠发生回避错误的次数明显增加;与对照组相比,苯乙烯染毒组DR1与3H-SCH-23390的结合密度由(0.20±0.08)pmol/(L.mg)蛋白降低到(0.14±0.03)pmol/(L.mg)蛋白;Kd值由(0.60±0.04)nmol/L上升到(0.65±0.24)nmol/L;3周的恢复期比腹腔注射L-dopa更能使结合密度和亲和力趋于正常。结论苯乙烯可以通过多巴胺通路产生对机体的神经损伤,表现为运动神经功能障碍和学习记忆能力衰退等有害效应。     

Simultaneous kinetic determination of levodopa and carbidopa by H-point standard addition method

The kinetic H-point standard addition method (HPSAM) was applied to the simultaneous determination of levodopa and carbidopa. The method was based on the difference in the rate of oxidation of these compounds with Cu(II)-neocuproine system and formation of Cu(I)-neocuproine complex at pH 5.5. The absorbance of the Cu(I)-neocuproine complex was monitored at 453 nm. Experimental conditions such as pH, reagent concentrations, ionic strength and temperature were optimized. Simultaneous determination of levodopa and carbidopa was performed in the range of 0.8-4 and 0.2-1.5 microg ml(-1), respectively. The proposed method was applied to the simultaneous determination of levodopa and carbidopa in pharmaceutical samples, and satisfactory results were obtained.