黄连─黄芩药对煎煮液沉淀物的分析

目的：研究黄连与黄芩复方煎煮液产生沉淀物的成分。方法：应用聚酰胺柱层析、薄层层析和飞行时间质谱对黄连黄芩药对煎煮液的沉淀物进行了分析。结果：沉淀物主要成分是黄连中的黄连碱、小檗碱、表小檗碱、巴马亭、药根碱及黄芩中的黄芩甙、汉黄芩甙等组成。结论：煎煮液的沉淀物为药材中的有效成分,为研究黄连黄芩药对的药效作用提供了新的科学资料。     

甲壳胺对硝苯地平片剂药代动力学和生物利用度的影响

 目的:测定甲壳胺对硝苯地平片剂药代动力学和生物利用度的影响?方法:采用气相色谱法研究了10名男性健康志愿者随机单剂量口服市售片和以甲壳胺为辅料的硝苯地平片剂后,药物在体内的经时过程并计算药代动力学参数?结果:以甲壳胺为辅料的片剂和市售片的t_1/2ka分别为0.41h 和0.77h,t_1/2ke分别为2.64h和2.63h,t_max分别为1.59h和2.03h,c_max分别为104.61μg·L^-1和57.36μg·L^-1,AUC分别为586.18μg·h·L^-1和342.27μg·h·L^-1,其相对生物利用度为151.8% ?结论:甲壳胺可显著提高硝苯地平的生物利用度,明显改善药物的吸收?     

Comparative bioavailability of two cefadroxil formulations in healthy human volunteers after a single-dose administration

OBJECTIVE: To compare the bioavailability of two cefadroxil capsule (500 mg) formulations (Cefadroxila from Eurofarma Laboratórios Ltd, Brazil, as test formulation and Cefamox from Bristol-Myers Squibb, Brazil S.A. as reference formulation) in 24 volunteers of both sexes. MATERIAL AND METHODS: The study was conducted open with randomized two-period crossover design and a 1-week washout period. Plasma samples were obtained over a 12-h interval. Cefadroxil concentrations were analysed by combined reversed-phase liquid chromatography and tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using a selected ion monitoring method. From the cefadroxil plasma concentration versus time curves the following pharmacokinetic parameters were obtained: AUC(last), AUC(0-infinity) and C(max). RESULTS: Geometric mean of Cefadroxila/Cefamox 500 mg individual percent ratio was 103.97% for AUC(last), 104.08% for AUC(0-infinity) and 95.23% for C(max). The 90% confidence intervals (CI) were 98.14-110.16%, 98.37-110.12%, and 85.59-105.96%, respectively. CONCLUSION: Since the 90% CI for C(max), AUC(last) and AUC(0-infinity) were within the 80-125% interval proposed by the Food and Drug Administration, it was concluded that the Cefadroxila 500 mg capsule was bioequivalent to the Cefamox 500 mg capsule, according to both the rate and extent of absorption.     

胶束电动毛细管色谱法测定兔血浆中氟比洛芬的浓度

目的：建立胶束电动毛细管色谱法测定兔血浆中氟比洛芬的浓度。方法：兔血浆经甲醇除蛋白质后,加入０．１ ｍ ｌ分离用缓冲液溶解后进样测定。电泳条件为：７５ μｍ ×１００ ｃｍ 空心石英毛细管柱,缓冲液为２０ ｍ ｍ ｏｌ／Ｌ 硼砂（含２５ ｍ ｍ ｏｌ／Ｌ十二烷基硫酸钠）。结果：本法以酮基布洛芬为内标,在１～２４ μｇ／ｍ ｌ内呈良好的线性关系和重现性,２．４,７．２和１２．０ μｇ 的加样回收率分别为９５．３６％ ,９３．５５％ 和９５．２２％ ,最低检测浓度为０．２ μｇ／ｍ ｌ。结论：本法准确、简便,可用于药代动力学研究。     

内源性乳糖结合凝集素在胃癌中的表达

目的：探讨内源性乳糖结合凝集素在胃癌中的表达及其意义。方法：采用亲和层析法分离纯化胃癌内源性乳糖结合颖集素,免疫家兔制备多克隆抗体,免疫组织化学方法（ＡＢＣ法）检测胃癌组织内源性乳糖结合凝集素表达。结果：纯化得到一分子量为３０ｋＤ的内源性乳糖结合凝集素,免疫组化检测发现胃癌乳糖结合凝集素表达阳笥率为３２．５％,Ⅰ、Ⅱ、Ⅲ期阳性率分别为２０．０％、２９．６％和５０．０％（Ｐ〉０．０５）,组织学高分子     

Evaluation of Prediction Accuracy for Volume of Distribution in Rat and Human Using In Vitro,In Vivo,PBPK and QSAR Methods

Volume of distribution at steady state (V_ss) is an important pharmacokinetic parameter of a drug candidate. In this study, V_ss prediction accuracy was evaluated by using: (1) seven methods for rat with 56 compounds, (2) four methods for human with 1276 compounds, and (3) four in vivo methods and three Kp (partition coefficient) scalar methods from scaling of three preclinical species with 125 compounds. The results showed that the global QSAR models outperformed the PBPK methods. Tissue fraction unbound (f_u,t) method with adipose and muscle also provided high V_ss prediction accuracy. Overall, the high performing methods for human V_ss prediction are the global QSAR models, Øie-Tozer and equivalency methods from scaling of preclinical species, as well as PBPK methods with Kp scalar from preclinical species. Certain input parameter ranges rendered PBPK models inaccurate due to mass balance issues. These were addressed using appropriate theoretical limit checks. Prediction accuracy of tissue Kp were also examined. The f_u,t method predicted Kp values more accurately than the PBPK methods for adipose, heart and muscle. All the methods overpredicted brain Kp and underpredicted liver Kp due to transporter effects. Successful V_ss prediction involves strategic integration of in silico, in vitro and in vivo approaches.     

Kidney and liver distribution of ochratoxin A in male and female F344 rats

The impact of age and gender on Ochratoxin A (OTA) distribution in kidney and liver were studied. OTA was quantified in kidney and liver of young and mature rats of both sexes. Data was fit simultaneously using the population approach with NONMEM program. Fed and fasted mature males showed a 30% decrease and an 11% increase in relative bioavailability, respectively, in comparison with the rest of the groups. The OTA concentrations reached in kidney and liver were very similar between both organs. The models that best fit to data were the ones that considered that distribution of OTA to kidney and liver occurs from the central compartment and that elimination occurs mainly from the liver compartment. The kinetic analysis revealed that both, the apparent volume of distribution of the central compartment (V/F) and the apparent volume of distribution of the liver and kidney compartments (V_L,K/F) increased significantly with body weight. Thus, the sex differences observed in organs distribution are a reflection of the differences in relative bioavailability observed in adult males, as a consequence of the fed and fasted conditions and to the significant higher body weight of mature males which directly affected the V/F and V_L,K/F.     

Laboratory confirmation of Amanita smithiana mushroom poisoning

Context. Here we present a case of Amanita smithiana poisoning resulting in acute kidney injury requiring dialysis, and highlight laboratory methods used to confirm the diagnosis. Identification of Amanita smithiana toxin using thin-layer chromatography can provide greater diagnostic certainty than history and renal function tests alone. Case details. A 63-year-old male presented to hospital with anuria and gastrointestinal symptoms, two days after consuming a soup of wild mushrooms he had picked. He was found to be in acute renal failure, requiring hemodialysis. After nine days of supportive treatment, he recovered renal function, and was discharged in good health 15 days post-ingestion. The patient provided a sample of leftover soup, and examination of cooked mushroom fragments by a mycologist provided preliminary identification of A. smithiana. Thin-layer chromatography revealed the presence of A. smithiana toxin in the soup, confirming this identification. Discussion. A. smithiana is a nephrotoxic mushroom that can be easily mistaken for the edible and highly prized Pine mushroom (Tricholoma magnivelare). It causes initial gastrointestinal symptoms, followed by acute renal failure. Treatment includes dialysis and supportive care until the patient recovers renal function. The chemical structure of the A. smithiana toxin is unknown, but it can be identified as a characteristic spot on thin-layer chromatography.     

Efficient factor VIII affinity purification using a small synthetic ligand

Summary.  Background:  Hemophilia A is currently treated by infusions of the coagulation factor (F) VIII, of which production and purification remain a challenging task. Current purification procedures using immunoaffinity chromatography are cumbersome, expensive, and suffer from the instability of the applied antibody ligands, which elute along with the product and contaminate it. Recently, FVIII was purified using octapeptide ligands, but their use is limited due to the low resistance to proteases. Objective:  Our goal was to develop and evaluate a novel ligand for FVIII purification, overcoming the drawbacks of current procedures. Methods:  Peptide ligands were screened for binding of ¹²⁵I-plasma-derived-FVIII (pdFVIII) in a microbead assay. A selected ligand-coated Toyopearl resin was then used for pdFVIII purification from cell-conditioned Delbucco's modified Eagle's medium (DMEM) containing fetal bovine serum. The proteolytic stability of ligand was measured by incubating with human serum and proteinase K, and its cytotoxicity towards human OV-MZ-6 cells was assayed. Results:  A high-affinity octapeptidic FVIII ligand was modified into the small, highly stable and non-toxic peptidomimetic ligand L4 by rational and combinatorial design without affecting its affinity for FVIII. Using ligand L4-coated Toyopearl resin, pdFVIII was isolated from cell-conditioned medium with high purity and 89% column retention after elution with a mild buffer containing 0.6  m NaCl at pH 6.8. Conclusions:  Ligand L4 offers a valuable alternative to antibody-based procedures for laboratory and industrial production. Its synthesis by established solid-phase procedures is straightforward and considerably cheaper than the biotechnological production of antibodies, and safety concerns associated with the use of biological material are overcome.     

Mass spectrometry identifies multiple organophosphorylated sites on tubulin

Acute toxicity of organophosphorus poisons (OP) is explained by inhibition of acetylcholinesterase in nerve synapses. Low-dose effects are hypothesized to result from modification of other proteins, whose identity is not yet established. The goal of the present work was to obtain information that would make it possible to identify tubulin as a target of OP exposure. Tubulin was selected for study because live mice injected with a nontoxic dose of a biotinylated organophosphorus agent appeared to have OP-labeled tubulin in brain as determined by binding to avidin beads and mass spectrometry. The experiments with live mice were not conclusive because binding to avidin beads could be nonspecific. To be convincing, it is necessary to find and characterize the OP-labeled tubulin peptide. The search for OP-labeled tubulin peptides was begun by identifying residues capable of making a covalent bond with OP. Pure bovine tubulin (0.012 mM) was treated with 0.01-0.5 mM chlorpyrifos oxon for 24 h at 37 °C in pH 8.3 buffer. The identity of labeled amino acids and percent labeling was determined by mass spectrometry. Chlorpyrifos oxon bound covalently to tyrosines 83, 103, 108, 161, 224, 262, 272, 357, and 399 in bovine alpha tubulin, and to tyrosines 50, 51, 59, 106, 159, 281, 310, and 340 in bovine beta tubulin. The most reactive were tyrosine 83 in alpha and tyrosine 281 in beta tubulin. In the presence of 1 mM GTP, percent labeling increased 2-fold. Based on the crystal structure of the tubulin heterodimer (PDB 1jff) tyrosines 83 and 281 are well exposed to solvent. In conclusion seventeen tyrosines in tubulin have the potential to covalently bind chlorpyrifos oxon. These results will be useful when searching for OP-labeled tubulin in live animals.