高效液相色谱法测定多潘立酮口腔崩解片的有关物质

目的建立高效液相色谱法测定多潘立酮口腔崩解片的有关物质。方法采用反相高效液相色谱法。固定相为ODSC18色谱柱(5μm,4.6mm×150 mm)以甲醇-0.5%醋酸铵溶液(65∶35)为流动相,流速为1.0mL/m in,柱温室温。检测波长为286nm。结果经过酸、碱、热、光破坏,分解产物均能与主峰很好的分离。结论方法准确,专属性强,适用于多潘立酮口腔崩解片的有关物质测定。     

Automatic system for the assay of guanidino compounds to assess uremic status

An automated system for HPLC-fluorometry of serum guanidino compounds was constructed. This system accomplished simultaneous removal of protein and uremic fluorescences, abundant in the sera of uremic patients, which interfere with the fluorometric assay. This system was applied to the detailed elucidation of the behavior of guanidinosuccinic acid and methylguanidine during and after hemodialysis therapy (HD). The uremic patients who are capable of excreting urine even under hemodialysis therapy showed low serum guanidinosuccinic acid and methylguanidine levels. The prolongation of the interval between HD for one of the patients capable of excreting urine was examined. The levels of guanidinosuccinic acid and methylguanidine did not significantly increase and no hazardous effect was observed by 2 d of prolongation.     

Toxicological assessment of orally delivered nanoparticulate insulin

Subacute toxicological assessment on diabetic rats was conducted after 15 days of daily oral administration of nanoparticulate insulin. Haematological and biochemical analyses were conducted on blood and urine, biopsies performed on organs and tissues, and histology analysed by optical microscopy. Insulin-loaded nanoparticles alone did not change liver or kidney functions. The increase of some hepatic parameters was attributed to diabetes physiopathology and to chemical inducement of diabetes and not to the nanoparticle composition since diabetic controls showed the same variations. In terms of kidney function, parameters such as urea nitrogen and creatinine, were also similar to normal rats with the exception of glycosuria. This single effect was due to diabetes physiopathology and the method of induction, and not to the nanoparticle composition, since non-dosed diabetic rats showed the same alteration. Even so, glycosuria levels of animals dosed with insulin-loaded nanoparticles were lower than control diabetic rats which may indicate an effective hypoglycaemic response. Nanoparticles did not exhibit toxicity in haematological parameters. Finally, organ histology was similar between dosed animals and normal rats with the exception of pancreas histology.     

Actions of orally administered organotin compounds on heme metabolism and cytochrome P-450 content and function in intestinal epithelium

The gastrointestinal tract is a major route by which humans are exposed to environmental chemicals. We have examined in these studies the effects of oral administration of organotin compounds in the small intestinal epithelium, an organ which exhibits highly active drug and other chemical metabolism. A series of n-butyltin compounds was administered by gavage to male Sprague-Dawley rats (225-275 g) in single doses up to 250 mumol/kg body weight. Bis(tri-n-butyltin)oxide (TBTO) produced dose- and time-dependent decreases in the content and functional activity of intestinal cytochrome P-450, together with an elevation (3-fold) in the activity of microsomal heme oxygenase. The effects of di-n-butyltin dichloride on heme oxygenase and cytochrome P-450 were pronounced in the small intestine and extended to the liver and kidneys within 21 hr after oral-exposure, whereas TBTO did not affect the liver until much later (6 days), when cytochrome P-450 content was reduced markedly (30%). Furthermore, the effects produced by tetra-n-butyltin on cytochrome P-450 at 24 hr were localized in the intestinal epithelium. These studies indicate important pharmacological effects of organotin compounds in the gut, and raise the possibility that concurrent oral ingestion of organotins with other environmental pollutants may alter the cytochrome P-450-dependent metabolism of xenobiotics and natural substrates of this monooxygenase system in the small intestine.     

Value of skin tests for managing allergic hypersensitivity reactions to platinum compounds

Background Platinum-based therapy continues to be one of the pillars of the treatment of different types of cancer. However, many times the responsible clinician renounces its use after the appearance of a hypersensitivity reaction. Objective To assess the value of skin tests (ST) in clinical practice to address the treatment of patients with suspicion of immediate hypersensitivity reactions (HSRs) to platinum compounds. Method Single-center retrospective study of 3 years. Adult patients treated with any platinum compound who experienced HSR symptoms and for whom an oncologist requested ST, were included. ST with cisplatin, carboplatin and oxaliplatin were performed. Results Twenty-two patients were included. ST were positive in 12 patients (54.5%), of which 4 (33%) presented cross-reactivity to another platinum compound. Fifteen patients continued platinum-based chemotherapy: 9 patients with positive ST (4 continued by desensitization and 5 with another platinum compound) and 6 patients with negative ST, of which 1 repeated an HSR. A NPV of 0.91 was calculated. Conclusion ST helped physicians identify patients most susceptible to platinum derivative allergies and resume platinum-based therapy in many patients for whom no suitable therapeutic alternative was clinically acceptable.

     

Novel poloxamer-based nanoemulsions to enhance the intestinal absorption of active compounds

The objective of the present work was to establish a simple and appropriated method for the quantification of thiol groups standing on the surface of core–shell nanoparticles elaborated with poly(isobutyl cyanoacrylates) and thiolated chitosan.

A critical analysis of the widely used Ellman's method for the determination of thiol groups in various compounds was made. The reduced solubility of the thiolated polymer at the optimal pH of the Ellman's assay (pH 8–8.5) made difficult the accessibility of the Ellman's reagent to thiol groups in the cross-linked polymer. Furthermore, the lack of stability of the Ellman's reaction with time lead to the conclusion that the Ellman's method was of limited value to evaluate thiol groups in thiolated polymers like thiolated chitosan.

An alternative and very simple thiol quantification method was developed on the bases of the classical iodine titration. The new method allowed the determination of thiol groups in small amount of samples at acidic pH, and the monitoring of the thiol determination kinetic with time. It was successfully applied to the quantification of active thiol groups on the surface of poly(isobutyl cyanoacrylates) nanoparticles coated with thiol chitosan.     

A decision-support tool for the formulation of orally active, poorly soluble compounds.

Physicochemical data for a set of potentially poorly soluble compounds was analysed in relation to suitable formulations for these compounds. Physical chemistry was found to be a key determinant of formulation class expressed in terms of conventional, solid dispersion, lipidic/surfactant, and crystalline nanoparticle systems. This relationship was used to build a decision-support tool aimed to guide formulation selection for poorly soluble compounds during product development. Tool components included a user interface, a database of compound cases together with known formulations, and predictive modules based on statistics, decision trees, and case-based reasoning. The tool was tested and exhibited significant and consistent predictive ability across testing conditions. This type of tool has the potential to improve the efficiency and predictability of the formulation development process.     

药物不良反应因果关系评价方法的探讨

机体在不同情况下的生物反应不同，使药物不良反应的评估有时会有一定的困难。通过实践，我们提出以提问回答形式，主要围绕不良反应的详细病史包括合并用药，以及既往药物不良反应史提问。顺序逐一回答问题，得出结论：肯定、很可能、可能、可疑、无关。８４例应用此法与经验评估法的评估结果进行比较，完全符合率为７９％。     

Cloxacepride and related compounds: a new series of orally active antiallergic compounds

4-[[(p-Chlorophenoxy)acetyl]amino]-5-chloro-2-methoxy-N-[2-(diethylamino)ethyl]benzamide (cloxacepride, 1), exhibited substantial oral antiallergic potential in a reaginic PCA test in rats over a wide range of antigenic challenge times. Available reference compounds with oral activity, such as doxantrazole and 7-(2-hydroxyethoxy)-9-oxoxanthene-2-carboxylic acid (AH 7725, 4), were active only when administered 15 min before challenge: 4, in particular, was not consistent in effect. Oral ED50 values for cloxacepride of 46-49 mg/kg were comparable to that of theophylline and to an intravenous injection of 2 mg/kg of disodium chromoglycate (DSCG) followed by immediate challenge. Following oral ED50 doses, 1 showed slower onset and longer duration of action than theophylline. The absence of inhibition of systemic anaphylaxis and of antihistaminic activity suggests specific effect or reaginic antigen antibody reactions. Structure-activity relationships of various chemical modifications were investigated and discussed in terms of essential substituents.     

High throughput microsomal stability assay for insoluble compounds

High throughput metabolic stability assays are widely implemented in drug discovery to guide structural modification, predict in vivo performance, develop structure-metabolic stability relationships, and triage compounds for in vivo animal studies. However, these methods are often developed and validated using commercial drugs. Many drug discovery compounds differ from commercial drugs, with many having high lipophilicity, high molecular weight and low solubility. The impact of very low solubility on metabolic stability assay results was explored. Two metabolic stability assays, the 'aqueous dilution method' and the 'cosolvent method, were compared. For commercial drugs and most discovery compounds having reasonable drug-like properties, the two methods gave comparable results. For highly lipophilic, insoluble drug discovery compounds, the 'aqueous dilution method' gave artificially higher stability results. The cosolvent method performs compound dilutions in solutions with higher organic solvent content and adds solutions directly to microsomes to assist with solubilization, minimize precipitation and reduce non-specific binding to plastics. This method is more applicable in drug discovery where compounds of a wide range of solubility are studied.     

Frog intestinal sac: a new in vitro method for the assessment of intestinal permeability

The aim of this study was to evaluate a new experimental protocol utilizing isolated frog intestinal sacs for the assessment of intestinal drug permeability in humans. Segments of approximately 5.0 cm in length were used for these experiments. The intestinal sacs were filled with a solution of the appropriate drug in frog Ringer (FR) and immersed in a vial containing fresh FR. The transport was monitored for a period ranging from 2 to 5 h by moving the intestinal sac at each time point to a new vial containing fresh medium (Method A). Alternatively, according to Method B, at predetermined times aliquots of receiving mixture were taken up without removing the intestinal sac, and replaced with fresh drug-free FR. In all cases, the samples were analyzed by HPLC. A series of 20 noncongeneric drugs, predominantly absorbed by passive diffusion mechanism, was examined. The results indicate that drugs completely absorbed in humans had Papp values greater than 1 x 10(-6) cm/s, while drugs absorbed <90% had Papp values lower than 1 x 10(-6) cm/s. By plotting Log Papp values against percent human absorption, an approximately sigmoidal relationship was obtained. The frog intestinal sac method was evaluated as a permeability model to classify the 20 studied drugs into the Biopharmaceutics Classification System (BCS). By comparing the predictions made by this new approach with those reported in literature, it can be concluded that a satisfactory biopharmaceutical classification may be based on the Papp values determined by the frog intestinal permeability. Molecular properties relevant to passive intestinal permeability were considered to evaluate the correlation with the frog intestinal permeability rates recorded. Good relationships were observed when hydrogen-bonding parameters were expressed as a function of the Log Papp values. It can be concluded that the in vitro permeability coefficient deduced from isolated frog intestinal experiments can be used for predicting peroral absorption in humans for passively absorbed compounds. Computational methods for prediction of frog intestinal permeability may be applied in a highly simplified manner.     

An assessment of the potential of the microbial assay for risk assessment (MARA) for ecotoxicological testing

Rapid microscale toxicity tests make it possible to screen large numbers of compounds and greatly simplify toxicity identification evaluation and other effect directed chemical analyses of effluents or environmental samples. Tests using Vibrio fischeri (such as Microtox?) detect toxicants that cause non-specific narcosis, but are insensitive to other important classes of contaminants. The microbial assay for risk assessment (MARA) is a 24 h multi-species test that seeks to address this problem by using a battery of ten bacteria and a fungus. But there has been little independent evaluation of this test, and there is no published information on its sensitivity to pesticides. Here, we assess the performance of MARA using a range of toxicants including reference chemicals, fungicides and environmental samples. Mean MARA microbial toxic concentrations and IC₂₀s (20% Inhibitory concentrations) indicate the toxicant concentrations affecting the more sensitive micro-organisms, while the mean IC₅₀ (50% Inhibitory concentration) was found to be the concentration that was toxic to most MARA species. For the two fungicides tested, the yeast (Pichia anomalia) was the most sensitive of the ten MARA species, and was more sensitive than the nine other yeasts tested. The test may be particularly valuable for work with fungicides. Mean MARA IC₅₀s were comparable to values for nine other yeast species and the lowest individual IC₅₀s for each toxicant were comparable to reported IC₅₀s for Daphnia magna, Selenastrum capricornutum and Microtox? bioassays. MARA organisms exhibited more variable sensitivities, with the most sensitive organism being different for different samples, enhancing the likelihood of toxicity detection and giving a toxicity “fingerprint” that may help identify toxicants. The test, therefore, has great potential and would be valuable for ecotoxicological testing of pollutants.     

通肠排气汤内服结合胃管灌注治疗肠梗阻68例临床观察

目的：研究通肠排气汤内服结合胃管灌注来诊治肠梗阻的效果。方法：选取本院2005年1月～2009年6月诊治的136例患者,并随机分成治疗组与对照组,其中对照组68例只使用胃肠减压、抗感染等常规西医方式来进行诊治。而治疗组中的68例患者则在对照组诊治基础上服用通肠排气汤结合胃管灌注等方式来治疗。结果：治疗组,共治愈患者60例,出现好转情况的为4例,总治愈率达94.12%,而对照组为68例,治愈患者35例,好转18例,总治愈率为77.94%,治疗组诊治效果明显优于对照组,P〈0.05。并且治疗组在24 h肠梗阻缓解时间上明显比对照组有优势,P〈0.05。结论：通肠排气汤内服并且结合肠管灌注的方式来治疗肠梗阻效果好,并具有无创伤与痛苦小等基本特点,值得临床推广。     

Oxazolone and diclofenac-induced popliteal lymph node assay reactions are attenuated in mice orally pretreated with the respective compound: potential role for the induction of regulatory mechanisms following enteric administration

The murine popliteal lymph node assay (PLNA) was examined as a preclinical assay with the potential to identify low-molecular-weight compounds (LMWCs) that are likely to be associated with immune-mediated drug hypersensitivity reactions (IDHRs) in humans. We hypothesized that the contact sensitizer oxazolone (OX) would cause a strong PLN reaction in naive mice and that the PLN reaction would be attenuated in mice orally pretreated with OX due to the induction of oral tolerance. In naive mice, OX induced a strong PLN reaction and caused dose-dependent increases in PLN size, weight, cellularity, percentage of CD4(+) PLN T cells, and percentage of PLN B cells, with a concomitant decrease in the percentage of CD8(+) PLN T cells. Next, the PLNA was conducted in mice gavaged three times with either OX or vehicle alone (olive oil). Mice pretreated with OX had suppressed PLN reactions following the footpad injection of OX (decrease in PLN size, weight, and cellularity), which was associated with an increase in the percentage of PLN CD8(+)T cells. In contrast, oral pretreatment with OX had no observable effect on the PLN reaction induced following footpad injection of the irrelevant hapten dinitrochlorobenzene (DNCB). Adoptive transfer studies were conducted to examine the mechanism of PLN hyporesponsiveness. It was found that either (1) unfractionated splenocytes or (2) purified CD8(+) splenocytes, but not (3) purified CD4(+) splenocytes isolated from mice gavaged with OX adoptively transferred PLN suppression to naive BALB/c mice. Because OX is not a pharmaceutical, we also examined the NSAID diclofenac (DF) (Voltaren). Like OX, DF caused dose-dependent increases in PLN size, weight, and cellularity in naive mice. Furthermore, like OX, the diclofenac-induced PLN reaction was attenuated in mice that had been orally pretreated three times with DF. However, splenocytes from mice orally treated with DF were not able to adoptively transfer PLN hyporesponsiveness. Collectively, these observations demonstrate that both OX and DF are potent immunostimulators in the PLNA. As importantly, these results demonstrate that the immunostimulating potential of OX and DF in the PLNA is significantly decreased in mice orally exposed to the respective drug, possibly due to the presence of a cellular mechanism of oral tolerance. For OX, the mechanism appears to involve, in part, CD8(+) T cells, whereas the mechanism(s) associated with PLN hyporesponsiveness using DF remain to be defined.     

Kinetic assessment of luminal degradation of orally effective prodrugs for rational drug development

Although prodrugging (prodrug derivatization) is a powerful technique for improving the pharmacokinetic characteristics of drugs, the intestinal pharmacokinetics of prodrugs has yet to be elucidated fully. A previous article reported the kinetic requirement of prodrugs to overcome membrane barriers. In the present article, the luminal degradation of prodrugs was kinetically assessed to understand crucial factors in the intestinal absorption of prodrugs and to show a rational development procedure. A kinetic model equation involving luminal degradation clearance (CL_deg) was derived, and CL_deg was estimated according to the equation with in vitro and in vivo reported data of two kinds of ampicillin prodrugs (lenampicillin and pivampicillin) and one acyclovir prodrug (valacyclovir). For lenampicillin ((2,2-dimethyl-1-oxopropoxy)methyl ester derivative), CL_deg was approximately 1.7 times as large as absorption clearance (CL_abs), whereas for pivampicillin ((5-methyl-2-oxo-1,3-dioxol-4-yl)methyl ester derivative), CL_deg was approximately one tenth of CL_abs. For valacyclovir (acyclovir prodrug), CL_deg was negligible. These results indicate that not only membrane permeability but also luminal stability should be assessed for the rational development of orally effective prodrugs, and that luminal stabilization can improve the intestinal absorption of prodrugs. A procedure was proposed to develop orally effective prodrugs considered for luminal degradation as well as membrane permeability. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:1078–1086, 2010