Reactivity of paraquat with sodium salicylate: formation of stable complexes

Sodium salicylate (NaSAL) has been shown to be a promising antidote for the treatment of paraquat (PQ) poisonings. The modulation of the pro-oxidant and pro-inflammatory pathways, as well as the anti-thrombogenic properties of NaSAL are probably essential features for the healing effects provided by this drug. Nevertheless, a possible direct chemical reactivity between PQ and NaSAL is also a putative pathway to be considered, this hypothesis being the ground of the present study. In accordance, it is shown, for the first time that PQ and NaSAL react immediately in aqueous medium and within 2-3 min in the solid state. Photographs and scanning electron photomicrographs indicated that a new chemical entity is formed when both compounds are mixed. This assumption was corroborated by the evaluation of the melting point, and through several analytical techniques, namely ultraviolet/visible spectroscopy, nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry/mass spectrometry (GC/MS/MS), liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry (LC/ESI/MS/MS) and infrared spectroscopy, which revealed that stable charge-transfer complexes are formed when PQ is mixed with NaSAL. LC/ESI/MS/MS allowed obtaining the stoichiometry of the charge-transfer complexes. In order to increase resolution, single value decomposition, acting as a filter, showed that the charge-transfer complexes with m/z 483, 643 and 803 correspond to the pseudo-molecular ions, respectively 1:2, 1:3 and 1:4 (PQ:NaSAL). In conclusion, these results provided a new and important mechanism of action of NaSAL against the toxicity mediated by PQ.     

水杨酸钠对顺铂所致耳毒性的保护作用

目的探讨水杨酸钠（SS）是否对顺铂（CDDP）所致的豚鼠耳毒性具有保护作用。方法将48只豚鼠随机分为4组：A组（对照组）、B组（SS组）、C组（CDDP组）、D组（SS＋CDDP组）,每组12只。对每组豚鼠右耳测用药前、后听性脑干反应（ABR）阈值;每组随机取6只耳蜗,通过免疫组化测定各组耳蜗螺旋神经节细胞（SGC）中Caspase-3的表达情况。结果 A组与B组用药后ABR阈值、SGC的Caspase-3表达量比较差异均无显著统计学意义（P〉0.05）;C、D组用药后ABR阈值、SGC的Caspase-3表达量明显高于A、B组（P〈0.05）;D组用药后ABR阈值、SGC的Caspase-3表达量明显低于C组（P〈0.05）。结论水杨酸钠对顺铂所致的耳毒性具有一定的保护作用。     

In vitro and in vivo evaluation of controlled-release and enteric-coated formulations of sodium salicylate

The bioavailability and pharmacokinetics of salicylic acid (SA) were studied after single and multiple doses of a new slow-release formulation, based on porous membrane diffusion of sodium salicylate (NaSA). A solution of NaSA and an enteric-coated tablet of NaSA were used for comparison. Dissolution rate studies were carried out at various pH values, and both solid formulations showed pH-dependent release rates. The entericcoated tablet released its content rapidly at intestinal pH but slowly and irregularly at gastric pH. The dissolution from the controlled-release formulation at intestinal pH was completed after 6 h and the drug was delivered at a constant rate. At gastric pH the release rate was lower but complete release was obtained within 24h. The novel formulation appeared to offer complete bioavailability of SA and an even and sustained release of SA, allowing twice-daily medication without increased fluctuations in SA concentrations.     

Effects of sodium salicylate, aminopyrine and chlorpromazine on behavioral temperature regulation.

To characterize drug actions on thermoregulatory processes it is necessary to know whether compounds which alter body temperature also cause changes in thermoregulatory motivation. In the present experiments the effects of sodium salicylate, aminopyrine and chlorpromazine (CPZ) on rectal temperature (Tre) and behavior were measured in rats trained to escape heat and obtain cooling. All three drugs produced hypothermia in a 23 degree C environment but the effects upon behavior suggest that the compounds have different actions. Sodium salicylate (60-300 mg/kg) increased the amount of time spent responding to escape heat and obtain cooling so that Tre was held below control levels. Aminopyrine (12.5-75 mg/kg) did not alter thermoregulatory motivation even though it caused marked hypothemia. The time spent responding decreased after CPZ (2 and 3 mg/kg) so that drug-induced hypothermias were compensated. The results suggest that sodium salicylate influences the central mechanisms of physiological and behavioral temperature control whereas CPZ affects either peripheral thermoeffectors or central effector pathways without disrupting thermoregulatory motivation. Aminopyrine is presumed to act on central temperature controls to lower body temperature and, at the same time, to reduce the significance of the low body temperature to behavior.     

HPLC法测定复方柳安咖注射液中水杨酸钠、安替比林和咖啡因的含量

目的建立HPLC法测定复方柳安咖注射液中水杨酸钠、安替比林和咖啡因的含量。方法色谱柱:Agela TechnologiesC18柱(150mm×4.6mm,5μm);流动相:0.02mol.L-1磷酸二氢钠溶液(用磷酸调节pH 2.6)-乙腈-甲醇(70∶15∶15);检测波长:280nm;柱温:35℃;流速:1.0mL.min-1;进样量:20μL。结果水杨酸钠、安替比林和咖啡因线性范围分别为13.79～124.1(r=0.999 9),4.016～36.14(r=0.999 9)和2.078～18.70μg.mL-1(r=0.999 9);平均回收率分别为100.1%(RSD为0.5%),100.0%(RSD为0.5%)和100.5%(RSD为0.4%)。结论该方法灵敏、准确、快速,专属性强,可有效地控制复方柳安咖注射液中水杨酸钠、安替比林、咖啡因的含量。     

去甲斑蝥素和去甲斑蝥酸钠从聚合物基质中的释药行为比较

目的：比较去甲斑蝥素和去甲斑蝥酸钠从聚合物基质中的释放行为。方法：采用混合和压膜方法制备载药的聚己内酯片,然后剪切成小片后考察其在不同释放介质中的释药行为,并探讨其释药机制。结果：去甲斑蝥酸钠的释药行为受磷酸缓冲盐浓度以及缓冲盐中氯化钠浓度的影响,而去甲斑蝥素的释药行为则基本不受其影响。结论：去甲斑蝥素和去甲斑蝥酸钠从聚合物中释药行为差异主要由药物渗透压引起。     

The release behavior and kinetic evaluation of tramadol HCl from chemically cross linked Ter polymeric hydrogels

Background and the purpose of the study

Hydrogels, being stimuli responsive are considered to be effective for targeted and sustained drug delivery. The main purpose for this work was to study the release behavior and kinetic evaluation of Tramadol HCl from chemically cross linked ter polymeric hydrogels.

Methods

Ter-polymers of methacrylate, vinyl acetate and acrylic acid cross linked with ethylene glycol dimethacrylate (EGDMA) were prepared by free radical polymerization. The drug release rates, dynamic swelling behavior and pH sensitivity of hydrogels ranging in composition from 1-10 mol% EGDMA were studied. Tramadol HCl was used as model drug substance. The release behavior was investigated at pH 8 where all formulations exhibited non-Fickian diffusion mechanism.

Results and major conclusion

Absorbency was found to be more than 99% indicating good drug loading capability of these hydrogels towards the selected drug substance. Formulations designed with increasing amounts of EGDMA had a decreased equilibrium media content as well as media penetrating velocity and thus exhibited a slower drug release rate. Fitting of release data to different kinetic models indicate that the kinetic order shifts from the first to zero order as the concentration of drug was increased in the medium, showing gradual independency of drug release towards its concentration. Formulations with low drug content showed best fitness with Higuchi model whereas those with higher concentration of drug followed Hixson-Crowell model with better correlation values indicating that the drug release from these formulations depends more on change in surface area and diameter of tablets than that on concentration of the drug. Release exponent (n) derived from Korse-Meyer Peppas equation implied that the release of Tramadol HCl from these formulations was generally non-Fickian (n > 0.5 > 1) showing swelling controlled mechanism. The mechanical strength and controlled release capability of the systems indicate that these co-polymeric hydrogels have a great potential to be used as colon drug delivery device through oral administration.     

Modelling of release kinetics of drugs from irradiated NaCMC matrix

The purpose of this work was to study the release kinetics of an active substance from a solid structure after irradiation, in order to examine the possible modifications induced in drug delivery. This method of sterilization seems to be convenient for obtaining sterile parenteral or ophthalmic dosage forms. The problem of controlled release of drug from a polymeric matrix is very complex. In this case, the phenomena take place under transient diffusion and the transfer of matter is controlled by diffusion. The modelling of the process has been successfully tested, by comparing experimental and calculated values. The diffusivity of the liquid through the various dosage forms increases significantly with irradiation.     

水杨酸钠对离体大鼠心脏缺血再灌损伤的影响

在离休大鼠心脏缺血再灌损伤模型上，研究水杨酸钠（ＳＡ）对缺血再灌后心功能恢复及心肌组织Ｃａ２＋含量的影响。与缺血再灌组比较，ＳＡ（０．１－１．０ｍｍｏｌ·Ｌ－１）呈剂量依赖性显著抑制心脏再灌后心功能的恢复。心肌组织Ｃａ２＋含量显著增高。络合剂ＥＤＴＡ和小牛血清白蛋白均能显著对抗ＳＡ诱导的心功能损害，使心肌组织Ｃａ２＋含量显著降低。提示ＳＡ能加重离休大鼠心脏缺血再灌损伤。其机理可能与其促进Ｃａ２＋超负荷引起的心肌损伤有关。ＥＤＴＡ和小牛血清白蛋白具有对抗ＳＡ的心肌毒性作用。     

水杨酸钠对胰岛素抵抗大鼠氧化应激水平的影响

目的探讨水杨酸钠对胰岛素抵抗大鼠胰岛素敏感性的影响及作用机制。方法分别给大鼠静脉输注脂肪乳＋肝素,脂肪乳＋肝素＋水杨酸钠和生理盐水7h,部分大鼠在输液的最后2h同时行清醒状态高胰岛素一正血糖钳夹试验,测定血浆葡萄糖、游离脂肪酸（FFA）、胰岛素、C肽、丙二醛（MDA）水平,检测肝脏、肌肉中MI）A含量及谷胱甘肽过氧化物酶（GSH—Px）活性。结果脂肪乳输注组葡萄糖输注率（GIR）是生理盐水输注组的45％,输注水杨酸钠可使GIR提高1．3倍（P〈0．01）。与生理盐水输注组比较,脂肪乳输注组血浆、肝脏、肌肉中MDA水平增加了2～4倍（P〈0．01）;GSH—PX活性降低45％～50％（P〈0．01）。水杨酸钠输注使MDA水平较脂肪乳输注组降低了62％-66％（P〈0．01）,GSH-PX活性升高35％～38％（P〈0．05）。结论FFA增高引起机体氧化应激增强,可能是导致胰岛素抵抗发生的机制之一。应用水杨酸钠后大鼠氧化应激减弱,胰岛素抵抗改善,故水杨酸钠可能通过降低氧化应激途径而发挥改善胰岛素抵抗的作用。     

双氯芬酸钠缓释微丸的制备及体外释放度

目的 :制备双氯芬酸钠缓释微丸 (DS SRMP)并研究其体外释药性能。方法 :选用乙基纤维素等辅料为阻滞剂制备了DS SRMP ,并采用紫外分光光度法进行了体外释放度的研究。结果 :实验研究表明DS SRMP体外释药符合零级动力学过程 ,Kr0 =8.78%·h-1(t≤ 8h)。结论 :DS SRMP具有较好的释药性能 ,为一种较理想的口服缓释剂型。     

Investigation of the release behavior of diethylhexyl phthalate from the polyvinyl-chloride tubing for intravenous administration

The release behavior of diethylhexyl phthalate (DEHP) from a polyvinyl-chloride (PVC) tube, which is part of an intravenous administration set, was investigated with the coexistence of polysorbate 80 (Tween 80) in various solutions such as physiological saline (PS), distilled water for injection (DWI) and glucose solution (TZ). The cumulative amount of DEHP released after 5 h was in the following order; PS, DWI>50% TZ. From a comparison of the amount of released DEHP and the critical micelle concentration (CMC) of various solutions, the lower the CMC of the solution, the higher the amount of DEHP released from the PVC tubing. When the concentration of Tween 80 was kept constant at 1 mg/ml, the cumulative amount of DEHP released with a flow rate 90 ml/h was higher than that at 60 ml/h. These results suggest that the release of DEHP from the PVC tubing is closely correlated with the interaction of Tween 80 and DEHP such as the formation of micelles, the collision of micelles against the surface of the PVC tubing and the diffusion properties of DEHP and/or Tween 80 in the liquid medium.     

铁叶绿酸钠对小鼠行为发育毒性的实验研究

铁叶绿酸钠为叶绿素衍生物,研究表明铁叶绿酸钠治疗妊娠期缺铁性贫血,疗效显著。由于妊娠期用药可能对子代产生行为发育毒性,因此本文重点针对铁叶绿酸钠在动物围产期用药后,可能对子代动物的神经行为发育产生的毒性进行了测试,试验结果表明在高、中、低三种剂量下其对子代小鼠无明显行为发育毒性。     

脂溶性药物在O/W型微乳中的分配行为

以亮菌甲素和氧氟沙星为模型药物，采用荧光光谱法考察微乳中各组分对药物荧光光谱的影响，以研究脂溶性小分子药物在O/W型微乳中的分配行为。结果显示在分别采用苯甲醇和PEG 400为助表面活性剂的微乳体系中，亮菌甲素主要存在于表面活性剂组成的界面膜中；氧氟沙星在油酸/橄榄油(1∶1)的微乳体系中的主要分布部位为油核，而在Gradamol GTCC为油相的微乳体系中主要存在于界面膜中；在各体系中药物均倾向于增溶在对药物溶解能力最强的组分所处的微环境中，具体的存在位置与该组分的用量有关。由此可见脂溶性药物在O/W型微乳中的存在部位可能取决于各组分对药物的溶解能力。     

Influence of intravenous acetylsalicylic acid and sodium salicylate on human renal function and lithium clearance

Summary The influence of intravenous acetylsalicylic acid (ASA; D,L-lysine-mono-acetylsalicylate), equimolar doses of sodium salicylate (SA) and placebo (P) on renal function has been studied in 6 healthy female volunteers, in 150 mmol sodium balance, and in lithium (Li) steady state with a plasma Li between 0.6 and 0.8 mmol/l. Following a bolus injection of 0.5 g ASA, 0.444 g SA or P (50 ml saline) given over 10 min and a subsequent continuous infusion of 1.5 g ASA, 1.332 SA or P (150 ml saline) over 170 min, urine was collected for 3 h as well as 6 plasma samples at 30-min intervals. Plasma ASA levels were between 13.8 and 22.1 µg/ml and for SA they were 20.8 to 82.6 µg/ml during ASA infusion, and between 22.5 and 108.9 µg/ml for SA during SA infusion. Neither ASA nor SA caused a significant change in urine volume, in the renal clearances of Na, K, free water, osmolality, creatinine, inulin and p-aminohippurate (PAH) or in plasma Li level. Renal Li clearance was slightly reduced by SA, from 37.8 to 29.4 ml/min (p<0.05). Since renal prostaglandin (PG) synthesis (urinary PGE₂ excretion) was 60.6% suppressed by ASA and was not affected by SA, the decrease in Li clearance cannot be related to inhibition of cyclooxygenase in the kidney.     

Development of controlled release spheroids using natural polysaccharide as release modifier

A polysaccharide hydrogel was isolated from the seeds of Tamarindus indica (tamarind) and was used as release modifier for the preparation of diclofenac sodium spheroids, using extrusion-spheronization technique. The process was studied for the effect of variables to arrive at spheroids with satisfactory particle shape, size and size-distribution. The prepared spheroids were characterized for surface morphology, qualitative surface porosity, friability, bulk density, and flow properties. The in vitro release studies exhibited a zero-order release kinetics that was confirmed by Higuchi's and Peppas' models. A credible correlation was obtained among swelling index, viscosity, surface roughness of the polysaccharide, and in vitro dissolution profile of the spheroids. In the comparative bioavailability study, we found that the developed spheroids were able to sustain the drug release over 8 hr and could improve the extent of absorption and bioavailability of the drug.     

Characterization of drug release from diltiazem-loaded polylactide microspheres prepared using sodium caseinate and whey protein as emulsifying agents

The influence of milk protein emulsifying agents on the characteristics, particularly drug release, of polylactide microspheres was investigated. Diltiazem loaded polylactide (PL) microspheres were successfully prepared using the dairy proteins, sodium casinate (SC) and whey protein isolate (WPI) as the emulsifying agents. Microspheres were characerized in terms of microsphere yield, electron microscopy, particle size, drug loading, DSC and XRD analysis and drug release. The yields of microspheres obtained were 53-63% and were independent of the emulsifying agent used. SEM revealed that, regardless of the emulsifying agent employed, the microspheres were of good sphericity, but the surface appearance of the microspheres was not the same in all cases. The milk proteins resulted in microspheres approximately half the size of those obtained with methylcellulose (MC). Significant differences in drug loading were observed between the three emulgents, the MC systems giving the highest values. Release profiles were sigmoidal in shape and were well fitted to the equation ln (x/1-x) = k·t - k·t_max, reflecting degradation controlled drug release. The parameter k increased with drug loading, while t_max decreased. The relationships between the release parameters [P(k and t_max)] and loading (L) could be quantified by equations of the form P = a·L^N, N being negative in the case of t_max. Apart from the effect on loading efficiency, neither SC nor WPI appeared to significantly alter drug release. The quantitative relationships observed in this study may have more general application in quantifying drug release from drug polymer composites at low loadings where polymer degradation controls drug release.