Effects of nitrendipine on the autoregulation of regional cerebral blood flow in the pithed rabbit

Summary Effects of the calcium-channel antagonist, nitrendipine, on the autoregulation of regional cerebral blood flow were studied by analysing the pressure-flow relationship in the cortex, subcortex and thalamus in pithed anesthetized rabbits. Arterial pressure was altered from 50 to 125 mm Hg by electrical stimulation of the spinal nerve roots. Regional blood flow was measured with the hydrogen clearance technique. Under control conditions, regional blood flow in the cortex, subcortex and thalamus did not change significantly within the range of mean arterial pressures of 50 to 100 mm Hg. Vascular resistance in each region rose significantly (P < 0.05) in a pressure-dependent manner. During the intravenous infusion of nitrendipine (0.3 and 1 g · kg^–1 · min^–1), blood flow to the three regions of the brain increased in a pressure-dependent manner when mean arterial pressure was increased from 50 to 125 mm Hg. The autoregulatory increase in regional vascular resistance was abolished. In addition, nitrendipine produced a blood pressure-dependent decrease of the vascular resistance in the subcortex and thalamus but not in the cortex. These results indicate that nitrendipine increases regional cerebral blood flows and suppresses regional autoregulations simultaneously. The autoregulatory adjustment in the cortex is more resistant to nitrendipine than that in the subcortex and thalamus. The observation that the action of nitrendipine was not the same in the three brain regions may be due to the vascular beds of these regions differing in their calciumchannel equipment.     

尼群地平与苯那普利联用治疗老年高血压病疗效观察

目的 :观察尼群地平与苯那普利联用治疗老年高血压病的临床疗效。方法 :将 6 0例老年高血压病人随机分为两组 :对照组 30例 ,单用尼群地平 10mg ,每日 3次口服。联用组 30例 ,尼群地平 10mg ,每日 3次 ,苯那普利 5mg ,每日 2次。两组病人均于用药第 1周、2周、3周、4周各测量两次血压及心电图 ,根据病情调节服药剂量。结果 :联用组在降低血压、减慢心率、改善心电图S—T段下移等方面均优于对照组 (P <0 .0 5 )。结论 :尼群地平与苯那普利联用治疗老年高血压病副作用少 ,只要注意禁忌症 ,治疗老年高血压病是安全有效的。     

苯那普利和尼群地平对高血压病患者肾血流动力学及微量蛋白的影响

为探讨苯那普利和尼群地平对高血压病患者肾血清动力学和微量蛋白的作用，本文观察了５８例高血压病患者服用苯那普利和尼群地平前后肾血浆流量及微量蛋白的变化。结果发现，治疗后苯那普利组患者有效肾血浆流量上升，肾小球滤过分数下降，尿微量蛋白减少（Ｐ均〈０．０１），尼群地平患者的此三项检查无明显变化（Ｐ〉０．０５）。结果提示，苯那普利对高血压病患者肾功能的改善作用倨于尼群地平。     

采用固体分散技术制备尼群地平缓释片

目的：制备具有良好体外释放的尼群地平缓释片。方法：以羟丙甲纤维素（HPMC）为凝胶骨架材料制备缓释片,对骨架材料用量、制备工艺等因素进行考察。结果：随着HPMC用量的增加药物释放明显减慢,固体分散工艺可改善药物的体外释放释药行为。结论：通过固体分散工艺及HPMC用量的适当调整可制备具有良好释放的NT缓释片。     

长期尼群地平治疗对老年收缩期高血压患者血压及左心功能的影响

４７例老年收缩期高血压患者经随机分组、尼群地平及安慰剂双盲对照治疗后，两组相比。治疗组血压控制满意、心血管并发症发生明显降低，且治疗组左室收缩功能及舒张功能均明显优于安慰剂组，表明尼群地平是适于老年收缩期高血压长期治疗的首选药物。     

尼群地平对食饵性家兔动脉粥样硬化的影响Ⅰ．对血浆总胆固醇和主动脉病变的作用

用新西兰白兔观察了尼群地平对实验性动脉粥样硬化的影响。结果发现，尼群地平时食饵性高脂血症影响不大，但可明显抑制其主动脉壁病变，降低主动脉组织胆固醇含量，表明尼群地平具有显著抗动脉粥样硬化作用。     

尼群地平固体分散物制备及体外溶出研究

目的：提高尼群地平（nitrendipine)的体外溶出速率。方法：在固体分散技术制备尼群地平固体分散物（nitrendipine solid dispersions)，对其体外溶出度进行测定，并采用X射线衍射方法进行固体分散物的物相分析。结果：尼群地平固体分散物X射线衍射图谱表明尼群地平以非晶体状态存在；尼群地平固定分散物X射线衍射图谱表明尼群地平以非晶体状态存在；尼群地平固体分散物体外溶出60min内达90％，而普通市售片只溶出到20％。结论：制备尼群地平固体分散物可以提高其体外溶出速率。     

依拉普利治疗中青年高血压的疗效观察

目的观察依拉普利治疗中青年原发性高血压（尤以舒张压增高为主）的临床疗效及安全性。方法将43例中青年高血压患者分为依拉普利治疗组和尼群地平对照组，进行疗效观察对比。结果总有效率治疗组95．7％，对照组55％，两组有显著差异p〈0．01（x^2=9．906）。结论依拉普利治疗中青年人原发性高血压，疗效好，安全性高，预后好。     

尼群的平对麻醉犬冠脉流量、心肌耗氧量、二氧化碳产生率的影响

尼群的平20μg/kg iv显著降低麻醉犬血压的过程,冠状窦流量明显增加。持续3h,冠状窦氧含量增加,氧摄取率、心肌耗氧量、二氧化碳产生率降低,持续了3h以上,说明该剂适用于高血压伴心肌缺血。     

Simultaneous HPLC determination of nitrendipine and impurities of the process of synthesis

A method has been developed for separation of nitrendipine and its impurities of reaction partners and side reaction products by high-performance liquid chromatographic method on a RP-18 column and detection at 238 nm. The mobile phase composition that provided an acceptable nitrendipine resolution, in large excess and possible impurities, in a short elution time, is methanol:water (70:30) and pH 3. Linearity (r≥0.999), reproducibility (RSD=0.8–1.4%), determination limit (0.5–2%) and recovery (99.8–102.3) were validated and found to be satisfactory. This method enables monitoring of the process of synthesis, as well as the choice of the synthetic design.