尼莫地平片溶出度的研究

采用转篮法对尼莫地平国产市售片，进口片和自制片在不同介质、不同转速和ＰＨ条件下的溶出度进行测试。结果表明，介质对尼莫地平溶出具有很大的影响，而最佳测定方法是以０．１％的十二烷基硫酸钠水溶液为介质，转速１５０ｒ／ｍｉｎ。     

Differential Stimulation of Noradrenaline Release by Reversal of the Na+/Ca2+ Exchanger and Depolarization in Chromaffin Cells

We compared the effectiveness of Ca²⁺ entering by Na⁺/Ca²⁺ exchange with that of Ca²⁺ entering by channels produced by membrane depolarization with K⁺ in inducing catecholamine release from bovine adrenal chromaffin cells. The Ca²⁺ influx through the Na⁺/Ca²⁺ exchanger was promoted by reversing the normal inward gradient of Na⁺ by preincubating the cells with ouabain to increase the intracellular Na⁺ and then removing Na⁺ from the external medium. In this way we were able to increase the cytosolic free Ca²⁺ concentration ([Ca²⁺]_c) by Na⁺/Ca²⁺ exchange to 325 ± 14 nM, which was similar to the rise in [Ca²⁺]_c observed upon depolarization with 35 mM K⁺ of cells not treated with ouabain. After incubating the cells with ouabain, K⁺ depolarization raised the [Ca²⁺]_c to 398 ± 31 nM, and the recovery of [Ca²⁺]_c to resting levels was significantly slower. Reversal of the Na⁺ gradient caused an −6-fold increase in the release of noradrenaline or adrenaline, whereas K⁺ depolarization induced a 12-fold increase in noradrenaline release but only a 9-fold increase in adrenaline release. The ratio of noradrenaline to adrenaline release was 1.24 ± 0.23 upon reversal of the Na⁺/Ca²⁺ exchange, whereas it was 1.83 ± 0.19 for K⁺ depolarization. Reversal of the Na⁺/Ca²⁺ exchange appeared to be as efficient as membrane depolarization in inducing adrenaline release, in that the relation of [Ca²⁺]_c to adrenaline release was the same in both cases. In contrast, we found that for the same average [Ca²⁺]_c, the Ca²⁺ influx through voltage-gated channels was much more efficient than the Ca²⁺ entering through the Na⁺/Ca²⁺ exchanger in inducing noradrenaline release from chromaffin ceils. This greater effectiveness of membrane depolarization in stimulating noradrenaline release suggests that there is a pool of noradrenaline vesicles which is more accessible to Ca²⁺ entering through voltage-gated Ca²⁺ channels than to Ca²⁺ entering through the Na⁺/Ca²⁺ exchanger, whereas the adrenaline vesicles do not distinguish between the source of Ca²⁺.     

尼莫地平控释片释放度试验研究

本文研究了尼莫地平控释片的释放度试验方法——转篮法，释放介质为含有２２％异丙醇的０．１ｍｏｌ·Ｌ－１盐酸液；磷酸盐缓冲液（ｐＨ５．８）和ｐＨ７．２的溶液。含量测定方法：紫外分光光度法，在三种介质中尼莫地平分别在１～３０μｇ·ｍｌ－１，１０～５０μｇ·ｍｌ－１和１０～５０μｇ·ｍｌ－１的范围内，浓度与吸收度有较好的线性关系。回归方程分别为Ａ＝０．６１５Ｃ＋０．０２３（ｒ＝０．９９９９）；Ａ＝０．０６１４Ｃ＋０．０１２（ｒ＝０．９９９５）；Ａ＝０．０６１２Ｃ＋０．００８８（ｒ＝０．９９９９）。平均回收率分别为９９．６３％，９９．９８％及１００．７７％，ＲＳＤ（％）分别为１．３４％，１．５９％及１．４１％。本方法的体外释放百分率与体内吸收分数有较好的相关性（ｒ＝０．９９１）。     

头孢氨苄缓释片在健康人体内的生物利用度和药物动力学

目的:比较头孢氨苄缓释片和普通胶囊的生物利用度和药物动力学。方法：10例健康志愿者分别单剂量口服500mg头孢氨苄缓释片和普通胶囊，血药浓度测定方法为HPLC法。结果：两种剂型体内过程均符合一室开放模型，缓释片的达峰时间（Tmax）为（2．58±0．59）h，峰浓度（Cmax）为（10．08±1．68）μg／ml．吸收速率常数（Ka）为（0．90±0．53）／h，消除速率常数（Ke）为（0.26±0.02）／g，半衰期（T1／2）为（2.67±0.23）h，清除率（Cl）为（6.93±1.71）L／h，分布容积（Vd）为（26.66±6.72）L，药一时曲线下面积（AUC）为（48.31±9.32）μg·h／ml。两种剂型T一C一Ka、Ke、T1／2和Cl均存在显著性差异（P＜0．01），Vd、AUC无显著性差异（P＞0．05）；缓释片的相对生物利用度为（104．90±8．35）％。结论：缓释片的吸收减慢，Tmax推迟，T1／2延长，可减少服药次数，提高药物治疗的顺应性。     

Preparation and evaluation of temperature sensitive liposomes containing adriamycin and cytarabine

Temperature sensitive liposomes (TSL) containing adriamycin (ADM) and cytarabine (Ara-C) were prepared. ADM and Ara-C were selected as model compounds of amphiphilic and hydrophilic drug, respectively. Encapsulation efficiency of ADM entrapped into TSL was about twice greater than that of Ara-C. It might be due to different polarity of the drugs. Lipid compositions of TSL had no effect on the encapsulation efficiency of drugs. Thermal behavior of TSL using a differential scanning calorimetry (DSC) was also investigated. Phase transition temperature (T_c) of TSL was dependent on the lipid compositions of TSL.ADM broadened thermogram of TSL but Ara-C did not. However, T_c of TSL was not changed by any drug. Release rate of drugs was highly dependent on temperature. The release profile of ADM was similar to that of Ara-C. The maximum release rate of drugs from TSL was occurred at the near T_c and observed at 39–41°C for DPPC (Dipalmitoylphosphatidylcholine) only, 52–54°C for DSPC (Distearoylphosphatidylcholine) only, 41–43°C for DPPC and DSPC (3∶1), and 43–45°C for DPPC and DSPC (1∶1), respectively. Effect of human serum albumin (HSA) on the release rate of ADM was investigated. HSA had no significant effect on the release of ADM below T_c. However, ADM release from TSL was increased at the near and above T_c. The HSA-induced leakage of drug may result from the interaction of liposomal constituents with HSA structure at the near T_c. From the fact that the release profiles of ADM from freshly prepared TSL and stored TSL for 1 week at 4°C was not changed, the TSL was considered to be stable for at least 1 week at 4°C. Based on these findings, TSL may be useful to deliver drugs to preheated target sites due to its thermal behaviors.     

Biological characterization of glutaraldehyde-modified Parietaria judaica pollen extracts

BACKGROUND: Allergoids are widely used in specific immunotherapy (SIT) for the treatment of IgE-mediated allergic diseases, but all techniques for standardization of conventional allergic extracts may not be appropriate for standardization of a glutaraldehyde (GA)-modified extract because of the unique characteristics of these extracts. OBJECTIVE: To assess an accurate methodology for standardization of chemically modified extracts. METHODS: GA-modified extracts from Parietaria judaica pollen were purified by diafiltration. Biochemical properties were investigated by determination of amino groups, chromatography, and SDS-PAGE. The IgE-binding activity was determined by skin prick test, enzyme allergosorbent test inhibition, basophil activation, and histamine release tests. Peripheral blood mononuclear cells (PBMCs) from P. judaica pollen-allergic subjects were stimulated with either native or allergoid extracts, and proliferation was measured. RESULTS: Biochemical data indicated a high degree of allergen polymerization resulting in extract components higher than 100 kDa. IgE-binding activity, both in vivo and in vitro, was reduced by more than 99.8%. Both allergen and allergoid induced PBMC proliferation and synthesis of blocking IgG antibodies at similar rates. Moreover, no evidence of introduction of new determinants by chemical modification was found. CONCLUSIONS: The preparation of GA-modified extracts by diafiltration is faster and more reliable than previous chromatographic methods. These modified extracts have drastically reduced their allergenicity while maintaining their immunogenicity, and therefore they can be used in safer and shortened schedules of SIT.     

甘草甜素和甘草酸单铵促进IL-2增强NK活性的研究

本实验采用乳酸脱氢酶释放法研究甘草甜素和甘草酸单铵对人外周血NK细胞活性的影响。结果表明,甘草甜素和甘草酸单铵本身无增强NK细胞活性的作用,但可明显促进IL-2增强NK活性,这种增强作用与甘草甜素和甘草酸单铵的浓度有关。     

一阶导数光谱法测定丙吡胺尿药浓度及其缓释片的相对生物利用度

本文报道了用导数光谱法测定磷酸丙吡胺的尿药浓度,本方法能消除尿中杂质干扰,测定结果准确。6名受试者交叉口服磷酸丙吡胺缓释片和普通片,测得尿药浓度计算消除速度常数K,排泄速率(Δx/Δt)_(max) 所需时间,证明缓稀片药物排泄慢,药效维持时间长,且缓释片的相对生物利用度与普通片基本相同。     

Model Features of a Cardiac lontophoretic Drug Delivery Implant

Pharmaceutical Research -     

吡哌酸片的电荷转移反应分光光度测定

研究了吡哌酸与四氯苯醌间的荷移反应．两者在硼砂缓冲溶液中形成１∶１的络合物，其λ_（ｍａｘ）为３３０．８ｎｍ，摩尔吸光系数ε＝１．６６×１０~４，ＲＳＤ为２．２％。用于测定制剂含量，结果与药典方法一致。