月桂酰吲达帕胺脂质体的制备及其质量控制*

目的:制备月桂酰吲达帕胺脂质体,并对其相关的性质进行考察。方法:在分散介质中加入一定量的Ca2 ,用乙醇注入法制备月桂酰吲达帕胺脂质体;用Sephadex G-50在线监测分离游离药物和脂质体,采取HPLC法对脂质体的载药量和药物的包封率进行了检测;并对脂质体的形态、粒径及ζ电位进行考察。结果:月桂酰吲达帕胺在脂质体中的包封率>90%;脂质体的外观形态良好,平均粒径为0.257μm,多分散系数为0.2,ζ电位随着载药量和Ca2 而变化。结论:制备的脂质体包封率高,质量控制方法简便、快捷、准确、重现性良好。     

月桂酰吲达帕胺脂质体中药物含量及包封率的测定

目的:建立月桂酰吲达帕胺脂质体中药物含量及包封率的测定方法。方法:采用高效液相色谱法,以Chrom asil C18柱为色谱柱;流动相:甲醇-四氢呋喃-0.2%三氟乙酸(pH 2.03)(170∶15∶20);流速:0.8 mL.min-1;检测波长:240 nm;采用SephadexG 50分离游离药物和脂质体,收集并检测脂质体部分药物的含量,计算包封率。结果:月桂酰吲达帕胺在0.01~25μg.mL-1范围内线性关系良好(r=0.9999),标准曲线为:Y=1.608×105X-5.926×102;空白脂质体饱和的SephadexG 50对月桂酰吲达帕胺脂质体的分离效果良好。结论:该方法操作简单,结果准确,适合于该药物脂质体的含量和包封率的测定。     

月桂酰吲达帕胺的电离常数及分配系数的测定

目的测定月桂酰吲达帕胺的电离常数(pKa)及分配系数。方法采用酸碱滴定法测定各不同体积比的丙酮-水溶液中药物半中和点时的pH值作为药物在该体积比的丙酮-水溶液中的pKa值,再外推至纯水中药物浓度无限稀释时的pKa值;采用HPLC配合摇瓶法测定药物的分配系数。结果月桂酰吲达帕胺的pKa为3.87,lgP值为3.190。结论月桂酰吲达帕胺为弱酸性亲脂性药物。     

依托泊苷长循环脂质体工艺处方设计与优化的研究

目的优化依托泊苷长循环脂质体的制备处方及工艺。方法以两亲性聚乙二醇一二硬脂酰磷脂乙醇胺为修饰体，采用薄膜超声．挤压法制备空白长循环脂质体；铵离子梯度法包封依托泊苷，制备依托泊苷长循环脂质体。以包封率为考察指标，采用正交设计法优化依托泊苷长循环脂质体的制备处方及工艺。结果优化后的依托泊苷长循环脂质体的工艺和处方：药脂比例为1：5tool·mol^-1、胆固醇与磷脂比例为0．3：1（W／w）、硫酸铵离子浓度为200mmol·L%^-1、包封温度为55℃。长循环脂质体平均粒径均小于1μm，药物平均包封率86．45％。结论该方法包封率高、粒径小且分布较窄，简便易行。     

透明质酸磷脂酰衍生物修饰姜黄素脂质体的制备及细胞毒性

采用逆相蒸发法制备了姜黄素脂质体.由于透明质酸脂溶性较差,先将其制成磷脂酰衍生物(透明质酸-磷脂酰乙醇胺,HA-DOP E),再用以修饰载药脂质体.所得脂质体的平均包封率为89％,该衍生物与脂质体的结合率为72％.脂质体于4℃保存30d包封率无明显改变,但结合率有轻微下降.细胞毒性试验显示,游离姜黄素、姜黄素脂质体及修饰后脂质体对高表达CD44受体的人肺腺癌A549细胞的IC50值分别为0.054、0.032和0.021 μmol/ml,未修饰和修饰后的姜黄素脂质体对低表达CD44受体的人肝癌HepG2细胞作用相当.     

丹皮酚前体脂质体的研制及其特性

目的：研究丹皮酚前体脂质体的制备方法，提高丹皮酚脂质体的稳定性。方法：采用薄膜一超声一冷冻干燥法。选择合适的冻干保护剂制备丹皮酚前体脂质体，并对水合后脂质体的形态、粒径、包封率和稳定性进行考察。结果：选择10％的蔗糖为保护剂。制得的丹皮酚前体脂质体经水合后主要为单室脂质体，粒径分布较均匀。平均粒径149．7nm．药物包封率为73．9％，25℃贮存6个月，外观、含量及包封率无明显变化。结论：该方法制备丹皮酚前体脂质体可行，包封率较高且有良好的稳定性。     

吲达帕胺治疗老年高血压的临床疗效

目的：观察吲达帕胺对老年人高血压的疗效和安全性。方法：选择100例轻、中度老年高血压患者,予吲达帕胺治疗。疗程8周,全部病例治疗前、后偶测血压（CBP）和电解质、血糖、胆固醇,其中30例于治疗前、后行24小时动态血压监测（ABPM）。结果：吲达帕胺对老年人高血压的降压总有效率为90％,ABPM为86．7％,对血钾、血糖、胆固醇无明显影响。结论：吲达帕胺对老年人高血压疗效好,价格便宜,经济方便。     

化学药吲达帕胺片2013年的检验结果分析

目的：分析化学药吲达帕胺片的检验情况。方法：依据《中国药典》2010年版二部对36批抽验吲达帕胺片片剂实验结果进行调查评价、汇总分析及探索性研究。结果：36批吲达帕胺片合格率为97．2％,不合格率为2．8％。结论：现行质控标准虽可较好地控制该化学药质量,但还可做进一步提高与完善。     

紫杉醇长循环热敏前体脂质体的制备与表征

目的:研究紫杉醇长循环热敏前体脂质体的制备并对其性质进行考察.方法:采用薄膜分散法制备紫杉醇长循环热敏脂质体,再用冷冻干燥技术制备紫杉醇长循环热敏前体脂质体;采用激光粒度仪考察粒径和Zeta电位;采用高效液相色谱法研究其含量与包封率;并考察脂质体的体外释药特性.结果:紫杉醇长循环热敏前体脂质体水合后形成紫杉醇长循环热敏脂质体,粒径均值为(108.6 ±3.6)nm,Zeta电位的均值为(-12.2±1.8)mV,包封率可达96.2％;该脂质体在相变温度42℃下药物释放达到95％以上.结论:紫杉醇长循环热敏前体脂质体的制备工艺稳定,载药量大,包封率高,具有良好的热敏性;含量及其包封率测定方法简单、快速、准确.本实验可为紫杉醇静脉注射用新制剂的开发提供研究基础.     

吲达帕胺治疗老年高血压病58例临床疗效观察

目的：探讨吲达帕胺在治疗老年高血压病中的地位和临床疗效。方法：采用自身对照法,对符合诊断标准的58例老年高血压病人,既往无应用吲达帕胺史,用其他降压药后血压仍高者,改为口服吲达帕胺2.5-5mg/d,用药6周观察疗效。结果：显效率74.2％,有效率22．4％,无效3．4％,总有效率96．6％,无不良反应。结论：吲达帕胺降压疗效确切、平稳、安全,耐受性好,特别适合老年高血压患者。     

脂质体阿霉素的制备及包封率测定方法的研究

目的：建立一种检测脂质体中阿霉素含量的方法。方法：对阿霉素溶液进行紫外可见光扫描,探求最佳波长。阿霉素脂质体溶液进行柱分离,找出脂质体和游离药物分离的最佳体积。结果：可以看出在２３２ｎｍ处阿霉素有最大吸收;脂质体和游离药物的最佳分离体积为２０ｍｌ。用紫外ＳｅｐｈａｄｅｘＧ５０法测定阿霉素脂质体的包封率为１０．３％±１．２％（ｎ＝４）,包封率测定回收实验表明,此法重复性好。结论：紫外ＳｅｐｈａｄｅｘＧ５０法测定阿霉素脂质体的包封率准确性高、重现性好、简便易行。     

紫杉醇冻干脂质体的制备及含量稳定性

目的制备水化后粒径较小且分布较窄的,具有良好稳定性的紫杉醇冻干脂质体。方法以商品大豆磷脂为膜材,采用薄膜分散-微孔滤膜挤出(或高压均质)-冷冻干燥工艺制备冻干脂质体产品,采用HPLC和微柱离心-HPLC法测定冻干脂质体重建后的含量及包封率。并以加速和长期实验来证实该产品的稳定性。结果薄膜分散-微孔滤膜挤出-冷冻干燥工艺制备的紫杉醇冻干脂质体粒径均一,在130 nm左右,其对药物的包封率较高,可保证在90%以上,储存半年后紫杉醇的含量及包封率均未有降低。结论薄膜分散-微孔滤膜挤出-冷冻干燥工艺是制备紫杉醇脂质体的可工业化生产的方法。     

Simple and efficient liposomal encapsulation of topotecan by ammonium sulfate gradient: stability,pharmacokinetic and therapeutic evaluation

Topotecan (TPT), a topoisomerase I inhibitor, is presently undergoing clinical evaluation worldwide. Previous studies have shown that entrapping TPT within multi-lamellar vesicle liposome can stabilize the lactone moiety, which is structurally important for biological activity. However, low drug:lipid ratios due to the amphipathic character and small entrapment volume in the unilamellar vesicle limits the development of pharmaceutically acceptable liposomal formulation. With an aim to improve on this drawback, we herein describe a method that utilizes the ammonium sulfate gradient to entrap TPT into liposomes. By this method, the encapsulation efficiency was over 90% and a drug:lipid molar ratio as high as 1:5.4 was reached. In comparison with free drug, liposome-encapsulated TPT is more stable in physiological conditions and shows higher in vitro cytotoxicity. Because of increased blood circulation time, the initial plasma concentration and area under the plasma concentration of liposomal drugs were 14 and 40 times, respectively, of those of free drug. Furthermore, liposome encapsulation enhanced the antitumor activity of TPT in syngeneic murine C-26 and human HTB-9 xenograft models in vivo. At a dose of 5 mg/kg, the tumor growth delay of liposomal formulation was significantly than that of free TPT. Based on these results, we believe that this liposomal TPT formulation is worthy of further clinical study.     

喷雾冷冻干燥技术制备盐酸伊立替康脂质体冻干微粒及其理化性质考察

目的:考察喷雾冷冻干燥(SFD)技术制备脂质体冻干微粒的可行性。方法:以盐酸伊立替康为模型药物,采用硫酸铵梯度法制备盐酸伊立替康脂质体,SFD技术制备脂质体冻干微粒;以喷嘴高度、物料流速、雾滴/液氮质量比为因素,应用Box-Behnk-enDesign(BBD)试验考察三者之间的配比对微粒包封率的影响以优化SFD工艺,并对所制备的脂质体及冻干微粒的理化性质进行了考察。结果:SFD优化工艺为物料流速5.5mL·min-1,喷嘴高度18.5cm,雾滴/液氮质量比3.7%,由此制备的脂质体冻干微粒的外观和再分散性好,平均粒径、粒度分布、主药含量及包封率等理化性质与原脂质体基本保持一致,且放置6个月后与原脂质体溶液比较稳定性更好。结论:SFD技术制备脂质体冻干微粒具有可行性,并提高了脂质体的稳定性。     

盐酸拓扑替康脂质体的体外细胞毒及体内抗肿瘤作用

目的对抗癌药物盐酸拓扑替康普通脂质体(Plain L)及PEG修饰脂质体(PEG L)的体外细胞毒及体内抗肿瘤作用进行研究。方法采用噻唑蓝(MTT)比色法测定Plain L与PEG L对人卵巢癌细胞A2780和人结肠直肠癌细胞HCT 8的抑制作用;对荷肝癌H22小鼠尾静脉注射给药进行Plain L、PEG L的体内抑瘤试验。结果与游离药物相比,Plain L、PEG L的细胞毒作用增强,对体外培养的人卵巢癌A2780细胞的IC50分别为(9.26±2.14)mg.L-1和(2.36±1.08)mg.L-1,相比于游离药物[IC50=(25.45±1.69)mg.L-1]分别降低了63.6%(P<0.005)和90.7%(P<0.001);对HCT 8细胞,Plain L[IC50=(10.66±1.25)mg.L-1]与PEG L[IC50=(4.50±0.31)mg.L-1]的细胞毒作用也强于游离药物[IC50=(16.72±2.45)mg.L-1],分别是游离药物的1.5倍(P<0.001)和3.6倍(P<0.005)。体内抑瘤实验结果表明,游离药物、Plain L与PEG L体积抑瘤率分别为58.2%、67.6%、83.5%,质量抑瘤率分别为56.3%、69.6%、85.7%;与游离药物相比,Plain L与PEG L的体内抗肿瘤作用明显提高。结论与游离药物相比,脂质体包封提高了盐酸拓扑替康的体外细胞毒作用及体内抗肿瘤效果,而经PEG修饰的脂质体相比于普通脂质体体内、外抗肿瘤效果更强。     

Modified hydrolysis kinetics of the active lactone moiety of 10-hydroxycamptothecin by liposomal encapsulation

The key structural requirement for the antitumor activity of 10-hydroxycamptothecin (HCPT) is the intact lactone moiety which is always instability and suffered from pH-dependent hydrolysis. The aim of this study was to evaluate the protection effects of liposomal encapsulation on the labile lactone ring. Mono-modal dispersed quasi-spherical liposomes with mean diameter of 145?nm and high drug entrapment efficiency of 90% were obtained under optimal conditions. The in vitro hydrolysis kinetics behaviors of lactone were studied in varied pH buffers. Compared to that of free HCPT in solution formulation, both the hydrolysis half-life and observed equilibrium constant of liposomal HCPT were increased significantly along with the decreased apparent hydrolysis rate constant. The plasma pharmacokinetics was studied by assessing the lactone stability versus time profiles in vivo following intravenous administration of free and liposomal HCPT. The liposomal encapsulation led to a twofold increase in the AUC values and significant decrease in the plasma clearance of lactone (P?<?0.05). There was a good correlation between in vitro and in vivo stability of HCPT-lactone. These results suggested a potential application of the novel liposome formulation for the stable delivery system of HCPT.     

Encapsulation of drugs and excipients in liposomes — measurements with drug-specific electrodes

In this study, the degree of encapsulation of benzalkonium chloride in liposomes was quantitatively measured using a potentiometric membrane electrode specific for benzalkonium chloride. The encapsulation of lidocaine hydrochloride was examined with another ion-selective electrode for comparison. Liposomes were prepared from a commercially available liposome concentrate (Phosal 75 SA). Photon correlation spectroscopy was used to detect the formation of liposomes in the size range of 200 nm.The measurements with the membrane electrode enabled the activity of the free drug to be quantitatively determined in the presence of liposomes. The investigations showed that, in the concentration range examined, up to 97% of the amphiphilic benzalkonium chloride is encapsulated in the liposomes. In the case of the hydrophilic lidocaine hydrochloride, virtually no liposomal encapsulation occurs.     

挤压器联动装置制备两性霉素B脂质体

目的考察挤压器联动装置制备两性霉素B脂质体制剂的稳定性。方法使用联动装置制备两性霉素B脂质体,用透析法检测两性霉素B脂质体的药物包封率,粒径仪器跟踪脂质体制剂的粒径及其分布,测定稳定性、泄漏率及毒性。结果所用联动装置可使脂质体的制备工艺简化,投料成品一步完成,同时可在线监控粒径。采用此装置制备的两性霉素B脂质体的粒径显著小于手动方式所制备,且粒径分布较窄;药物包封率为97．3％。通过与手动方法制备的脂质体制剂的多项技术指标对比,表明采用联动装置制备的两性霉素B脂质体制剂的药物包封率高,制剂稳定性好,药物渗漏率低。结论挤压器联动装置可用于工业化生产两性霉素B脂质体制剂的产品质量稳定、可控。     

Liposome transport of hydrophobic drugs: gel phase lipid bilayer permeability and partitioning of the lactone form of a hydrophobic camptothecin, DB-67

The design of liposomal delivery systems for hydrophobic drug molecules having improved encapsulation efficiency and enhanced drug retention would be highly desirable. Unfortunately, the poor aqueous solubility and high membrane binding affinity of hydrophobic drugs necessitates extensive validation of experimental methods to determine both liposome loading and permeability and thus the development of a quantitative understanding of the factors governing the encapsulation and retention/release of such compounds has been slow. This report describes an efflux transport method using dynamic dialysis to study the liposomal membrane permeability of hydrophobic compounds. A mathematical model has been developed to calculate liposomal membrane permeability coefficients of hydrophobic compounds from dynamic dialysis experiments and partitioning experiments using equilibrium dialysis. Also reported is a simple method to study the release kinetics of liposome encapsulated camptothecin lactone in plasma by comparing the hydrolysis kinetics of liposome entrapped versus free drug. DB-67, a novel hydrophobic camptothecin analogue has been used as a model permeant to validate these methods. Theoretical estimates of DB-67 permeability obtained from the bulk solubility diffusion model and the "barrier-domain" solubility diffusion model are compared to the experimentally observed value. The use of dynamic dialysis in drug release studies of liposome and other nanoparticle formulations is further discussed and experimental artifacts that can arise without adequate validation are illustrated through simulations.