磷脂种类对吲哚菁绿脂质体制剂学性质的影响

目的 探究磷脂种类对吲哚菁绿（ICG）脂质体制剂学性质的影响。方法 采用薄膜水化挤出法分别制备以氢化大豆卵磷脂（HSPC）、蛋黄卵磷脂为脂质成分的脂质体（ICG-H-Lipo、ICG-E-Lipo）。采用Zetasizer3000HS粒径仪测定脂质体的粒径、聚合物分散性指数（PDI）和Zeta电位;透射电子显微镜观察脂质体形态;超滤离心法分别测定ICG-H-Lipo和ICG-E-Lipo的包封率。用紫外分光光度计分别测定ICG-E-Lipo、ICG-H-Lipo及游离ICG在400～1 000 nm的紫外吸收光谱。以粒径变化为指标,考察脂质体用纯水稀释10倍、4℃条件下储存1个月的长期稳定性,考察脂质体在模拟血浆（pH 7.4大鼠血浆）中的稳定性,考察脂质体用纯水稀释10倍后给予808 nm激光辐照（1 w·cm^-2、5 min）7 d内稳定性;将ICG-HLipo、ICG-E-Lipo和游离ICG 4℃避光保存,分别于0、1、3、5、7 d检测ICG在780 nm处的吸光度（A）值。将ICG-ELipo、ICG-H-Lipo和游离ICG配制成ICG质量浓度为25 μg·mL^-1的溶液,给予1 w·cm^-2、808 nm激光辐照5 min,用红外热像仪记录温度变化;给予5个808 nm激光开-关辐照（1 w·cm^-2,开5 min,关15 min）,用红外热成像仪记录温度变化;采用1 w·cm^-2、808 nm激光分别辐照0、1、2、3、4 min,用紫外分光光度计检测A值变化;以评价不同制剂的光热效率。结果 成功制备了ICG-H-Lipo和ICG-E-Lipo,粒径分布均匀,ICG的包封率分别为77.97%和70.67%。ICG-E-Lipo、ICG-H-Lipo均在895 nm处出现了强吸收峰,相比于游离ICG,ICG-E-Lipo、ICG-H-Lipo均发生了明显红移。稳定性结果表明,ICG-H-Lipo和ICG-E-Lipo在去离子水、血浆溶液中及激光照射后粒径没有明显变化;储存7 d后的紫外吸收光谱图显示,ICG-E-Lipo和ICG-H-Lipo具有比游离ICG更好的稳定性（P＜0.05、0.001） ,且ICG-H-Lipo中的ICG稳定性最好。经过808 nm激光辐照5 min后,ICG-E-Lipo、ICG-H-Lipo、游离ICG的温度均能达到肿瘤细胞的死亡温度;在5次激光开-关循环照射后,ICG-H-Lipo的产热效率相对稳定,而ICG-E-Lipo略有下降,游离ICG的产热效率下降了64%;激光照射4 min后的紫外吸收光谱图表明,游离ICG发生严重的光漂白现象,ICG脂质体吸收峰下降较缓慢。结论 脂质体能显著改善ICG的稳定性;ICG脂质体的制剂学性质与磷脂种类密切相关;相同处方下,与蛋黄卵磷脂相比,HSPC制备的ICG脂质体具有更好的稳定性和光热性能。     

魔芋葡甘聚糖分子链形态及链参数研究魔芋葡甘聚糖分子链形态及链参数研究

目的研究魔芋葡甘聚糖分子链形态，测定分子链参数。方法采用光散射、凝胶渗透色谱及粘度法测定溶液行为；采用原子力显微镜及透射电镜直接观测分子形貌。结果魔芋葡甘聚糖重均分子量M_w、均方根旋转半径〈S₂〉^1/2以及第二维利系数A₂分别为1.04×10⁶, (105.0±0.9) nm,和 (-1.59±0.28)×10^-3 mol·mL·g^-2，多分散系数M_w/M_n为1.02，Mark-Houwink方程为［η］=5.96×10^-2M^0.73_w；分子链参数M_L=982.82 nm^-1,q=27.93 nm, d=0.74 nm,h=0.26 nm,L=1 054.11 nm。结论直接观察到的分子形貌和根据溶液行为的推测均说明，魔芋葡甘聚糖为伸展的有一定刚性的半屈曲性直链分子，不存在支链。     

藏药二十五味鬼臼丸对金黄色葡萄球菌的抑菌作用及机制研究

目的 研究藏药二十五味鬼臼丸对金黄色葡萄球菌的抑菌作用,初步探讨相关抑菌机制。方法 采用琼脂平板打孔法,测定二十五味鬼臼丸（50、100、200mg·mL^-1）对金黄色葡萄球菌的抑菌圈大小。通过微量肉汤稀释法,测定最小抑菌浓度（MIC）。调整肉汤培养基中的二十五味鬼臼丸浓度为0.5MIC、1.0MIC和2.0MIC,分别加入1.0×10⁸CFU·mL^-1菌悬液,以不含药液而含菌量相同的培养基作为对照组,在37℃、120r·min^-1恒温培养箱中振荡培养,每小时取样,用紫外可见分光光度计在600nm处测定吸光度（A₆₀₀）值,绘制细菌的生长曲线;每2小时取样,离心取上清液,试剂盒法测定碱性磷酸酶（AKP）活性;每小时取样,离心取上清液,用紫外可见分光光度计在260nm处测定A₂₆₀值,以A₂₆₀值表示DNA/RNA大分子相对量;每小时取样,离心取上清液,加入考马斯亮蓝G250溶液,于595nm处测定A₅₉₅值,检测胞外可溶性蛋白含量;培养8h后,离心留沉淀,进行SDS-PAGE电泳,检测菌体蛋白含量。结果 二十五味鬼臼丸50、100、200mg·mL^-1对金黄色葡萄球菌的抑菌圈直径分别为（12.33±0.75）、（16.33±0.41）、（19.17±0.68）mm;对金黄色葡萄球菌的MIC为100mg·mL^-1;与对照组相比,二十五味鬼臼丸组的金黄色葡萄球菌生长显著减缓（P＜0.05）,胞外的AKP活性显著升高（P＜0.05）,胞外DNA/RNA大分子相对量显著升高（P＜0.01）,胞外可溶性蛋白含量显著升高（P＜0.01）,菌体总蛋白表达量明显减少。结论 二十五味鬼臼丸对金黄色葡萄球菌具有抑菌作用,其抗菌作用可能与致细菌细胞壁、细胞膜结构破损,且对菌体蛋白具有一定抑制作用有关。     

麻黃揮发油的研究

本文报告由麻黄中提取出一种淡黄色具有花香的挥发油,n_D²⁰1.4940,[α]_D²⁰—31.44°,d₂₀²⁰0.8819。将此油反复减压分馏和用氧化铝柱层离后得到一种萜醇(C₁₀H₁₈O),经制备其衍生物和红外吸收光谱、气相层离法鉴定,证明为l-a-萜松醇。     

不同粒径聚乙二醇化维生素K1脂质体的制备及体内外评价

目的 制备不同粒径聚乙二醇化维生素K₁（VK₁）脂质体,并对其进行制剂学表征,考察体内药动学和促凝药效。方法 采用薄膜分散法制备不同粒径的VK₁脂质体,采用马尔文粒径仪测定粒径、聚合物分散性指数（PDI）、Zeta电位;透射电子显微镜观察形态;以粒径为指标,考察脂质体在4℃下储存1个月、在磷酸缓冲液（PBS,pH 6.8）及pH 1.2水溶液中48 h的稳定性;采用超滤离心法测定包封率与载药量;采用大鼠在体肠吸收模型考察肠吸收特性;ig给药考察脂质体在大鼠体内药动学行为;以华法林钠诱导大鼠低凝血酶原血症,采用ELISA试剂盒检测血浆中凝血因子II、V、VII和IX含量,检测凝血酶原时间（PT）,评价不同粒径VK₁脂质体（2 mg·kg^-1）促凝效果。结果 制备了3种VK₁脂质体（Lip-180、Lip-120、Lip-60）,粒径分别为（182.40±2.17） nm、（114.38±0.60） nm和（68.42±0.73） nm,PDI分别为0.21±0.01、0.12±0.00和0.17±0.01 ,电位分别为（-27.67±1.58）、（-22.93±1.81）、（-26.63±1.37）mV,脂质体均呈球形,分布均匀,包封率均>90%,载药量均>2.90%,稳定性良好。与Lip-180相比,Lip-120和Lip-60表现出更缓慢的释放性能和更好的跨膜吸收速率。Lip-120及Lip-60的药时曲线下面积（AUC_0-∞）分别是Lip-180的1.52和1.80倍,并且Lip-120与Lip-60的AUC_0-∞分别是维生素K₁注射剂（市售对照）的1.24与1.46倍。与低凝血酶原血症模型大鼠比较,经ig给药Lip-180、Lip-120、Lip-60及维生素K₁注射剂后,PT显著降低（P<0.001）,凝血因子Ⅱ、Ⅶ、Ⅸ、Ⅹ水平均升高,其中,Lip-60作用最显著,除给药后6 h的凝血因子Ⅹ外,均差异显著（P<0.05、0.01、0.001）。结论 聚乙二醇化VK₁脂质体分布均匀,稳定性高,释放缓慢,口服生物利用度高,体内促凝效果较好,优选粒径最小的Lip-60。     

胰岛素柔性纳米脂质体的口腔给药研究

目的探讨柔性纳米脂质体经口腔粘膜转运蛋白多肽类药物的可能性。方法用反相蒸发法制备胰岛素柔性纳米脂质体和普通脂质体,对其包封率、形态和粒径大小进行测定。以家兔为动物模型,口腔给药(bu)后,进行体内降糖实验,同时测定胰岛素水平变化。结果胰岛素柔性纳米脂质体与普通脂质体的包封率分别为(18.9±1.8)%和(22.1±2.2)%;粒径分别为(42±20) nm和(60±34) nm。透射电镜下,胰岛素柔性纳米脂质体的指纹状结构比普通脂质体更多,其他无明显区别。以sc胰岛素溶液(1 U·kg^-1)为对照,bu胰岛素柔性纳米脂质体组(10 U·kg^-1)的药理相对生物利用度为15.59%,相对生物利用度为19.78%,高于bu胰岛素溶液对照组(P<0.05)、胰岛素普通脂质体组(P<0.05)及空白柔性纳米脂质体与胰岛素混合物组(P<0.05)。结论胰岛素柔性纳米脂质体可能成为经口腔粘膜转运蛋白多肽类药物的有效载体。     

肝靶向氟尿嘧啶类脂纳米粒的研究

目的　为了提高氟尿嘧啶(5-Fu)的疗效,降低其毒副作用,制备具肝靶向的5-Fu类脂纳米粒。方法　利用氟尿嘧啶与硬脂酰氯进行反应,制备了5-Fu前体药物N₁-硬脂酰-5-Fu,通过红外光谱及核磁共振谱对合成的目标化合物进行结构确认。同时研究了前体药物的性质及稳定性。采用物理凝聚法制备类脂纳米粒,并研究其形态、粒径及粒径分布、载药量、体外释药特征、动物体内分布与药代动力学参数等。结果　平均粒径d_av=240.19 nm,载药量为20.53%。体外释药速率符合一级动力学模型。与5-Fu水针剂比较,类脂纳米粒组在肝脏中药物含量平均增加了一倍以上。家兔体内主要药动学参数为：V_c=0.04336 L.kg^-1,T_1/2β=1.2834 h,CL=0.1632 L.h^-1。结论　利用前体药物可提高药物的脂溶性,首次以物理凝聚法制备类脂纳米粒,小鼠体内分布研究表明类脂纳米粒有明显的肝靶向,有一定的优越性和参考价值。     

丹参酮ⅡA聚合物脂质纳米粒制备及脑部药物递送研究

目的 为了改善丹参酮Ⅱ_A（TanⅡ_A）的溶解性、增加脑组织中的药物浓度，制备TanⅡ_A聚合物脂质纳米粒（TanⅡ_APLNs）并进行体外释放、药动学、脑组织分布研究。方法 建立TanⅡ_A含量测定的高效液相色谱（HPLC）法，以纳米制剂的包封率和粒径为指标，优化TanⅡ_A-PLNs的制备工艺，分别优化TanⅡ_A与蛋黄磷脂（Egg-PC）的比例、Egg-PC与聚乳酸-羟基乙酸共聚物（PLGA）的比例、有机相与水相的比例；进行TanⅡ_A-PLNs的处方验证、稳定性考察、体外释放考察。建立TanⅡ_A在血浆和脑匀浆中的液-质联用（LC-MS）检测方法。SPF级雄性SD大鼠6只，随机分为2组，给药前12 h禁食，一组ig 25 mg·kg^-1的TanⅡ_A混悬液，另一组尾iv 5 mg·kg^-1的TanⅡ_A-PLNs溶液，于给药后5、15、30、60、120、240、360、480、720 min眼眶取血约0.5 mL，LC-MS法进行药动学检测。取KM小鼠4只，尾iv DiR标记的TanIIA-PLNs，给药30、60、120、240 min后处死解剖，通过荧光成像观察TanIIA-PLNs在组织中的分布情况。取KM小鼠12只，随机分成4组，给药前12 h禁食，尾iv 2.5 mg·kg^-1的TanⅡ_A-PLNs溶液，于给药后30、60、120、240 min处死小鼠，剥离完整大脑组织，称质量，加入2倍超纯水匀浆，LC-MS法检测TanⅡ_A水平。结果 TanⅡ_A-PLNs的最优处方为TanⅡ_A∶Egg-PC为1∶4、Egg-PC∶PLGA为5∶2、有机分散体系∶水分散体系为1∶15。以Egg-PC/PLGA作为脂质纳米粒的膜材，采用纳米粒沉淀法制备的TanⅡ_A-PLNs的平均粒径为272 nm，Zeta电位为-4.93 mV，包封率为88.2%，载药量为18%。在避光、干燥（室温）的条件下TanIIA-PLNs冻干粉稳定。TanIIA原料药在48 h内释放完全，累积释放率为（93.75±0.75）%，与Korsmeyer-Peppas释放方程拟合程度较好； TanIIAPLNs在400 h左右释放完全，累积释放率为（89.44±2.22）%，与零级释放方程拟合度最好。药动学结果表明，大鼠尾iv TanⅡ_A-PLNs给药剂量是ig TanⅡ_A原料药剂量的1/5，TanⅡ_A-PLNs的AUC_0-t和t_1/2ß是TanⅡ_A原料药的2.8和1.5倍。组织分布实验结果显示，30 min时肝组织显示荧光； 60 min时脑组织显示出荧光，120 min时脑组织荧光最强，240 min时脑组织荧光变弱。TanⅡ_A-PLNs给药2 h后，TanⅡ_A脑匀浆质量浓度为235.5 ng·g^-1。结论 制备的TanⅡ_A-PLNs均一稳定，包封率较高，聚合物脂质纳米颗粒的应用提高了TanⅡ_A的血药浓度，可增加药物在脑部的暴露。     

Adenosinergic modulation of 3α-hydroxy-5α-pregnan-20-one induced catalepsy in mice

  Rationale: Neurosteroid 3α, 5α THP, a positive allosteric modulator of the GABA_A receptor Cl^– ionophore complex, induces catalepsy-like dopamine antagonists, adenosine agonists or GABA agonists. Adenosine and dopamine receptors are co-localized on GABAergic neurons in the striatum and regulate GABA-mediated neurotransmission. Moreover, the antagonistic interactions between specific subtypes of adenosine and dopamine receptors are involved in motor depressant or motor stimulant effects of adenosine receptor agonists or antagonists, respectively. Such interaction may modulate neurosteroid-induced catalepsy. Objective: This study examined the modulation of 3α, 5α THP-induced catalepsy by adenosinergic agents. Methods: Catalepsy induced by 3α, 5α THP (2–8 μg, ICV) was assessed by bar test periodically up to 3 h in mice. Adenosine A₁, A_2A or A₃ receptor agonists or antagonists were given IP or ICV prior to 3α, 5α THP. Some animals received IP dopamine D₂ receptor agonist or antagonist 30 min prior to above combination treatment. Results: Adenosine A₁, A_2A, and A₃ receptor agonists potentiated, whereas adenosine A_2A receptor antagonists, but not A₁ antagonists, reversed 3α, 5α THP-induced catalepsy. These effects of adenosine agonists and antagonists were abolished by prior administration of bromocriptine, the dopamine D₂ receptor agonist and spiperone, the dopamine D₂ receptor antagonist, respectively. Conclusions: These findings suggest specific adenosine-dopamine receptor interaction in the striatum to modulate 3α, 5α THP-induced catalepsy. Received: 1 November 1998 / Final version: 5 January 1999     

Comparison of CGS 15943, ZM 241385 and SCH 58261 as antagonists at human adenosine receptors

Three structurally related non-xanthine compounds, CGS 15943, ZM 241385 and SCH 58261, are potent A_2A adenosine receptor antagonists and have been used as tools in many pharmacological studies. We have now characterized their affinity and selectivity profile on human adenosine receptors stably transfected into either CHO cells (A₁ and A_2B receptors) or HEK-293 cells (A_2A and A₃ receptors). In binding studies using [³H]SCH 58261 as a radioligand, the three compounds were equally potent at A_2A receptors, their K _i value being less than 1 nM. Affinity for A₁ and A₃ receptors was measured using [³H]DPCPX and [¹²⁵I]AB-MECA as radioligands. Given the lack of selective ligands, interaction with A_2B receptors was assessed using the cAMP accumulation assay following stimulation by the adenosine receptor agonist N-ethylcarboxamidoadenosine (NECA). CGS 15943 was almost as potent at A₁ receptors (K _i 3.5 nM) as at A_2A receptors, showed moderate affinity for A₃ receptors (K _i 95 nM) and also interacted with A_2B receptors (K _i 44 nM; pA₂ 7.5). ZM 241385 showed little affinity for A₁ receptors (K _i 255 nM), and did not interact with A₃ receptors (K _i>10 μM); however, it displayed moderate affinity for A_2B receptors (K _i 50 nM; pA₂ 7.3). SCH 58261 had weak affinity for A₁ receptors (K _i 287 nM), no interaction with A₃ receptors (K _i>10 μM), and showed negligible interaction with A_2B receptors (K _i 5 μM; pA₂ 6.0). These data indicate that SCH 58261 is the most selective A_2A antagonist currently available. Moreover, the different receptor selectivity of these three chemically related compounds provides useful information to progress with structure-activity relationship studies. Received: 2 July 1998 / Accepted: 6 October 1998     

The effect of ileal brake activators on the oral bioavailability of atenolol in man

The aims of this study were to develop novel liposome formulations for tranexamic acid (TA) from various lipid compositions [neutral (hydrogenated soya phosphatidylcholine and cholesterol), positive (stearylamine) or negative (dicetyl phosphate) charged lipid], and to investigate the effects of concentrations of TA (5 and 10% in DI water) and charges on the physicochemical properties of liposomes. Liposomes were prepared by chloroform film method with sonication. The physical (appearance, pH, size, morphology) and chemical (drug encapsulation efficiency, transition temperature, enthalpy of transition) properties of liposomes were characterized. The TA contents were determined spectrophotometrically at 415 nm, following derivatization with 2,4,6-trinitrobenzosulfonic acid. The charged liposomes demonstrated better physical stability than the neutral liposomes. The percentages of TA entrapped in all liposome formulations varied between 13.2 and 15.6%, and were independent of TA concentrations and charges of liposomes. Charges affected the physical stability, pH and size of liposomes. The particle sizes of negative blank and positive liposomes (with and without the entrapped drug) were approximately 10 times larger than the negative liposome with the entrapped TA. The multilamellar 7:2:1 molar ratio of hydrogenated soy phosphatidylcholine/cholesterol/dicetyl phosphate entrapped with 10% TA liposome (10%TA,-) was selected for further release study, due to its high physical stability, small particle size and relatively high drug encapsulation efficiency.     

盐酸多柔比星脂质体的制备及体外质量评价

目的：制备盐酸多柔比星脂质体并进行体外质量评价,以期实现自制脂质体质量与市售盐酸多柔比星脂质体注射液Doxil一致,并为其生物体内等效及产业化提供研究基础。方法：采用乙醇注入法结合硫酸铵梯度法制备盐酸多柔比星脂质体,以包封率为评价指标通过单因素筛选和正交试验优化制备工艺,以市售Doxil为参比制剂,对比最优工艺制得的脂质体与市售Doxil的微观结构、粒径大小及分布、Zeta电位、相变温度、包封率等理化指标,考察最优工艺制得的脂质体与市售Doxil在加速条件的体外释放及储存条件下稳定性情况。结果：自制盐酸多柔比星脂质体最优制备工艺为高速剪切速率13 000 r·min^-1,挤出3次,载药孵育温度65℃,载药孵育时间60 min,最优工艺制得的脂质体与市售Doxil外观均为椭圆形,平均粒径分别为（90.81±0.58） nm （n=3）和（89.05±0.66） nm （n=3）,分布较为均匀,Zeta电位分别为（-41.9±1.8） mV （n=3）和（-44.9±4.2） mV （n=3）,相变温度范围相同,包封率分别为98.0%和97.9%,体外释放较为一致,稳定性好。结论：采用最优工艺制备的盐酸多柔比星脂质体制备工艺可行,与市售Doxil相比,理化指标及体外释放无明显差异,自制脂质体体外质量良好,符合实验预期。     

Circulation and biodistribution profiles of long-circulating PEG-liposomes of various sizes in rabbits

To determine the largest size of liposomes that can retain stealth behavior conferred by poly(ethylene glycol)-DSPE, neutral liposomes were studied in rabbits for their circulation and distribution. Five sizes (136.2, 165.5, 209.2, 275 and 318 nm) of liposomes (DSPC, Cholesterol, PEG-DSPE and alpha-tocopherol, 90:80:4.5:3.9 molar ratio) were made by extrusion technique and radiolabeled with technetium-99m (Tc-99m) to follow their distribution through 24 h. Although all liposomes showed prolonged circulation in blood, the amount still in circulation at 24 h was dependent on their size. Radioactivity accumulation in spleen progressively increased with increase in size of the liposomes. In the size range of approximately 160-220 nm, liver uptake was minimum, spleen uptake was moderate while the amount of circulating liposomes was maximum. Gamma camera scintigraphy corroborated the distribution pattern of liposomes on necropsy. Images within 1h showed high blood pool activities for liposomes of all sizes. However, at 24h, the blood pool activity was diminished for 275 nm and negligible for 308 nm liposomes; the smaller sized liposomes (136.2-209.2 nm) continued to show high blood pool activity. The amounts of radioactivity still circulating at 24h were 46.4, 50.4, 46.8, 36.2 and 14.5% for 136.2, 165.5, 209.2, 275 and 318 nm liposomes, respectively. Corresponding circulation T(1/2)s were 21.7, 26.5, 24.9, 18.7 and 8.9h, respectively. Thus, the optimum size of PEG-liposomes for prolonged circulation in rabbits is 160-220 nm. Beyond this range, the stealth property of PEG-liposomes is significantly compromised and the distribution is characterized by high RES accumulation.     

Cholesterol succinyl chitosan anchored liposomes: preparation,characterization, physical stability,and drug release behavior

The purpose of this study was to prepare cholesterol succinyl chitosan anchored liposomes (CALs) and to investigate their characterization, physical stability, and drug release behavior in vitro. Three cholesterol succinyl chitosan (CHCS) conjugates with different substitution degrees (DS) of the cholesterol moiety were synthesized and used as the anchoring materials to coating on the liposome surface by the incubation method. CALs were almost spherical and had a classic shell-core structure. Compared with plain liposomes and chitosan-coated liposomes (CCLs), CALs had larger sizes, higher zeta potentials, and better physical stability after storage at 4 ± 2°C and 25 ± 2°C. Epirubicin, as a model drug, was effectively loaded into CALs and exhibited the more sustained release in both phosphate buffer solution (pH 7.4) and 1% (vol/vol) aqueous fetal bovine serum compared to plain liposomes and CCLs.From the Clinical EditorCholesterol succinyl chitosan anchored liposomes (CAL) as delivery vehicles are characterized in this work, including their physical stability and drug release behavior in vitro. Epirubicin as a model drug, was effectively loaded into CALs, and exhibited sustained release behavior both in phosphate buffer solution (PBS, pH 7.4) and 1% (V/V) aqueous fetal bovine serum (FBS).     

紫外分光光度法测定头孢哌酮注射剂含量

目的　建立紫外分光光度法测定头孢哌酮注射剂含量。方法　在 2 0 0～ 4 0 0nm波长范围内扫描,确定测定波长。然后进行吸收度A与浓度C的线性关系实验;精密度测定;回收实验;稳定性实验。结果　确定 2 2 8 4nm为测定波长。头孢哌酮在浓度2 5～ 4 0 0 μg·ml-1范围内与吸收度呈良好的线性关系(r =0 9999);平均回收率为 99 6 %。结论　本法简便、准确。     

Stability of poly(Acrylic Acid)‐grafted phospholipid liposomes in gastrointestinal conditions

Major limitations in the use of liposomes for oral formulation relate to their physical and chemical instability in the GI tract. In this study, the conjugate (PAA‐DSPE) of poly(acrylic acid) and distearoylphosphatidylethanolamine (DSPE) was synthesized, and liposomes were prepared with the mixture of PAA‐DSPE and DSPE to improve the stability of liposomes in the GI tract. The prepared PAA‐DSPE was characterized by FT‐IR and ¹³C‐NMR to confirm the coupling between PAA and DSPE. In the elemental analysis, the coupling ratio of PAA and DSPE in PAA‐DSPE was calculated as 1:1.73. The average size of a PAA‐DSPE/DSPE liposome, measured by dynamic light scattering, was in the range of 300–500 nm, and the minimum average size was 320 nm at 6 mol% of PAA‐DSPE. The stability of the prepared liposomes was evaluated in different pH (2, 5, 7.4) solutions, and in different concentrations of bile acid (0, 0.1, 1, 10%) and pancreatin solutions (0, 0.03, 0.3, 3%). The stability of liposomes in different conditions was determined by measuring the fluorescence intensity of 5(6)‐CF leaked from liposomes. The amount of the 5(6)‐CF leakage from the PAA‐DSPE/DSPE liposomes of 6 mol% PAA‐DSPE was the lowest in all the cases of acidic, bile, and pancreatin solutions. In conclusion, the optimum amount of PAA‐DSPE in liposome was 6 mol%, and PAA‐DSPE/DSPE liposomes could improve the stability in the GI tract. Drug Dev. Res. 61:13–18, 2004. © 2004 Wiley‐Liss, Inc.     

The effect of PEG coating on in vitro cytotoxicity and in vivo disposition of topotecan loaded liposomes in rats

Amphoteric drugs encapsulated in PEGylated liposomes may not show superior therapeutic antitumor activity due to increased leakage rate of these drugs in presence of PEG-lipids. In order to investigate the effect of PEG coating on in vitro and in vivo characteristics of topotecan loaded liposomes, an amphoteric anticancer drug, PEGylated and conventional liposomes were prepared by lipid film hydration method. Various properties of the prepared nanoliposomes such as encapsulation efficiency, size, zeta potential, physical stability as well as the chemical stability of lactone form of topotecan, cytotoxicity and topotecan pharmacokinetics were evaluated. In vitro cytotoxic activity was evaluated on murine Lewis lung carcinoma (LLC) and human mammary adenocarcinoma (BT20) cells. Pharmacokinetic was evaluated in Wistar rats after i.v. injection of topotecan, formulated in PBS pH 7.4 or in conventional or in PEGylated liposomes. The conventional liposome (CL) formulation was composed of DSPC/cholesterol/DSPG (molar ratio; 7:7:3), while for PEGylated liposome the composition was DSPC/cholesterol/DSPG/DSPE-PEG(2000) (molar ratio; 7:7:3:1.28). The size of both liposomes was around 100 nm with polydispersity index of about 0.1. In comparison with free drug, liposomal topotecan showed more stability for topotecan lactone form in vitro. Compared to free topotecan, PEGylated and conventional liposomes improved cytotoxic effect of topotecan against the two cancer cell line studied. The results of pharmacokinetic studies in rats showed that both CL and PEGylated liposomal formulations increased the concentration of total topotecan in plasma, however, initial concentration and the values of AUC, MRT and t(1/2 beta) were much higher (P<0.001) for PEGylated liposomal drug than for conventional one or free drug. PEGylated liposome resulted in a 52-fold and 2-fold increases in AUC(0-infinity) compared with that of free topotecan and CL, respectively. These results indicated that PEG modified liposome might be an effective carrier for topotecan.     

Interactions of amiodarone with model membranes and amiodarone-photoinduced peroxidation of lipids.

The potent antiarrhythmic drug, amiodarone (AMIO) exhibits phototoxicity, which is thought to be related to its interaction with biological membranes. We report here a spectroscopic study of the interactions of this drug with phosphatidylglycerol (PG) and phosphatidylcholine (PC) liposomes used as membrane model systems. A linear increase in absorbance at 300 nm was observed with increasing addition of AMIO to dimyristoyl-DL-PC (DMPC) liposomes over all the drugs-lipid molar ratio (Ri)s tested. In contrast, in the dimyristoyl-DL-PG (DMPG) liposomes, there was a dramatic increase in absorbance at values of Ri above unity. Light scattering by DMPG liposomes at 350 nm increased with increasing AMIO concentration up to a Ri = 1, and then decreased with increasing drug concentration. Such changes were not observed with the DMPC liposomes. Moreover, addition of AMIO changed the fluorescence polarization rate of 1,6-diphenyl 1,3,5-hexatriene embedded in these liposomes. It reduced the rate below the phase transition temperature (Tt) of the lipid, but increased it above this temperature. These effects on the lipidic phases observed at low Ri were more pronounced on the DMPG than on the DMPC liposomes. The strong interactions of AMIO with phospholipids, especially the acidic ones, were confirmed by liposome size determinations. All these data strongly suggest that the drug was incorporated in the core of the lipid bilayers. Such a penetration would favor a drug-photoinduced peroxidation of lipids. Indeed, UV irradiation of AMIO-DOPG mixtures led to the disappearance of the unsaturated fatty acids of phospholipids, checked by gas chromatography measurements, which was correlated with the amount of oxygen consumed. This showed that AMIO did photosensitize phospholipid peroxidation.     

海参皂苷nobiliside A脂质体及其溶血行为的初步研究

本文旨在制备海参皂苷nobiliside A(Nob A)脂质体，建立脂质体中Nob A的含量和包封率的测定方法，考察该脂质体的体内外溶血行为。以高效液相色谱-蒸发光散射检测法(HPLC-ELSD)测定脂质体中Nob A含量，微柱离心法测定其包封率。以溶血率和包封率、粒径为指标，单因素考察了制备方法、磷脂用量、胆固醇用量和药脂比。根据单因素的考察结果，以薄膜超声法制备3批脂质体，与同浓度的药物溶液进行体内外溶血行为的比较。结果显示：用于含量测定和包封率测定的HPLC-ELSD和微柱离心法准确、快速，采用薄膜超声法制备的脂质体形态圆整，粒径较为均匀。当磷脂与胆固醇比例为2∶1，药脂比为1∶40时，Nob A脂质体的平均包封率为95.7%，平均粒径为87.6 nm。Nob A以脂质体作为给药载体，其体内外溶血行为大大降低，有望成为静脉注射用脂质体。     

氧化苦参碱脂质体的制备及其质量评价

目的:制备氧化苦参碱脂质体并建立其质量评价方法。方法:采用逆相蒸发法,以包封率为检测指标,利用正交试验法优选处方和制备工艺;考察优选处方所制脂质体形态与粒径,并采用透析法结合反相高效液相色谱法测定其包封率。结果:最佳处方为磷酸盐缓冲液pH7.2,大豆卵磷脂与胆固醇的质量比为2∶1,大豆卵磷脂与氧化苦参碱质量比为10∶1,水相与有机相体积比为1∶3;制备的脂质体为球状小囊泡,外观圆整,粒径范围60～150nm,包封率为60.72%;氧化苦参碱检测浓度线性范围为10～150μg.mL-1(r=0.9998),平均回收率为98.62%(RSD=1.47%,n=5)。结论:优选处方和制备工艺稳定可行,可为开发其新剂型提供参考。