由空白前体脂质体制备抗癌药物脂质体

以空白前体脂质体作为药物载体,将药物溶液分散在载体中,制成药物脂质体.空白前体脂质体对5Fu等几种抗癌药物均可达到一定的包裹率,阿霉素在一定条件下可达到85%以上,并与传统薄膜法进行了比较.抑瘤活性及毒性实验结果表明:与游离药物相比,5Fu、阿霉素等药物的抑瘤活性都有不同程度的提高.急性毒性实验表明:除AraC外,几种药物的毒性均有所降低,以顺铂最明显.     

脂质体前体制剂研究进展

目的：脂质体前体的制备解决了脂质体分散系的物理不稳定性：如药物的渗漏、粒子的聚集以及磷脂在液态下的氧化、水解,为脂质体在临床上的应用提供了一个行之有效的方法,它使脂质体以固态形式贮存,只是在临用前加入分散介质即可再分散形成脂质体。方法：对近年来国内外脂质体前体的研究情况做文献检索,介绍了各种制备方法及影响新脂质体粒径和药物包裹率的因素。结果：通过适当的方法及选择合适的支持剂,可以制备出稳定性好、包裹率高的脂质体前体。结论：对脂质体前体的进一步研究有一定的意义     

脂质体前体制剂研究进展

目的;脂质体前体的制备解决了脂质体分散系的物理不稳定性：如药物的渗漏,粒子的聚集以及磷脂在液态下的氧化,水解,为脂质体在临床上的应用提供了一个行之有效的方法,它使脂质体以固态形式贮存,只是在临用前加入分散介质即可再分散形成脂质体。方法;对近年来国内外脂质前体的研究情况做文献检索,介绍了各种制备方法及影响新脂质体粒径和药物包裹率的因素。     

高效毛细管电泳测定盐酸小檗碱脂质体包封率

目的：建立一个快速、简便且经济的盐酸小檗碱脂质体包封率测定方法。方法：采用高效毛细管电泳法，分析条件为，石英毛细管，７０ｃｍ×７５μｍｉｄ；温度，２０℃，运行缓冲液，１０ｍｍｏｌ／Ｌ磷酸氢二钠（０１ｍｏｌ／Ｌ氢氧化钠调至ｐＨ１０８１）；运行电压，３０ｋｖ；检测波长，２５４ｎｍ。结果：线性范围１００～５０００ｍｇ／Ｌ，ｒ＝０９９８９，平均回收率９８７％（ｎ＝５），ＲＳＤ＝３５１％，薄膜分散法的包封率（１９５±２３）％远高于乙醇注入法的包封率（８３±３７）％。结论：本法适用于盐酸小檗碱脂质体包封率测定     

冷冻干燥法制备α-细辛脑前体脂质体

目的:研制α-细辛脑前体脂质体.方法:采用冷冻干燥法,选择甘露醇/蔗糖做冻干剂,制备α-细辛脑前体脂质体,并考察水化后脂质体的形态、粒径分布、黏度和包封率.结果:α-细辛脑前体脂质体经水化后,脂质体粒径分布均匀,平均粒径为0.655μm,粘度为1.6 mPaS,药物包封率约96%.结论:冷冻干燥法可用于α-细辛脑前体脂质体的制备.     

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。     

粉防己碱，Fura 2－AM和Bay k 8644对脂多糖刺激大鼠腹腔巨噬细胞释放血小板活化因子的影响

目的：研究钙与脂多糖（ＬＰＳ）刺激大鼠腹腔巨噬细胞（ＰＭ）释放血小板活化因子（ＰＡＦ）的关系．方法：通过ＰＡＦ的生物测定法，观察了粉防己碱（Ｔｅｔ）、Ｆｕｒａ２ＡＭ和Ｂａｙｋ８６４４对ＬＰＳ刺激ＰＭ释放ＰＡＦ的影响．结果：ＬＰＳ刺激ＰＭ释放ＰＡＦ，但并不使其细胞内钙增高，Ｔｅｔ在０１，１０，１０，１００μｍｏｌ·Ｌ－１和Ｆｕｒａ２ＡＭ在００１，０１，１０，１０μｍｏｌ·Ｌ－１时降低ＬＰＳ刺激的ＰＭ释放ＰＡＦ（分别为９８±１１，６５±１６，４７±０８，３４±０４，９２±１７，５２±１３，３７±０４，３．２±０３μｇ·Ｌ－１，无药物时１１８±１２μｇ·Ｌ－１），Ｂａｙｋ８６４４在１０，５０，１０μｍｏｌ·Ｌ－１时能增加ＬＰＳ刺激的ＰＡＦ释放能增加ＬＰＳ刺激的ＰＡＦ释放（分别为１３２±１７，１６２±１４，１７６±１５μｇ·Ｌ－１），并且Ｂａｙｋ８６４４在５０μｍｏｌ·Ｌ－１时能全部或部分逆转Ｔｅｔ和Ｆｕｒａ２ＡＭ对ＰＡＦ释放的抑制作用．结论：尽管ＬＰＳ并不明显增加巨噬细胞内钙，但细胞内钙对ＬＰＳ刺激的ＰＡＦ释放是必要的．     

超氧化物歧化酶脂质体的制备

用均匀设计法优化ＳＯＤ脂质体（Ｌ－ＳＯＤ）的制备工艺；制得包封率为６４．５２±３．３５％、粒径为０．０４～１．０μｍ的Ｌ－ＳＯＤ。并发现将此Ｌ－ＳＯＤ分散于１０ｍｍｏｌ／ＬＰＢＳ（含０．１５ｍｏｌ／ＬＮａＣｌ，ｐＨ７．４０）中比较稳定，在４℃避光密封贮存６个月，其ＳＯＤ活性存留率仍在７０％以上。     

白术挥发油脂质体的制备及质量考察

目的制备白术挥发油脂质体并考察其性质。方法采用薄膜分散法制备白术挥发油脂质体,正交设计优化处方,低温高速离心法分离脂质体和游离药物,HPLC测定脂质体的包封率,并测定其zeta电位和粒径,考察其稳定性。结果白术挥发油脂质体包封率为62．7％,zeta电位为36．65mV,平均粒径为206．9nm。结论薄膜分散法制得的白术挥发油脂质体包封率高。粒径分布均一,稳定性较好。     

盐酸多西环素脂质体凝胶剂的制备与评价

以薄膜-振荡分散法制备盐酸多西环素脂质体，再以卡波姆为基质制备脂质体凝胶剂。比较了制品及普通凝胶剂对离体鼠皮的经皮渗透作用。结果表明，制品平均粒径为200～300nm，包封率为80．1％。体外透皮实验中，脂质体凝胶剂24h的药物浓度为156，7μg／ml，明显高于普通凝胶剂（83．3μg／m1）。     

Formulation Development and in vitro Characterization of Proliposomes for Topical Delivery of Aceclofenac

Non-steroidal antiinflammatory drugs are routinely prescribed for the patients with rheumatic disease and such patients are at increased risk of serious gastrointestinal complications, when non-steroidal antiinflammatory drugs administered by oral route. The aim of the present study was to develop and characterized a vesicular drug carrier system (proliposome) for topical delivery of aceclofenac to overcome the problems related with oral route. Aceclofenac proliposome were prepared by the film-deposition on carriers method and characterized for size and surface morphology, drug content in both proliposomes and liposomal system, percent yield, in vitro drug release studies and drug permeation studies. The prepared system was also characterized for drug-excipients interaction by Fourier transform infrared spectrophotometer and stability studies. The size and surface morphology were studied using optical microscopy, scanning electron microscopy and transmission electron microscopy. A spherical shape of reconstituted aceclofenac liposome with an average vesicular size of about 500 nm was observed in photomicrographs. The maximum entrapment efficiency of reconstituted liposomes was 80.31% whereas the drug content in proliposomes was found to be more than 90%. In vitro release of drug was significantly retarded indicating sustained release of aceclofenac from proliposomes. Stability study was performed at various temperatures indicating that aceclofenac proliposomes are stable at lower temperature.     

槲皮素前体脂质体的质量考察

目的制备液体型槲皮素前体脂质体,并对制剂质量进行考察。方法采用一种新型前体脂质体制备方法制备液体型槲皮素前体脂质体,将脂质体膜材和药物等以一定比例溶于分散介质中,形成一种无水的澄明溶液。考察其水合后粒子形态、粒径、电位、包封率及自组装速度等理化性质,并评价其体外释药性质。结果槲皮素前体脂质体遇水即可快速自组装成纳米级含药脂质体混悬液,水合后形态多为类球形,平均粒径为228.7nm,Zeta电位为21.2 mV,包封率可达90%以上,体外释药符合Higuchi方程。结论槲皮素口服前体脂质体制备工艺简单可行,包封率高,具有一定的缓释效果。     

新型前体脂质体载药及影响因素考察

Aim A new proliposomal technology was used to trap several drugs, such as tegafur, silymarin, cistanosides, oleanolic acid. And then these proliposomal characters were studied. Methods These proliposomes formed liposomes after mixing with water. And then the liposomal morphology was determined by electron microscope, and the liposomal particle size determined by particle sizes instrument. The trap efficiency was determined by the column chromatography, and then the influence factors on the trap efficiency were investigated. Results The liposomes looked round, some with multiply layers, the particle was small, and the ξ potential was about -30 mV. The trap efficiency changed with the partition coefficient and pH. When the partition coefficient and pH increased, the trap efficiency increased. Furthermore, the trap efficiency was not influenced by the molecular weight. Conclusion This kind of liposomal technology trapped the drugs efficiently, and the lipophilic drugs were trapped more easily. Some Chinese traditional drugs could be trapped too.     

Liposomal gels for vaginal drug delivery

The aim of our study was to develop a liposomal drug carrier system, able to provide sustained and controlled release of appropriate drug for local vaginal therapy. To optimise the preparation of liposomes with regards to size and entrapment efficiency, liposomes containing calcein were prepared by five different methods. Two optimal liposomal preparations (proliposomes and polyol dilution liposomes) were tested for their in vitro stability in media that simulate human vaginal conditions (buffer, pH 4.5). To be closer to in vivo application of liposomes and to achieve further improvement of their stability, liposomes were incorporated in vehicles suitable for vaginal self-administration. Gels of polyacrylate were chosen as vehicles for liposomal preparations. Due to their hydrophilic nature and bioadhesive properties, it was possible to achieve an adequate pH value corresponding to physiological conditions as well as desirable viscosity. In vitro release studies of liposomes incorporated in these gels (Carbopol 974P NF or Carbopol 980 NF) confirmed their applicability as a novel drug carrier system in vaginal delivery. Regardless of the gel used, even 24 h after the incubation of liposomal gel in the buffer pH 4.5 more than 80% of the originally entrapped substance was still retained.     

Proliposomes for oral delivery of dehydrosilymarin: preparation and evaluation in vitro and in vivo

Aim:

To formulate proliposomes with a polyphase dispersed system composed of soybean phospholipids, cholesterol, isopropyl myristate and sodium cholate to improve the oral bioavailability of dehydrosilymarin, an oxidized form of herbal drug silymarin.

Methods:

Dehydrosilymarin was synthesized from air oxidation of silymarin in the presence of pyridine, and proliposomes were prepared by a film dispersion-freeze drying method. Morphological characterization of proliposomes was observed using a transmission electron microscope. Particle size and encapsulation efficiency of proliposomes were measured. The in vitro release of dehydrosilymarin from suspension and proliposomes was evaluated. The oral bioavailability of dehydrosilymarin suspension and proliposomes was investigated in rabbits.

Results:

The proliposomes prepared under the optimum conditions were spherical and smooth with a mean particle size in the range of 7 to 50 nm. Encapsulation efficiency was 81.59%±0.24%. The in vitro accumulative release percent of dehydrosilymarinloaded proliposomes was stable, which was slow in pH 1.2, and increased continuously in pH 6.8, and finally reached 86.41% at 12 h. After oral administration in rabbits, the relative bioavailability of proliposomes versus suspension in rabbits was 228.85%.

Conclusion:

Proliposomes may be a useful vehicle for oral delivery of dehydrosilymarin, a drug poorly soluble in water.     

Solid dispersion and effervescent techniques used to prepare docetaxel liposomes for lung-targeted delivery system: in vitro and in vivo evaluation

A lung-targeting liposomal docetaxel was developed to improve therapeutic index and to reduce side effects. Docetaxel proliposomes composed of docetaxel/Tween-80/Phospholipon 90H/cholesterol/citric acid at molar ratio of 0.18:0.09:3.78:3.78:91.17 were prepared by solid dispersion technique, and then were hydrated with NaHCO₃ solution to obtain docetaxel liposomes by effervescent technique. The stability of proliposomes containing docetaxel, characterization and evaluation of lung-targeting effect of docetaxel liposomes in rabbit were studied. Docetaxel proliposomes were stable at 6?±?2°C for at least 12 months. The particle size, zeta-potential, and entrapment efficiency of the resulted liposomes were 1011?±?22?nm, ?23.7?±?0.26?mv, and 90.12?±?0.36%, respectively. As far as the targeting parameters are concerned, the relative intake rate (R_e) and the ratio of peak concentration (C_e) of lung were 28.91 and 74.28, respectively. Compared with liver, spleen, and kidney, the ratios of targeting efficacy (T_e)_liposomes to (T_e)_injection of lung were increased by a factor of 3.16, 23.00, and 27.83, respectively. In conclusion, the negatively charged docetaxel liposomes with diameter of about 1 µm described in this study have favorable lung-targeting effect and are a promising lung-targeting carrier.     

洛伐他汀自组装前体脂质体的制备及其理化性质的研究

目的:为研究洛伐他汀新剂型,制备洛伐他汀新型前体脂质体,并对其质量进行考察。方法:采用一种新型前体脂质体制备方法将洛伐他汀制成自组装前体脂质体,对水合后脂质体的形态、粒径、Zeta电位、包封率、自组装速度、稳定性等进行考察,验证这种新型前体脂质体制备方法用于制备洛伐他汀脂质体的可行性。结果:所形成的洛伐他汀脂质体包封率为95.4%±6.7%,平均粒径为(327.4±29.6)nm,Zeta电位值为-(22.4±1.5)mV。洛伐他汀自组装前体脂质体可在60 s内自发形成脂质体并达到分散平衡;以人工胃液为稀释介质,洛伐他汀脂质体在12 h内稳定。结论:采用新型前体脂质体制备方法可将洛伐他汀制成洛伐他汀脂质体,形成的脂质体包封率较高且具有良好的稳定性。     

卡铂前体脂质体的制备及安全性的初步评价

目的：制备卡铂前体脂质体,并对用药安全性进行初步评价.方法：采用薄膜挤压法制备卡铂脂质体,加入冻干支持剂冷冻干燥后得到卡铂前体脂质体.对豚鼠全身用药的过敏性、家兔全身用药的血管刺激性以及溶血性进行考察.结果：制备所得的卡铂前体脂质体水合后的包封率为72.0%,载药量为24.0%,平均粒径为125.1 nm.卡铂前体脂质体不引起豚鼠过敏反应,不引起家兔溶血和红细胞凝集反应,静脉注射对家兔血管无刺激性.结论：制备所得的卡铂前体脂质体有较高的包封率和载药量,水合后粒径均匀,形态圆整,且具有较好的用药安全性.     

水飞蓟素前体脂质体的制备和大鼠药代动力学的研究水飞蓟素前体脂质体的制备和大鼠药代动力学的研究

目的为了提高水飞蓟素的口服生物利用度，研制水飞蓟素前体脂质体并对其理化性质进行考察；研究水飞蓟素前体脂质体的大鼠体内生物利用度。方法采用薄膜载体沉积法制备水飞蓟素前体脂质体，通过研究水合后脂质体的包封率、粒径、稳定性来考察其理化性质；将水飞蓟素前体脂质体在体外进行水合，再给予大鼠灌胃，用RP-HPLC法测定不同时间血浆中总的和游离的水飞蓟素的浓度，通过3P97程序计算药代动力学参数。结果用该法制得的前体脂质体包封率可达90%以上，平均粒径为238.8 nm，稳定性较好；药代动力学研究表明水飞蓟素脂质体在体内吸收较快，生物利用度较高。结论采用薄膜载体沉积法制备水飞蓟素前体脂质体，制备工艺简单，易于工业化生产；将水飞蓟素制备成前体脂质体提高了水飞蓟素的生物利用度。     

Mixed micelle proliposomes for preparation of liposomes containing amphotericin B, in-vitro and ex-vivo studies

The aim of this work was to produce a form of injectable liposomes containing amphotericin B derived from mixed micelle proliposomes. Mixed micelles were derived from a mixture of lecithin/sodium cholate in aqueous media. The solubility of amphotericin B in proliposomes was studied as a function of lipid composition (total lipid concentration, molar ratio of lecithin/sodium cholate), and the dispersion media (pH, ionic strength, presence or absence of human serum albumin), and the temperature. The data show that micelle-->liposome transformation occurs during the dilution of proliposomes containing amphotericin B. These transformations could be followed via transmission electron microscopy (TEM). Data related to dilution of proliposomes as well, show that under no circumstance there occurs any precipitation that might be assigned to the decreased solubility of amphotericin B. These indicate that the incorporated drug also participates during the transformation of the proliposomes into liposomes. It is thus concluded that mixed micelle proliposomes are prime candidates for the production of a form of injectable amphotericin B in liposomes.