微柱离心-HPLC法测定盐酸丁卡因脂质体包封率

目的:建立测定盐酸丁卡因脂质体包封率的方法。方法:采用微柱离心法分离脂质体与游离药物,以高效液相色谱法测定药物浓度并计算包封率。结果:微柱离心法能很好地将脂质体与游离药物分离,空白脂质体的回收率为90.4%～100.1%,游离药物吸附率为96.6%～99.2%;盐酸丁卡因脂质体包封率均在80%左右。结论:所建盐酸丁卡因脂质体包封率的测定方法简单、快速、重现性好。     

葡聚糖凝胶微柱结合高效液相色谱法测定奥沙利铂脂质体包封率

目的：对奥沙利铂脂质体进行质量评价,建立奥沙利铂脂质体包封率的测定方法。方法：采用凝胶微柱离心法分离游离药物与脂质体,以HPLC法测定奥沙利铂的药物含量,计算脂质体的包封率。结果：奥沙利铂浓度在0.02~1mg.mL-1范围内线性关系良好（r=0.9999）,结果3批次奥沙利铂脂质体的包封率分别为56.6%,57.5%,60.0%。结论：该方法简便、迅速,可准确地测定出奥沙利铂脂质体的包封率。     

微柱凝胶离心分离-HPLC法测定克霉唑脂质体的包封率

目的:建立克霉唑脂质体包封率的测定方法。方法:采用 HPLC 法测定药物含量,色谱柱为 Hypersil ODS2柱(250mm×4.6 mm,5 μm),检测波长为260 nm,流动相为甲醇-0.025 mol·L~(-1)磷酸氢二钠溶液(90:10),流速为1.0 mL·min~(-1)。采用 Sephadex G-50微柱离心分离脂质体与游离药物,以500 r·min~(-1)离心6s 制备微柱,加样量0.2 mL,洗脱液为pH7.0的磷酸盐缓冲液,2000 r·min~(-1)离心5 min,重复3次。结果:在本色谱条件下克霉唑与辅料分离良好,克霉唑的线性范围为15.1～105.7μg·mL~(-1)(r=0.9991),日内和日间精密度 RSD 均小于0.63%(n=6),平均回收率为97.2%～100.1%(n=3)。Sephadex G-50微柱对克霉唑的平均吸附率大于96.3%,而对空白脂质体的洗脱率大于96.6%。结论:采用 Sephadex G-50微柱离心分离脂质体与游离药物,再用 HPLC 法测定克霉唑脂质体中药物包封率,简便快速,结果重复性好。     

微柱离心高效液相法测定吉非替尼脂质体包封率

目的：建立测定吉非替尼脂质体包封率的微柱离心高效液相法。方法：采用Sephadex G-50制备的微型凝胶柱分离脂质体和游离药物,采用高效液相色谱法检测脂质体中的药物浓度和过柱前脂质体混悬液中的药物浓度,通过公式计算吉非替尼脂质体包封率。结果：洗脱曲线结果表明Sephadex G-50分离脂质体与游离药物的效果较好,最佳离心分离条件为2000r·min-1,3min,最佳洗脱方法为蒸馏水-硫酸铵混合洗脱,该法测定3批吉非替尼脂质体平均包封率为50.9%。结论：微柱离心高效液相法可以作为吉非替尼脂质体包封率测定的有效方法。     

洛莫司汀脂质体包封率的测定

目的对洛莫司汀脂质体进行质量评价,建立洛莫司汀脂质体包封率的测定方法。方法采用微柱离心法分离洛莫司汀脂质体与游离药物,采用HPLC法测定洛莫司汀含量。结果微柱离心法对洛莫司汀游离药的吸附率在97.25%~98.36%内,空白脂质体回收率在98.60%~100.5%内,洛莫司汀脂质体和游离洛莫司汀得到良好的分离;在选定色谱条件下,洛莫司汀与脂质体分离良好,辅料不干扰测定,洛莫司汀质量浓度在0.5~50.0 mg.L-1内与峰面积呈良好的线性关系(r=0.999 9),日内和日间RSD均小于2%(n=5),加样回收率在97.96%~98.79%内。结论微柱离心-HPLC法可用于洛莫司汀脂质体包封率的测定。     

微柱凝胶离心-HPLC测定酮康唑醇质体包封率

目的建立酮康唑醇质体包封率的微柱凝胶离心-HPLC测定方法。方法药物含量采用HPLC测定,醇质体与游离药物的分离采用葡聚糖凝胶微柱离心法。色谱条件为：色谱柱Sinochrom ODS-BP（4.6 mm×200 mm,5μm）,流动相乙腈-水-三乙胺（60∶40∶0.5,磷酸调pH 8.6）,流速1.0 mL.min-1,检测波长243 nm,进样量20μL。分离条件为：以2 000 r.min-1离心3 min制备葡聚糖凝胶微柱,测样量0.2 mL,以2 400 r.min-1离心5 min,再用0.2 mL蒸馏水洗脱,重复3次。结果微柱对酮康唑的平均吸附率〉99.30%,对空白醇质体洗脱率〉99.49%。结论葡聚糖凝胶微柱离心-HPLC可作为醇质体包封率测定的简单快捷方法。     

微柱离心-HPLC法测定卡培他滨脂质体包封率

采用薄膜分散法制备卡培他滨脂质体。采用葡聚糖凝胶Sephadex G-50微柱离心法分离卡培他滨脂质体和游离药物,以HPLC法测定卡培他滨浓度并计算包封率。使用C18色谱柱,以甲醇-水(55∶45)为流动相,检测波长240 nm。结果 3批脂质体的包封率分别为46.2%、45.2%和44.8%。     

微柱离心-紫外分光光度法测定超氧化物歧化酶模拟物脂质体的包封率

目的:建立超氧化物歧化酶(superoxide dismutase,SOD)模拟物脂质体包封率的测定方法。方法:利用紫外分光光度法测定SOD模拟物的含量,检测波长为371 nm。以薄膜分散法制备SOD模拟物脂质体,采用葡聚糖凝胶-微柱离心-紫外分光光度法测定其包封率。结果:SOD模拟物在60.0～240.0μg.mL-1范围内线性关系良好(r=0.999 3),微柱离心法能有效地将脂质体与游离药物分离,加样回收率测定结果为(99.18±1.05)%,利用该方法测定的SOD模拟物脂质体包封率为(91±1.63)%。结论:紫外分光光度法可以作为SOD模拟物的含量测定方法,微柱离心法操作简单,重现性好,适用于SOD模拟物脂质体包封率的测定。     

紫杉醇脂质体药物包封率的测定

目的：测定紫杉醇脂质体的药物包封率。方法：采用葡聚糖凝胶柱进行分离，HPLC法测定药物的含量。结果：用磷酸盐缓冲液作为洗脱液，在葡聚糖凝胶柱上能使包封药物与游离药物得到很好分离，结果表明混溶膜法制备的紫杉醇脂质体药物包封率最高。结论：该方法重现性好，柱子回收率高，是测定脂溶性药物包封率的首选方法。     

苦参碱脂质体的制备与包封率测定

目的 制备苦参碱脂质体并测定其包封率. 方法 采用硫酸铵梯度法制备苦参碱脂质体, 采用葡聚糖凝胶G-100分离苦参碱脂质体和游离苦参碱, 并用高效液相色谱法测定脂质体的包封率. 结果 苦参碱脂质体包封率为33.4%, 苦参碱在0.005～0.500 mg•mL-1范围内线性关系良好（r=0.999 8）. 结论 硫酸铵梯度法制备出包封率相对高的苦参碱脂质体, 高效液相色谱法测定脂质体的包封率简单快速, 方法准确, 重现性好.     

Determination of the encapsulation efficiency in liposomes obtained by the 'extruder method'

The encapsulation efficiency of carboxyfluorescein in liposomes obtained by the 'extruder method' has been determined. The encapsulating efficiency has also been related to the captured volume. The results show that the efficiency is proportional to the liposome diameter.     

微柱离心-药脂比测定脂质体药物包封率

目的建立一种准确测定脂质体包封率的方法。方法以氟吡洛芬、酮洛芬、拓扑替康为模型药物脂质体,通过葡聚糖凝胶(Sephadex G-50)微柱离心去除游离药物,以HPLC法测定药物含量,以定磷法测定磷脂含量,通过药脂比测定药物包封率。结果无需将脂质体完全洗脱,通过检测洗脱脂质体中的药脂比能够准确测定脂质体包封率;对于水溶性药物拓扑替康,若将脂质体完全洗脱,则可能无法将游离药物完全分离。结论在一定条件下微柱离心去除游离药物,通过药脂比测定包封率方便准确。     

Effect of preparation method and cholesterol on drug encapsulation studies by phospholipid liposomes

Unilamellar liposomes, prepared from synthetic lipid mixture of DMPC and DMPG either by sonication or extrusion, were used to entrap water soluble and water insoluble molecules to investigate the efficacy of encapsulation by different liposome preparation methods. In the case of entrapment of hydrophilic protein cytochrome-C, the solutions were subjected to a series of ultrafiltration steps to eliminate any free protein outside the vesicles. It was observed that the protein could be encapsulated by the vesicles only if cholesterol was present in the bilayer. The release of cytochrome-C was observed spectrophotometrically upon vesicle-breakdown. The amount of protein encapsulated depended on the method of preparation and was found to be 10 times greater in extruded liposomes compared to those produced by sonication. Hydrophobic Vitamin E, on the other hand, could be encapsulated in the liposome bilayer, independently of the presence of cholesterol and the method of preparation. These fundamental results can be used to develop more efficient drug encapsulations and to have better understanding about their release.     

阳离子交换纤维微柱离心法测定盐酸表阿霉素脂质体包封率

目的建立盐酸表阿霉素脂质体包封率的测定方法。方法以改良乙醇注入-pH梯度法制备盐酸表阿霉素脂质体,以阳离子交换纤维装柱,离心分离脂质体和游离药物,采用可见分光光度法测定药物含量,计算包封率。结果盐酸表阿霉素在5.0～35.0 mg.L-1内线性关系良好(r=0.9998),柱长为1 cm的阳离子交换纤维柱可以完全吸附0.1 mL质量浓度为0.5～2.0 g.L-1的盐酸表阿霉素溶液,且脂质体柱回收率大于99.0%。结论阳离子交换纤维微柱离心法可用来测定盐酸表阿霉素脂质体包封率。     

顺铂脂质体含量及其包封率的测定

目的:采用高效液相色谱法测定顺铂脂质体的含量和包封率.方法:色谱柱Lichrospher NH2,流动相:乙腈-甲醇-0.9%NaCl溶液(65:25:10,V/V/V),流速: 0.7 mL·min-1,检测波长: 220 nm.结果:顺铂的保留时间为6.36 min,最低检测限是0.256 ng,标准曲线范围为3.2 μg·mL-1～240 μg·mL-1 (r=0.999 9),方法回收率为100.98%,RSD为0.65%,包封率>50%.结论:此法适用于直接测定顺铂脂质体的含量和包封率,与脂质体中磷脂、胆固醇等辅料的分离效果较好.     

脂质体中蛋白类药物包封率的测定

目的建立脂质体中蛋白类药物包封率的测定方法。方法以牛血清白蛋白(bovine serum al-bumin,BSA)为模型蛋白,采用逆向蒸发法制备了平均粒径为5.129μm的BSA脂质体。采用离心-参照法测定BSA脂质体的包封率,并以凝胶过滤、超速离心、超滤和透析4种常用方法对包封率的结果进行比较。结果该方法平均回收率为101.7%,RSD为2.32%(n=5),BSA质量浓度在1.02～1 507.5 mg.L-1内线性关系良好。离心-参照法测定3批BSA脂质体的平均包封率为69.74%,RSD为1.34%。而其他几种方法测定同一批脂质体的包封率值偏高或偏低,即测定方法存在问题。结论该法简便灵敏,测得值真实、可靠,可以用于蛋白类药物脂质体中包封率的测定。     

微柱离心-气相色谱法测定β-榄香烯脂质体包封率

目的建立毛细管气相色谱法测定 β 榄香烯脂质体包封率的方法。 方法用葡聚糖凝胶(SephadexG— 5 0 )微柱离心法分离脂质体和游离药物 ,采用SE— 30毛细管柱为分离柱 ,正辛醇为内标物 ,乙醚为萃取剂 ,无水乙醇为定容剂 ,测定脂质体中药物含量 ,计算包封率。结果SephadexG— 5 0对 β 榄香烯的吸附率为 96 89% ,对空白脂质体无吸附 ;洗脱率为 10 0 5 % ;含量测定的线性范围为 0 12 5 0～ 8 0 18g·L-1;该方法平均回收率为 99 2 %～ 10 3 0 % ;低浓度的日内RSD和日间RSD分别为 3 4 9%和 3 96 %。结论微柱离心 气相色谱法可作为 β 榄香烯脂质体制剂质量控制的手段之一     

Influence of physicochemical properties of fluoroquinolones on encapsulation efficiency in liposomes

Three fluoroquinolones, ciprofloxacin, norfloxacin and a newly synthesized compound (CNV-8912), were encapsulated in liposomes of DPPC at pH 7.40 and encapsulation efficiency was determined by two methods: spectrophotometry of isopropanol-lysed vesicles and HPLC. These methods are compared with a view to the reproducibility and sensitivity of each technique. Physicochemical properties such as octanol-buffer coefficients and pKs were determined in order to interpret the encapsulation efficiency values in terms of affinity for lipid environments and microspeciation at pH 7.40.     

黄芩苷脂质体的包封率测定和体外释放度考察

目的：测定黄芩苷脂质体的包封率，并考察其体外释放规律。方法：用逆相法制备黄芩苷脂质体。用葡聚糖凝胶G-50柱分离脂质体和游离药物，用HPLC法测定包封率。按照中国药典2005年版溶出度第三法考察黄芩苷脂质体体外释放规律。结果：测得黄芩苷脂质体平均包封率为54．4％，黄芩苷脂质体的体外释放规律符合一级动力学方程。结论：黄芩苷脂质体具有较高的包封率，在体外具有良好的缓释作用。     

Encapsulation efficiency of water-soluble and insoluble drugs in liposomes prepared by the microencapsulation vesicle method

The microencapsulation vesicle (MCV) method is a liposome preparation technique that reproducibly produces liposomes with homogeneous particle sizes with a high encapsulation efficiency. Liposomes encapsulating water-soluble drugs, lipophilic drugs and an amphiphilic drug were prepared by the MCV method and the encapsulation efficiency of the drugs was examined. Three kinds of egg yolk lecithin with different iodine values, i.e., purified egg yolk lecithin (PEL), partially hydrogenated purified egg yolk lecithin (R-20) and completely hydrogenated purified egg yolk lecithin (R-5), were used for membrane materials in order to explore the possible effects of membrane rigidity or surface area on the encapsulation efficiency of the drug. Water-soluble 5-fluorouracil showed 12-15% encapsulation efficiency, which was higher than those reported in the literature (less than 10%). With the MCV method, theoretically the initial drug-containing water phase was always separated from the dispersion medium by the lecithin-containing oil phase, which was advantageous to maintaining a higher encapsulation efficiency of the water-soluble drug. The encapsulation efficiency of lipophilic ibuprofen and flurbiprofen was around 90%. As for ketoprofen and liposomes were not formed when using hydrogenated egg yolk lecithin R-5, while the encapsulation efficiency using PEL or R-20 was around 80%. Amphiphilic amitriptyline hydrochloride resulted in a slightly higher encapsulation efficiency when dissolved in the water than the chloroform. Among the three kinds of lecithin, the most unsaturated PEL tended to show a higher encapsulation efficiency, probably due to differences in the packing geometry of the hydrophobic carbon chains in the membrane bilayer. The encapsulation efficiency of these drugs strongly correlated to the logP(octanol/water) and also tended to correlate to the logP(chloroform/water) for the order of the logP(chloroform/water) was almost the same as the order of the logP(octanol/water) in the drugs examined. As far as the results of this study, the logP(octanol/water) was considered to be a better indicator of the encapsulation efficiency of a drug in the MCV method.