NGR多肽修饰的9-硝基喜树碱隐形脂质体药剂学性质与抗肿瘤作用研究

目的 考察NGR修饰前后9-硝基喜树碱(9-nitrocamptothecin,9-NC)隐形脂质体的药剂学性质与抗肿瘤作用。方法 采用薄膜-超声化法制备NGR修饰9-NC隐形脂质体,以未经NGR修饰的隐形脂质体作对照,考察包封率、体外释放度、内酯稳定性等药剂学性质;以HT1080为细胞模型,MTT法考察NGR修饰与未修饰9-NC隐形脂质体对细胞生长的影响,流式细胞实验比较NGR修饰与未修饰组的入胞效率。结果 NGR修饰对9-NC隐形脂质体的药剂学性质没有显著影响。修饰后的9-NC隐形脂质体对HT1080细胞的抑制率明显高于未修饰组(P<0.05),流式细胞实验显示修饰后的脂质体入胞效率显著提高。结论 NGR修饰能够显著提高9-NC隐形脂质体的抗肿瘤效果和入胞效率。     

吐温80对9-硝基喜树碱脂质体药物动力学性质的影响

目的:考察吐温80对9-硝基喜树碱(9-NC)脂质体体内药物动力学以及内酯型/羧酸盐型平衡的影响。方法:采用薄膜法制备9-NC脂质体以及吐温80修饰的9-NC脂质体;12只大鼠随机分为两组,按1.5 mg.kg-1剂量分别给予9-NC普通脂质体和吐温80修饰的脂质体,于不同时间点取血,处理后测定9-NC内酯型浓度和总浓度(内酯/羧酸盐)。采用统计矩模型利用3P97程序计算药物动力学参数。结果:采用表面活性剂吐温80进行修饰后,9-NC内酯型和总浓度的AUC分别提高了1.47倍和1.65倍,内酯型和总浓度的清除率CL和表观分布容积Vss显著下降(P<0.01)。此外,总浓度的MRT以及t1/2延长(P<0.05)。结论:吐温80修饰使得9-NC内酯型比例有所下降,但没有显著性差异,9-NC吐温修饰对9-NC脂质体具有一定的长循环效果。     

HPLC法测定大鼠尿液中9-硝基喜树碱的浓度

目的:建立 HPLC 法测定大鼠尿液中9-硝基喜树碱(9-NC)浓度。方法:尿液样品中加入内标喜树碱后,用甲醇-乙腈(1:1)沉淀后离心取上清液进样。采用 Diamonsil C~(18)柱(250 mm×4.6 mm,5 μm)分离,流动相为乙-1%三乙胺(冰醋酸调 pH 至6.5)(45:55),流速1.0 mL·min~(-1),检测波长370 nm。测定静脉注射3 mg·kg~(-1)9-NC 溶液和其脂质体溶液后大鼠尿液中原形药物的排泄情况。结果:线性范围72～18000 ng·mL~(-1),定量限为72 ng·mL~(-1)。静脉注射9-NC 溶液和脂质体溶液后24 h 尿液中原形药物的累积排泄量分别为给药剂量的5.9%和7.6%。结论:本方法简便实用,定量准确,并成功应用于静脉注射9-NC 脂质体后原形药物肾排泄的研究。     

共聚物胶束对硝基喜树碱内酯环稳定性的影响

目的 评价共聚物胶束对9-硝基喜树碱(9-NC)内酯环稳定性的影响.方法 采用HPLC法测定,以甲醇-PBS(70:30,pH6.5)为流动相,检测波长370 nm,流速1ml ·min-1.结果 内酯和羧酸盐形式的9-NC能完全分离;在PBS(pH7.4)中培养160 min后,载药胶束中具有抗肿瘤活性的9-NC内酯比例占80%,而无胶束包覆的原料药中内酯比例仅15%.结论 共聚物胶束能有效提高9-NC内酯环结构的稳定性.     

正在研究中的抗肿瘤新药9-硝基喜树碱

9-硝基喜树碱(9-NC)为一个半合成喜树碱衍生物,其药理作用主要表现为对拓扑异构酶Ⅰ的抑制.目前,对9-NC的研究已进入Ⅱ期或Ⅲ期临床试验,具有广泛的抗肿瘤活性,且毒性较低,是极具潜力的抗肿瘤新药.现对其药理作用、药动学、临床前研究等作一综述.     

9-硝基喜树碱磷脂/胆盐混合胶束的制备及其性质研究

目的 制备9-硝基喜树碱磷脂/胆盐混合胶束(9-NC MMs),进行单因素处方筛选及初步性质研究.方法 采用共沉淀法制备9-NC MMs;通过单因素考察,研究蛋黄卵磷脂(EPC)/脱氧胆酸钠(SDC)比例、辅料总浓度、水化介质离子强度对9-NC在混合胶束中溶解度的影响及抗氧剂叔丁基羟基茴香醚(BHA)用量筛选;拟定处方,考察9-NC MMs的粒径、形态、稀释稳定性和溶血性.结果 9-NC MMs优化处方为:EPC/(EPC+ SDC)为0.4;辅料总浓度为2.5％;水化介质为0.9％NaC1溶液,BHA用量为0.005％.在此处方下,9-NC在水中的溶解度可提高到1 mg· mL-1;9-NC MMs具有良好的稀释稳定性,载药胶束平均粒径为7.04 nm,透射电镜说明胶束形态为均匀类圆形,无溶血作用.结论 9-NC EPC/SDC MMs的制备工艺简便,能有效提高9-NC溶解度,粒径分布理想、稳定性好、安全性好,便于临床静脉注射的应用.     

静脉注射9-硝基喜树碱脂质体后原形药物经大鼠胆汁的排泄

目的:考察静脉注射9-硝基喜树碱脂质体后原形药物经大鼠胆汁的排泄。方法:建立了利用HPLC法测定大鼠胆汁中9-硝基喜树碱浓度的方法;测定了9-硝基喜树碱在大鼠空白胆汁中的内酯型浓度、总浓度和内酯型比例的变化;测定了静脉注射3mg.kg-19-硝基喜树碱溶液和脂质体后大鼠胆汁中原形药物的排泄情况。结果:9-硝基喜树碱内酯型结构在胆汁中不稳定,内酯型浓度和比例迅速下降但总浓度保持恒定。静脉注射9-硝基喜树碱溶液和脂质体后12h胆汁中原形药物的累积排泄量分别为给药剂量的7.9%和8.1%。结论:脂质体包封对于9-硝基喜树碱静脉注射后的胆汁排泄没有显著影响     

9-硝基喜树碱口服自微乳化系统的制备与体外评价

目的:制备9-硝基喜树碱(9-NC)口服自微乳给药系统(SMEDDS),并考察其对肿瘤细胞生长抑制作用.方法:采用伪三元相图法优化微乳处方组成.稀释法评价了9-NC SMEDDS乳化性能,并考察了9-NC SMEDDS乳化后获得的微乳制剂(9-NCME)对4种肿瘤细胞的体外细胞毒活性.结果:由油酸乙酯,Tween 80,PEG400,无水乙醇组成的9-NC SMEDDS遇水可白发形成粒径＜50 nm的稳定微乳(9-NCME).体外细胞毒研究表明,与溶液剂组(9-NCSol)和混悬液组(9-NCSu)相比,微乳制剂(9-NCME)对肿瘤细胞MDA-MDB-231,MCF-7,SKOV3和SH5Y的IC50值显著减小(P＜0.01).结论:本研究中制备的9-NCSMEDDS具备良好的自乳化性能,并可增强9-NC的体外抗肿瘤活性.     

9-硝基喜树碱的稳定性初步考察

目的:研究影响因素试验(光线、温度、湿度)、加速试验、长期试验中9-硝基喜树碱(9-NC)的外观性状、有关物质(12-NC)及含量的变化,初步考察其稳定性。方法:利用高效液相色谱法,通过与对照品比较,观察变化的情况。色谱柱:Eclipse~XDB-C_(18)(4.6 mm×150 mm,5μm);流动相:乙腈-水(28.5:71.5);流速:1.0 mL·min~(-1);检测波长:368 nm;柱温:25℃。结果:9-NC 仅对光不稳定,其外观性状、有关物质及含量在高温、高湿度试验,加速试验和长期试验中无明显变化。结论:9-NC 应当避光保存,保证其相对稳定。     

不同内酯型比例9-硝基喜树碱对胆汁排泄的影响

目的考察9-硝基喜树碱(9-nitrocamptothecin,9-NC)不同形式(内酯型或羧酸盐型)给药对胆汁排泄的影响。方法建立HPLC测定胆汁中9-NC浓度的方法,比较不同内酯型比例的9-NC溶液以4 mg·kg?1剂量静脉注射后大鼠胆汁中原形药物的排泄量。结果静脉注射100%,75%,50%,25%,0%内酯型比例的9-NC在8 h内的胆汁累积排泄百分数分别为(7.03±2.23)%,(13.36±0.83)%,(22.68±4.83)%,(28.01±6.71)%,(32.65±2.82)%。结论 9-NC羧酸盐型更易经胆汁途径排泄。     

Self-microemulsifying drug delivery system (SMEDDS) improves anticancer effect of oral 9-nitrocamptothecin on human cancer xenografts in nude mice.

9-Nitrocamptothecin (9-NC) is an orally administered topoisomerase-I inhibitor for the treatment of pancreatic carcinoma, but its oral absorption and bioavailability are poor. The main objective of this study was to develop optimal 9-nitrocamptothecin (9-NC) microemulsion prepared by self-microemulsifying drug delivery system (SMEDDS). Two SMEDDS formulations of 9-NC prepared from a mixture of ethyl oleate, Tween-80 (T-form) or Cremophor EL (C-form), and PEG-400/ethanol were formed as microemulsions under dilution with aqueous phase. The resulting microemulsions were evaluated in vitro and in vivo, including the kinetics and antitumor effects in SKOV-3 human ovarian cancer xenograft in nude mice. Following 1:10 aqueous dilution of optimal 9-NC SMEDDS, the droplet sizes of resulting microemulsions were (30.8+/-4.6)nm and (39.8+/-8.2)nm for SMEDDS T-form and C-form, respectively, and the zeta potential values were -(4.3+/-0.5)mV and -(5.7+/-0.5)mV, respectively. In SKOV-3 cells, the growth inhibition (IC(50)) of various 9-NC formulations was greatest with SMEDDS T-form (3.5+/-0.7nM) followed by SMEDDS C-form (4.6+/-0.4nM), 9-NC solution (6.6+/-1.4nM) and 9-NC suspension (26.0+/-2.9nM) (P<0.01). It was indicated that the area under the plasma concentration-time curve (AUC(0-->8h)) values of various formulations of 9-NC after oral administration ranked as the following sequence: SMEDDS T-form (360.12+/-19.44ngh/ml) approximately SMEDDS C-form (351.71+/-33.66ngh/ml)>9-NC solution (241.21+/-24.67ngh/ml)>9-NC suspension (161.24+/-24.31ngh/ml). The 9-NC SMEDDS formulations also produced significantly more tumor shrinkage (P<0.01) when compared to 9-NC suspension in nude mice bearing human ovarian cancer xenografts. The results suggest that SMEDDS is a promising drug delivery system to increase the oral bioavailability and antitumor effects of 9-NC and may be applied to other lipophilic drugs. 9-NC SMEDDS represents a novel 9-NC therapy for cancer patients.     

9-nitrocamptothecin polymeric nanoparticles: cytotoxicity and pharmacokinetic studies of lactone and total forms of drug in rats

The objective of this study was to evaluate the cytotoxicity and pharmacokinetics of total and lactone forms of 9-nitrocamptothecin (9-NC), an effective antineoplastic drug, after intravenous injection of drug incorporated into poly (DL-lactic-glycolic acid) nanoparticles (NPs). Drug-loaded NPs (9-NC.NP) were prepared by the nanoprecipitation method and examined for particle characteristics and in-vitro release in phosphate buffered saline. The best formulation showed a narrow size with an average diameter of 207+/-26 nm and a drug loading of more than 33.5%. The drug release profile showed a sustained 9-NC release up to 160 h. For a pharmacokinetic study, the concentration of 9-NC as the lactone form (9-NC.lac) and as the total of the lactone and carboxylate forms (9-NC.tot) in plasma was determined by using reverse-phase high performance liquid chromatography after intravenous administration of 9-NC.NP and a control solution to cannulated Wistar rats. In-vitro cytotoxic activity of 9-NC.NP and control solution was evaluated on the human ovarian cancer cell line (A2780sn) by MTT cell cytotoxicity assay. Results of in-vivo studies showed that NP encapsulation markedly increased the plasma concentration of both lactone and total forms of 9-NC compared with free drug. In comparison with free drug, NPs resulted in 3.63-fold and 5.40-fold increases in area under the plasma concentration-versus-time curve (AUC(0-infinity)) for lactone and total forms of 9-NC, respectively. The values of mean residence time and elimination half-life (T(1/2)) were also significantly higher for NPs than for free drug. The in-vitro cytotoxicity study revealed that the IC50 value of NPs decreased 10-fold compared with the drug solution. Prepared NPs described here were considered potentially useful in both stabilizing and delivering 9-NC and enhancing the efficacy of this drug for cancer treatment for which high drug retention in the body, protection from the drug-active lactone form, and gradual drug release appeared to be related.     

A phase II clinical and pharmacological study of oral 9-nitrocamptothecin in patients with refractory epithelial ovarian, tubal or peritoneal cancer.

9-Nitrocamptothecin (9-NC) is a water-insoluble topoisomerase I inhibitor with a broad antitumor activity in animal models. A phase II study was performed in patients with heavily refractory ovarian, tubal or peritoneal cancer (median number of previous chemotherapy regimens > 3) to determine the activity of a daily oral dose of 9-NC. 9-NC dose was 1.5 mg/m2/day for four consecutive days every week. Increments of 0.25 mg/day were authorized in patients without significant side effects. Of 29 evaluable patients, a 7% remission rate was observed. Thirty-four percent of patients had stable disease. The median survival was 8 months. Toxicity was evaluated in 31 patients. Grade 3 or 4 hematologic toxicity consisted of anemia in 10 patients (32%), neutropenia in eight (26%) and thrombocytopenia in three (10%). Grade > or = 2 non-hematologic toxic effects were nausea and vomiting in 26 (84%), diarrhea in 12 (39%), weight loss in seven (22%), chemical cystitis in six (19%) and neutropenic sepsis in six (19%). 9-NC was tolerated for sustained periods of time in some patients (up to 47 weeks). The observed 8-month survival in such a refractory patient population is noteworthy. Further clinical research of prolonged exposure to less toxic analogs of 9-NC is warranted.     

Pharmacokinetics of lactone, carboxylate and total 9-nitrocamptothecin with different doses and administration routes in rats

9-Nitrocamptothecin (9-NC) is a newly developed poorly soluble derivative of camptothecin and has a wide spectrum of anticancer activity in preclinical evaluation. The effects of the dose and administration route on pharmacokinetics and lactone/carboxylate equilibrium of 9-NC were studied in rats. A single intravenous dose of 1.5, 3 or 6 mg/kg of 9-NC solution was given to male rats (n = 6 per dose level). In another study, a single dose of 6 mg/kg 9-NC solution was given orally to rats (n = 6). Plasma samples were drawn at predetermined intervals and the concentrations of lactone, carboxylate and total 9-NC were determined by a validated HPLC method. Pharmacokinetic analysis was performed using non-compartmental analysis. Analysis of variance showed that the pharmacokinetic characteristics of lactone, carboxylate and total 9-NC were all independent of dose (p > 0.05). Based on the AUC measurements, the lactone 9-NC constituted 52% +/- 4%, 49% +/- 6% and 55% +/- 6% of the circulating total 9-NC in rats after intravenous administration of 1.5, 3, 6 mg/kg 9-NC solution, respectively. After oral administration of 6 mg/kg, the pharmacokinetics parameters were significantly different from those of intravenous administration at the same dose (p < 0.05). The lactone ratio was 60% +/- 14%. The absolute bioavailability of lactone and total 9-NC were calculated to be 23.4% and 22.7%, respectively. In conclusion, the pharmacokinetics of lactone, carboxylate and total 9-NC are not dose-dependent. Lactone, carboxylate and total 9-NC are poorly absorbed following oral administration. Both the dose and the route of administration have little effect on the lactone/carboxylate equilibrium of 9-NC in rats in vivo. But the route of administration plays an important part on the pharmacokinetics of 9-NC.     

米托蒽醌隐形阳离子脂质体的制备及体内外抗肿瘤活性

目的:制备米托蒽醌隐形阳离子脂质体(YM),并研究其制剂学性质及体内外抗肿瘤作用。方法:膜材料中引入2-二油酰基羟丙基-3-N,N,N-三甲铵氯(DOTAP)和聚乙二醇2000-二硬脂酰磷脂乙醇胺(DSPE-PEG₂₀₀₀)分别作为阳性和隐形膜材,采用硫酸铵梯度法制备YM,并以泄漏率为指标,考察其稳定性;高内涵扫描仪考察2 h时其在B16F10细胞中的摄取情况;MTT 法测定其对B16F10细胞的增殖影响;B16F10皮下移植瘤模型研究其体内抗肿瘤作用。结果:YM的粒径和Zeta电位分别为(118.2±4.6)nm和(31.6±4.9)mV;载药量和包封率分别为(6.5±0.2)%和(96.2±1.8)%;血清中48 h累积泄漏率<30%,稳定性良好;YM的细胞摄取量是普通长循环脂质体(CM)的10倍,IC₅₀与CM相比显著降低(P<0.05),体内抑瘤率为58.8%,显著高于CM组的42.7%。结论:YM稳定性良好,具有较好的体内外抗肿瘤活性。     

Preparation and characterization of novel polymeric micelles for 9-nitro-20(S)-camptothecin delivery.

9-Nitro-20(S)-camptothecin (9-NC) has achieved remarkable curative effect in anticancer research. However, the clinical application of 9-NC is largely hampered by its poor solubility and stability. In this paper, novel amphiphilic block copolymers derived from d,l-lactide, trimethylene carbonate, and methylated poly(ethylene glycol) (mPEG) (PECA) with different molecular weight were synthesized and characterized. Self-assembly PECA micelles loaded with 9-NC were prepared. The micelles were regular spheres with a diameter ranged from 20 to 120 nm. The critical micelle concentration (CMC) decreased with the increase of the hydrophobic components. The solubility of 9-NC was improved obviously with micelle encapsulation. The stability experiments proved that over 90% of 9-NC could keep its lactone form in micelle solution after incubating in phosphate-buffered saline for 100 min, while the corresponding proportion for free drug solution was 25%. The release of 9-NC was nearly zero-order after the burst release, and the long hydrophobic chain length led to slower release rate. The novel PECA copolymer micelles could be effective carriers to improve the solubility, stability, and release performance of 9-NC.     

Encapsulation of 9-nitrocamptothecin, a novel anticancer drug, in biodegradable nanoparticles: factorial design, characterization and release kinetics.

This study was aimed at developing a polymeric drug delivery system for a new and potent antitumor drug, 9-nitrocamptothecin (9-NC), intended for both intravenous administration and improving the therapeutic index of the drug. To achieve these goals, 9-NC loaded poly(DL-lactide-co-glycolide) (PLGA) nanoparticles were prepared by nanoprecipitation method and characterized. The full factorial experimental design was used to study the influence of four different independent variables on response of nanoparticle drug loading. Analysis of variance (ANOVA) was used to evaluate optimized conditions for the preparation of nanoparticles. The physical characteristics of PLGA nanospheres were evaluated using particle size analyzer, scanning electron microscopy, differential scanning calorimetry and X-ray diffractometry. The results of optimized formulations showed a narrow size distribution with a polydispersity index of 0.01%, an average diameter of 207+/-26 nm, and a drug loading of more than 30%. The in vitro drug release profile showed a sustained 9-NC release up to 160 h indicating the suitability of PLGA nanoparticles in controlled 9-NC release. Thus prepared nanoparticles described here may be of clinical importance in both stabilizing and delivering camptothecins for cancer treatment.     

Preparation and in vitro characterization of paclitaxel-loaded pH-responsive polymeric micelles based on poly(2-ethyl-2-oxazoline)-vitamin E succinate

To ensure the delivery of antitumor drugs to tumor site and quick release in tumor cells, we designed and prepared pH-sensitive polymeric micelles by combining cationic ring-opening polymerization of 2-ethyl-2-oxazoline (EOz) with vitamin Esuccinate (VES), and then encapsulating paclitaxel (PTX) into the micelles self-assembled by poly(2-ethyl-2-oxazoline)-vitamin E succinate (PEOz-VES). The structure of the synthesized PEOz-VES was confirmed by ¹H NMR spectrum, and the molecular weight measured by GPC was 1212 g/mol. The pK_a of PEOz-VES with a low critical micelle concentration of (5.84±0.02) mg/L was determined to be 6.01. The PTX-loaded PEOz-VES polymeric micelles prepared by film hydration method were characterized to have a nanoscaled size of about 30 nm in diameter, a positive Zeta potential of 4.86 mV and uniform spherical morphology by TEM observation. The drug loading content and encapsulation efficiency were (2.63±0.16)% and (84.1±3.38)%, respectively. The in vitro release behavior of PTX from PEOz-VES micelles in PBS displayed pH-dependent pattern and was gradually accelerated with decrease of pH value, implying that the micelles could distinguish endo/lysosomal pH and tumor extracellular pH from physiological pH by accelerating drug release. Therefore, the designed PEOz-VES micelles might have significant promise for anti-cancer drug delivery.     

Effect of injection routes on pharmacokinetics and lactone/carboxylate equilibrium of 9-Nitrocamptothecin in rats

Pharmacokinetics and lactone/carboxylate equilibrium of 9-Nitrocamptothecin (9-NC) were compared after intravenous (i.v.) and intramuscular (i.m.) injection at a dose of 1.5 mg/kg 9-NC solution. The concentrations of three different forms of 9-NC, namely lactone, carboxylate and total 9-NC, were measured by HPLC analysis. Injection routes were demonstrated to have significant effect on pharmacokinetics of 9-NC. Compared with i.v. injection route, mean residence time (MRT) of 9-NC three forms was significantly prolonged following i.m. route (p < 0.05). The AUC_0–∞ ratios of i.m. to i.v. route were calculated to be 102 ± 43%, 273 ± 221% and 150 ± 62% for lactone, carboxylate and total 9-NC, respectively. Compared with i.v. injection route, although AUC_0–∞ was barely changed, MRT of lactone 9-NC was dramatically prolonged 4.5-fold after i.m. injection, which may account for the reported improved antitumor efficacy. However, the results of the present study also demonstrated that i.m. injection route increased both AUC_0–∞ and MRT of carboxylate 9-NC more significantly. Since the carboxylate form of CPT analogs including 9-NC is associated with their unwanted toxicity, i.m. injection route might lead to severe toxicity compared with i.v. route. Lactone/carboxylate equilibrium was also significantly influenced by injection routes. Based on the AUC_0–∞ measurements, the lactone 9-NC constituted 50 ± 8% and 32 ± 7% of circulating total 9-NC after i.v. or i.m. administration, respectively (p < 0.01).