9-硝基喜树碱内酯型在大鼠体内外的稳定性

目的考察9-硝基喜树碱内酯型在大鼠体内和离体大鼠血浆中的稳定性.方法建立利用HPLC法测定大鼠血浆中9-硝基喜树碱内酯型浓度和总浓度的方法;利用此法测定9-硝基喜树碱在离体大鼠血浆、全血及体内血浆中的内酯型比例变化以及大鼠尾静脉注射后不同时间点的内酯浓度和总浓度;并对体内外实验结果进行比较以确定影响血浆中内酯型稳定性的主要因素.结果9-硝基喜树碱内酯型在大鼠体内的稳定性显著优于体外,在体外全血中的稳定性显著优于血浆.结论血细胞具有稳定9-硝基喜树碱内酯型的作用;药物从血浆中的清除是影响体内大鼠血浆中9-硝基喜树碱内酯型比例的主要因素;9-硝基喜树碱内酯型浓度和总浓度在大鼠体内的药代动力学过程符合二室模型,而羧酸盐型浓度符合一室模型.     

9-硝基喜树碱内酯型在大鼠体内外的稳定性9-硝基喜树碱内酯型在大鼠体内外的稳定性

目的考察9-硝基喜树碱内酯型在大鼠体内和离体大鼠血浆中的稳定性。方法建立利用HPLC法测定大鼠血浆中9-硝基喜树碱内酯型浓度和总浓度的方法；利用此法测定9-硝基喜树碱在离体大鼠血浆、全血及体内血浆中的内酯型比例变化以及大鼠尾静脉注射后不同时间点的内酯浓度和总浓度；并对体内外实验结果进行比较以确定影响血浆中内酯型稳定性的主要因素。结果9-硝基喜树碱内酯型在大鼠体内的稳定性显著优于体外，在体外全血中的稳定性显著优于血浆。结论血细胞具有稳定9-硝基喜树碱内酯型的作用；药物从血浆中的清除是影响体内大鼠血浆中9-硝基喜树碱内酯型比例的主要因素；9-硝基喜树碱内酯型浓度和总浓度在大鼠体内的药代动力学过程符合二室模型，而羧酸盐型浓度符合一室模型。     

静脉注射不同比例内酯型9-硝基喜树碱的荷瘤小鼠药动学和组织分布

采用摇瓶法测定内酯型和羧酸盐型9-硝基喜树碱(1)的油水分配系数,结果为145.5±2.96和0.034±0.26.建立了HPLC法同时测定小鼠组织和血浆中1的内酯型浓度和总浓度.静脉注射给予S180荷瘤小鼠不同比例的内酯型1溶液,结果显示给药时内酯型比例对其在小鼠体内的组织分布有明显影响.在血浆中,测得的内酯型浓度随给药时内酯型比例的变化而变化,而总浓度却与给药时内酯型比例关系不大.在肿瘤组织中,给药的内酯型1比例为100％和75％时,测得的内酯型和总量的AUC结果相近;其他各组测得的内酯型和总量的浓度均随给药时内酯型1比例(50％、25％和0)降低而降低.肝、肾组织中测得的内酯型比例与给予比例没有明显相关性(如肾)或呈现出负相关(如肝).这可能与肝、肾是羧酸盐型1的主要排泄途径有关.     

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。     

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     

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。     

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.     

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.     

羟喜树碱冻干粉针和纳米制剂在原位肝肿瘤小鼠的组织分布研究

目的测定静脉注射羟喜树碱(HCPT)冻干粉针及纳米制剂后小鼠肝组织、肝肿瘤及血浆中的药物质量浓度,探讨改良纳米羟喜树碱对肝癌疗效的提升作用。方法以HPLC法检测小鼠血浆、正常肝组织和肝肿瘤组织中羟喜树碱的质量浓度。原位肝肿瘤模型小鼠50只,其中20只随机分成2组,每组10只,分别尾静脉注射HCPT冻干粉针和纳米制剂,给药剂量5 mg.kg-1,给药后15 min,内眦取血,测定肝组织、肝肿瘤及血浆中的药物质量浓度;另30只设氯化钠对照组、HCPT粉针剂组和HCPT纳米治疗组,每组10只,给药剂量5 mg.kg-1,每周给药2次,分别于第1和第4天给药,共给药2周。2周后内眦取血,测定肝组织、肝肿瘤及血浆中的药物质量浓度。结果给药后15 min HCPT纳米制剂血药质量浓度最高(612.32±21.12)μg.L-1,HCPT纳米在肝脏及肿瘤组织中药物质量浓度是HCPT粉针剂组的12和11倍;给药2周后HCPT纳米在肝脏、肿瘤组织中药物质量浓度为(89.45±16.35)和(93.74±18.91)μg.L-1,且HCPT纳米在肝脏及肝脏肿瘤组织中药物质量浓度与血浆药物质量浓度[(2.13±0.51)μg.L-1]比较,差异有统计学意义(P<0.05)。结论 HCPT纳米与粉针剂相比,可稳定内酯环结构,增加组织亲和力,提高靶向疗效,是可靠的改良新剂型。     

载药胶束在大鼠血液和组织中的分布

目的评价负载9-硝基喜树碱(9-NC)共聚物胶束在大鼠血液和组织中的分布情况。方法大鼠尾静脉注射1.5mg.kg-1载药胶束,在各时间点测定血液和组织样品中的药物浓度,检测波长370 nm。结果与原料药相比,载药胶束能降低其在网状内皮组织的药物分布浓度,并有效延长血液循环时间;可穿越血脑屏障,实现药物在大脑组织中的分布。结论共聚物胶束能延长9-NC在血液中的循环时间和改善在大鼠体内的组织分布。     

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.     

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.     

9-硝基喜树碱纳米脂质载体系统的释放、细胞摄取及组织分布特性

目的研究9-硝基喜树碱纳米脂质载体系统的体外释放、巨噬细胞摄取及体内组织分布特性。方法以BLB/C小鼠腹腔巨噬细胞为细胞模型进行9-硝基喜树碱纳米脂质载体系统的体外细胞吞噬实验；以一级昆明种小鼠为动物模型进行体内组织分布实验；并进行多晶X-射线衍射及体外释放实验的测定。结果9-硝基喜树碱可能以无定形物分散在纳米脂质载体中，液态脂质的加入并没有改变纳米粒固态内核的性质；体外释放实验表明纳米脂质载体系统具有一定的缓释特性；PEG的修饰使巨噬细胞对纳米粒的摄取减少，且能够增强纳米粒抵抗蛋白吸附的能力；纳米脂质载体系统能够延长9-硝基喜树碱在血中的滞留时间，并改变其在小鼠体内的分布特征。结论由Myrj59制备的纳米脂质载体系统具有缓释特性，且具有良好的长循环性及肝、肺靶向性。     

HPLC法测定人血浆中9-硝基喜树碱内酯型浓度和总浓度

目的:建立以高效液相色谱法测定人血浆中9-硝基喜树碱内酯型浓度和总浓度的方法。方法:血浆样品采用—20℃甲醇快速沉淀蛋白后进行测定,其中色谱柱为shim-packCLS-ODS,流动相为甲醇∶1%三乙胺(冰醋酸调pH6.5)=55∶45,流速为1.0mL·min-1,检测波长370nm,进样量为50μL,柱温为40℃。测定总浓度的样品采用冰醋酸酸化上清液。并以该法测定了不同时间点离体人血浆中9-硝基喜树碱内酯型、羧酸盐型浓度和总浓度的变化。结果:9-硝基喜树碱血药浓度在0.10～10.0μg·mL-1范围内线性关系良好(r=0.9991),定量下限为0.10μg·mL-1,平均方法回收率、酸化回收率各为101.02%、101.46%。结论:本法操作简便、快速,适用于9-硝基喜树碱内酯结构稳定性的研究。     

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).     

Plasma and tissue disposition of non-liposomal DB-67 and liposomal DB-67 in C.B-17 SCID mice

Purpose: DB-67 is a silatecan, 7-silyl-modified camptothecin, with enhanced lipophilicity and increased blood stability of the active-lactone ring. The generation of a liposomal formulation of DB-67 may be an attractive method of intravenous (IV) administration and may maintain DB-67 in the active-lactone form. We evaluated the tissue and plasma disposition of DB-67 lactone and hydroxy acid after administration of non-liposomal (NL) and liposomal (L) DB-67 in severe combined immunodeficient (SCID) mice. Methods: NL-DB-67 and L-DB-67 10 mg/kg IV x 1 were administered via a tail vein in SCID mice. After dosing, mice (n = 3 per time point) were euthanized and blood ( approximately 1 ml) and tissue were collected from 5 min to 48 h after administration. DB-67 lactone and hydroxy acid concentrations in plasma and DB-67 total (sum of lactone and hydroxyl acid) concentrations in tissues were determined by high-performance liquid chromatography (HPLC) with fluorescence detection. Results: Clearance of DB-67 lactone after administration of NL-DB-67 and L-DB-67 were 1.6 and 3.5 l/h/m(2), respectively; DB-67 lactone half-lives after administration of NL-DB-67 and L-DB-67 were 1.4 and 0.9 h, respectively. The percentages of DB-67 lactone in plasma after administration of NL-DB-67 and L-DB-67 were 92% and 89%, respectively. Liver, kidney, spleen, and lung tissues had longer exposure times to DB-67 after administration of L-DB-67 compared with NL-DB-67. Conclusion: In plasma, the majority of DB-67 remained in the lactone form after administration of NL-DB-67 and L-DB-67. The plasma disposition of DB-67 was similar after administration of NL-DB-67 and L-DB-67, suggesting that most of the DB-67 is immediately released from the L-DB-67 formulation. Following administration of L-DB-67, the higher and longer exposure of DB-67 in the spleen, as compared with NL-DB-67, is consistent with splenic clearance of liposomes by the reticuloendothelial system.     

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.     

9-硝基喜树碱包合物脂质体的制备与评价

目的:制备9-硝基喜树碱包合物脂质体以提高其抗肿瘤效果。方法:饱和水溶液法制备9-硝基喜树碱包合物,考查制备包合物脂质体的最佳方法和工艺,制备9-硝基喜树碱包合物隐形脂质体并评价其药剂学性质及抗肿瘤效果。结果:9-NC包合物脂质体最佳工艺为乙醇注入法以10 mg胆固醇,720 mg磷脂,1.0 g包合物处方制备。所制备的9-NC包合物脂质体平均粒径为(112.10±0.81) nm,包封率为(60.11±1.08)%,且体外抗肿瘤效果显著提高。结论:包合物脂质体是喜树碱类药物的抗肿瘤应用的有效载体。