紫杉醇隐形脂质体的制备及在小鼠体内的组织分布

目的　研究紫杉醇隐形脂质体的制备方法并考察其在小鼠体内的组织分布。方法　采用共沉淀和微流态化两步法制备紫杉醇隐形脂质体,用两亲性聚乙二醇-二硬脂酰磷脂酰乙醇胺(PEG-DSPE)修饰脂质体膜。以RP-HPLC法测定小鼠组织内紫杉醇药物浓度。结果　隐形脂质体粒径≤100 nm,药物包封率≥98%。均以5 mg.kg^-1经iv脂质体紫杉醇和游离紫杉醇,24 h后紫杉醇隐形脂质体在血液中驻留35%以上,在肝脾组织中摄取不足10%。而膜材中不含PEG-DSPE的紫杉醇传统脂质体在血液中驻留10%,被单核吞噬细胞系统(mononuclear phagocyte system, MPS)捕获了50%以上。证明紫杉醇隐形脂质体延长了在血循环中的时间并减少了MPS的吞噬。血液AUC隐形脂质体约为传统脂质体的2.0倍。结论　采用共沉淀和微流态化法可制得包封率高、粒径小的脂质体,用PEG-DSPE修饰磷脂膜可以增加隐形脂质体的AUC,并延长其在血循环中的时间。     

阿米卡星脂质体在小鼠体内的组织分布

用微生物测定法对阿米卡星脂质体在小鼠体内各组织中的药物浓度进行测定，研究了给药后组织浓度及分布情况，并将其与游离阿米卡星作比较。结果表明：小鼠单剂量静脉注射５２ｍｇ／ｋｇ游离的或脂质体硫酸阿米卡星后，测定０．５、１、３、７、１２、２４ｈ各组织中药物浓度，以肾脏浓度为最高。与游离药物相比，阿米卡星脂质体明显提高了心（６．２倍）、肝（９．５倍）、脾（２８４倍）、肺（３倍）、脑（１４．７倍）、血清（３倍）中的药物分布，降低了肾脏的分布（１／２）。阿米卡星脂质体不仅改变了该游离药物的体内组织分布，而且延长了半衰期，血药浓度可维持２４ｈ（游离药物仅７ｈ）。说明阿米卡星脂质体具有靶向和缓释的双重作用。     

磁性脂质体的制备及其在小鼠体内的分布磁性脂质体的制备及其在小鼠体内的分布

目的制备磁性脂质体并考察其理化性质及在小鼠体内的自然分布和诱导分布,从而探讨该系统在小鼠体内分布的规律和磁响应性。 方法采用反相蒸发法制备磁性脂质体,以邻二氮菲染色法测定脂质体中铁磁性物质的包载量,按中国药典之规定对其理化性质进行测定,采用同位素示踪的方法研究其在小鼠体内的分布情况。 结果 磁性脂质体平均粒径为602.5 nm,每毫升脂质体悬液可包载88.1 μg Fe₃O₄。自然状态下经尾静脉给药后磁性脂质体主要被脾脏摄取;而在磁场诱导条件下脾脏中摄取量减少,左右侧肝叶、左右侧肾脏中制剂分布产生明显的差异。结论采用反相蒸发法可以制得稳定、粒径均一、铁磁性物质包载量较高的磁性脂质体,同时其在小鼠体内能够对外磁场产生响应而定向分布。     

支链淀粉修饰双嘧达莫脂质体的制备及其在小鼠体内的组织分布

目的研究支链淀粉修饰双嘧达莫(DIP)脂质体的制备方法并考察其在小鼠体内的组织分布。方法 采用薄膜-分散法制备普通DIP脂质体；合成两亲性的棕榈酰化支链淀粉并用其修饰DIP脂质体；比较修饰前后包封率、zeta电位、平均粒径和径距的变化；采用反相高效液相法测定小鼠组织中的DIP浓度。结果修饰后DIP脂质体的包封率降低，zeta电位增加，平均粒径和径距无明显变化；普通脂质体可以增强DIP在肺部、肝脏和脾脏的分布，而较之普通脂质体，支链淀粉修饰的脂质体可以进一步增加肺部DIP水平，同时减少DIP在肝脏和脾脏的分布，并延长在肺部的滞留时间。结论与普通脂质体和注射液比较，支链淀粉修饰的脂质体可以改变DIP在小鼠体内的组织分布，具有显著的肺靶向性。     

紫杉醇糖被复脂质体的制备及其在小鼠体内的组织分布

用HPLC法测定小鼠单剂量（10mg／kg）尾静脉注射自制紫杉醇糖被复脂质体或市售紫杉醇注射剂后的心、肝、脾、肺、肾和血浆的药物浓度。结果表明，糖被复脂质体组紫杉醇主要被肺摄取，在肺部的滞留时间明显延长，肺中AUC为注射剂的9．6倍；并减少了肝、脾组织的蓄积量。说明此紫杉醇糖被复脂质体在小鼠体内的分布优于注射液，有明显的肺靶向性。     

卡莫司汀脂质体的制备及其在小鼠体内的分布

采用旋转蒸发法制备卡莫司汀(1)脂质体,以HPLC法测定小鼠单剂量(62.5 mg/kg)尾静脉注射1脂质体混悬液或溶液后血浆和各组织(脑、心、肺、脾和肾)中的药物浓度.结果表明,1脂质体组的血浆、脑、心、肺、脾和肾中的AUC分别为1溶液组的1.77、1.84、1.25、1.56、2.81和1.22倍.表明1制成脂质体后在小鼠体内的稳定性提高.     

星点设计-效应面法优化异长春花碱脂质体的处方

目的采用星点设计-效应面法优化异长春花碱脂质体的处方。方法以磷脂/药(质量比)、胆固醇/磷脂(摩尔比)、水化温度为考察因素,以脂质体的包封率和脂质体的平均粒径为指标,采用二次多项式方程描述考察指标和影响因素之间的数学关系,根据此数学模型描绘效应面,选择最佳处方,并进行预测分析。结果所建立的考察指标和影响因素之间的数学模型具有较高的可信度。以优化后的处方制备样品,各指标实测值与预测值偏差较小。结论所建立的模型预测性良好,制备的脂质体符合设计要求。     

肺靶向羟基喜树碱脂质体的制备及其在小鼠体内的组织分布研究

目的： 研究羟基喜树碱脂质体的制备方法并考察其肺靶向及在小鼠体内的分布。方法： 采用薄膜分散－冻融法制备,添加D-甘露糖和十八胺修饰可得到肺靶向羟基喜树碱脂质体;用HPLC法测定给药后小鼠体内不同组织中的药物浓度。结果： 制得的脂质体平均粒径大于2 μm,表面电荷为+21.5 mV,包封率大于65%,稳定性好,符合要求。羟基喜树碱脂质体和注射液经小鼠尾静脉给药后,脂质体主要被肺摄取,在肺部停留的时间较普通注射剂显著延长,其相对摄取率r_e为60.72,脂质体组的肺靶向效率t_e为17.57。结论： 本实验制得羟基喜树碱脂质体具有较高包封率及稳定性,在小鼠肺部浓度高、滞留时间长,能达到肺靶向目的。     

氟尿嘧啶脂质体在小鼠体内的组织分布及靶向性评价研究

目的:研究氟尿嘧啶脂质体(FU-Lip)在小鼠体内的组织分布,并评价其靶向性。方法:将90只小鼠随机均分为10组,前5组静脉注射FU-Lip,后5组静脉注射FU注射液,剂量均为25mg·kg-(1以FU计),采用高效液相色谱法测定各组小鼠血浆、心脏、肝、脾、肺、肾中24h内的FU浓度,分析药物组织分布情况,以24h内的相对摄取率(re=AUC脂质体/AUC注射液)和靶向效率(te=AUC组织/AUC血浆)判断FU-Lip对主要器官的靶向性。结果:各组织中FU浓度均先升高后降低;与FU注射液比较,静脉注射FU-Lip后24h内的平均FU浓度在肝、脾中均升高,在其他组织中的浓度均降低;FU-Lip在肝中的re为17.13,其他组织的re均≤7.017;肝、脾中FU-Lip的te1与FU注射液te2的比值分别为5.616、2.301,其他组织均≤1。结论:FU-Lip能提高药物在肝、脾中的分布,具有肝、脾靶向性,尤其是肝靶向性。     

黄芩苷脂质体的制备及在小鼠体内的分布

目的制备黄芩苷脂质体并考察其在小鼠体内的分布 ,为黄芩苷脂质体治疗乙型肝炎提供依据。方法用逆相蒸发法制备黄芩苷脂质体 ,测定其粒径及包封率 ,观察静脉注射黄芩苷脂质体及黄芩苷水溶液后 ,不同时间在小鼠体内的分布。结果 5批黄芩苷脂质体平均粒径为 (36 0± 4 2 )nm ,平均包封率为 (5 6 .0± 5 .3) %。黄芩苷脂质体主要分布于肝、脾 ,以肝脏中分布最多 ,而在血中清除加快。结论逆相蒸发法制备黄芩苷脂质体条件易控制 ,重复性好 ,可获得较高包封率和符合肝靶向要求的脂质体 ;黄芩苷脂质体具有一定的肝靶向性 ,可延缓黄芩苷在体内的代谢为乙肝治疗提供新途径。     

墨旱莲对高脂喂养小鼠调血脂作用的影响

摘 要 目的：研究墨旱莲对高脂喂养C57BL/6J小鼠调血脂作用的影响。 方法: 选取60只雌性C57BL/6J小鼠,按体质量分为正常对照组、模型组和墨旱莲低（40 mg·kg-1）、中（120 mg·kg-1）、高（360 mg·kg-1）剂量组,每组12只。对照组和模型组分别喂饲基础饲料和高脂饲料并给予1.0%羧甲基纤维素钠溶液灌胃,给药组在喂饲高脂饲料的同时给予1.0%羧甲基纤维素钠溶液溶解的墨旱莲颗粒灌胃,1次/d,连续6周。在第2周和第6周分别测定小鼠体质量、体长、Lee’s指数和体质指数（BMI）;第6周测定小鼠血清丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）、葡萄糖（GLU）、总胆固醇（TC）、三酰甘油（TG）含量,于相同部位取肝脏、腹部及肾周脂肪,称质量并计算脏体比及脂体比,解剖分离小鼠的肝脏,制作HE切片。 结果: 给药2周后,模型组与各给药组小鼠体质量、体长、Lee’s指数、BMI值差异无统计学意义（P>0.05）;给药6周后,各给药组小鼠的体质量、Lee’s指数、BMI、脂肪质量、脂体比、TC、TG均显著低于模型组（P＜0.05）,各给药组小鼠的体长、肝质量、肝体比、ALT、AST、GLU与模型组相比均无统计学意义（P>0.05）。模型组可见小鼠肝脏HE切片中有大量脂肪空泡,而高剂量给药组肝细胞脂肪变性明显减少。 结论: 墨旱莲对高脂喂养C57BL/6J小鼠有明显的降血脂作用。     

C57BL/6J糖尿病小鼠模型的优化研究

目的 优化链脲佐菌素（streptozotocin,STZ）诱导的C57BL/6J糖尿病小鼠模型。方法 采用单用不同剂量STZ（180 mg·kg^-1单次给药和275 mg·kg^-1均分5次,每次55 mg·kg^-1,连续5 d）或4周高脂饮食联合不同剂量STZ（50 mg·kg^-1单次给药;100 mg·kg^-1单次给药;150 mg·kg^-1单次给药;200 mg·kg^-1均分2次给药,间隔72 h）,建立糖尿病小鼠模型,检测各组小鼠空腹血糖、体质量、日饮水量及日进食量,比较各组造模成功率及稳定性。结果 STZ 180 mg·kg^-1单次给药、高脂饮食4周+STZ 150 mg·kg^-1单次给药、高脂饮食4周+STZ 200 mg·kg^-1均分2次给药得到的糖尿病小鼠模型,其高血糖的持续时间较长且稳定。结论 STZ 180 mg·kg^-1单次给药是较为理想的1型糖尿病模型;4周高脂饮食联合STZ 150 mg·kg^-1单次给药或200 mg·kg^-1均分2次给药均是较为理想的2型糖尿病模型。     

紫杉醇脂质体在大鼠和荷瘤裸鼠体内的组织分布

目的：运用LC—MS／MS法测定紫杉醇脂质体在大鼠和荷瘤裸鼠体内的组织分布,比较注射用紫杉醇脂质体和紫杉醇注射液的体内分布特征。方法：大鼠分组后分别iv．7mg·kg-1受试和参比试剂,于给药前、给药后10min、1h、4h采集组织样品;荷瘤裸鼠分组后分别iv．10mg·kg-1受试和参比试剂,于给药前、给药后10min,1h,4h,8h采集组织样品,利用LC—Ms／Ms法对组织样品中药物含量进行测定。结果：大鼠iv．紫杉醇脂质体后10min在肝、心、肾、脑、子宫分布达到最大值．4h后各组织中药物含量均下降：荷瘤裸鼠iv．给药后10min在血、肝、脾、肺、肾、脂肪、睾丸分布量最大,8h后在脾、肠、肝、肿瘤中药物含量依然较高。结论：紫杉醇脂质体和紫杉醇注射液在大鼠和裸鼠体内的组织分布一致。静脉注射紫杉醇脂质体后．均能特异地分布到肝脏、肺和肠等。两制剂比较,紫杉醇脂质体具有更好的靶向性和更高的安全性。     

Acute anorectic effect of single and combined drugs in mice using a non-deprivation protocol

RATIONALE: Studies of the effect of anorectic drugs such as fenfluramine in mice have indicated the desirability of using experimental protocols that do not involve deprivation. OBJECTIVE: We have developed a non-deprivation or "dessert" protocol for use in mice that are maintained in standard housing conditions, and examine the effects of a serotonergic agent dexfenfluramine (DFEN), a dopaminergic agent phentermine (PHEN), and a selective norepinephrine uptake inhibitor thionisoxetine (TNIX) alone and in combination. METHODS: Female C57BL/6J mice were adapted to 30 min daily presentation of a gelatinized form of sweetened milk using a holder that hooks over the side of the cage during tests; food spillage and contamination are minimal. Dose-inhibition curves were determined for DFEN, PHEN, and TNIX alone and for fixed ratio combinations of DFEN with either PHEN or TNIX. RESULTS: Each drug produced a near linear dose-inhibition curve with the 50% inhibitory doses (DI50) of 5.6, 3.2 and 12.2 mg/kg, respectively. By isobolographic analysis, the effects of the drug combinations were strictly additive. CONCLUSION: The procedure described is highly suitable for testing anorectic drugs in mice and is adaptable to a variety of housing conditions and diets. The DFEN+ PHEN combination was additive, which contrasts with its reported supra-additive effect in rats.     

Voluntary ethanol drinking in C57BL/6J and DBA/2J mice before and after sensitization to the locomotor stimulant effects of ethanol

RATIONALE: Drug-induced sensitization has been associated with enhanced drug self-administration and may contribute to drug addiction. OBJECTIVES: We investigated the possible association between sensitization to the locomotor stimulant effects of ethanol (EtOH) and voluntary EtOH consumption. METHODS: Mice of the EtOH-avoiding DBA/2J (D2) and EtOH-preferring C57BL/6J (B6) inbred strains were offered the choice of an EtOH solution versus tap water (EtOH-experienced) or just water (Na), and voluntary consumption was measured. Mice from each condition then received repeated EtOH or saline injections, and locomotor responses were measured. Subsequently, all mice were offered the choice of EtOH versus water, and voluntary consumption was again measured. A subsequent study examined relative susceptibility of D2 and B6 mice to EtOH-induced locomotor sensitization. RESULTS: Voluntary EtOH consumption induced locomotor sensitization to an EtOH challenge in B6 mice. D2 mice consumed little EtOH, but developed sensitization with repeated EtOH treatments as expected. EtOH consumption was not altered in EtOH-sensitized D2 mice. Unexpectedly, B6 mice developed significant sensitization, and following sensitization, the EtOH-experienced EtOH-sensitized group consumed more EtOH than their EtOH-experienced salinetreated (non-sensitized) counterparts. In an independent study, B6 mice required between three and five EtOH injections to express sensitization, whereas for D2 mice, between one and three EtOH exposures were sufficient. CONCLUSIONS: Development of sensitization to the locomotor stimulant effects of EtOH may be associated with increased EtOH consumption in mice with high initial avidity for EtOH. In the same mice, voluntary EtOH consumption can also produce behavioral sensitization to the effects of EtOH.     

Cadmium‐induced microsatellite instability in the kidneys and leukocytes of C57BL/6J mice

Cadmium is a cytotoxic, carcinogenic, and mutagenic industrial product or byproduct. The correlation between metal exposure and microsatellite instability (MSI) has been reported by several groups. In the present study, 50 C57BL/6J mice at 6 weeks of age were divided into five groups and intraperitoneally injected with 0, 0.25, 0.5, 1, or 2 mg/kg cadmium chloride quaque die alterna for 4 weeks. Then, the liver, kidney, testis, leukocytes, bone marrow, and small intestine were collected from the treated mice and weighed. Portions of these tissues were fixed for further histological analysis, and the remaining tissues were subjected to genomic DNA extraction for the analysis of a panel of 42 microsatellite markers. The liver and testis weight coefficients were significantly changed in the 1 and 2 mg/kg cadmium chloride‐treated groups compared with the control group. Simultaneously, severe histopathologic changes in the liver and kidneys, along with a complete disorganization of testicular structure and obvious severe necrosis in the testes were observed in the cadmium‐treated group. The cadmium accumulated in the liver and kidneys of the mice in all cadmium‐treated groups; the tissue cadmium concentrations were significantly higher than those in the control group. After STR scanning, MSI was found at three loci (D15Mit5, D10Mit266, and DxMit172) in the kidneys and leukocytes of mice in the lower dose groups (0.25 and 0.5 mg/kg). In summary, we have successfully established a sub‐chronic cadmium exposure model and confirmed that cadmium exposure can induce MSI in mice. We also identified two loci that could be regarded as “hotspots” of microsatellite mutation in mice. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 683–692, 2015.     

Dietary administration of diquat for 13 weeks does not result in a loss of dopaminergic neurons in the substantia nigra of C57BL/6J mice

Male and female C57BL/6J mice were administered diquat dibromide (DQ∙Br₂) in their diets at concentrations of 0 (control), 12.5 and 62.5 ppm for 13 weeks to assess the potential effects of DQ on the nigrostriatal dopaminergic system. Achieved dose levels at 62.5 ppm were 6.4 and 7.6 mg DQ (ion)/kg bw/day for males and females, respectively. A separate group of mice was administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) ip as a positive control. The comparative effects of DQ and MPTP on the substantia nigra pars compacta (SNpc) and/or striatum were assessed using neurochemical, neuropathological and stereological endpoints. Morphological and stereological assessments were performed by investigators who were “blinded” to dose group. DQ had no effect on striatal dopamine concentration or dopamine turnover. There was no evidence of neuronal degeneration, astrocytic or microglial activation, or a reduction in the number of tyrosine hydroxylase positive (TH⁺) neurons in the SNpc or neuronal processes in the striatum of DQ-treated mice. These results are consistent with the rapid clearance of DQ from the brain following a single dose of radiolabeled DQ. In contrast, MPTP-treated mice exhibited decreased striatal dopamine concentration, reduced numbers of TH⁺ neurons in the SNpc, and neuropathological changes, including neuronal necrosis, as well as astrocytic and microglial activation in the striatum and SNpc.     

Tryptophan availability,central serotonergic function and methionine sulphoximine-induced convulsions

A convulsant dose (100 mg/kg) of l-methionine-RS-sulphoximine (MSO) produced temporally correlated decreases in central 5-hydroxytryptamine (5-HT) and plasma and brain tryptophan (TRY) concentrations in C57BL/6J mice. In contrast, a subconvulsant dose of MSO (50 mg/kg) had no effect on central 5-HT levels and only decreased brain tryptophan at one time-point after its administration. The pattern of findings suggests that the decrease in central 5-HT levels resulting from a convulsant dose of MSO is related to an impairment in 5-HT synthesis resulting from a restriction of tryptophan availability. Administration of 25 mg/kg and 100 mg/kg doses of l-tryptophan with convulsant doses of MSO significantly increased seizure latency. It is suggested that the central 5-HT system modulates the expression of MSO-induced seizures.     

Phenobarbital during pregnancy alters operant behavior of offspring in C57BL/6J mice.

Offspring of C57BL/6J injected daily with phenobarbital for the last third of pregnancy responded less than control animals when maintained on various fixed ratio schedules of reinforcement. The response decrement became more pronounced as the schedule demands were increased and was noted in offspring of both sexes. The higest dose (80 mg/kg) was less effective than the 2 lower doses (20 mg and 40 mg/kg) in producing the decrement which may reflect a selection factor due to high neonatal mortality previously reported at this dose. The study provides no evidence of the mechanism mediating the long term behavioral abnormality but does clearly extend the finding of such changes to doses which do not produce increased neonatal mortality or noticeable morphological changes.