Nano-Encapsulation of Plitidepsin: In Vivo Pharmacokinetics,Biodistribution, and Efficacy in a Renal Xenograft Tumor Model

Purpose

Plitidepsin is an antineoplasic currently in clinical evaluation in a phase III trial in multiple myeloma (ADMYRE). Presently, the hydrophobic drug plitidepsin is formulated using Cremophor®, an adjuvant associated with unwanted hypersensitivity reactions. In search of alternatives, we developed and tested two nanoparticle-based formulations of plitidepsin, aiming to modify/improve drug biodistribution and efficacy.

Methods

Using nanoprecipitation, plitidepsin was loaded in polymer nanoparticles made of amphiphilic block copolymers (i.e. PEG-b-PBLG or PTMC-b-PGA). The pharmacokinetics, biodistribution and therapeutic efficacy was assessed using a xenograft renal cancer mouse model (MRI-H-121 xenograft) upon administration of the different plitidepsin formulations at maximum tolerated multiple doses (0.20 and 0.25 mg/kg for Cremophor® and copolymer formulations, respectively).

Results

High plitidepsin loading efficiencies were obtained for both copolymer formulations. Considering pharmacokinetics, PEG-b-PBLG formulation showed lower plasma clearance, associated with higher AUC and Cmax than Cremophor® or PTMC-b-PGA formulations. Additionally, the PEG-b-PBLG formulation presented lower liver and kidney accumulation compared with the other two formulations, associated with an equivalent tumor distribution. Regarding the anticancer activity, all formulations elicited similar efficacy profiles, as compared to the Cremophor® formulation, successfully reducing tumor growth rate.

Conclusions

Although the nanoparticle formulations present equivalent anticancer activity, compared to the Cremophor® formulation, they show improved biodistribution profiles, presenting novel tools for future plitidepsin-based therapies.     

In vivo pharmacokinetic and tissue distribution studies in mice of alternative formulations for local and systemic delivery of Paclitaxel: gel, film, prodrug, liposomes and micelles

The aim of this study was to increase the understanding on the pharmacokinetic and tissue distribution of paclitaxel as influenced by formulation approach. For this purpose, various formulations investigated in Swiss mice included liposomes, poloxamer 407 gel and chitosan film for subcutaneous route; and water-soluble methacrylate prodrug, liposomes and poloxamer micelles for systemic administration. During this study, the currently marketed formulation of Cremophor EL of paclitaxel was used as the reference. A highest plasma concentration following intravenous administration of paclitaxel was observed for rigid and 'Stealth((R))' liposomes containing the prodrug while, least was for covalently incorporated paclitaxel micelles. Further, poloxamer micelles demonstrated both the highest mean residence time of 7.34 h and volume of distribution (VSS=4.82 and VZ=5.87 L/kg) for paclitaxel. This was followed by prodrug loaded 'Stealth' liposomes, which showed a mean residence time of 4.96 h but were least distributed into apparent physiological volume (VSS=2.12 and VZ=3.16 L/kg). These results clearly signify the role of formulation/excipient in drug disposition and possible interactions. Importantly, due to decrease in the clearance rate of drug, the area under curve values of paclitaxel increased by 1.64- and 2.5-fold for micellar and prodrug loaded 'Stealth' liposomal formulations, respectively over reference formulation. While thermoreversible gels served to decrease plasma concentration of paclitaxel (8-fold) after subcutaneous administration, systemic levels were totally absent after implantation of films. In tissue distribution studies, maximum percent of paclitaxel was observed in liver for reference formulation, conventional liposomes and micelles whereas highest levels of prodrug and 'Stealth((R))' liposomes were in kidney and spleen, respectively. The novel formulations significantly altered tissue accumulation profiles of paclitaxel relative to the reference formulation, for example, reduction in uptake by heart from liposomes and micelles, as well as the major recognition mechanism for elimination. It is proposed that a combination therapy with liposomes and micelles of paclitaxel for systemic delivery along with implantation of chitosan film for local delivery, may serve not only to improve patient compliance by obliterating the need to administer Cremophor EL, but also increase patient survival.     

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。     

Preparation and Characterization of PEG-albumin-curcumin Nanoparticles Intended to Treat Breast Cancer

The aim of present research was to prepare novel serum stable long circulating polymeric nanoparticles for curcumin with a modification to the well known and novel nanoparticle albumin bound technology. polyethylene glycol-albumin-curcumin nanoparticles were prepared using serum albumin and poly ethylene glycol using desolvation technique. Nanoparticles were characterized for encapsulation efficiency, particle size and surface morphology. Drug excipient compatibility was determined using fourier transform infrared spectroscopy. Physical state of the drug in the formulations was known by differential scanning colorimetry. In vitro release and solubility of the drug from nanoparticles were determined. In vivo Drug release, tissue uptake and kupffer cell uptake was determined with optimized nanoformulation in rats after intravenous administration. Cell viability assay was determined using breast cancer cell line MD-MB-231. Entrapment efficiency for prepared nanoparticle was above 95%. The polyethylene glycol-albumin-curcumin nanoparticles exhibited an interesting release profile with small initial burst followed by slower and controlled release. Solubility of the drug from the formulation was increased. A sustained release of drug from nanoparticles was observed for 35 days in both in vitro and in vivo studies with the optimized formulation. Polyethylene glycol-albumin-curcumin nanoparticles showed lesser liver and kupffer cell uptake as compared to that of curcumin-albumin nanoparticles suggesting the bestowment of stealthness to nanoparticles with pegylation. Also, the antiproliferative activity of polyethylene glycol-albumin-curcumin nanoparticle formulation was more as compared to native curcumin. Polyethylene glycol-albumin-curcumin nanoparticles thus developed can be conveniently used in breast cancer with improved efficacy compared to conventional therapies and as an alternate to nanoparticle albumin bound technology which is used in producing Abraxane, albumin based breast cancer targeting nanoparticles of paclitaxel.     

Biodistribution and pharmacokinetic analysis of Paclitaxel and ceramide administered in multifunctional polymer-blend nanoparticles in drug resistant breast cancer model

In this study, we have investigated the biodistribution and pharmacokinetic analysis of paclitaxel (PTX) and the apoptotic signaling molecule, C6-ceramide (CER), when administered in a multifunctional polymer-blend nanoparticle formulation to female nude mice bearing an orthotopic drug sensitive MCF7 and multidrug resistant MCF7 TR (MDR-1 positive) human breast adenocarcinoma. A polymer-blend nanoparticle system was engineered to incorporate temporally controlled sequential release of the combination drug payload. Hereby, PTX was encapsulated in the pH-responsive rapid releasing polymer, poly(beta-amino ester) (PbAE), while CER was present in the slow releasing polymer, poly(D,L-lactide-co-glycolide) (PLGA) within these blend nanoparticles. When particle formulations were administered intravenously to MCF7 and MCF7 TR tumor bearing mice, higher concentrations of PTX were found in the blood due to longer retention time and an enhanced tumor accumulation relative to administration of free drug. In addition, the PLGA/PbAE blend nanoparticles were effective in enhancing the residence time of both drugs at the tumor site by reducing systemic clearance. Overall, these results are highly encouraging for development of multifunctional polymer-blend nanoparticle formulations that can be used for temporal-controlled administration of two drugs from a single formulation.     

玳玳果黄酮降脂提取物体内组织分布规律及特征研究

目的：建立UPLC-MS/MS分析方法同时测定玳玳果黄酮降脂提取物效应组分新橙皮苷和柚皮苷在大鼠10种脏器组织中含量，分布规律及特征。方法：采用UPLC-MS/MS技术建立提取物效应组分新橙皮苷及柚皮苷在大鼠心、肝、脾、肺、肾、脑、胃、小肠、脂质、肌肉组织中的定量分析方法；大鼠给药后分别于0.33，0.67，1，4，8 h的5个时间点，分别摘取以上10种脏器组织，测定脏器组织及血液中效应组分的质量浓度，采用DAS（V 2.0）药动学软件对各样本的药物浓度-时间数据进行房室拟合，并计算不同组织效应组分的药-时曲线下面积（AUC）及平均滞留时间（MRT）。结果：所建立的UPLC-MS/MS定量分析方法具备良好的专属性、标准曲线及线性范围良好、方法准确度与精密度、定量下限均符合有关规定；玳玳果黄酮降脂提取物效应组分在血液中的分布符合一室模型，除肾脏及脑组织外，其余脏器中提取物效应组分的房室特征多为静脉注射的二室模型，柚皮苷在肾脏中的拟合结果为非静脉注射的二室模型，新橙皮苷在脑组织拟合结果为静脉注射的三室模型，给药后8 h各组织中效应组分新橙皮苷及柚皮苷AUC值大小顺序均为小肠 > 胃 > 肾 > 脂质 ≈ 脾脏 > 肺 > 肌肉 > 肝 > 心 > 脑，效应组分在各脏器中均无明显蓄积；效应组分在血液、肾脏、肝脏中的滞留时间较长，MRT均大于2 h，脂质最短，MRT不足1 h；各脏器中新橙皮苷的药-时曲线下面积约是柚皮苷的3倍，而心、肝、肾中则是3.5，2.1和3.4倍。结论：玳玳果黄酮降脂提取物效应组分在大鼠组织中分布迅速，达峰时间早于血液；效应组分在肠道内消除缓慢，给药8 h后在各脏器中的含量均显著下降且无特异的蓄积部位。研究结果揭示玳玳果黄酮降脂提取物效应组分在大鼠体内的分布特征及规律，为进一步理解玳玳果黄酮降脂提取物在体内的作用靶点及机制奠定了基础。     

Repeated administration of the food additive E171 to mice results in accumulation in intestine and liver and promotes an inflammatory status

Abstract

Titanium dioxide (TiO₂) is widely used in pharmaceuticals preparations, cosmetics, and as a food additive (E171). It contains microparticles and a fraction of nanoparticles (NPs) which can be absorbed systemically by humans after ingestion. Increasing concern has been aroused about the impact of oral exposure to TiO₂ NPs from dietary and non-dietary sources on human health. In spite of several toxicological studies conducted in recent years, a solid risk assessment of oral exposure to E171 has not been satisfactorily achieved. We investigated whether repeated oral administration of E171 to mice at a dose level (5?mg/kg body weight for 3?days/week for 3?weeks) comparable to estimated human dietary exposure, results in TiO₂ deposition in the digestive system and internal organs, and in molecular and cellular alterations associated with an inflammatory response. To reproduce the first phase of digestion, a new administration approach involving the dripping of the E171 suspension into the mouth of mice was applied. Significant accumulation of titanium was observed in the liver and intestine of E171-fed mice; in the latter a threefold increase in the number of TiO₂ particles was also measured. Titanium accumulation in liver was associated with necroinflammatory foci containing tissue monocytes/macrophages. Three days after the last dose, increased superoxide production and inflammation were observed in the stomach and intestine. Overall, the present study indicates that the risk for human health associated with dietary exposure to E171 needs to be carefully considered.     

Fabrication of 3-O-sn-Phosphatidyl-L-serine Anchored PLGA Nanoparticle Bearing Amphotericin B for Macrophage Targeting

Purpose

To fabricate, characterize and evaluate 3-O-sn-Phosphatidyl-L-serine (PhoS) anchored PLGA nanoparticles for macrophage targeted therapeutic intervention of VL.

Materials and Methods

PLGA-AmpB NPs were prepared by well-established nanoprecipitation method and decorated with Phos by thin film hydration method. Physico-chemical characterization of the formulation was done by Zetasizer nano ZS and atomic force microscopy.

Results

The optimized formulation (particle size, 157.3?±?4.64 nm; zeta potential, ? 42.51?±?2.11 mV; encapsulation efficiency, ～98%) showed initial rapid release up to 8 h followed by sustained release until 72 h. PhoS generated ‘eat-me’ signal driven augmented macrophage uptake, significant increase in in-vitro (with ～82% parasite inhibition) and in-vivo antileishmanial activity with preferential accumulation in macrophage rich organs liver and spleen were found. Excellent hemo-compatibility justified safety profile of developed formulation in comparison to commercial formulations.

Conclusion

The developed PhoS-PLGA-AmpB NPs have improved efficacy, and necessary stability which promisingly put itself as a better alternative to available commercial formulations for optimized treatment of VL.

     

Determination of norcantharidin in mouse tissues by liquid chromatography coupled to tandem mass spectrometry and its tissue distribution study

The purpose of this study is to determine the concentrations of norcantharidin (CAS NO: 5442-12-6) in mouse tissues and investigate its tissue distribution after intragastric administration of disodium norcantharidate solution. A highly sensitive and specific liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated, using ribavirin (CAS NO: 36791-04-5) as the internal standard (IS). Norcantharidin and IS were extracted from 0.3 mL tissue homogenates using protein precipitation with acetone under acid condition. The analyte was separated on a C18 reverse phase column and analyzed by MS/MS in the multiple reaction monitoring (MRM) mode using ESI with positive ionization, m/z 169→123 for norcantharidin and m/z 267→135 for IS. The developed method was validated over a linear range of concentrations 0.01~5 μg·mL - 1 in liver, lung, kidney, stomach, small intestine, uterus and testis, 0.005~0.5 μg·mL - 1 in heart, spleen and brain, the correlation coefficients (r2) were between 0.9918 and 0.9976. The tissue distribution study result was as follows: The AUC0-t of norcantharidin in tissues was in the order as follows: small intestine, stomach, uterus, kidney, testis, liver, lung, spleen, heart, brain.     

Pharmacokinetics of paclitaxel-containing liposomes in rats

In animal models, liposomal formulations of paclitaxel possess lower toxicity and equal antitumor efficacy compared with the clinical formulation, Taxol. The goal of this study was to determine the formulation dependence of paclitaxel pharmacokinetics in rats, in order to test the hypothesis that altered biodistribution of paclitaxel modifies the exposure of critical normal tissues. Paclitaxel was administered intravenously in either multilamellar (MLV) liposomes composed of phosphatidylglycerol/phosphatidylcholine (L-pac) or in the Cremophor EL/ethanol vehicle used for the Taxol formulation (Cre-pac). The dose was 40 mg/kg, and the infusion time was 8 to 9 minutes. Animals were killed at various times, and pharmacokinetic parameters were determined from the blood and tissue distribution of paclitaxel. The area under the concentration vs time curve (AUC) for blood was similar for the 2 formulations (L-pac: 38.1±3.32 μg-h/mL; Cre-pac: 34.5±0.994 μg-h/mL), however, the AUC for various tissues was formulation-dependent. For bone marrow, skin, kidney, brain, adipose, and muscle tissue, the AUC was statistically higher for Cre-pac. For spleen, a tissue of the reticuloendothelial system that is important in the clearance of liposomes, the AUC was statistically higher for L-pac. Apparent tissue partition coefficients (K_p) also were calculated. For bone marrow, a tissue in which paclitaxel exerts significant toxicity, K_p was 5-fold greater for paclitaxel in Cre-pac. The data are consistent with paclitaxel release from circulating liposomes, but with efflux delayed sufficiently to retain drug to a greater extent in the central (blood) compartment and reduce penetration into peripheral tissues. These effects may contribute to the reduced toxicity of liposomal formulations of paclitaxel.     

Tissue Distribution and Gender-Specific Protein Expression of Cytochrome P450 in five Mouse Genotypes with a Background of FVB

Purpose

To systematically investigate tissue distribution and gender-specific protein expression of Cytochrome P450 (Cyps) in five mouse genotypes with a background of Friend virus B (FVB).

Methods

The Cyps were extracted from the tissue S9 fractions of the main metabolic organs and then absolutely quantified by applying the UHPLC-MS/MS method.

Results

The liver had the highest expression of Cyps, followed by the small intestine and kidney. In the liver, Cyp1a2, Cyp2c29, Cyp2c39, Cyp2d22, Cyp2e1, and Cyp3a11 were the main isoforms. Cyp1a2 and Cyp2c29 were male-specific, while Cyp2c39 was female-specific. Compared with the expression in Wild-type (WT) FVB mice, the expression of Cyp1a2, Cyp1b1, Cyp2d22, and Cyp3a25 significantly decreased in female efflux transporter (ET) knockout mice. In the small intestine, Cyp2c29 and Cyp3a11 were the major isoforms. Knockout of ET didn’t alter the expression levels of most Cyps. However, female ET knockout mice presented higher Cyp2c29 expression than WT FVB mice. The Cyp7a1 expression was markedly decreased in ET knockout mice except Bcrp1^?/? mice. In the kidney, Cyp2e1 was the main isoform and exhibited male specificity. Knockout of ET slightly affected the protein expression of Cyps in the brain, heart, lung, spleen and stomach.

Conclusions

A comprehensive understanding of the distribution characteristics and gender-specific expression of Cyps in major metabolic organs of WT and ET knockout FVB mice should contribute to a better understanding of drug efficacy and toxicity, and drug-drug interactions.

     

A comparison of tissue gold levels in guinea-pigs after treatment with myocrisin injected intramuscularly and triethylphosphine gold chloride and myocrisin administered orally.

A comparative study of tissue gold levels produced in guinea-pigs after the oral administration of either triethylphosphine gold chloride or Myocrisin (sodium aurothiomalate) or after the injection of Myocrisin intramuscularly is reported. Gold concentrations were determined 5, 24 and 168 hours after administration in stomach, small intestine, large intestine, kidney, liver and spleen and 5 and 24 hours after administration in skin, adrenals, heart, lung and brain. In gastrointestinal tissues, tissue gold concentrations were highest with triethylphosphine gold chloride. The stomach gold level 5 hours after oral administration of triethylphosphine gold chloride is particularly high and, taken in conjunction with the other gastrointestinal gold levels measured, suggests that a stomach rather than an intestinal absorption mechanism may predominate. A more extensive time-course study on kidney and liver is reported and the possible relationship between tissue concentration and toxicity is discussed.     

Pulmonary Gene Silencing in Transgenic EGFP Mice Using Aerosolised Chitosan/siRNA Nanoparticles

Purpose

This work describes the production and application of an aerosolised formulation of chitosan nanoparticles for improved pulmonary siRNA delivery and gene silencing in mice.

Methods

Aerosolised chitosan/siRNA nanoparticles were pneumatically formed using a nebulising catheter and sized by laser diffraction. In vitro silencing of aerosolised and non-aerosolised formulations was evaluated in an EGFP endogenous-expressing H1299 cell line by flow cytometry. Non-invasive intratracheal insertion of the catheter was used to study nanoparticle deposition by histological detection of Cy3-labeled siRNA and gene silencing in transgenic EGFP mouse lungs using a flow cytometric method.

Results

Flow cytometric analysis demonstrated minimal alteration in gene silencing efficiency before (68%) and after (62%) aerosolisation in EGFP-expressing H1299 cells. Intratracheal catheter administration in mice resulted in nanoparticle deposition throughout the entire lung in both alveoli and bronchiolar regions using low amounts of siRNA. Transgenic EGFP mice dosed with the aerosolised nanoparticle formulation showed significant EGFP gene silencing (68% reduction compared to mismatch group).

Conclusions

This work provides a technology platform for effective pulmonary delivery and gene silencing of RNAi therapeutics with potential use in preclinical studies of respiratory disease treatment.     

大鼠口服东莨菪素后的组织分布和排泄特征研究(英文)

研究东莨菪素在大鼠体内的组织分布和排泄特征,SD大鼠灌胃东莨菪素(50mg/kg),分别于给药后5,15,30,60,120,240分钟取大鼠心、肝、脾、肺、肾、肌肉、脂肪、脑、睾丸、子宫、胃、小肠等组织器官测定其原形药物浓度。结果表明,东莨菪素广泛分布于各组织器官且于给药后15分钟浓度即达峰值,其中肝、肾、胃和小肠含量较高。此外,东莨菪素在胆汁、尿液、粪便的排泄研究显示,胆汁、尿液、粪便的累积排泄量分别为0.032%,3.752%和0.784%。表明东莨菪素在大鼠体内主要以代谢物的形式消除。     

Safety,Toxicokinetics and Tissue Distribution of Long-Term Intravenous Liposomal Amphotericin B (ambisome®): A 91-day Study in Rats

Purpose. Amphotericin B in small, unilamellar liposomes (AmBisome) is safer and produces higher plasma concentrations than other formulations. Because liposomes may increase and prolong tissue exposures, the potential for drug accumulation or delayed toxicity after chronic AmBisome was investigated. Methods. Rats (174/sex) received intravenous AmBisome (1, 4, or 12 mg/kg), dextrose, or empty liposomes for 91 days with a 30-day recovery. Safety (including clinical and microscopic pathology) and toxicokinetics in plasma and tissues were evaluated. Results. Chemical and histopathologic changes demonstrated that the kidneys and liver were the target organs for chronic AmBisome toxicity. Nephrotoxicity was moderate (urean nitrogen [BUN] 51 mg/dl; creatinine unchanged). Liposome-related changes (vacuolated macrophages and hypercholesterolemia) were also observed. Although plasma and tissue accumulation was nonlinear and progressive (clearance and volume decreased, half-life increased with dose and time), most toxic changes occurred early, stabilized by the end of dosing, and reversed during recovery. There were no delayed toxicities. Concentrations in liver and spleen greatly exceeded those in plasma; kidney and lung concentrations were similar to those in plasma. Elimination half-lives were 1-4 weeks in all tissues. Conclusions. Despite nonlinear accumulation, AmBisome revealed predictable hepatic and renal toxicities after 91 days, with no new or delayed effects after prolonged treatment at high doses that resulted in plasma levels >200 g/ml and tissue levels >3000 g/g.     

Metallothionein, cadmium, copper and zinc levels of human and rat tissues

Metallothionein (MT), zinc (Zn), copper (Cu) and cadmium (Cd) were determined in 10 tissues (brain, heart, kidney cortex, liver, lung, muscle, pancreas, small intestine, spleen and stomach) from human autopsies (10 male individuals, mean age 43 +/- 9 years, all smokers) and Wistar rats. The mean tissue concentrations of MT in the human samples varied between 3.8 and 495 micrograms/g wet weight in spleen and kidney cortex, respectively. In most tissues human MT levels were high as compared to rats; particularly in liver and kidney cortex human MT levels exceeded those of rats about 25- and 10-fold, respectively. Positive linear relationships were observed between Zn or Cu and MT in human liver and between Cd and MT in human kidney cortex.     

Tissue distribution study of naringin in rats by liquid chromatography-tandem mass spectrometry

Naringin (CAS 10236-47-2), a flavanone glucoside widely present in fruits of citrus plants, has received extensive studies on its potential effects on health benefits and was recently demonstrated to be a putative antitussive. In this study, we determined the tissue distributions of naringin and its metabolites (naringenin and naringenin's conjugates) in rats to examine whether they undergo selective uptake by specific organs. Naringin was administered orally to rats at the dose of 42 mg/kg and the concentrations of naringin and its metabolites in tissue compartments were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The areas under curve values in the individual tissues decreased as follows: stomach, small intestine, liver, trachea, muscle, kidney, lung, fat, heart, spleen, ovary, testis, brain for naringin; and liver, stomach, small intestine, kidney, trachea, lung, testis, heart, ovary, fat, spleen, muscle, brain for total naringenin (including free and its conjugates). Naringin and total naringenin were rapidly and widely distributed to all the tissues except brain in rats. They had difficulties in crossing the blood-brain barrier. There are no accumulations in rats. This study identifying naringin in several organs including lung and trachea may explain its effects as antitussive.     

紫杉醇胶束与紫杉醇注射剂在荷瘤裸鼠体内的组织分布

目的评价紫杉醇胶束与注射剂在荷瘤裸鼠体内组织分布特征,为胶束制剂的临床应用提供参考依据。方法将Balb/c雄性荷瘤小鼠前肢腋皮下接种人结肠癌HT29细胞,待瘤体长到100 mm3左右后,分别经尾静脉注射给予紫杉醇胶束(PTX-PM)和紫杉醇注射剂(PTXI)均20 mg.kg-1,每3 d一次,共给药7次。于最后一次给药后30、60、180、360 min时处死裸鼠取血和各主要组织器官(心、肝、肠、肾、胃、肺、脾等),用HPLC法测定组织中紫杉醇的药物浓度。结果 2种制剂经静脉注射后,在各个时间点对各组织的药物分布趋势相似,以浓度高低依次为肝、肠、肾、胃、脾、肺、心等;PTX-PM组的紫杉醇在主要器官组织的浓度明显低于PTXI组(P<0.01或P<0.05)。其中PTX-PM组的紫杉醇在血浆中的浓度显著低于PIXI组(P<0.01),而30 min时PTX-PM组的紫杉醇在肝脏的浓度却高于PTXI组(P<0.01)。在各个时间点PTX-PM组的紫杉醇在主要器官组织的浓度与血浆浓度的比值明显高于PTXI组(P<0.01)。结论紫杉醇胶束有助于减少紫杉醇对血液系统的毒性,避免紫杉醇注射剂中聚氧乙烯蓖麻油引起的过敏反应,具有良好的临床应用前景。     

Biodistribution Studies of Nanoparticles Using Fluorescence Imaging: A Qualitative or Quantitative Method?

Purpose

The biodistribution of Lipid/Calcium/Phosphate (LCP) nanoparticles (NPs) in tumor-bearing mice was investigated using fluorescence imaging. A quantitative validation of this method was done by ³H and ¹¹¹In labeling of the nanoparticles.

Methods

The biodistribution of LCP NPs containing oligonucleotides was investigated using three different probes: Texas-Red labeled oligonucleotides, ³H-labeled oligonucleotides, and ¹¹¹In-labled calcium phosphate.

Results

A discrepancy was found between the radioactivity and the fluorescence signals. Signals from ³H and ¹¹¹In exhibited very similar distribution patterns, suggesting that liver and spleen were the major accumulation sites. However, fluorescence imaging indicated that tumor accumulation was predominant. We further confirmed that the fluorescence signals in both liver and spleen were greatly attenuated compared with those in the tumor due to the intrinsic tissue absorption and scattering. Near-infrared (NIR) dye Cy5.5 also suffered from the same problem, in that the quantitative data from whole organs was dramatically affected by absorption and scattering properties of the tissue.

Conclusions

Careful attention must be paid to the quantification and interpretation of fluorescence imaging measurements when comparing different tissues.     

Significant Transport of Doxorubicin into the Brain with Polysorbate 80-Coated Nanoparticles

Purpose. To investigate the possibility of delivering of anticancer drugs into the brain using colloidal carriers (nanoparticles). Methods. Rats obtained 5 mg/kg of doxorubicin by i v. injection in form of 4 preparations : 1. a simple solution in saline, 2. a simple solution in polysorbate 80 1% in saline, 3. bound to poly (butyl cyanoacrylate) nanoparticles, and 4. bound to poly(butyl cyanoacrylate) nanoparticles overcoated with 1% polysorbate 80 (Tween^® 80). After sacrifice of the animals after 10 min, 1, 2, 4, 6, and 8 hours, the doxorubicin concentrations in plasma, liver, spleen, lungs, kidneys, heart and brain were determined after extraction by HPLC. Results. No significant difference in the body distribution was observed between the two solution formulations. The two nanoparticle formulations very significantly decreased the heart concentrations. High brain concentrations of doxorubicin (>6 g/g) were achieved with the nanoparticles overcoated with polysorbate 80 between 2 and 4 hours. The brain concentrations observed with the other three preparations were always below the detection limit (< 0.1 |g/g). Conclusions. The present study demonstrates that the brain concentration of systemically administered doxorubicin can be enhanced over 60-fold by binding to biodegradable poly(butyl cyanoacrylate) nanoparticles, overcoated with the nonionic surfactant polysorbate 80. It is highly probable that coated particles reached the brain intact and released the drug after endocytosis by the brain blood vessel endothelial cells.