Cytotoxicity of doxorubicin bound to poly(butyl cyanoacrylate) nanoparticles in rat glioma cell lines using different assays

The cytotoxicity of doxorubicin bound to poly(butyl cyanoacrylate) nanoparticles (Dox-PBCA-NP) was investigated in the rat glioma cell lines GS-9L, F-98 and RG-2. MTT and LDH assays were used as cytotoxic assays. In general, the cytotoxicity of nanoparticle-bound doxorubicin (Dox) was enhanced compared to the free drug in solution. However, responses of the cell lines towards the drug effects were different. In the case of free Dox in solution, this difference correlated with different intracellular concentrations of Dox, which in turn, depended on the level of P-glycoprotein (P-gp) expression in these cell lines. Accordingly, the 9L gliosarcoma (GS-9L) cells, which appeared to be most resistant towards Dox, were characterized by the highest P-gp expression.

Additionally, the influence of surfactants on the cytotoxic effect was investigated at different Dox concentrations. It was shown that the presence of polysorbate 80 (Tween® 80) in the nanoparticle formulation significantly enhanced the cytotoxicity, whereas poloxamer 188 (Pluronic® F68) and poloxamine 908 (Tetronic® 908) had a negligible influence.     

Brain targeting of nerve growth factor using poly(butyl cyanoacrylate) nanoparticles

The nerve growth factor (NGF) is essential for the survival of both peripheral ganglion cells and central cholinergic neurons in the basal forebrain. The accelerated loss of central cholinergic neurons during Alzheimer’s disease may be a determinant cause of dementia, and this observation may suggest a possible therapeutic benefit from treatment with NGF. In recent years, convincing data have been published involving neurotrophic factors for the modulation of dopaminergic transmission within the brain and concerning the ability of NGF to prevent the degeneration of dopaminergic neurons. In this connection, the administration of NGF may slow down the progression of Parkinson’s disease. However, NGF, as well as other peptidic neurotrophic factors, does not significantly penetrate the blood–brain barrier (BBB) from the circulation. Therefore, any clinical usefulness of NGF as a potential CNS therapy will depend on the use of a suitable carrier system that enhances its transport through the BBB. The present study investigates brain delivery of NGF adsorbed on poly(butyl cyanoacrylate) (PBCA) nanoparticles coated with polysorbate 80 and the pharmacological efficacy of this delivery system in the model of acute scopolamine-induced amnesia in rats as well as in the model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonian syndrome. As shown by the passive avoidance reflex (PAR) test, the intravenous administration of the nanoparticle-bound NGF successfully reversed scopolamine-induced amnesia and improved recognition and memory. This formulation also demonstrated a significant reduction of the basic symptoms of Parkinsonism (oligokinesia, rigidity, tremor). In addition, the efficient transport of NGF across the BBB was confirmed by direct measurement of NGF concentrations in the murine brain. These results demonstrate that the PBCA nanoparticles coated with polysorbate 80 are an effective carrier system for the transport of NGF to the central nervous system across the BBB following intravenous injection. This approach may improve the NGF-based therapy of age-related neurodegenerative diseases.     

聚乙二醇-聚十六烷基氰丙烯酸酯聚合物及其纳米粒的制备

聚乙二醇氰乙酸酯和十六烷基氰乙酸酯聚合得到两亲性的标题聚合物,通过IR、1HNMR及凝胶渗透色谱法等确证结构.将此聚合物用溶剂-非溶剂法所制得的纳米粒粒径为100～400nm,分布均匀.     

Physiological uptake and retention of radiolabeled resveratrol loaded gold nanoparticles (99mTc-Res-AuNP) in colon cancer tissue

When tagged with a suitable radionuclide, the cancer targeting properties of trans-resveratrol could be utilized to locate cancerous sites in the body using radionuclide imaging technique. However, the polyphenol due to its rapid and extensive metabolism exhibits low bioavailability in vivo. The study was designed to enhance the cancer targeting efficacy of radiolabeled resveratrol using nano-based technology. Technetium-99m labeled resveratrol loaded gold nanoparticles (Res-AuNP) were synthesized, characterized and evaluated for their cancer targeting efficacy in HT29 colon cancer cells and in animal cancer model. Results of various investigations were compared to corresponding results obtained for ^99mTc-AuNP and ^99mTc-resveratrol. Cancer cell internalization observed for ^99mTc-Res-AuNP was significantly higher than that of ^99mTc-AuNP and ^99mTc-resveratrol. Also, a gradual rise in target to nontarget uptake with time was observed following i.v. administration of ^99mTc-Res-AuNP to colon tumor bearing rats, demonstrating better in vivo targeting of colon adenocarcinoma with ^99mTc-Res-AuNP when compared to ^99mTc-resveratrol.     

Direct Evidence That Polysorbate-80-Coated Poly(Butylcyanoacrylate) Nanoparticles Deliver Drugs to the CNS via Specific Mechanisms Requiring Prior Binding of Drug to the Nanoparticles

Purpose. It has recently been suggested that the poly(butylcyanoacrylate) (PBCA) nanoparticle drug delivery system has a generalized toxic effect on the blood-brain barrier (BBB) (8) and that this effect forms the basis of an apparent enhanced drug delivery to the brain. The purpose of this study is to explore more fully the mechanism by which PBCA nanoparticles can deliver drugs to the brain. Methods. Both in vivo and in vitro methods have been applied to examine the possible toxic effects of PBCA nanoparticles and polysorbate-80 on cerebral endothelial cells. Human, bovine, and rat models have been used in this study. Results. In bovine primary cerebral endothelial cells, nontoxic levels of PBCA particles and polysorbate-80 did not increase paracellular transport of sucrose and inulin in the monolayers. Electron microscopic studies confirm cell viability. In vivo studies using the antinociceptive opioid peptide dalargin showed that both empty PBCA nanoparticles and polysorbate-80 did not allow dalargin to enter the brain in quantities sufficient to cause antinociception. Only dalargin preadsorbed to PBCA nanoparticles was able to induce an antinociceptive effect in the animals. Conclusion. At concentrations of PBCA nanoparticles and polysorbate-80 that achieve significant drug delivery to the brain, there is little in vivo or in vitro evidence to suggest that a generalized toxic effect on the BBB is the primary mechanism for drug delivery to the brain. The fact that dalargin has to be preadsorbed onto nanoparticles before it is effective in inducing antinociception suggests specific mechanisms of delivery to the CNS rather than a simple disruption of the BBB allowing a diffusional drug entry.     

盐酸表柔比星-聚乳酸-羟基乙酸共聚物纳米粒的制备

摘要目的制备盐酸表柔比星 聚乳酸 羟基乙酸（PLGA）共聚物纳米粒,对其进行质量评价。方法采用乳化 溶剂挥发法制备盐酸表柔比星纳米粒;对主要处方因素如PLGA用量、外水相中聚山梨酯 80用量、泊洛沙姆188和聚山梨酯 80比例进行正交设计,以药物的包封率、载药量和药物利用率等为考察指标。结果采用优化后处方制得的纳米粒药物包封率为（32.6±1.2）%,载药量为（7.2±0.5）%,药物利用率为（51.6±3.4）%,纳米粒平均粒径166.6 nm,药物可持续160 h释放。结论该方法制备盐酸表柔比星纳米粒工艺简单,无需使用聚乙烯醇,药物释放缓慢。     

Evaluation of Poly(isobutylcyanoacrylate) Nanoparticles for Mucoadhesive Ocular Drug Delivery. I. Effect of Formulation Variables on Physicochemical Characteristics of Nanoparticles

A factorial design was applied to evaluate the effect of formulation variables on physicochemical properties of poly(isobutylcyanoacrylate) nanoparticles. Formulation variables were dextran T40 or T70 and Pluronic F68 or Tween 20 acting as stabilizer and surfactant respectively, and three pH levels (2, 4 and 7). Nanoparticles possessed unimodal particle size distribution with significant effect of dextran, surfactant and pH. A wide range of molecular weight distribution was observed with significant effect of pH and dextran on average molecular weight. NMR studies revealed the presence of dextran, monomer and surfactants in the nanoparticles. Solid state surface analysis using X-ray photoelectron spectroscopy confirmed the presence of three chemical environments to the carbon envelope, O – C = O,C – O/CN and C – C.     

Novel Approach for Delivery of Insulin Loaded Poly(lactide-co-glycolide) Nanoparticles Using a Combination of Stabilizers

Insulin stability during microencapsulation and subsequent release is essential for retaining its biological activity. The successful delivery of insulin relies on the proper selection of stabilizers in addition to other parameters. Attempts were made to address the problem with a few combination of stabilizers for maintaining the integrity of insulin during formulation and delivery. Insulin loaded nanoparticles with different stabilizers such as pluronic F68, trehalose, and sodium bicarbonate were prepared by the double emulsion evaporation method using two different copolymer ratios of poly(DL-lactide-co-glycolide) (50:50 and 85:15). The presence of stabilizers in the nanoparticles resulted in an increase in the particle size but a reduction of encapsulation efficiency. Insulin release rate was comparatively higher for the batches containing stabilizers when compared with controls for both the copolymer ratios. Also the presence of stabilizers resulted in sustained release of insulin resulting in prolonged reduction of blood glucose levels in streptozotocin induced diabetic rats. From the in vitro and in vivo studies, we concluded that a combination of stabilizers results in beneficial effects without compromising the advantages of delivery systems.     

Influence of surfactants,polymer and doxorubicin loading on the anti-tumour effect of poly(butyl cyanoacrylate) nanoparticles in a rat glioma model

Poly(n-butyl cyanoacrylate) nanoparticles coated with polysorbate-80 can enable the transport of bound drugs across the blood–brain barrier (BBB) after i.v. injection. In the present study the influence of different formulation parameters on the anti-tumoural effects of doxorubicin nanoparticles against glioblastoma 101/8 was investigated. The manufacturing parameters of poly(alkyl cyanoacrylate) doxorubicin-loaded nanoparticles were optimized concerning drug loading. The nanoparticles were coated with different surfactants and injected intravenously on days 2, 5 and 8 after intra-cranial implantation of glioblastoma 101/8 to rats. The survival times of all doxorubicin containing preparations, including a doxorubicin solution, increased the survival times significantly compared to untreated tumour-bearing rats. The most pronounced increase in survival was obtained with the poly(n-butyl cyanoacrylate) doxorubicin-loaded nanoparticles coated with polysorbate 80 and 35% of these animals survived for over 180 days (termination of the experiments). The other nanoparticle preparations yielded lower survival times. Poly(n-butyl cyanoacrylate) doxorubicin-loaded nanoparticles coated with polysorbate 80-coated proved to be very efficient against glioblastoma 101/8. The data suggest that the interaction of nanoparticles with the blood after injection as well as the enhanced permeability and retention effect (EPR effect) contributed differently to the anti-tumoural efficacy depending on nanoparticle formulation and surface properties.     

Biodistribution and Targeting Potential of Poly(ethylene glycol)-modified Gelatin Nanoparticles in Subcutaneous Murine Tumor Model

Purpose: In order to develop a safe and effective systemically-administered biodegradable nanoparticle delivery system for solid tumors, the comparative biodistribution profiles of gelatin and poly(ethylene-glycol)(PEG)-modified (PEGylated) gelatin nanoparticles was examined in subcutaneous Lewis lung carcinoma (LLC)-bearing female C57BL/6J mice.

Methods: Type-B gelatin and PEGylated gelatin nanoparticles were radiolabeled (¹²⁵I) for the in vivo biodistribution studies after intravenous (i.v.) administration through the tail vein in LLC-bearing mice. At various time intervals, the mice were sacrificed and blood, tumor, and major organs harvested for analysis of radioactivity corresponding to the localization of the nanoparticles. Percent recovered dose was determined and normalized to the weight of the fluid or tissue sample. Non-compartmental pharmacokinetic analysis was performed to determine the long-circulating property and preferential tumor targeting potential of PEGylated gelatin nanoparticles in vivo.

Results: From the radioactivity in plasma and various organs collected, it was evident that the majority of PEGylated nanoparticles were present either in the blood pool or taken up by the tumor mass and liver. For instance, after 3 h, the concentrations of PEGylated gelatin nanoparticles was almost 2-fold higher in the blood pool than the control gelatin nanoparticles. PEGylated gelatin nanoparticles remained in the blood pool for a longer period of time due to the steric repulsion effect of the PEG chains as compared to the gelatin nanoparticles. In addition, approximately 4–5% of the recovered dose of PEGylated gelatin nanoparticles was present in the tumor mass for up to 12 h. The plasma and the tumor half-lives, the mean residence time, and the area-under-the-curve of the PEGylated gelatin nanoparticles were significantly higher than those for the gelatin nanoparticles.

Conclusions: The results of this study show that PEGylated gelatin nanoparticles do possess long circulating properties and can preferentially distribute in the tumor mass after systemic delivery.     

Tetanus Toxoid Loaded Nanoparticles from Sulfobutylated Poly(Vinyl Alcohol)-Graft-Poly(Lactide-co-Glycolide): Evaluation of Antibody Response After Oral and Nasal Application in Mice

Purpose. Aim of the study was the evaluation of the potential of novel tetanus toxoid (TT) loaded nanoparticles (NP) for electing an immune response in mice against TT. Methods. Six week-old female Balb/c mice were immunized by oral (p.o.), nasal (i.n.) and intraperitoneal (i.p.) application of TT NP loaded by adsorption. As polymer a novel polyester, sulfobutylated poly(vinyl alcohol)-graft-poly(lactide-co-glycolide), SB(43)-PVAL-g-PLGA was used. Blood samples were collected 4 and 6 weeks after immunization and assayed for serum IgG- as well as IgA antibody titers by ELISA. NP formulations varying in size and loading were compared to alum adsorbates as well as to TT solutions. Results. Both, p.o. and i.n. administration of TT associated NP increased serum titers up to 3 × 10³ (IgG) and 2 × 10³ (IgA). While small NP induced significantly higher titers then larger ones after oral administration, intermediate NP induced antibodies after nasal application. Of the mucosal routes investigated, i.n. seems to be more promising compared to p.o. immunization. Conclusions. Antigen loaded NP prepared from surface modified polyesters combined with CT show considerable potential as a vaccine delivery system for mucosal immunization. The results warrant further experiments to explore in more detail the potential use of NP as mucosal vaccine delivery system.     

Doxorubicin release from core-shell type nanoparticles of poly(DL-lactide-co-glycolide)-grafted dextran

In this study, we prepared core-shell type nanoparticles of a poly(DL-lactide-co-glycolide) (PLGA) grafted-dextran (DexLG) copolymer with varying graft ratio of PLGA. The synthesis of the DexLG copolymer was confirmed by 1H nuclear magnetic resonance (NMR) spectroscopy. The DexLG copolymer was able to form nanoparticles in water by self-aggregating process, and their particle size was around 50 nm approximately 300 nm according to the graft ratio of PLGA. Morphological observations using a transmission electron microscope (TEM) showed that the nanoparticles of the DexLG copolymer have uniformly spherical shapes. From fluorescence probe study using pyrene as a hydrophobic probe, critical association concentration (CAC) values determined from the fluorescence excitation spectra were increased as increase of DS of PLGA. 1H-NMR spectroscopy using D2O and DMSO approved that DexLG nanoparticles have core-shell structure, i.e. hydrophobic block PLGA consisted inner-core as a drug-incorporating domain and dextran consisted as a hydrated outershell. Drug release rate from DexLG nano-particles became faster in the presence of dextranase in spite of the release rate not being significantly changed at high graft ratio of PLGA. Core-shell type nanoparticles of DexLG copolymer can be used as a colonic drug carrier. In conclusion, size, morphology, and molecular structure of DexLG nanoparticles are available to consider as an oral drug targeting nanoparticles.     

Poly (amino acid) micelle nanocarriers in preclinical and clinical studies

Polymeric micelles are expected to increase the accumulation of drugs in tumor tissues utilizing the EPR effect and to incorporate various kinds of drugs into the inner core by chemical conjugation or physical entrapment with relatively high stability. The size of the micelles can be controlled within the diameter range of 20 to 100 nm, to ensure that the micelles do not pass through normal vessel walls; therefore, a reduced incidence of the side effects of the drugs may be expected due to the decreased volume of distribution.

These are several anticancer agent-incorporated micelle carrier systems under clinical evaluation. Phase 1 studies of a CDDP incorporated micelle, Nc-6004, and an sN-38 incorporated micelle, NK012, are now underway. A phase 2 study of a PTX incorporated micelle, NK105, against stomach cancer is also underway.     

Formulation and Lyoprotection of Poly(Lactic Acid-Co-Ethylene Oxide) Nanoparticles: Influence on Physical Stability and In Vitro Cell Uptake

Purpose. To investigate the feasibility of producing freeze-dried poly-(ethylene oxide) (PEO)-surface modified nanoparticles and to study their ability to avoid the mononuclear phagocytic system (MPS), as a function of the PEO chain length and surface density. Methods. The nanoparticles were produced by the salting-out method using blends of poly(D,L-lactic acid) (PLA) and poly(D,L-lactic acid-co-ethylene oxide) (PLA-PEO) copolymers. The nanoparticles were purified by cross-flow filtration and freeze-dried as such or with variable amounts of trehalose as a lyoprotectant. The redispersibility of the particles was determined immediately after freeze-drying and after 12 months of storage at –25° C. The uptake of the nanoparticles by human monocytes was studied in vitro by flow cytometry. Results. PLA-PEO nanoparticles could be produced from all the polymeric blends used. Particle aggregation after freeze-drying was shown to be directly related to the presence of PEO. Whereas this problem could be circumvented by use of trehalose, subsequent aggregation was shown to occur during storage. These phenomena were possibly related to the specific thermal behaviours of PEO and trehalose. In cell studies, a clear relationship between the PEO content and the decrease of uptake was demonstrated. Conclusions. The rational design of freeze-dried PEO-surface modified nanoparticles with potential MPS avoidance ability is feasible by using the polymer blends approach combined with appropriate lyoprotection and optimal storage conditions.     

Noninvasive Visualization of Pharmacokinetics,Biodistribution and Tumor Targeting of Poly[<Emphasis Type="BoldItalic">N</Emphasis>-(2-hydroxypropyl)methacrylamide] in Mice Using Contrast Enhanced MRI

Purpose To study a non-invasive method of using contrast enhanced magnetic resonance imaging (MRI) to visualize the real-time pharmacokinetics, biodistribution and tumor accumulation of paramagnetically labeled poly[N-(2-hydroxypropyl)methacrylamide] (PHPMA) copolymer conjugates with different molecular weights and spacers in tumor-bearing mice. Materials and Methods Paramagnetically labeled HPMA copolymer conjugates were synthesized by free radical copolymerization of HPMA with monomers containing a chelating ligand, followed by complexation with Gd(OAc)₃. A stable paramagnetic chelate, Gd-DO3A, was conjugated to the copolymers via a degradable spacer GlyPheLeuGly and a non-degradable spacer GlyGly, respectively. The conjugates with molecular weights of 28, 60 and 121 kDa and narrow molecular weight distributions were prepared by fractionation with size exclusion chromatography. The conjugates were injected into athymic nude mice bearing MDA-MB-231 human breast carcinoma xenografts via a tail vein. MR images were acquired before and at various time points after the injection with a 3D FLASH sequence and a 2D spin-echo sequence at 3T. Pharmacokinetics, biodistribution and tumor accumulation of the conjugates were visualized based on the contrast enhancement in the blood, major organs and tumor tissue at various time points. The size effect of the conjugates was analyzed among the conjugates. Results Contrast enhanced MRI resulted in a real-time, three-dimensional visualization of blood circulation, pharmacokinetics, biodistribution and tumor accumulation of the conjugates, and the size effect on these pharmaceutical properties. HPMA copolymer conjugates with high molecular weight had a prolonged blood circulation time and high passive tumor targeting efficiency. Non-biodegradable HPMA copolymers with molecular weights higher than the threshold of renal filtration demonstrated higher efficiency for tumor drug delivery than biodegradable poly(L-glutamic acid). Conclusions Contrast enhanced MRI is an effective method for non-invasive visualization of in vivo properties of the paramagnetically labeled polymer conjugates in preclinical studies.     

Poly (lactide-co-glycolide)-Polymethacrylate Nanoparticles for Intramuscular Delivery of Plasmid Encoding Interleukin-10 to Prevent Autoimmune Diabetes in Mice

Purpose

Determine the efficiency of cationic nanoparticles prepared by blending poly (lactide-co-glycolide; PLGA) and methacrylate copolymer (Eudragit® E100) to deliver a therapeutic gene encoding mouse interleukin-10, in vitro and in vivo.

Methods

Nanoparticles prepared with PLGA and E100 were evaluated for delivery of plasmid DNA encoding mouse interleukin-10 in vitro and in vivo in mice upon intramuscular injection. Blood-glucose, serum interferon-gamma levels and histology of pancreas were studied to determine therapeutic efficacy. Histological evaluation of skeletal muscle from the injection site was performed to assess the biocompatibility of nanoparticles.

Results

PLGA/E100 nanoparticles showed endosomal escape evidenced by confocal microscopy and buffering ability. Transfecting HEK293 cells with plasmid-loaded PLGA/E100 nanoparticles resulted in significantly (p?Conclusions Nanoparticles prepared by blending PLGA with methacrylate can efficiently and safely deliver plasmid DNA encoding mouse interleukin-10 leading to prevention of autoimmune diabetes.     

Genetic research and structural dysplasia assessment of anorectal malformations in neonatal male rats induced by di(n‐butyl) phthalate

This study was the first to investigate the genetic abnormalities and structural dysplasia of anorectal malformations (ARMs) in male rats induced by di(n‐butyl) phthalate (DBP). DBP was administered to timed‐pregnant rats to establish the ARM rat model. The incidence of ARMs in male offspring was 39.5%. In neonatal period, decreased body weight and anogenital distance were observed. The general image and histological analysis of male offspring confirmed the presence of ARMs. Anatomical examination of the ARM male rats revealed the dysplasia in solid organs (heart‐lung, liver, spleen, and kidney). The decreases of serum testosterone concentration and androgen receptor expression in terminal rectum were indicative of the antiandrogenic effects of DBP. Moreover, significant decreased mRNA expressions of these androgen‐related genes such as sonic hedgehog, Gli2, Gli3, bone morphogenetic protein 4, Wnt5a, Hoxa13, Hoxd13, fibroblast growth factor 10, and fibroblast growth factor receptor 2 were found in terminal rectum of the ARM male pubs. These results demonstrated that development of ARM rats was impaired by maternal exposure to DBP. The antiandrogenic effects of DBP disturbing the androgen‐related signaling networks might play an important role in the occurrence of ARMs. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 261–268, 2016.     

In vitro and in vivo Evaluation of Poly(Methylidene Malonate 2.1.2) Microparticles Behavior for Oral Administration

The goal of this paper was to investigate the fate of novel poly(methylidene malonate 2.1.2) microparticles with different surface properties, i.e. prepared with or without polyvinylalcohol (PVA), after oral administration, using in vitro cell culture and an in vivo mice model. Incubation of particles with Caco-2 cells induced no cytotoxicity except for the microparticles prepared without PVA at high concentrations. At subtoxic concentrations, microparticles were highly associated to cells, independently of particles concentrations, particles surface properties (with or without PVA) or incubation time. Confocal microscopy analysis revealed that adsorption was the main phenomenon leading to the association of particles to cells. However, association was greater at 37°C than at 4°C, suggesting that an active process, such as endocytosis, could also occur. In vivo, radiolabeled particles were mainly found in luminal content and also adsorbed onto the epithelium. After 24 hours, more than 15% of PVA-free microparticles were still present in the gastrointestinal tract, compared to 5% for particles prepared with PVA. However, histological evaluation revealed low uptake of particles by Peyer's patches. As a conclusion, this study provided a good correlation between in vitro and in vivo evaluation. These particles could be useful for oral sustained release and delivery of drugs to intestinal and colon epithelium.     

PARP抑制剂WZ-8体内外抗肿瘤作用研究

目的 研究PARP抑制剂WZ-8对人源性肿瘤细胞增殖及裸鼠移植人结肠癌（HCT116）生长的抑制作用。方法 SRB染色法和裸小鼠移植瘤模型研究WZ-8在体内外抗肿瘤作用。结果 体外WZ-8对多种人肿瘤细胞增殖有明显抑制作用,其中对结肠癌细胞HCT116的半数抑制浓度IC50为（0.21±0.01）mg·mL^-1。体内研究表明WZ-8（20 mg·kg-1）对小鼠移植HCT116肿瘤生长有一定抑制效果,其体内外抗肿瘤活性均高于同类化合物Iniparib。结论 WZ-8在体外对人源性肿瘤细胞增殖有明显抑制作用,在体内可抑制裸鼠移植人结肠癌细胞HCT116的生长。     

Gamma Scintigraphy of a 123I-Labelled N-(2-Hydroxypropyl)Methacrylamide Copolymer-Doxorubicin Conjugate Containing Galactosamine Following Intravenous Administration to Nude Mice Bearing Hepatic Human Colon Carcinoma

Abstract

Polymer drug conjugates composed of N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymer covalently bound, doxorubicin, and containing additionally galactosamine to facilitate hepatocyte-specific targeting (HPMA copolymer-dox-gal), were synthesised to contain a small amount (～1 mol%) of the monomer methacryloyltyrosinamide to permit radioiodination with [¹²³I]iodide. After intravenous administration to both normal mice and nude mice bearing hepatic human colon carcinoma, the biodistribution of the conjugate was monitored using the gamma camera, and also by dissection analysis. Efficient liver accumulation of HPMA copolymer-dox-gal was seen in the gamma camera images within 20 min, both in normal and rumour-bearing animals. Quantitatively liver uptake was ～40% dose administered/g liver. Images of the tumour-bearing animals showed clearly a much lower accumulation of HPMA copolymer-dox-gal in the colon carcinoma deposits within the liver (3-9% dose/g tumour), and this lack of uptake was verified by ex vivo imaging of the tumour-containing liver and also by dissection analysis. It can be concluded that ¹²³I-labelled HPMA copolymer conjugates offer great potential as effective imaging agents and can be used for future non-invasive clinical studies. This nuclear imaging method will enable optimisation of the dosing schedule by identification of doses of HPMA copolymer-dox-gal that display receptor saturation (and hence diminished targeting efficiency). In addition this conjugate can provide negative images of liver-associated tumour deposits that do not express the asialoglycoprotein receptor.