Combination of paclitaxel- and retinoic acid-incorporated nanoparticles for the treatment of CT-26 colon carcinoma

The aim of this study was to evaluate the antitumor effect of combinatorial targeted therapy with paclitaxel and all-trans retinoic acid (ATRA) nanoparticles in vitro. Paclitaxel-incorporated pullulan acetate (PA) nanoparticles were prepared by the nanoprecipitation-solvent evaporation method. ATRA-incorporated nanoparticles were prepared by dialysis using a methoxy poly(ethylene glycol)-grafted chitosan (ChitoPEG) copolymer. Particle sizes of paclitaxel-incorporated nanoparticles and ATRA-incorporated nanoparticles were about 160 nm and 60 nm, respectively. Nanoparticles were reconstituted in various aqueous media such as deionized water, phosphate-buffered saline, and fetal bovine serum-supplemented cell culture media. The combination of paclitaxel + ATRA (10 + 10 μg/mL) delivered by nanoparticles showed a synergistic antiproliferative effect against CT26 cells that was not observed with other combinations. Furthermore, the activity of MMP-2, a key enzyme in tumor cell invasion, was significantly decreased in cells treated with the combination of paclitaxel and ATRA while other combinations and single agents did not significantly affect its activity. A matrigel assay supported these results, indicating that paclitaxel/ATRA combination nanoparticles are effective for the inhibition of the invasion of tumor cells. The results of the present study suggest that combination treatment with paclitaxel and ATRA could be an effective treatment for the inhibition of tumor cell proliferation and invasion, and that nanoparticles are promising candidates for antitumor drug delivery.     

Antitumor effect of adriamycin-encapsulated nanoparticles of poly(DL-lactide-co-glycolide)-grafted dextran

In this study, we prepared adriamycin (ADR)-encapsulated core-shell type nanoparticles of a poly(DL-lactide-co-glycolide) (PLGA) grafted-dextran (DexLG) copolymer and evaluated its antitumor activity in vitro and in vivo. The particle size of ADR-encapsulated DexLG nanoparticles was around 50-200 nm and the morphology was spherical shapes at transmission electron microscopy (TEM) observation. Since reconstitution of lyophilized nanoparticles is essential to practical use in vivo, ADR-encapsulated DexLG nanoparticles were lyophilized and reconstituted them into deionized water. Although reconstitution process caused increase of particle size, drug release behavior of nanoparticles was not significantly changed before and after reconstitution process. The ADR-encapsulated DexLG nanoparticles were less cytotoxic than free ADR plus empty nanoparticles at in vitro, while empty DexLG nanoparticles did not significantly affect cell viability. Even if free ADR plus empty nanoparticles are most effective to inhibit tumor growth at tumor-induced animal model using CT-26 cells, ADR-encapsulated DexLG nanoparticles showed increased survivability of mice. These results indicated that ADR-encapsulated DexLG nanoparticles are promising vehicles for antitumor drug delivery.     

Doxorubicin release from self-assembled nanoparticles of deoxycholic acid-conjugated dextran

In this study, we synthesized deoxycholic acid (DA)-conjugated dextran (DexDA) and prepared doxorubicin (DOX)-encapsulated nanoparticles using DexDA conjugates. Since DexDA conjugates have amphiphilic properties, they will show self-aggregation behavior at aqueous environment. To approve self-aggregation behavior, critical aggregation concentration value of DexDA conjugates was evaluated using fluorescence spectroscopy. DOX-incorporated DexDA nanoparticles were less than 200 nm. The higher substitution degree of DA and higher drug feeding ratio resulted in increased particle size. Drug release was decreased by increase of substitution degree value of DA and increase of drug feeding ratio. At in vitro cytotoxicity test using DOX-resistant CT26 colon carcinoma cells, higher antitumor activity was obtained with DOX-incorporated nanoparticles compared to free DOX. Fluorescence microscopic observation verified this result, i.e. nanoparticles were properly entered into tumors cells and maintained longer compared to DOX itself. These results suggested that DOX-incorporated DexDA nanoparticles are promising vehicles for antitumor drug delivery.     

Discovery of a tetrahydroisoquinoline-based hydroxamic acid derivative (ZYJ-34c) as histone deacetylase inhibitor with potent oral antitumor activities

Histone deacetylase (HDAC) has emerged as an attractive target for the development of antitumor agents during the past decade. Previously tetrahydroisoquinoline-bearing hydroxamic acid analogue, ZYJ-25e (1), was identified and validated as a potent histone deacetylase inhibitor (HDACi) with marked in vitro and in vivo antitumor potency. In the present study, further modification of 1 led to another more potent, orally active HDACi, ZYJ-34c (4). Compared to FDA-approved drug suberoylanilide hydroxamic acid (SAHA), compound 4 exhibited higher in vivo antitumor potency in a human breast carcinoma (MDA-MB-231) xenograft model and in a mouse hepatoma-22 (H22) pulmonary metastasis model and similar in vivo antitumor potency in a human colon tumor (HCT116) xenograft model.     

Peracetylation as a means of enhancing in vitro bioactivity and bioavailability of epigallocatechin-3-gallate.

(-)-Epigallocatechin-3-gallate (EGCG) is the widely studied catechin in green tea (Camellia sinensis). Previously, we have reported the low bioavailability of EGCG in rats and mice. As a means of improving the bioavailability of EGCG, we have prepared a peracetylated EGCG derivative (AcEGCG) and herein report its growth inhibitory activity and cellular uptake in vitro, as well as bioavailability in mice. AcEGCG exhibited enhanced growth inhibitory activity relative to EGCG in both KYSE150 human esophageal (IC50 = 10 versus 20 microM) and HCT116 human colon cancer cells (IC50 = 32 versus 45 microM). AcEGCG was rapidly converted to EGCG by HCT116 cells, and treatment of cells with AcEGCG resulted in a 2.8- to 30-fold greater intracellular concentration of EGCG as compared with treatment with EGCG. AcEGCG was also more potent than EGCG at inhibiting nitric oxide production (4.4-fold) and arachidonic acid release (2.0-fold) from lipopolysaccharide-stimulated RAW264.7 murine macrophages. Intragastric administration of AcEGCG to CF-1 mice resulted in higher bioavailability compared with administration of equimolar doses of EGCG. The plasma area under the curve from 0 to infinity (AUC0-->infinity) of total EGCG was 465.0 and 194.6 [(microg/ml) . min] from the administration of AcEGCG and EGCG, respectively. The t1/2 of EGCG was also increased following administration of AcEGCG compared with EGCG (441.0 versus 200.3 min). The AUC0-->infinity and t1/2 were also increased in small intestinal (2.8- and 4.3-fold, respectively) and colonic tissues (2.4- and 6.0-fold, respectively). These data suggest that acetylation represents a means of increasing the biological potency in vitro, increasing the bioavailability of EGCG in vivo, and may improve cancer-preventive activity.     

Mannosylated liposomes improve therapeutic effects of paclitaxel in colon cancer models

Mannose receptor (MR) is a highly effective endocytic receptor. It is closely related to tumour immune escape and metastasis. We found that MR was highly expressed in some colon cancer cell lines such as CT26 and HCT116 cells. Therefore, MR might be a potential target in colon cancer therapy. In this study, we aimed to develop mannosylated liposomes containing anticancer drug paclitaxel and investigate the potential effects on targeted therapy for colon cancer. Mannosylated liposomes were prepared by film dispersion method. Characterisation, drug release behaviour, cytotoxicity, cellular uptake, anti-tumour efficacy and safety profiles of liposomes were investigated. The results showed that mannosylated liposomes had a higher CT26 cells uptake efficiency and tumour inhibition rate, which might be due to the target effect to MR. And no notable toxicity was observed. Taken together, these data demonstrated that mannosylated liposomes could target colon cancer and improve the efficacy of chemotherapy.     

Preparation,characterization, in vitro drug release and anti-inflammatory of thymoquinone-loaded chitosan nanocomposite

In this study, we formulated Thymoquinone-loaded nanocomposites (TQ-NCs) using high-pressure homogenizer without sodium tripolyphosphate. The TQ-NCs were characterized and their anti-inflammatory determined by the response of the LPS-stimulated macrophage RAW 264.7 cells in the production of nitric oxide, prostaglandin E2, tumor necrosis factor-α, interleukin-6, and interleukin-1β. The physicochemical properties of TQ-NC were determined using different machines. TQ was fully incorporated in the highly thermal stable nanoparticles. The nanoparticles showed rapid release of TQ in the acidic medium of the gastric juice. In medium of pH 6.8, TQ-NC exhibited sustained release of TQ over a period of 100 h. The results suggest that TQ-NC nanoparticles have potential application as parenterally administered therapeutic compound. TQ-NC effectively reduce production of inflammatory cytokines by the LPS-stimulated RAW 264.7 cells, indicating that they have anti-inflammatory properties. In conclusion, TQ-NC nanoparticles have the characteristics of efficient carrier for TQ and an effective anti-inflammatory therapeutic compound.     

Therapeutic effects of hybrid liposomes composed of phosphatidylcholine and docosahexaenoic acid on the hepatic metastasis of colon carcinoma along with apoptosis in vivo

Therapeutic effects of hybrid liposomes (L-α-dimyristoylphosphatidylcholine (DMPC)/docosahexaenoic acid (DHA)) composed of 50 mol% DMPC and 50 mol% DHA on the metastasis of human colon carcinoma (HCT116) cells were examined in vivo. DMPC/DHA having a hydrodynamic diameter less than 100 nm were preserved for one month. Remarkably high therapeutic effects were obtained in the hepatic metastasis mouse models of HCT116 cells after the intravenous injection of DMPC/DHA. The histological analysis indicated the induction of apoptosis was observed in the liver section of the hepatic metastasis mouse models treated with DMPC/DHA in vivo. Furthermore, prolonged survival was obtained in the hepatic metastasis mouse models after the treatment with DMPC/DHA. Therapeutic effects of DMPC/DHA without any drugs on the hepatic metastasis were revealed on the basis of histological and biochemical analyses for the first time in vivo.     

Desipramine induces apoptotic cell death through nonmitochondrial and mitochondrial pathways in different types of human colon carcinoma cells

Cytotoxic effects of desipramine on human colon carcinoma HT29 and HCT116 cells were examined. Desipramine reduced the viability of HT29 cells in a concentration-dependent manner, but failed to cause any significant change in the viability of HCT116 cells by the concentration up to 50 mumol/l, at which an approximately 60% reduction of the viability of HT29 cells was observed. Despite their different sensitivities, desipramine caused the nonoxidative apoptotic damage to both of them. In contrast to HT29 cells, desipramine might cause the apoptotic death of HCT116 cells through the disturbance of mitochondrial function. These results suggest that desipramine may cause the nonoxidative apoptotic damage to different types of human colon carcinoma cells through either a nonmitochondrial or a mitochondrial pathway, which may confer the different sensitivities to this drug on these tumor cells.     

Characterization of rhodamine loaded PEG-g-PLA nanoparticles (NPs): effect of poly(ethylene glycol) grafting density

In our previous study, PEG-g-PLA nanoparticles were developed and characterized. The aim of the present work is to investigate the effect of PEG grafting density (% PEG inserted onto poly(d, l)-lactide, PLA backbone) on both physicochemical and biological properties (mainly plasma protein binding and in vitro macrophage uptake) of PEG-g-PLA NPs. Rhodamine B (RHO) loaded NPs were prepared from a 1:1 (wt/wt) blend of PLA and PEG-g-PLA copolymer of varying PEG grafting density (1, 7, or 20% mol/mol of lactic acid monomer) by an o/w emulsion solvent evaporation method. These NPs were characterized with regard to their morphology, size, surface charge, loading efficiency, and rhodamine release. The extent of protein adsorption to the surface of different NPs was qualitatively investigated by dynamic light scattering technique. Additionally, the in vitro macrophage uptake following incubation of RAW 264.7 cells with rhodamine loaded PEG-g-PLA and PLA particles was investigated by confocal laser scanning microscopy (CLSM). The amount of NPs phagocytosed following incubation of RAW 264.7 cells with different concentrations of rhodamine loaded PLA or pegylated NPs for 24h at 37 °C was also determined by fluorescence spectroscopy. ALL lyophilized NPs showed larger diameter in the range of 300-400 nm compared to freshly prepared NPs suspension indicating particle aggregation upon lyophilization. % EE of rhodamine was found to be between 10% and 68% wt/wt depending on PEG grafting density. The higher the grafting density of PEG over PLA backbone, the more the entrapment efficiency. All pegylated NPs showed low zeta potential (close to zero) values. In vitro release analysis revealed that rhodamine leaked from all nanoparticles at a very slow rate at physiological pH, thus making it suitable for both imaging and uptake studies with RAW 264.7 cells. All PEG-g-PLA NPs of different PEG grafting density were well tolerated and exhibited no toxicity to RAW 264.7 cells as seen by cell proliferation assays. Cellular uptake of NPs was mainly dependent on polymer type as well as PEG grafting density. Grafted copolymer NPs resulted in lower degree of macrophage uptake compared to PLA NPs in macrophages cell lines. The higher the PEG grafting density, the lower the uptake of NPs by macrophage cells. Minimum NPs uptake for all the investigated concentrations was achieved when the PEG grafting density was 7% mol/mol of lactic acid. When increasing the PEG grafting density in the nanoparticles above 7%, no significant reduction in NPs phagocytosis was achieved. Thus, this study shows that the optimal PEG density required for designing stealth PEG-g-PLA NPs suitable for drug delivery applications might vary from 4 to 7%.     

小檗碱抗肿瘤作用与Wnt/-βcaten in信号转导关系

目的证明小檗碱抗肿瘤作用机制可能与信号转导过程的调控有关。方法采用细胞增殖抑制和Hoechst 33258染色凋亡实验比较小檗碱和黄连总碱对人结肠癌HCT116和SW 480细胞的作用。利用Tcf-4报告基因研究小檗碱对肿瘤细胞的信号转导影响。结果小檗碱在5~40 mg.L-1浓度范围内呈浓度依赖性和时间依赖性抑制人结肠癌HCT116和SW 480细胞的增殖;小檗碱(20 mg.L-1)处理72 h后的HCT116和SW 480细胞出现明显凋亡;相当于小檗碱浓度的黄连总碱有类似于小檗碱的作用。20~40 mg.L-1小檗碱和黄连总碱均能明显抑制-βcaten in/Tcf介导的转录活性。结论黄连总碱的抗肿瘤作用可能与其主要成分小檗碱有关;其抗肿瘤作用机制至少与抑制W nt/-βcaten in信号通路有关。     

5-Fluorouracil enteric-coated nanoparticles for improved apoptotic activity and therapeutic index in treating colorectal cancer

5-Fluorouracil (5-FU) is one among the anti-cancer agents in FOLFORINOX treatment along with oxaliplatin and irinotecan for the treatment of colorectal cancer. Despite its potential activity on the tumor cells, it lacks site specificity partly attributed by its biodistribution to healthy cells resulting in toxic effects to healthy cells. Therefore, we have formulated 5-fluorouracil enteric-coated nanoparticles (5-FUEC) to localize the drug in the colon area that enables its prolonged presence in target area in a sustained manner. The current work emphasizes on enhanced anti-cancer activity of 5-FUEC sequencing its apoptotic activity on HCT 116 colorectal cancer cell lines in vitro. MTT assay exhibited 5.5-fold decrease in IC50 value of nanoparticles comparable to 5-FU. Nuclear fragmentation with irregular edges in nucleus of cells justified its improved activity. Furthermore, flow cytometric analysis confirms the majority of cells gated in early apoptotic (39.75%) and late apoptotic phase (36.25%). Acridine orange/ethidium bromide staining (AO/EB) exhibited cells with red fluorescence (indicating apoptosis) comparable to the control and 5-FU. γ-Scintigraphic studies determined the applicability and feasibility of the enteric coating with mean gastric emptying time, mean intestinal transit time and mean colon arrival time of 1.89?±?0.03, 2.15?±?0.05 and 4.03?±?0.27?h, respectively. Moreover, nanoparticulate approach was found significant in reducing tumor size and volume in xenograft tumor models in vivo along with sustained release. These superior anti-cancer activities exhibited by 5-FUEC indicated that it could be a potential alternative to chemotherapy for colorectal cancer.     

In vitro &in vivo targeting behaviors of biotinylated Pluronic F127/poly(lactic acid) nanoparticles through biotin-avidin interaction

Biotinylated Pluronic F127/poly(lactic acid) block copolymers (B-F127-PLA) were successfully synthesized previously by our group. In the present study, the release behaviors of paclitaxel-loaded B-F127-PLA nanoparticles and their targeting properties to human ovarian carcinoma cells were investigated. Paclitaxel (pac) loaded in B-F127-PLA nanoparticles shows an initial burst release in the first 6h and followed by a slow release. The in vitro targeting behaviors of B-F127-PLA nanoparticles against human ovarian cancer cells (OVCAR-3, SKOV-3) were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) tests and fluorescence microscopy (FM) technique. Targeting was based on a three-step biotin-avidin targeting approach using biotinylated anti-CA125 antibody specific for the CA-125 antigen that is highly expressed on OVCAR-3 cells but not expressed on SKOV-3 cells. MTT results show that the anticancer effect of paclitaxel in B-F127-PLA nanoparticles over OVCAR-3 cells was stronger than that over SKOV-3 cells, indicating that B-F127-PLA nanoparticles were delivered more effectively to OVCAR-3 cells than to SKOV-3 cells. The targeting behaviors of B-F127-PLA nanoparticles were further confirmed by FM technique. The intracellular distribution of B-F127-PLA nanoparticles was also studied using a triple-labeling method. It was observed that B-F127-PLA nanoparticles are mainly localized within the cytoplasm of OVCAR-3 cells. The in vivo antitumor efficacy of pac-loaded B-F127-PLA nanoparticles by three-step method as measured by change in tumor volume of OVCAR-3 implanted in Balb/C nude mice was greater than that by one-step method.     

紫杉醇长循环固态脂质纳米粒的制备和体内外研究

目的以硬脂酸为载体材料制备紫杉醇的长循环脂质纳米粒,并考察其体内外性质。方法用“乳化蒸发-低温固化”法制备Brij78固态脂质纳米粒(Brij78-SLN)和Poluromic F₆₈固态脂质纳米粒(F₆₈-SLN);用透射电镜考察了紫杉醇纳米粒的形态;建立了脂质纳米粒和血清中测定紫杉醇的HPLC方法;考察了纳米粒于30％乙醇溶液中的体外药物释放;以市售紫杉醇注射剂对照,测定了两种纳米粒于小鼠体内的药物动力学参数。结果脂质纳米粒基本呈圆球状或椭圆球状,大小比较均匀。激光散射法测定Brij78-SLN粒径为(104±29) nm。F₆₈-SLN粒径为(220±98) nm。Brij78-SLN和F₆₈-SLN包封率分别为47%和75%。两种纳米粒都缓慢地释放药物,24 h后分别释放药物总量的8%和20%。两种纳米粒都可以延长紫杉醇的体内滞留时间,Brij78-SLN,F₆₈-SLN和紫杉醇注射剂的消除半衰期分别为4.88,10.06和1.36 h。结论硬脂酸纳米粒可能成为一种新型的药物载体。     

lncRNA FOXCUT调控Notch通路抑制结肠癌细胞增殖、侵袭的实验研究#br#

目的　研究长链非编码RNA（lncRNA）FOXC1启动子临近转录体（FOXCUT）对结肠癌细胞（HCT116）增殖、侵袭的影响及作用机制。方法　向HCT116细胞转染FOXCUT siRNA（FOXCUT siRNA组）,以转染阴性siRNA为阴性对照组（FOXCUT siRNA-NC组）,未转染组为正常对照组（NC组）,通过qPCR法确定FOXCUT干扰效果,并检测结肠癌及癌旁组织、人结肠癌细胞株（SW480、SW620、HCT116、HT29）和人正常结肠上皮细胞（NCM460）中FOXCUT mRNA表达水平;通过CCK-8、集落形成实验和Transwell实验检测沉默FOXCUT对HCT116细胞增殖、集落形成能力及侵袭能力的影响;qPCR检测沉默FOXCUT后HCT116细胞中Notch1、Hes1 mRNA表达变化;蛋白免疫印迹（Western blot）实验检测HCT116细胞中Notch1、Hes1蛋白表达情况。结果　与癌旁组织比较,结肠癌组织中FOXCUT mRNA表达水平显著增高（P＜0.01）;与NCM460细胞比较,SW480、SW620、HCT116、HT29结肠癌细胞株中FOXCUT mRNA表达水平均显著增高（P＜0.05）,其中以HCT116细胞中表达水平最高;与FOXCUT siRNA-NC组比较,FOXCUT siRNA组HCT116细胞中FOXCUT mRNA表达水平显著降低（P＜0.01）;NC组、FOXCUT siRNA-NC组HCT116细胞中FOXCUT mRNA表达水平差异无统计学意义（P＞0.05）;沉默FOXCUT可显著抑制细胞增殖、集落形成能力及侵袭（P＜0.05）,并抑制Notch1、Hes1 mRNA及蛋白表达（P＜0.01）。结论　沉默FOXCUT可抑制结肠癌HCT116细胞增殖及侵袭,可能与抑制Notch通路有关。     

Anti-proliferation activity of total flavonoids isolated from Diospyros kaki L. f. leaves against human cancer celllines

OBJECTIVE To investigate the in vitro anti-proliferation activity of PLF against several human cancer cell lines and revealed its potentials as anticancer agent. METHODS The anti-proliferation activity of PLF against six human cancer cell lines and three normal human cell lines was evaluated by Alarma Blue method.The apoptosis induction of PLF in HCT116 cells was detected using high-content analysis with FITC-Annexin Ⅴ/propidium iodide(PI) double staining. The production of intracellular reactive oxygen species(ROS) induced by PLF was accessed using DHE dye. The ability of PLF to scavenge free radical was investigated by DPPH assay.RESULTS In a concentration of up to 30 mg·L~(-1), PLF showed moderate to high anti-proliferation activity against six different types of human cancer cells, but little cytotoxicity to normal human cells. PLF induced apoptosis and intracellular ROS in HCT116 human colon cancer cells. In addition, PLF showed strong DPPH free radical scavenging ability in the antioxidant assay. CONCLUSION PLF demonstrated significant inhibition against the proliferation of liver, breast, and colon cancer cells in vitro.The anti-proliferation activity of PLF against cancer cells was related to the promotion of oxidative stress and the induction of apoptosis. PLF can be a potential candidate as anticancer drug due to the activities shown in vitro and in vivo and worth further research.     

Doxorubicin-Bound Albumin Nanoparticles Containing a TRAIL Protein for Targeted Treatment of Colon Cancer

Purpose

We developed a new nanoparticle formulation comprised of human serum albumin (HSA) for co-delivery of doxorubicin (Dox) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with the goal of apoptotic synergy in the treatment of colon cancer.

Methods

TRAIL (0.2, 0.4, 1.0%)- and Dox-loaded HSA nanoparticles (TRAIL/Dox HSA NPs) were prepared by using the nab^TM technology. Morphological and physicochemical characterizations were investigated by dynamic light scattering and transmission electron microscopy. Synergistic cytotoxicity, apoptotic activity, and potential penetration into mass tumor were determined in HCT116 cell-based systems. Furthermore, antitumor efficacy and tumor targeting were also investigated.

Results

TRAIL/Dox HSA NPs were uniformly spherical with sizes of 60?~?120 nm. The encapsulation efficacy of Dox and TRAIL was 68.9–77.2% and 80.4–86.0%, respectively. TRAIL 1.0%/Dox HSA NPs displayed the best inhibition of HCT116 colon cancer cells; inhibition was 6 times higher than achieved with Dox HSA NPs. The TRAIL 1.0%/Dox HSA NPs formulation was studied further. Flow cytometry analysis and TUNEL assay revealed that TRAIL 1.0%/Dox HSA NPs had markedly greater apoptotic activity than Dox HSA NPs. In HCT116 tumor-bearing BALB/c nu/nu mice, TRAIL 1.0%/Dox HSA NPs had significantly higher antitumor efficacy than Dox HSA NPs (tumor volume; 933.4 mm³ vs. 3183.7 mm³, respectively). TRAIL 1.0%/Dox HSA NPs penetrated deeply into tumor masses in a HCT116 spheroid model and localized in tumor sites after tail vein injection.

Conclusions

Data indicate that TRAIL 1.0%/Dox HSA NPs offer advantages of co-delivery of Dox and TRAIL in tumors, with potential synergistic apoptosis-based anticancer therapy.

     

Self-assembled polymeric nanoparticles of poly(ethylene glycol) grafted pullulan acetate as a novel drug carrier

Self-assembling nanospheres of hydrophobized pullulan have been developed. Pullulan acetate (PA), as hydrophobized pullulan, was synthesized by acetylation. Carboxymethylated poly(ethylene-glycol) (CMPEG) was introduced into pullulan acetate (PA) through a coupling reaction using N,N'-dicyclohexyl carbodiimide (DCC). A synthesized PA-PEG-PA (abbreviated as PEP) conjugate was confirmed by Fourier transform-infrared (FT-IR) spectroscopy. Since PEP conjugates have amphiphilic characteristics in aqueous solution, polymeric nanoparticles of PEP conjugates were prepared using a simple dialysis method in water. From the analysis of fluorescence excitation spectra primarily, the critical association concentration (CAC) of this conjugate was found to be 0.0063 g/L. Observations by scanning electron microscopy (SEM) showed the spherical morphologies of the PEP nanoparticles. The particle size distribution of the PEP conjugates was determined using photon correlation spectroscopy (PCS) and the intensity-average particle size was 193.3 +/- 13.53 nm with a unimodal distribution. Clonazepam (CNZ), as a model drug, was easy to entrap into polymeric nanoparticles of the PEP conjugates. The drug release behavior was mainly diffusion controlled from the core portion.     

Antitumor activity of adriamycin-incorporated polymeric micelles of poly(gamma-benzyl L-glutamate)/poly(ethylene oxide)

The multiblock copolymer composed of poly(gamma-benzyl L-glutamate) (PBLG) and poly(ethylene oxide) (PEO) was synthesized to prepare polymeric micelles as an anticancer drug carrier. Adriamycin (ADR) used as an anticancer drug was incorporated into the polymeric micelles prepared by the multiblock copolymer. The higher the drug feeding ratio, the higher the drug loading contents and the lower the drug loading efficiency. The increased drug feeding ratio resulted in increased particle sizes. At all of the formulations, particle sizes were less than 150 nm. The particles were observed as spherical shapes. ADR release from ADR-loaded polymeric micelles in vitro was decreased with an increased drug loading contents. In in vitro antitumor activity test using CT 26 tumor cells, polymeric micelles showed almost similar cytotoxicity when compared to ADR itself while polymeric micelles themselves did not affect cytotoxicity. In in vivo antitumor activity test using mice tumor xenograft model, the polymeric micelles showed improved survivability of mice with minimized weight changes and excellent tumor growth suppression efficacy. Polymeric micelles of the multiblock copolymer suggested to be a good candidate for anticancer drug delivery carrier.