Self-Assembled Biodegradable Nanoparticles Developed by Direct Dialysis for the Delivery of Paclitaxel

Purpose The main objective of this study was to obtain self-assembled biodegradable nanoparticles by a direct dialysis method for the delivery of anticancer drug. The in vitro cellular particle uptake and cytotoxicity to C6 glioma cell line were investigated. Methods Self-assembled anticancer drugs—paclitaxel-loaded poly(d,l-lactic-co-glycolic acid) (PLGA) and poly(l-lactic acid) (PLA) nanoparticles—were achieved by direct dialysis. The physical and chemical properties of nanoparticles were characterized by various state-of-the-art techniques. The encapsulation efficiency and in vitro release profile were measured by high-performance liquid chromatography. Particle cellular uptake was studied using confocal microscopy, microplate reader, and flow cytometry. In addition, the cytotoxicity of this drug delivery system was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on C6 glioma cell line to predict the possible dose response of paclitaxel-loaded PLGA and PLA nanoparticles. Results PLGA and PLA nanoparticles with or without vitamin E tocopherol polyethylene glycol succinate (TPGS) as an additive were obtained, in which the sustained release of paclitaxel of more than 20 days was achieved. The coumarin6-loaded PLGA and PLA nanoparticles could penetrate the C6 glioma cell membrane and be internalized. The cytotoxicity of paclitaxel-loaded nanoparticles seemed to be higher than that of commercial Taxol? after 3 days incubation when paclitaxel concentrations were 10 and 20 μg/ml. Conclusions Direct dialysis could be employed to achieve paclitaxel-loaded PLGA and PLA nanoparticles, which could be internalized by C6 glioma cells and enhance the cytotoxicity of paclitaxel because of its penetration to the cytoplasm and sustained release property.     

Glioma homing peptide-modified PEG-PCL nanoparticles for enhanced anti-glioma therapy

Background: Peptide-mediated drug delivery system (DDS) has been increasingly used to promote on-demand treatment efficacy of cancers. Herein, LTLRWVGLMS (LS10) peptide is selected as the functional ligand for specific glioma-targeting drug delivery. LS10 peptide selectively binds to NG2 proteins that are widely overexpressed in the glioma cells and restricted in normal tissue. LS10 peptide-decorated DDS is expected to hold vast promises in glioma therapy and decrease unwanted side effects.

Methods: LS10 peptide was conjugated on the surface of poly(ethylene glycol)-poly(?-caprolactone) (PEG-PCL) nanoparticles via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysulfosuccinimide coupling reaction. Using U87MG cells as the glioma cell model, cellular uptake, internalization mechanism, cellular cytotoxicity and apoptosis were investigated. 1,1′-Dioctadecyl-3,3,3′,3′-tetramethyl indotricarbocyanine iodide were used as fluorescence probes to investigated in vivo glioma targeting capability of LS10-NP. The glioma therapeutic efficacy of paclitaxel-loaded LS10-NP was studied on glioma-bearing nude mice.

Results: The LS10-NP with size of 119?nm enhanced cellular uptake on U87MG cells, increased cytotoxicity of the loaded paclitaxel (PTX), and improved penetration in 3D U87MG glioma spheres. In vivo biodistribution experiments showed that LS10-NP exhibited the enhanced drug localization at glioma site, which resulted in prolonged survival time of glioma-bearing mice.

Conclusion: Our results indicated that LS10 peptide-modified nanoparticulate DDS could significantly improve the anti-glioma efficacy.     

Brain-targeted delivery of doxorubicin using glutathione-coated nanoparticles for brain cancers

Abstract

Objectives: To prepare and characterize in vitro a novel brain-targeted delivery of doxorubicin using glutathione-coated nanoparticles (NPs) for the treatment of brain cancer.

Methods: Doxorubicin-loaded NPs were prepared by the nanoprecipitation method using PLGA-COOH (dl-lactide-co-glycolide). The NPs were coated with a glutathione-PEG conjugate (PEG-GSH) in order to target delivery to the brain. The NPs were characterized via in vitro studies to determine particle size, drug release, cellular uptake, immunofluorescence study, cytotoxic assay, and in vitro blood–brain barrier (BBB) assay.

Results: The NPs showed a particle size suitable for BBB permeation (particle size around 200?nm). The in vitro release profile of the NPs exhibited no initial burst release and showed sustained drug release for up to 96?h. The immunofluorescence study showed the glutathione coating does not interfere with the drug release. Furthermore, in vitro BBB Transwell? study showed significantly higher permeation of the doxorubicin-loaded NPs compared with the free doxorubicin solution through the coculture of rat brain endothelial (RBE4) and C6 astrocytoma cells (p?<?0.05).

Conclusions: We conclude that the initial in vitro characterization of the NPs demonstrates potential in delivering doxorubicin to cancer cells with possible future application in targeting brain cancers in vivo.     

RGD-modified PEG–PAMAM–DOX conjugates: In vitro and in vivo studies for glioma

This work was based on our recent studies that a promising conjugate, RGD-modified PEGylated polyamidoamine (PAMAM) dendrimer with doxorubicin (DOX) conjugated by acid-sensitive cis-aconityl linkage (RGD-PPCD), could increase tumor targeting by binding with the integrin receptors overexpressed on tumor cells and control release of free DOX in weakly acidic lysosomes. To explore the application of RGD-PPCD to glioma therapy, the effects of the conjugate were further evaluated in glioma model. For comparative studies, DOX was also conjugated to PEG–PAMAM by acid-insensitive succinic linkage to produce the PPSD conjugates, which was further modified by RGD to form RGD-PPSD. In vitro cytotoxicity of the acid-sensitive conjugates against C6 cells was higher than that of the acid-insensitive ones, and further the modification of RGD enhanced the cytotoxicity of the DOX-polymer conjugates as a result of the increased cellular uptake of the RGD-modified conjugates by C6 cells. In vivo pharmacokinetics, biodistribution and antitumor activity were investigated in an orthotopic murine model of C6 glioma by i.v. administration of DOX-polymer conjugates. In comparison with DOX solution, all the conjugates showed significantly prolonged half-life and increased AUC and exhibited higher accumulation in brain tumor than normal brain tissue. Although RGD-PPCD was more than 2-fold lower tumor accumulation than RGD-PPSD, it exhibited the longest survival times among all treatment groups, and therefore, RGD-PPCD conjugate provide a desirable candidate for targeted therapy of glioma.     

Mannosylated nanoparticulate carriers of rifabutin for alveolar targeting

The objective of the present study was to evaluate the prospective of engineered nanoparticles for selective delivery of an antituberculosis drug, rifabutin, to alveolar tissues. Drug-loaded solid lipid nanoparticles (SLNs) were synthesized and efficiently mannosylated. The formation of uncoated and coated SLNs was characterized by FTIR spectroscopy and SEM studies. A variety of physicochemical parameters such as drug loading, particle size, polydispersity index, zeta potential, and in vitro drug release were determined. The toxicity and targeting potential of the prepared formulation were assessed with alveolar macrophage uptake, hematological studies, and in vivo studies of uncoated and coated SLNs. Ex vivo cellular uptake studies of SLNs formulations in alveolar macrophages depicted almost six times enhanced uptake due to mannose coating. The hematological studies proved mannose-conjugated system to be less immunogenic and suitable for sustained delivery as evaluated against uncoated formulation. Further, the serum level and organ distribution studies demonstrated efficiency of the system for prolonged circulation and spatial delivery of rifabutin to alveolar tissues. Finally, it was concluded that mannose-conjugated SLNs can be exploited for effective and targeted delivery of rifabutin compared to its uncoated formulation and ultimately increasing the therapeutic margin of safety while reducing the side effects.     

Brain-targeted delivery of paclitaxel using glutathione-coated nanoparticles for brain cancers

Paclitaxel is not effective for treatment of brain cancers because it cannot cross the blood–brain barrier (BBB) due to efflux by P-glycoprotein (P-gp). In this work, glutathione-coated poly-(lactide-co-glycolide) (PLGA) nanoparticles (NPs) of paclitaxel were developed for brain targeting for treatment of brain cancers. P-gp ATPase assay was used to evaluate the NP as potential substrates. The NP showed a particle size suitable for BBB permeation (particle size around 200?nm) and higher cellular uptake of the NP was demonstrated in RG2 cells. The P-gp ATPase assay suggested that the NP were not substrate for P-gp and would not be effluxed by P-gp present in the BBB. The in vitro release profile of the NP exhibited no initial burst release and showed sustained drug release. The proposed coated NP showed significantly higher cytotoxicity in RG2 cells compared with uncoated NP (p?≤?0.05). Tubulin immunofluorescent study showed higher cell death by the NP due to increased microtubule stabilization. In vivo brain uptake study in mice showed higher brain uptake of the NP containing coumarin-6 compared with solution. The proposed brain-targeted NP delivery of paclitaxel could be an effective treatment for the brain cancers.     

Synthesis and anti-proliferative activity evaluation of N3-acyl-N5-aryl-3,5-diaminoindazole analogues as anti-head and neck cancer agent

Background

Nanotechnology has received great attention since a decade for the treatment of different varieties of cancer. However, there is a limited data available on the cytotoxic potential of Temozolomide (TMZ) formulations. In the current research work, an attempt has been made to understand the anti-metastatic effect of the drug after loading into PLGA nanoparticles against C6 glioma cells. Nanoparticles were prepared using solvent diffusion method and were characterized for size and morphology. Diffusion of the drug from the nanoparticles was studied by dialysis method. The designed nanoparticles were also assessed for cellular uptake using confocal microscopy and flow cytometry.

Results

PLGA nanoparticles caused a sustained release of the drug and showed a higher cellular uptake. The drug formulations also affected the cellular proliferation and motility.

Conclusion

PLGA coated nanoparticles prolong the activity of the loaded drug while retaining the anti-metastatic activity.     

Mannose 6‐phosphate‐modified bovine serum albumin nanoparticles for controlled and targeted delivery of sodium ferulate for treatment of hepatic fibrosis

Objectives The aim was to prepare neoglycoprotein‐based nanoparticles for targeted drug delivery to hepatic stellate cells, and to evaluate their characteristics in vitro and in vivo. Methods The neoglycoprotein of bovine serum albumin modified with mannose 6‐phosphate was synthesised from mannose, and used as wall material to nanoencapsulate the model natural antifibrotic substance sodium ferulate using a desolvation method. The morphology, drug loading capacity, release in vitro and biodistribution in vivo of the nanoparticles were studied. Selectivity of the nanoparticles for hepatic stellate cells was evaluated by immunohistochemical analysis of fibrotic rat liver sections. Key findings The spherical nanoparticles were negatively charged with zeta potential ranging from ?2.73 to ?35.85 mV, and sizes between 100 and 200 nm with a narrow size distribution. Drug entrapment efficiency of about 90% (w/w) and loading capacity of 20% (w/w) could be achieved. In vitro, the nanoparticles showed an initial rapid continuous release followed by a slower sustained release. After intravenous injection into mice, the nanoparticles showed a slower elimination rate and a much higher drug concentration in liver compared with the sodium ferrate solution, and less distribution to the kidneys and other tissues. Immunohistochemistry indicated that the neoglycoprotein‐based nano‐particles were taken up specifically by hepatic stellate cells. Conclusions The nanoparticles may be an efficient drug carrier targeting hepatic stellate cells.     

Development and evaluation of carboplatin-loaded PCL nanoparticles for intranasal delivery

Context: The study was aimed to develop a polymeric nanoparticle formulation of anticancer drug carboplatin using biodegradable polymer polycaprolactone (PCL). The formulation is intended for intranasal administration to treat glioma anticipating improved brain delivery as nasal route possess direct access to brain and nanoparticles have small size to overcome the mucosal and blood–brain barrier.

Objective: Development and evaluation of carboplatin-PCL nanoparticles for brain delivery by nasal route.

Methodology: Carboplatin-loaded PCL nanoparticles (CPCs) were prepared by double emulsion-solvent evaporation technique and characterized by particle size, zeta potential, entrapment efficiency, scanning electron microscopy and differential scanning calorimetry. The CPCs were assessed for in vitro release kinetics, ex vivo permeation and in situ nasal perfusion. Cytotoxic potential of CPCs in vitro was evaluated on LN229 human glioblastoma cells.

Results and discussion: The optimized formulation of carboplatin-PCL nanoparticle CPC-08 with particle size of 311.6?±?4.7?nm and zeta potential ?16.3?±?3.7?mV exhibited percentage entrapment efficiency of 27.95?±?4.21. In vitro drug release showed initial burst release followed by slow and continues release indicating biphasic pattern. The ex vivo permeation pattern through sheep nasal mucosa also exhibited a similar release pattern as for in vitro release studies. In situ nasal perfusion studies in Wistar rats demonstrate that CPCs show better nasal absorption than carboplatin solution. In vitro cytotoxicity studies on LN229 cells showed an enhancement in cytotoxicity by CPCs compared to carboplatin alone.

Conclusion: CPC-08 effectively improves nasal absorption of carboplatin and can be used for intranasal administration of carboplatin for improved brain delivery.     

Poly(Ethylene Oxide)-Modified Poly(β-Amino Ester) Nanoparticles as a pH-Sensitive System for Tumor-Targeted Delivery of Hydrophobic Drugs: Part 2. <Emphasis Type="BoldItalic">In Vivo</Emphasis> Distribution and Tumor Localization Studies

Purpose This study was carried out to determine the biodistribution profiles and tumor localization potential of poly(ethylene oxide) (PEO)-modified poly(β-amino ester) (PbAE) as a novel, pH-sensitive biodegradable polymeric nanoparticulate system for tumor-targeted drug delivery. Methods The biodistribution studies of PEO-modified PbAE and PEO-modified poly(ɛ-caprolactone) (PCL), a non-pH-sensitive polymer, nanoparticle systems were carried out in normal mice using ¹¹¹indium-oxine [¹¹¹In] as a lipophilic radiolabel encapsulated within the polymeric matrix, and the distribution of the nanoparticles was studied in plasma and all the vital organs following intravenous administration. Solid tumors were developed on nude mice using human ovarian carcinoma xenograft (SKOV-3) and the change in concentrations of tritium [³H]-labeled paclitaxel encapsulated in polymeric nanoparticles was examined in blood, tumor mass, and liver. Results Study in normal mice with a gamma-emitting isotope [¹¹¹In] provided a thorough biodistribution analysis of the PEO-modified nanoparticulate carrier systems, whereas ³H-paclitaxel was useful to understand the change in concentration and tumor localization of anticancer compound directly in major sites of distribution. Both PEO-PbAE and PEO-PCL nanoparticles showed long systemic circulating properties by virtue of surface modification with PEO-containing triblock block copolymer (Pluronic?) stabilizer. Although the PCL nanoparticles showed higher uptake by the reticuloendothelial system, the PbAE nanoparticles effectively delivered the encapsulated payload into the tumor mass. Conclusions PEO-modified PbAE nanoparticles showed considerable passive tumor targeting potential in early stages of biodistribution via the enhanced permeation and retention (EPR) mechanism. This prompts a detailed biodistribution profiling of the nanocarrier for prolonged periods to provide conclusive evidence for superiority of the delivery system.     

Hydrophobic binding peptide-conjugated hybrid lipid-mesoporous silica nanoparticles for effective chemo-photothermal therapy of pancreatic cancer

Nanoparticle-based drug delivery systems are designed to reach tumor sites based on their enhanced permeation and retention effects. However, a lack of interaction of these nanoparticles with cancer cells might lead to reduced uptake in the tumors, which might compromise the therapeutic efficacy of the system. Therefore, we developed bortezomib and IR-820-loaded hybrid-lipid mesoporous silica nanoparticles conjugated with the hydrophobic-binding peptide, cyclosporine A (CsA), and referred to them as CLMSN/BIR. Upon reaching the tumor site, CsA interacts hydrophobically with the cancer cell membranes to allow effective uptake of the nanoparticles. Nanoparticles ～160?nm in size were prepared and the stability of IR-820 significantly improved. High cellular uptake of the nanoparticles was evident with pronounced apoptotic effects in PANC-1 and MIA PaCa-2 cells that were mediated by the chemotherapeutic effect of bortezomib and the photothermal and reactive oxygen species generation effects of IR-820. An in vivo biodistribution study indicated there was high accumulation in the tumor with an enhanced photothermal effect in PANC-1 xenograft mouse tumors. Furthermore, enhanced antitumor effects in PANC-1 xenograft tumors were observed with minimal toxicity induction in the organs of mice. Cumulatively, these results indicated the promising effects of CLMSN/BIR for effective chemo-phototherapy of pancreatic cancers.     

Synthesis and evaluation of biodegradable PCL/PEG nanoparticles for neuroendocrine tumor targeted delivery of somatostatin analog

Purpose: Neuroendocrine tumors often present a diagnostic and therapeutic challenge. We have aimed to synthesize and develop biodegradable nanoparticles of somatostatin analogue, octreotide for targeted therapy of human neuroendocrine pancreatic tumor.

Methods: Direct solid phase peptide synthesis of octreotide was done. Octreotide loaded PCL/PEG nanoparticles were prepared by solvent evaporation method and characterized for transmission electron microscopy, differential scanning calorimetery (DSC), Zeta potential measurement studies. The nanoparticles were evaluated in vitro for release studies and peptide content. For biological evaluations, receptor binding & cytotoxicity studies were done on BON-1 neuroendocrine tumor cell line. Biodistribution of radiolabeled peptide and nanoparticles, tumor regression studies were performed on tumor-bearing mouse models.

Results: We have synthesized and purified octreotide with the purity of 99.96% in our laboratory. PEG/PCL nanoparticles with an average diameter of 130–195 nm having peptide loading efficiency of 66–84% with a negative surface charge were obtained with the formulation procedure. Octreotide nanoparticles have a negative action on the proliferation of BON-1 cells. In vivo biodistribution studies exhibited major accumulation of octreotide nanoparticles in tumor as compared to plain octreotide. Octreotide nanoparticles inhibited tumor growth more efficiently than free octreotide.

Conclusions: Thus, it was concluded that the PCL/PEG nanoformulation of octreotide showed high tumor uptake due to the enhanced permeation and retention (EPR) effect and then peptide ligand imparts targetability to the sst2 receptor and there by showing increase tumor growth inhibition. Selective entry of nanoparticles to the tumor also give the reduce side effects both in vivo and in vitro.     

Pharmacokinetics and biodistribution of surface modification polymeric nanoparticles

The objective of this study is to investigate the pharmacokinetics and biodistribution of free breviscapine (BVP) and coated BVP-loaded poly (D, L-lactic acid) nanoparticles (BVP-PLA-NPs) in rats after i.v. administration. Coated BVP-PLA-NPs were prepared by the spontaneous emulsification solvent diffusion method and characterized. The BVP content in the NPs, the biological samples and in vitro release was measured by the high-performance liquid chromatography (HPLC). The mean sizes of coated BVP-PLA-NPs were 177 and 319 nm with a narrow distribution and smooth sphere shapes, entrapment efficiency of 86.9% and 93.1%, respectively. Drug release profiles in phosphate buffer and plasma exhibited a biphasic release phenomenon. After i.v. administration of free BVP and NPs suspensions in rats, area under plasma concentration-time curve and elimination t _1/2 were increased 9.3-fold and 10.9-fold for 177 nm of NPs, and 4.4-fold and 17.1-fold for 319 nm of NPs compared with that of free BVP, respectively. NPs were mainly distributed in liver, spleen, heart and brain. In addition, NPs could penetrate blood brain barrier (BBB) and the particle size had some effect on pharmacokinetics and biodistribution. Coated BVP-PLA-NPs could effectively avoid the capture by the reticuloendothelial system and prolong the half-life of BVP. Moreover, these NPs could penetrate BBB and enhance the accumulation of BVP in brain.     

Unraveling the cytotoxic potential of Temozolomide loaded into PLGA nanoparticles

Background

Nanotechnology has received great attention since a decade for the treatment of different varieties of cancer. However, there is a limited data available on the cytotoxic potential of Temozolomide (TMZ) formulations. In the current research work, an attempt has been made to understand the anti-metastatic effect of the drug after loading into PLGA nanoparticles against C6 glioma cells.Nanoparticles were prepared using solvent diffusion method and were characterized for size and morphology. Diffusion of the drug from the nanoparticles was studied by dialysis method. The designed nanoparticles were also assessed for cellular uptake using confocal microscopy and flow cytometry.

Results

PLGA nanoparticles caused a sustained release of the drug and showed a higher cellular uptake. The drug formulations also affected the cellular proliferation and motility.

Conclusion

PLGA coated nanoparticles prolong the activity of the loaded drug while retaining the anti-metastatic activity.     

Development of Nanoparticles for Drug Delivery to Brain Tumor: The Effect of Surface Materials on Penetration Into Brain Tissue

Surface-modified poly(d,l-lactic-co-glycolic acid) PLGA nanoparticles (NPs) were fabricated via nanoprecipitation for obtaining therapeutic concentration of paclitaxel (PTX) in brain tumor. The cellular uptake and cytotoxicity of NPs were evaluated on C6 glioma cells in vitro, and BALB/c mice were used to study the brain penetration and biodistribution upon intravenous administration. Results showed that by finely tuning nanoprecipitation parameters, PLGA NPs coated with surfactants with a size around 150 nm could provide a sustained release of PTX for >2 weeks. Surface coatings could increase cellular uptake efficiency when compared with noncoated NPs, and d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) showed the most significant enhancement. The in vivo evaluation of TPGS-PLGA NPs showed amplified accumulation (>800% after 96 h) of PTX in the brain tissue when compared with bare NPs and Taxol^®. Therefore, PLGA-NPs with PLGA-TPGS coating demonstrate a promising approach to efficiently transport PTX across blood-brain barrier in a safer manner, with the advantages of easy formulation, lower production cost, and higher encapsulation efficiency.     

载阿霉素透明质酸聚合物纳米粒的构建及其体外性质研究

目的 合成透明质酸（HA）接枝单油酸甘油酯（GMO）两亲性聚合物HGO,并研究其所制备载阿霉素（DOX）纳米粒的理化性质及体外抗肿瘤效果。方法 HA与GMO通过酯化反应制得载体聚合物HGO,通过核磁共振波谱法及红外光谱法对其进行结构表征;采用芘荧光探针法测定聚合物临界聚集浓度（CAC）。采用透析法制备聚合物HGO载阿霉素（DOX@HGO）纳米粒,并对其进行粒径分布、Zeta电位及微观形态的表征;通过检测其在不同离子强度、不同pH条件下的粒径变化考察纳米粒的体外稳定性;考察DOX@HGO纳米粒在不同pH条件下的体外释放行为;CCK-8法考察DOX@HGO纳米粒对MDA-MB-231细胞的体外抑瘤效果;并通过荧光显微镜研究MDA-MB-231细胞对DOX溶液、DOX@HGO纳米粒的摄取能力,以及HA预处理对DOX@HGO纳米粒摄取的影响。结果 成功制得两亲性聚合物HGO,聚合物HGO中GMO的取代度为15.8%,CAC为0.023 mg·mL^-1。DOX@HGO纳米粒呈规则的球形,平均粒径为（130.800±1.709）nm,平均电位为（-32.600±0.153）mV,包封率和载药量分别为（98.65±0.74）%和（33.03±0.17）%,在不同离子强度下、模拟胃肠液中表现出良好的稳定性;DOX@HGO纳米粒的体外释放表现出pH依赖性。体外抗肿瘤活性实验表明,DOX@HGO纳米粒对MDA-MB-231细胞的生长具有较好的抑制作用;与DOX溶液比较,DOX@HGO纳米粒显著增加肿瘤细胞对于DOX的摄取（P＜0.05） ,HA预处理显著减少肿瘤细胞对DOX@HGO的摄取（P＜0.05）。结论 所构建的DOX@HGO纳米粒具有良好的理化性质,并且具有一定的pH敏感性及靶向抗肿瘤细胞的能力,是具有应用潜力的药物载体。     

A Polymeric Nanoparticle Consisting of mPEG-PLA-Toco and PLMA-COONa as a Drug Carrier: Improvements in Cellular Uptake and Biodistribution

No HeadingPurpose. To evaluate a new polymeric nanoparticulate drug delivery formulation that consists of two components: i) an amphiphilic diblock copolymer having tocopherol moiety at the end of the hydrophobic block in which the hydrophobic tocopherol moiety increases stability of hydrophobic core of the nanoparticle in aqueous medium; and ii) a biodegradable copolyester having carboxylate end group that is capable of forming ionic complex with positively charged compounds such as doxorubicin.Methods. A doxourubicin-loaded polymeric nanoparticle (Dox-PNP) was prepared by solvent evaporation method. The entrapment efficiency, size distribution, and in vitro release profile at various pH conditions were characterized. In vitro cellular uptake was investigated by confocal microscopy, flow cytometry, and MTT assay using drug-sensitive and drug-resistant cell lines. Pharmacokinetics and biodistribution were evaluated in rats and tumor-bearing mice.Results. Doxorubicin (Dox) was efficiently loaded into the PNP (higher than 95% of entrapment efficiency), and the diameter of Dox-PNP was in the range 20~25 nm with a narrow size distribution. In Vitro study showed that Dox-PNP exhibited higher cellular uptake into both human breast cancer cell (MCF-7) and human uterine cancer cell (MES-SA) than free doxorubicin solution (Free-Dox), especially into drug-resistant cells (MCF-7/ADR and MES-SA/Dx-5). In pharmacokinetics and tissue distribution study, the bioavailability of Dox-PNP calculated from the area under the blood concentration-time curve (AUC) was 69.8 times higher than that of Free-Dox in rats, and Dox-PNP exhibited 2 times higher bioavailability in tumor tissue of tumor-bearing mice.Conclusions. Dox-PNP exhibited enhanced cellular uptake of the drug. In the cytotoxic activity study, this improved cellular uptake was proved to be more advantageous in drug-resistant cell. Dox-PNP exhibited much higher bioavailability in blood plasma and more drug accumulation in tumor tissue than conventional doxorubicin formulation. The results of this study suggest that the PNP system is an advantageous carrier for drug delivery.     

Octreotide-conjugated PAMAM for targeted delivery to somatostatin receptors over-expressed tumor cells

Abstract

Purpose: An octreotide-conjugated polyamidoamine (PAMAM) dendrimer was synthesized and employed as nanocarriers of methotrexate (MTX), for targeting to the somatostatin receptors over-expressed tumor cells.

Methods: PAMAM–PEG–octreotide (PPO) and PAMAM–PEG (PPG) were synthesized and characterized. The cellular uptake of fluorescein isothiocyanate (FITC)-labeled PPO (PPO-FITC) and PPG (PPG-FITC) were investigated. The cytotoxicity of MTX and MTX nanoparticles were conducted in the MCF-7 cells. Besides, the pharmacokinetics studies on MTX nanoparticles were carried out in rats.

Results: The structure of PPO was verified by NMR detection and the diameter was 11.05?±?1.80?nm, with the amount of MTX encapsulated by PPO was 30?(molecule/molecule). MTX nanoparticles possessed significantly higher cytotoxicity against MCF-7 cells compared with free MTX, especially the PPO/MTX nanoparticles. Correspondingly, the PPO-FITC carrier had higher cellular uptake efficiency compared to PPG-FITC. In addition, pharmacokinetics studies showed that PPO/MTX nanoparticles increased mean residence time and bioavailability of MTX distinctly.

Discussion and conclusion: With further cellular uptake test of FITC-labeled carriers, the enhanced cytotoxicity of PPO/MTX nanoparticles was reasonable to ascribe to the specific receptor-mediated endocytosis induced by octreotide. The present study suggests that this PAMAM–PEG–octreotide nanocarrier opens a new path for treating cancer with higher efficacy.     

Surfactant-polymer Nanoparticles: A Novel Platform for Sustained and Enhanced Cellular Delivery of Water-soluble Molecules

Purpose Nanoparticles, drug carriers in the sub-micron size range, can enhance the therapeutic efficacy of encapsulated drug by increasing and sustaining the delivery of the drug inside the cell. However, the use of nanoparticles for small molecular weight, water-soluble drugs has been limited by poor drug encapsulation efficiency and rapid release of the encapsulated drug. Here we report enhanced cellular delivery of water-soluble molecules using novel Aerosol OT™ (AOT)-alginate nanoparticles recently developed in our laboratory. Materials and Methods AOT-alginate nanoparticles were formulated using emulsion-crosslinking technology. Rhodamine and doxorubicin were used as model water-soluble molecules. Kinetics and mechanism of nanoparticle-mediated cellular drug delivery and therapeutic efficacy of nanoparticle-encapsulated doxorubicin were evaluated in two model breast cancer cell lines. Results AOT-alginate nanoparticles demonstrated sustained release of doxorubicin over a 15-day period in vitro. Cell culture studies indicated that nanoparticles enhanced the cellular delivery of rhodamine by about two–tenfold compared to drug in solution. Nanoparticle uptake into cells was dose-, time- and energy-dependent. Treatment with nanoparticles resulted in significantly higher cellular retention of drug than treatment with drug in solution. Cytotoxicity studies demonstrated that doxorubicin in nanoparticles resulted in significantly higher and more sustained cytotoxicity than drug in solution. Conclusions AOT-alginate nanoparticles significantly enhance the cellular delivery of basic, water-soluble drugs. This translates into enhanced therapeutic efficacy for drugs like doxorubicin that have intracellular site of action. Based on these results, AOT-alginate nanoparticles appear to be suitable carriers for enhanced and sustained cellular delivery of basic, water-soluble drugs.     

Promising galactose-decorated biodegradable poloxamer 188-PLGA diblock copolymer nanoparticles of resibufogenin for enhancing liver cancer therapy

Liver cancer is one of the major diseases affecting human health. Modified drug delivery systems through the asialoglycoprotein receptor, which is highly expressed on the surface of hepatocytes, have become a research focus for the treatment of liver cancer. Resibufogenin (RBG) is a popular traditional Chinese medicine and natural anti-cancer drug that was isolated from Chansu, but its cardiotoxicity and hydrophobicity have limited its clinical applications. Galactosyl-succinyl-poloxamer 188 and galactosyl-succinyl-poloxamer 188-polylactide-co-glycolide (Gal-SP188–PLGA) were synthesized using galactose, P188, and PLGA to achieve active liver-targeting properties. RBG-loaded Gal-SP188–PLGA nanoparticles (RGPPNs) and coumarin-6-loaded Gal-SP188–PLGA nanoparticles (CGPPNs) were prepared. The in vitro cellular uptake, cytotoxicity, and apoptosis of nanoparticles in HepG2 cells were analyzed. The in vivo therapeutic effects of nanoparticles were assessed in a hepatocarcinogenic mouse model. The results showed that Gal-SP188–PLGA was successfully synthesized. The cellular uptake assay demonstrated that CGPPNs had superior active liver-targeting properties. The ratio of apoptotic cells was increased in the RGPPN group. In comparison to the other groups, RGPPNs showed superior in vivo therapeutic effects and anticancer efficacy. Thus, the active liver-targeting RGPPNs, which can enhance the pharmacological effects and decrease the toxicity of RBG, are expected to become a promising and effective treatment for liver cancer.