Enhancement of cancer therapy efficacy by trastuzumab-conjugated and pH-sensitive nanocapsules with the simultaneous encapsulation of hydrophilic and hydrophobic compounds

Trastuzumab-conjugated pH-sensitive double emulsion nanocapsules (DENCs) stabilized by a single-component Poly (vinyl alcohol) (PVA) with magnetic nanoparticles can be fabricated through a two-step double emulsion process; these nanocapsules can be used to encapsulate hydrophilic doxorubicin (Dox) and hydrophobic paclitaxel (PTX) simultaneously. When PMA_SH was attached to the shell of the DENCs, enhanced dual drug release of PTX/Dox was detected, specifically in intracellular acidic pH environments. The targeting ability of these Trastuzumab-conjugated DENCs was demonstrated with confocal images, which revealed a significantly elevated cellular uptake in HER-2 overexpressing SkBr3 cells. More importantly, an intravenous injection of this co-delivery system followed by magnetic targeting (MT) chemotherapy suppressed cancer growth in vivo more efficiently than the delivery of either PTX or Dox alone. The integration of the functionalities makes this combination therapy system a powerfully new tool for in vitro/in vivo cancer therapy, especially for in HER-2 positive cancers.From the Clinical EditorTrastuzumab-conjugated pH-sensitive nanocapsules were used in this study for simultaneous targeted delivery of hydrophobic (PTX) and hydrophilic (Dox) anti-cancer agents to HER-2 positive cancer cells. Additional use of magnetic targeting demonstrated superior efficacy of this delivery system compared to PTX or Dox alone.     

Effects of receptor tyrosine kinase inhibitors on VEGF165a- and VEGF165b-stimulated gene transcription in HEK-293 cells expressing human VEGFR2

Background and Purpose

Receptor tyrosine kinase inhibitors (RTKIs) targeted at VEGF receptor 2 (VEGFR2) have proved to be attractive approaches to cancer therapy based on their ability to reduce angiogenesis. Here we have undertaken a quantitative analysis of the interaction of RTKIs and two VEGF splice variants, VEGF₁₆₅a and VEGF₁₆₅b, with VEGFR2 by studying nuclear factor of activated T-cells (NFAT) reporter gene activity in live HEK-293 cells.

Experimental Approach

HEK-293 cells expressing the human VEGFR2 and a firefly luciferase reporter gene regulated by an NFAT response element were used for quantitative analysis of the effect of RTKIs on VEGF₁₆₅a- and VEGF₁₆₅b-stimulated luciferase gene expression.

Key Results

VEGF₁₆₅a produced a concentration-dependent activation of the NFAT-luciferase reporter gene in living cells that was inhibited in a non-competitive fashion by four different RTKIs (cediranib, pazopanib, sorafenib and vandetanib). The potency obtained for each RTKI from this analysis was similar to those obtained in binding studies using purified VEGFR2 kinase domains. VEGF₁₆₅b was a lower-efficacy agonist of the NFAT-luciferase response when compared with VEGF₁₆₅a. Analysis of the concentration–response data using the operational model of agonism indicated that both VEGF₁₆₅ isoforms had similar affinity for VEGFR2.

Conclusions and Implications

Quantitative pharmacological analysis of the interaction of VEGF₁₆₅ isoforms and RTKIs with VEGFR2 in intact living cells has provided important insights into the relative affinity and efficacy of VEGF₁₆₅a and VEGF₁₆₅b for activation of the calcineurin- NFAT signalling pathway by this tyrosine kinase receptor.     

A positive circuit of VEGF increases Glut-1 expression by increasing HIF-1α gene expression in human retinal endothelial cells

Treatment of human retinal microvascular endothelial cells (HRMECs) with vascular endothelial growth factor 165 (VEGF₁₆₅) increased hypoxia-inducible factor 1α (HIF-1α), VEGF, and glucose transporter 1 (Glut-1) mRNA expression and Glut-1 protein localization to the membrane. In contrast, treatment of human retinal pigment epithelium cells with VEGF₁₆₅ did not induce HIF-1α, VEGF, and Glut-1 gene expression. Microvascular endothelial cells are surrounded by astrocytic end feet in the retina. Astrocyte-derived A-kinase anchor protein 12 overexpression during hypoxia downregulated VEGF secretion, and this conditioned medium reduced VEGF and Glut-1 expression in HRMECs, suggesting that communications between astrocytes and endothelial cells may be the determinants of the blood vessel network. In HRMECs, HIF-1α small interfering RNA transfection blocked the VEGF₁₆₅-mediated increase in VEGF and Glut-1 gene expression. Inhibition of protein kinase C (PKC) with inhibitor GF109203X or with a small interfering RNA targeting PKCζ attenuated the VEGF₁₆₅-induced Glut-1 protein expression and VEGF and Glut-1 mRNA expression. In addition, results of an immunoprecipitation assay imply an interaction between VEGF receptor 2 (VEGFR2) and PKCζ in HRMECs. Therefore, VEGF secretion by hypoxic astrocytes may upregulate HIF-1α gene expression, inducing VEGF and Glut-1 expression via the VEGFR2–PKCζ axis in HRMECs.     

Pharmacokinetics,pharmacodynamics and pre-clinical characteristics of ophthalmic drugs that bind VEGF

Drugs that prevent the binding of VEGF to its trans-membrane cognate receptors have revolutionized the treatment of the most important chorioretinal vascular disorders: exudative age-related macular degeneration, diabetic macular edema, and retinal vein occlusions. Pegaptanib, which binds to VEGF₁₆₅ and longer isoforms, ranibizumab and bevacizumab, which bind all VEGF-A isoforms, and aflibercept, which binds VEGF-A, VEGF-B, and placental growth factor, all bind VEGF₁₆₅ with high affinity. The drugs have relatively long half-lives (7 to 10 days) after intravitreal depot injections and clinical durations of action that usually exceed 4 weeks. Plasma VEGF concentrations decrease after intravitreal injections of bevacizumab and aflibercept because their systemic half-lives are extended by their Fc fragments. Extensive in vitro and in vivo testing shows that the drugs prevent VEGF-mediated activation of endothelial cells while exhibiting little evidence of toxicity. Further anti-VEGF drug development is on-going.     

Angiopoiesis and bone regeneration via co expression of the hVEGF and hBMP genes from an adeno-associated viral vector in vitro and in vivo

Aim:

To investigate the therapeutic potential of adeno-associated virus (AAV)-mediated expression of vascular endothelial growth factor (VEGF) and bone morphogenetic protein (BMP).

Methods:

Four experimental groups were administered the following AAV vector constructs: rAAV-hVEGF₁₆₅-internal ribosome entry site (IRES)-hBMP-7 (AAV-VEGF/BMP), rAAV-hVEGF₁₆₅-GFP (AAV-VEGF), rAAV-hBMP-7-GFP (AAV-BMP), and rAAV-IRES-GFP (AAV-GFP). VEGF₁₆₅ and BMP-7 gene expression was detected using RT-PCR. The VEGF₁₆₅ and BMP-7 protein expression was determined by Western blotting and ELISA. The rabbit ischemic hind limb model was adopted and rAAV was administered intramuscularly into the ischemic limb.

Results:

Rabbit bone marrow-derived mesenchymal stem cells (BMSCs) were cultured and infected with the four viral vectors. The expression of GFP increased from the 7th day of infection and could be detected on the 28th day post-infection. In the AAV-VEGF/BMP group, the levels of VEGF165 and BMP-7 increased with prolonged infection time. The VEGF₁₆₅ and BMP-7 secreted from BMSCs in the AAV-VEGF/BMP group enhanced HUVEC tube formation and resulted in a stronger osteogenic ability, respectively. In rabbit ischemic hind limb model, GFP expression increased from the 4th week and could be detected at 8 weeks post-injection. The rAAV vector had superior gene expressing activity. Eight weeks after gene transfer, the mean blood flow was significantly higher in the AAV-VEGF/BMP group. Orthotopic ossification was radiographically evident, and capillary growth and calcium deposits were obvious in this group.

Conclusion:

AAV-mediated VEGF and BMP gene transfer stimulates angiogenesis and bone regeneration and may be a new therapeutic technique for the treatment of avascular necrosis of the femoral head (ANFH).     

PVA-PEG physically cross-linked hydrogel film as a wound dressing: experimental design and optimization

The development of hydrogel films as wound healing dressings is of a great interest owing to their biological tissue-like nature. Polyvinyl alcohol/polyethylene glycol (PVA/PEG) hydrogels loaded with asiaticoside, a standardized rich fraction of Centella asiatica, were successfully developed using the freeze–thaw method. Response surface methodology with Box–Behnken experimental design was employed to optimize the hydrogels. The hydrogels were characterized and optimized by gel fraction, swelling behavior, water vapor transmission rate and mechanical strength. The formulation with 8% PVA, 5% PEG 400 and five consecutive freeze–thaw cycles was selected as the optimized formulation and was further characterized by its drug release, rheological study, morphology, cytotoxicity and microbial studies. The optimized formulation showed more than 90% drug release at 12?hours. The rheological properties exhibited that the formulation has viscoelastic behavior and remains stable upon storage. Cell culture studies confirmed the biocompatible nature of the optimized hydrogel formulation. In the microbial limit tests, the optimized hydrogel showed no microbial growth. The developed optimized PVA/PEG hydrogel using freeze–thaw method was swellable, elastic, safe, and it can be considered as a promising new wound dressing formulation.     

Enhanced anti-glioblastoma efficacy by PTX-loaded PEGylated poly(ɛ-caprolactone) nanoparticles: In vitro and in vivo evaluation

The aim of this work was to investigate the anti-tumor effect of paclitaxel (PTX)-loaded methoxy poly(ethylene glycol)-poly(?-caprolactone) nanoparticles (MPEG-NP/PTX) against glioblastoma multiforme (GBM). MPEG-NP/PTX was prepared by the emulsion and evaporation technique with particle size of 72.5±2.2nm and did not change remarkably during the period of 21-day storage at 4°C. The drug-loading coefficient and encapsulation ratio of optimized formulation were 8.2±0.6% and 90.4±2.3%, respectively. The in vitro release behavior exhibits a biphase release manner and was affected by PEG segment. In vitro cytotoxicity was assessed using C6 cell lines and was compared to Taxol and PTX-loaded poly(?-caprolactone) conventional nanoparticles (NP/PTX). Cell viability assay against C6 cells exhibited higher or at least comparable cytotoxicity than that of Taxol and NP/PTX. More importantly, in vivo real-time fluorescence imaging analysis in intracranial C6 glioblastoma bearing mice showed that the methoxy poly(ethylene glycol)-poly(?-caprolactone) nanoparticles (MPEG-NP) displayed much stronger fluorescence signal and 3-fold larger Area-Under-Curve (AUC) than poly(?-caprolactone) conventional nanoparticles (NP) in tumor-bearing brain. Furthermore, in vivo anti-glioblastoma effect exhibited the mean survive time of MPEG-NP/PTX (28 days) was much longer than those of Taxol injection (20 days) and NP/PTX (23 days). Therefore, MPEGylated poly(?-caprolactone) nanoparticles significantly enhanced the anti-glioblastoma activity of PTX and might be considered a promising drug delivery system against advanced glioblastoma.     

紫杉醇对兔血管内皮和平滑肌细胞增生影响的差异及意义

目的探讨紫杉醇对兔血管内皮和平滑肌增生影响的差异及意义.方法将兔血管平滑肌细胞接种于共培养体系上室、内皮细胞接种于下室建立体外内膜修复模型,观察紫杉醇对兔血管平滑肌和内皮细胞3H-TdR掺入、细胞计数和迁移率的影响,用直线回归法计算紫杉醇对平滑肌和内皮细胞增生迁移的半数有效抑制浓度IC50.结果在1 nmol·L-1～1 μmol·L-1之间,紫杉醇呈浓度依赖地抑制平滑肌细胞3H-TdR掺入、细胞计数和迁移(n=6, P＜0.01).在10 nmol·L-1～1 μmol·L-1之间,紫杉醇呈浓度依赖地抑制内皮细胞3H-TdR掺入、细胞计数和迁移(n=6, P＜0.01).1 nmol·L-1紫杉醇对内皮细胞3H-TdR掺入和细胞计数有抑制倾向,但与对照组相比无统计学差异.而1 nmol·L-1的紫杉醇却已显著抑制内皮细胞迁移(n=6, P＜0.01).紫杉醇对兔血管平滑肌细胞增生、迁移抑制的IC50分别为 10.09±0.47、9.16±0.54 nmol·L-1,对内皮细胞增生、迁移抑制的IC50分别为 19.05±0.35、5.37±0.51 nmol·L-1.10 nmol·L-1紫杉醇作用 20 min 在观察时间内能持续抑制融合内皮组平滑肌增生,而对数内皮组平滑肌增殖在10 d时明显高于对照组.结论紫杉醇在抑制兔血管平滑肌细胞增生的同时也抑制内皮增生,紫杉醇干预后平滑肌细胞增生延迟与内皮细胞再生延迟密切相关.     

Studies on controlled release of indomethacin from PVA hydrogel

The polyvinyl alcohol (PVA) hydrogel containing 1-methyl-2-pyrrolidinone (MP) and sorbitol was preapred by the freeze and thaw method. The release rate of indomethacin from PVA hydrogel was used as a criterion for deciding the optimum formula of hydrogel using the computer optimization technique. The hydrogel of optimum formula was composed of PVA (10 w/v%), MP (0 w/v%), and sorbitol (40 w/v%) and the release rate of indomethacin was 1.981 μg/ml·min^1/2.     

Intratumoral delivery of paclitaxel using a thermosensitive hydrogel in human tumor xenografts

Poly(organophosphazene), a novel thermosensitive hydrogel, is an injectable drug delivery system (DDS) that transforms from sol to gel at body temperature. Paclitaxel (PTX) is a mitotic inhibitor used in the treatment of various solid tumors. Due to its poor solubility in water and efflux systems in the gastrointestinal tract, PTX is a good candidate for local DDS. Here, we evaluated the penetration kinetics of PTX released from the PTX-poly(organophosphazene) hydrogel mixture in multicellular layers (MCLs) of human cancer cells. We also investigated the tumor pharmacokinetics of PTX (60 mg/kg) when administered as an intratumoral injection using poly(organophosphazene) in mice with human tumor xenografts. When PTX was formulated at 0.6 % w/w into a 10 % w/w hydrogel, the in vitro and in vivo release were found to be 40 and 90 % of the dose, respectively, in a sustained manner over 4 weeks. Exposure of MCLs to PTX-hydrogel showed time-dependent drug penetration and accumulation. In mice, the hydrogel mass was well retained over 6 weeks, and the PTX concentration in the tumor tissue was maximal at 14 days, which rapidly decreased and coincided with rebound tumor growth after 14 days of suppression. These data indicate that PTX-hydrogel should be intratumorally injected every 14 days, or drug release duration should be prolonged in order to achieve a long-term antitumor effect. Overall, poly(organophosphazene) represents a novel thermosensitive DDS for intratumoral delivery of PTX, which can accommodate a large dose of the drug in addition to reducing its systemic exposure by restricting biodistribution to tumor tissue alone.     

Fmoc-Conjugated PEG-Vitamin E2 Micelles for Tumor-Targeted Delivery of Paclitaxel: Enhanced Drug-Carrier Interaction and Loading Capacity

The purpose of this study is to develop an improved drug delivery system for enhanced paclitaxel (PTX) loading capacity and formulation stability based on PEG_5K-(vitamin E)₂ (PEG_5K-VE₂) system. PEG_5K-(fluorenylmethoxycarbonyl)-(vitamin E)₂ (PEG_5K-FVE₂) was synthesized using lysine as the scaffold. PTX-loaded PEG_5K-FVE₂ micelles were prepared and characterized. Fluorescence intensity of Fmoc in the micelles was measured as an indicator of drug-carrier interaction. Cytotoxicity of the micelle formulations was tested on various tumor cell lines. The therapeutic efficacy and toxicity of PTX-loaded micelles were investigated using a syngeneic mouse model of breast cancer (4T1.2). Our data suggest that the PEG_5K-FVE₂ micelles have a low CMC value of 4 μg/mL and small sizes (~60 nm). The PTX loading capacity of PEG_5K-FVE₂ micelles was much higher than that of PEG_5K-VE₂ micelles. The Fmoc/PTX physical interaction was clearly demonstrated by a fluorescence quenching assay. PTX-loaded PEG_5K-FVE₂ micelles exerted more potent cytotoxicity than free PTX or Taxol formulation in vitro. Finally, intravenous injection of PTX-loaded PEG_5K-FVE₂ micelles showed superior anticancer activity compared with PEG_5K-VE₂ formulation with minimal toxicity in a mouse model of breast cancer. In summary, incorporation of a drug-interactive motif (Fmoc) into PEG_5K-VE₂ micelles represents an effective strategy to improve the micelle formulation for the delivery of PTX.

Electronic supplementary material

The online version of this article (doi:10.1208/s12248-014-9651-2) contains supplementary material, which is available to authorized users.KEY WORDS: drug delivery, drug-interactive motif, micelles, paclitaxel, vitamin E derivative     

Synthesis and evaluation of water-soluble poly(vinyl alcohol)-paclitaxel conjugate as a macromolecular prodrug

Paclitaxel (PTX) is an antitumor agent for the treatment of various human cancers. Cremophor EL and ethanol are used to formulate PTX in commercial injection solutions, because of its poor solubility in water. However, these agents cause severe allergic reaction upon intravenous administration. The aim of this study is to synthesize water-soluble macromolecular prodrugs of PTX for enhancing the therapeutic efficacy. Poly(vinyl alcohol) (PVA, 80 kDa), water-soluble synthetic polymer, was used as a drug carrier which is safe and stable in the body. The 2'-hydroxyl group of PTX was reacted with succinic anhydride and then carboxylic group of the succinyl spacer was coupled to PVA via ethylene diamine spacer, resulting the water-soluble prodrug of poly(vinyl alcohol)-paclitaxel conjugate (PVA-SPTX). The solubility of PTX was greatly enhanced by the conjugation to PVA. The release of PTX from the conjugate was accelerated at the neutral to basic conditions in in vitro release experiment. [125 I]-labeled PVA-SPTX was retained in the blood circulation for several days and was gradually distributed into the tumorous tissue after intravenous injection to the tumor-bearing mice. PVA-SPTX inhibited the growth of sarcoma 180 cells subcutaneously inoculated in mice. It was suggested that the water-solubility of PTX was markedly enhanced by the conjugation to PVA, and PVA-SPTX effectively delivered PTX to the tumorous tissue due to the enhanced permeability and retention (EPR) effect.     

Sustained release formulations of rhVEGF165 produce a durable response in a murine model of peripheral angiogenesis

Local delivery of therapeutic angiogenic agents that stimulate blood vessel formation represents a promising strategy for the treatment of peripheral vascular disease (PVD). At present, requirements for temporal and spatial parameters for localized delivery are unclear, with a variety of sustained delivery approaches being examined. Two polymer-based sustained formulations containing the 165 amino acid isoform of human recombinant vascular endothelial growth factor-A (rhVEGF₁₆₅) were evaluated for their potential application in the treatment of PVD following intramuscular injection. Microspheres prepared from a 50:50 ratio of polylactic-co-glycolic acid (PLGA) and a gel of PLGA polymer solubilized in N-methyl pyrrolidone (PLGA:NMP) were each loaded with rhVEGF₁₆₅ and tested in vitro and in vivo. PLGA microspheres averaged ∼30 μm in diameter and contained 8.9% (w/w) rhVEGF₁₆₅, while the PLGA:NMP gel was formulated with varying amounts of spray freeze-dried rhVEGF₁₆₅ to result in final gel formulations having concentrations of 0.36, 0.72, or 3.6 mg/mL rhVEGF₁₆₅. In vitro release of rhVEGF₁₆₅ from PLGA microspheres showed ∼10% cumulative release by day 6, whereas the cumulative release of rhVEGF₁₆₅ from the PLGA:NMP gel matrices (0.65% w/w loading) was less than 0.25% at this same time point. While the in vitro release characteristics of these two sustained release formulations were broadly different, the plasma rhVEGF₁₆₅ concentration-time profiles following hind-limb intramuscular (IM) injection of these formulations in non-compromised rats revealed similar in vivo pharmacokinetics. Three-dimensional resin casts of vascular architecture were prepared at days 3, 7, 14, 21, 28, 60, and 75 following a single IM dosing of these sustained release microsphere and gel matrix formulations in the gastrocnemius muscle of immune-compromised mice. Scanning electron microscopic visualization of these vascular casts demonstrated spatial arrangement of capillary sprouts and vessel enlargement consistent with profound vascular changes occurring within 3 days of dosing that persisted for 2 months, approximately 1 month beyond the anticipated completion of rhVEGF₁₆₅ release from these sustained delivery formulations. Vascular re-modeling events were correlated with histological and immunohistochemical parameters attributed to known biological actions of rhVEGF₁₆₅ signaling. Together, these pharmacokinetic and pharmacodynamic results support the use of sustained release PLGA-based formulations for the local delivery of rhVEGF₁₆₅ to achieve a durable vascular re-modeling response.     

Sustained Vascular Endothelial Growth Factor Delivery Enhances Angiogenesis and Perfusion in Ischemic Hind Limb

Purpose We hypothesized that sustained delivery of vascular endothelial growth factor (VEGF) using a polymer [85:15 poly(lactide-co-glycolide) (PLG)] would enhance angiogenesis and improve perfusion of ischemic tissue.Methods C57BL/6J mice (n = 20/group) underwent unilateral hind limb ischemia surgery and were randomized to groups of no scaffold implantation (∅-Implant), unloaded scaffold implantation (Empty-PLG), or implantation of scaffolds incorporating 3 μg of VEGF₁₆₅ (PLG-VEGF). Endpoints included laser Doppler perfusion imaging (LDPI, ischemic/nonischemic limb, %), local vessel counts, immunohistochemistry for CD31, and α-smooth muscle actin. In vitro release kinetics of VEGF from PLG was also measured.Results PLG-VEGF resulted in improved lower extremity perfusion vs. controls as measured by LDPI% at 7, 14, 21, and 28 days (p < 0.05). PLG-VEGF was associated with significantly greater percentage of vessels staining for CD31 and α-smooth muscle actin compared to the Empty-PLG or ∅-Implant (p < 0.05 for both).Conclusions The PLG-VEGF scaffolds resulted in sustained VEGF delivery, improved tissue perfusion, greater capillary density, and more mature vasculature compared to the controls. The sustained-release PLG polymer vehicle is a promising delivery system for therapeutic neovascularization applications.     

Injectable poly(organophosphazene) hydrogel system for effective paclitaxel and doxorubicin combination therapy

Abstract

Combination therapy is an important option for gastric cancer which is the second leading cause of cancer-related death worldwide. The administration schedule of cell cycle-specific drugs, such as doxorubicin (DOX) and paclitaxel (PTX), is important for therapeutic efficacy. However, to control the schedule is clinically inconvenient. Additionally, in vitro cytotoxicity tests against human gastric cancer cells (SNU-601) showed that the combination indices (CIs) of DOX and PTX were 1.43 (α?=?0) and 1.90 (α?=?1), respectively, indicating that the DOX and PTX interaction was antagonistic. Thus, based on the finding that the release rate of drugs from poly(organophosphazene) (PPZ) hydrogel is dependent on the hydrophobicity of the drugs, we used injectable PPZ hydrogel in combination therapy. In vivo anticancer activity test in human gastric cancer cell-xenografted mice showed that intratumoral injection with aqueous PPZ solution, containing DOX (15?mg/kg) and PTX (30?mg/kg), resulted in the highest tumor inhibition and safety (no mortality for approximately 3 months) in the experimental groups. Consequently, PPZ hydrogel is expected to be a promising drug delivery system for cell cycle-specific drugs, facilitating the control of their administration schedule for effective combination therapy.     

PCL films incorporated with paclitaxel/5-fluorouracil: Effects of formulation and spacial architecture on drug release

The bi/tri-layered poly(?-caprolactone) (PCL)-based films co-loaded with 5-fluorouracil (5-FU) and paclitaxel (PTX) are presented for biodegradable film-based stent application. A gradient elution HPLC analytical method was used for simultaneous quantification of 5-FU and PTX. Scanning electron microscopy (SEM) was performed to observe the microscopic architecture and morphologies, and X-ray diffraction (XRD) was employed for analyzing the physical state of the components in the single layer film. Horizontal cells diffusion test results indicated that the multi-layered structure endowed the film with drug release in unidirectional pattern. The in vitro release results showed that drug release was dependent on the drug loading, the ratio of 5-FU/PTX, the composition of surface layer, as well as the addition of hydrophilic PEG. The cytotoxicity results indicated that the PCL-based films co-loaded with 5-FU and PTX could effectively inhibit the proliferation of Eca-109 cells. The in vivo drug release results showed that the in vivo drug release was highly correlative with the in vitro drug releases. This study provided PCL-based films co-loaded with 5-FU and PTX with great potential for anti-tumor stent application, due to their unidirectional and rate-tunable drug release characteristics and dual drug loading capacity.     

基于壳聚糖/海藻酸钠-聚乙烯醇的双层复合水凝胶膜伤口敷料研究

目的 制备聚乙烯醇（PVA）/海藻酸钠（SA）-聚乙烯醇（PVA）/壳聚糖（CS）双层（PAPCS）水凝胶膜伤口敷料，并进行质量评价。方法 将PVA与SA以质量比2∶1混合，配制PVA/SA混合溶液；将PVA与CS分别以质量比1∶1、2∶1、3∶1、4∶1、5∶1混合，配制不同质量比的PVA/CS混合溶液；采用涂布法制备PAPCS双层水凝胶膜伤口敷料。通过水蒸气透过率、溶胀性能、保水性、力学性能、体外凝血性能和血液相容性考察对水凝胶膜的性能进行评价、筛选PVA与CS质量比；通过傅里叶变换红外光谱检测（FTIR）和扫描电子显微镜（SEM）对PAPCS水凝胶膜的结构和形貌进行表征；通过抑菌实验比较PAPCS以及PAPCS复合载碘交联环糊精金属有机骨架（I₂@COF@PAPCS）的体外抗菌性能。结果 PVA与CS质量比为2∶1时，PAPCS水凝胶膜综合性能较好。PAPCS水凝胶膜为多孔结构，具有良好的溶胀性能、保水性以及力学性能；PAPCS水凝胶膜的水蒸气透过率为（2 643.76±91.62）g·m^-2·d^-1，接近理想范围；与PVA/SA相比，PAPCS的凝血指数显著降低（P＜0.01），为（72.93±3.58）%，溶血率小于5%，具有促进血液凝固的能力且血液相容性良好；与PVA/SA相比，PAPCS对于金黄色葡萄球菌、大肠埃希菌均有明显抑制作用，抑菌圈直径分别为（11.89±0.22）、（12.28±0.25） mm；I₂@COF@PAPCS对金黄色葡萄球菌、大肠埃希菌的抑菌圈直径分别为（21.95±1.47）、（18.89±0.81）mm，抑菌效果显著优于PAPCS（P＜0.001）。结论 采用涂布法可成功制备双层PAPCS水凝胶膜敷料，其各项性能指标良好，具有明显的凝血、抑菌效果，与I₂@COF复合使用，抑菌作用进一步增强。     

Co-delivery of paclitaxel (PTX) and docosahexaenoic acid (DHA) by targeting lipid nanoemulsions for cancer therapy

Breast cancer is one of the most common types of cancer in female patients with high morbidity and mortality. Multi-drug chemotherapy has significant advantages in the treatment of malignant tumors, especially in reducing drug toxicity, increasing drug sensitivity and reducing drug resistance. The objective of this research is to fabricate lipid nanoemulsions (LNs) for the co-delivery of PTX and docosahexaenoic acid (DHA) with folic acid (FA) decorating (PTX/DHA-FA-LNs), and investigate the anti-tumor activity of the PTX/DHA-FA-LNs against breast cancer both in vitro and in vivo. PTX/DHA-FA-LNs showed a steady release of PTX and DHA from the drug delivery system (DDS) without any burst effect. Furthermore, the PTX/DHA-FA-LNs exhibited a dose-dependent cytotoxicity and a higher rate of apoptosis as compared with the other groups in MCF-7 cells. The cellular uptake study revealed that this LNs were more readily uptaken by MCF-7 cells and M2 macrophages in vitro. Additionally, the targeted effect of PTX/DHA-FA-LNs was aided by FA receptor-mediated endocytosis, and its cytotoxicity was proportional to the cellular uptake efficiency. The anti-tumor efficiency results showed that PTX/DHA-FA-LNs significant inhibited tumor volume growth, prolonged survival time, and reduced toxicity when compared with the other groups. These results indicated that DHA increases the sensitivity of tumor cells and tumor-associated macrophages (ATM2) to PTX, and synergistic effects of folate modification in breast cancer treatment, thus PTX/DHA-FA-LNs may be a promising nanocarrier for breast cancer treatment.     

Synthesis of poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine) and preparation of its hydrogel solution containing doxorubicin

Many pH- and temperature-responsive polymers have been designed for preparing hydrogel. In the present study, in order to decrease the pH sensitivity of reported poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine) (PAA₁₅₈₀-PEG₄₆₀₀-PAA₁₅₈₀), we designed and synthesized poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine) (PAA-PEG-PAA) with shorter length of PAA chain by decreasing reaction temperature for preparing PAA-PEG-PAA hydrogel solution containing doxorubicin (DOX). The PAA-PEG-PAA was synthesized via the Michael-addition polymerization. The characteristic of PAA-PEG-PAA was evaluated.The PAA-PEG-PAA hydrogel solution was prepared and investigated. DOX-loaded PAA-PEG-PAA hydrogel solution was prepared, and its in vitro DOX release and in vitro anti-tumor activity were evaluated. Our results indicated that the viscosity of PAA-PEG-PAA hydrogel solution was concentration- and temperature-dependent. The sol-gel transition temperature of PAA-PEG-PAA hydrogel solution (12 %, w/w) ranged from 35 to 29 ºC, and its pH ranged from 6.0 to 7.4. The released DOX from DOX-loaded PAA-PEG-PAA hydrogel showed sustained release characteristics. The in vitro anti-tumor activity of DOX-loaded PAA-PEG-PAA hydrogel was confirmed in B16F10 cell line. Considering the acidic tumor microenvironment, this DOX-loaded PAA-PEG-PAA hydrogel solution would be easy in situ administration for intra-tumor injection or para-tumor injection forming hydrogel at body temperature. We suggested that this DOX-loaded PAA-PEG-PAAhydrogel solution, if containing photothermal conversion agents, would have a potential further use for photothermal therapy.