叶酸靶向聚合物纳米粒共传输紫杉醇和吉西他滨用于乳腺癌的治疗（英文）

针对肿瘤细胞不同信号通路的多药递药系统具有协同治疗的作用。本文中,我们开发了一种由聚-L-赖氨酸(PLL)和负载有紫杉醇/吉西他滨的聚谷氨酸(PGA-PTX和PGA-GEM)组装的叶酸(FA)修饰的聚合物多药纳米粒(FA-PMDNPs),用于FA受体靶向的乳腺癌协同治疗。PGA富含大量的羧基,为药物负载提供了充足的反应位点和负电荷。透射电子显微镜(TEM)结果表明制备的FA-PMDNPs粒径均一,为球形。溶血实验表明FA-PMDNP具有良好的生物相容性。由于乳腺癌细胞(4T1)的FA受体(FR)高表达,体外细胞活性和体内疗效结果表明FA-PMDNP比单药能够更有效地抑制乳腺癌细胞(4T1)的增殖。与单药相比,FA-PMDNPs可以有效地靶向癌细胞。因此,FA受体靶向双重载药递药系统是一种具有潜力的肿瘤纳米治疗平台。     

Preparation,characterisation and evaluation of curcumin with piperine-loaded cubosome nanoparticles

Abstract

Objective: In this study, curcumin was designed into the nanoformulation called cubosome with piperine in order to improve oral bioavailability and tissue distribution of curcumin. Methods: The characteristic of the cubosome was studied by using scanning electron microscope (SEM), Infrared spectrum and small angle X-ray scattering (SAXS) techniques. Tissue distribution of cubosome was measured by liquid chromatography-mass spectrometry (LC-MS) method in mice. Results: The characteristic of the cubosome was demonstrated that the curcumin and piperine were encapsulated in the interior of the cubosome and the crystal form was Pn3m space. The pharmacokinetic test revealed that the cubosome could improve the oral bioavailability significantly compared to the suspension of curcumin with piperine and be mainly absorbed by the spleen. Conclusion: These findings provide the reference to a preferable choice of the curcumin formulation and contribute to therapeutic application in clinical research.     

Co-delivery of sorafenib and crizotinib encapsulated with polymeric nanoparticles for the treatment of in vivo lung cancer animal model

To treat various cancers, including lung cancer, chemotherapy requires the systematic administering of chemotherapy. The chemotherapeutic effectiveness of anticancer drugs has been enhanced by polymer nanoparticles (NPs), according to new findings. As an outcome, we have developed biodegradable triblock poly(ethylene glycol)–poly(ε-caprolactone)–poly(ethylene glycol) (PEG–PCL–PEG, PECE) polymeric NPs for the co-delivery of sorafenib (SORA) and crizotinib (CRIZ) and investigated their effect on lung cancer by in vitro and in vivo. There is little polydispersity in the SORA–CRIZ@NPs, an average size of 30.45 ± 2.89 nm range. A steady release of SORA and CRIZ was observed, with no burst impact. The apoptosis rate of SORA–CRIZ@NPs was greater than that of free drugs in 4T1 and A549 cells. Further, in vitro cytotoxicity of the polymeric NPs loaded with potential anticancer drugs was more quickly absorbed by cancer cells. On the other hand, compared to free drugs (SORA + CRIZ), SORA + CRIZ@NPs showed a substantial reduction of tumor development, longer survival rate, and a lowered side effect when delivered intravenously to nude mice xenograft model with 4T1 cancer cells. TUNEL positivity was also increased in tumor cells treated with SORA–CRIZ@NPs, demonstrating the therapeutic effectiveness. SORA–CRIZ@NPs might be used to treat lung cancer soon, based on the results from our new findings.     

Combination therapy of cRGD-DOX self-assembled nanoparticles and bevacizumab for breast cancer

The interplay among diverse cell populations in the tumor microenvironment contributes to tumor progression. Targeting to different cell populations might result in improved therapeutic effects on malignant tumors. Integrins high express on many kinds of tumor cells, and VEGF has a strong effect on tumor angiogenesis. Therefore, based on tumor cells and angiogenesis, we fabricated integrin-targeting cRGD-DOX nanoparticles and combined them with the anti-VEGF antibody bevacizumab. We evaluated the antitumor effect of this combination therapy in an integrin-overexpressing MDA-MB-231 tumor model. The cRGD-DOX nanoparticles were effectively uptake by MDA-MB-231 cells and the uptake was related to the expression of integrinin; cRGD-DOX nanoparticles showed less cytotoxic than free DOX; Bevacizumab did not show significant cytotoxicity against MDA-MB-231 cells at concentrations less than 1 mg/mL. The in vivo results showed that bevacizumab could reduce tumor interstitial fluid pressure; the combination of bevacizumab and cRGD-DOX nanoparticles showed enhanced antitumor effects compared with the corresponding single-agent treatments. These findings suggested the combination of angiogenesis antibody and integrin-targeting nanoparticle loaded with a cytotoxic drug was a promising cancer treatment regimen.     

P-gp与ER及PR在原发性乳腺癌的表达及其临床意义

目的探讨乳腺癌组织中P-gp与ER及PR的表达水平、相互关系及临床意义。方法采用免疫组化S-P法,检测43例乳腺癌组织中P-gp蛋白的表达水平。每例组织在我院已用免疫组化法检测ER及PR的表达,其结果纳入本次研究。结果乳腺癌组织P-gp、ER及PR的阳性表达率分别为48．8％、41．9％、44．2％;P-gp的表达与年龄、月经状况、肿瘤大小、有无淋巴结转移、病理类型、ER及PR受体状况无关(P>0．05)。结论部分乳腺癌组织部分具有多药耐药性,P-gp的表达与 ER及PR表达无关。     

生物可降解纳米药物转运系统研究进展

纳米药物载体有延长药物作用时间、增加疗效、降低毒副作用、缓控释给药等优点。而生物可降解高分子材料因其良好的生物利用度、载药能力和控释能力以及较低的毒性而被广泛用于纳米药物。本文综述了聚乳酸-羟基乙酸共聚物(PLGA)、聚乳酸(PLA)、聚己内酯(PCL)高分子化合物制备纳米粒的合成和载药方法及应用。     

Tumor-targeted/reduction-triggered composite multifunctional nanoparticles for breast cancer chemo-photothermal combinational therapy

Breast cancer has become the most commonly diagnosed cancer type in the world. A combination of chemotherapy and photothermal therapy (PTT) has emerged as a promising strategy for breast cancer therapy. However, the intricacy of precise delivery and the ability to initiate drug release in specific tumor sites remains a challenging puzzle. Therefore, to ensure that the therapeutic agents are synchronously delivered to the tumor site for their synergistic effect, a multifunctional nanoparticle system (PCRHNs) is developed, which is grafted onto the prussian blue nanoparticles (PB NPs) by reduction-responsive camptothecin (CPT) prodrug copolymer, and then modified with tumor-targeting peptide cyclo(Asp-d-Phe-Lys-Arg-Gly) (cRGD) and hyaluronic acid (HA). PCRHNs exhibited nano-sized structure with good monodispersity, high load efficiency of CPT, triggered CPT release in response to reduction environment, and excellent photothermal conversion under laser irradiation. Furthermore, PCRHNs can act as a photoacoustic imaging contrast agent-guided PTT. In vivo studies indicate that PCRHNs exhibited excellent biocompatibility, prolonged blood circulation, enhanced tumor accumulation, allow tumor-specific chemo-photothermal therapy to achieve synergistic antitumor effects with reduced systemic toxicity. Moreover, hyperthermia-induced upregulation of heat shock protein 70 in the tumor cells could be inhibited by CPT. Collectively, PCRHNs may be a promising therapeutic way for breast cancer therapy.     

Polymeric nanoencapsulation of zaleplon into PLGA nanoparticles for enhanced pharmacokinetics and pharmacological activity

Zaleplon (ZP) is a sedative and hypnotic drug used for the treatment of insomnia. Despite its potent anticonvulsant activity, ZP is not commonly used for the treatment of convulsion since ZP is characterized by its low oral bioavailability as a result of poor solubility and extensive liver metabolism. The following study aimed to formulate specifically controlled release nano‐vehicles for oral and parenteral delivery of ZP to enhance its oral bioavailability and biological activity. A modified single emulsification–solvent evaporation method of sonication force was adopted to optimize the inclusion of ZP into biodegradable nanoparticles (NPs) using poly (dl‐lactic‐co‐glycolic acid) (PLGA). The impacts of various formulation variables on the physicochemical characteristics of the ZP‐PLGA‐NPs and drug release profiles were investigated. Pharmacokinetics and pharmacological activity of ZP‐PLGA‐NPs were studied using experimental animals and were compared with generic ZP tablets. Assessment of gamma‐aminobutyric acid (GABA) level in plasma after oral administration was conducted using enzyme‐linked immunosorbent assay. The maximal electroshock‐induced seizures model evaluated anticonvulsant activity after the parenteral administration of ZP‐loaded NPs. The prepared ZP‐PLGA NPs were negatively charged spherical particles with an average size of 120–300 nm. Optimized ZP‐PLGA NPs showed higher plasma GABA levels, longer sedative, hypnotic effects, and a 3.42‐fold augmentation in oral drug bioavailability in comparison to ZP‐marketed products. Moreover, parenteral administration of ZP‐NPs showed higher anticonvulsant activity compared to free drug. Oral administration of ZP‐PLGA NPs achieved a significant improvement in the drug bioavailability, and parenteral administration showed a pronounced anticonvulsant activity.     

Curcumin-loaded solid lipid nanoparticles with Brij78 and TPGS improved in vivo oral bioavailability and in situ intestinal absorption of curcumin

Abstract

Purpose: The present study was to formulate curcumin solid lipid nanoparticles (Cur-SLNs) with P-gp modulator excipients, TPGS and Brij78, to enhance the solubility and bioavailability of curcumin.

Methods: The formulation was optimized by Plackett–Burman screening design and Box–Behnken experiment design. Then physiochemical properties, entrapment efficiency and in vitro release of Cur-SLNs were characterized. In vivo pharmacokinetics study and in situ single-pass intestinal perfusion were performed to investigate the effects of Cur-SLNs on the bioavailability and intestinal absorption of curcumin.

Results: The optimized formulations showed an average size of 135.3?±?1.5?nm with a zeta potential value of ?24.7?±?2.1?mV and 91.09%?±?1.23% drug entrapment efficiency, meanwhile displayed a sustained release profile. In vivo pharmacokinetic study showed AUC_0→t for Cur-SLNs was 12.27-folds greater than curcumin suspension and the relative bioavailability of Cur-SLNs was 942.53%. Meanwhile, T_max and t_1/2 of curcumin for Cur-SLNs were both delayed comparing to the suspensions (p?<?0.01). The in situ intestinal absorption study revealed that the effective permeability (P_eff) value of curcumin for SLNs was significantly improved (p?<?0.01) comparing to curcumin solution.

Conclusion: Cur-SLNs with TPGS and Brij78 could improve the oral bioavailability and intestinal absorption of curcumin effectively.     

Folic acid-modified ROS-responsive nanoparticles encapsulating luteolin for targeted breast cancer treatment

Luteolin (Lut) is a natural flavonoid polyphenolic compound with multiple pharmacological activities, such as anti-oxidant, anti-inflammatory, and anti-tumor effects. However, the poor aqueous solubility and low bioactivity of Lut restrict its clinical translation. Herein, we developed a reactive oxygen species (ROS)-responsive nanoplatforms to improve the bioactivity of Lut. Folic acid (FA) was employed to decorate the nanoparticles (NPs) to enhance its targeting ability. The size of Lut-loaded ROS-responsive nanoparticles (Lut/Oxi-αCD NPs) and FA-modified Lut/Oxi-αCD NPs (Lut/FA-Oxi-αCD NPs) is 210.5 ± 6.1 and 196.7 ± 1.8 nm, respectively. Both Lut/Oxi-αCD NPs and Lut/FA-Oxi-αCD NPs have high drug loading (14.83 ± 3.50 and 16.37 ± 1.47%, respectively). In vitro cellular assays verified that these NPs could be efficiently internalized by 4T1 cells and the released Lut from NPs could inhibit tumor cells proliferation significantly. Animal experiments demonstrated that Lut/Oxi-αCD NPs, especially Lut/FA-Oxi-αCD NPs obviously accumulated at tumor sites, and inhibited tumor growth ∼3 times compared to the Lut group. In conclusion, the antitumor efficacy of Lut was dramatically improved by targeting delivery with the ROS-responsive nanoplatforms.     

PLGA nanoparticles for the oral delivery of nuciferine: preparation,physicochemical characterization and in vitro/in vivo studies

This article reports a promising approach to enhance the oral delivery of nuciferine (NUC), improve its aqueous solubility and bioavailability, and allow its controlled release as well as inhibiting lipid accumulation. NUC-loaded poly lactic-co-glycolic acid nanoparticles (NUC-PLGA-NPs) were prepared according to a solid/oil/water (s/o/w) emulsion technique due to the water-insolubility of NUC. PLGA exhibited excellent loading capacity for NUC with adjustable dosing ratios. The drug loading and encapsulation efficiency of optimized formulation were 8.89?±?0.71 and 88.54?±?7.08%, respectively. NUC-PLGA-NPs exhibited a spherical morphology with average size of 150.83?±?5.72?nm and negative charge of ?22.73?±?1.63?mV, which are suitable for oral administration. A sustained NUC released from NUC-PLGA-NPs with an initial exponential release owing to the surface associated drug followed by a slower release of NUC, which was entrapped in the core. In addition, ～77?±?6.67% was released in simulating intestinal juice, while only about 45.95?±?5.2% in simulating gastric juice. NUC-PLGA-NPs are more efficient against oleic acid (OA)-induced hepatic steatosis in HepG₂ cells when compared to naked NUC (n-NUC, *p < 0.05). The oral bioavailability of NUC-PLGA-NPs group was significantly higher (**p < 0.01) and a significantly decreased serum levels of total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), as well as a higher concentration of high-density lipoprotein cholesterol (HDL-C) was observed, compared with that of n-NUC treated group. These findings suggest that NUC-PLGA-NPs hold great promise for sustained and controlled drug delivery with improved bioavailability to alleviating lipogenesis.     

Co-delivery of docetaxel and gemcitabine using PEGylated self-assembled stealth nanoparticles for improved breast cancer therapy

The present report deals with conjugation of dual drug; docetaxel (DTX) and gemcitabine (GEM) with linker poly-ethylene-glycol (PEG) to develop amphiphilic molecule having self-assembled property. The synthesized conjugate (DTX-PEG-GEM) demonstrated critical micelle concentration (CMC) in the range of 5–10 μg/ml which self-assembled to form NPs with size 124.2?±?5.7. Remarkably higher coumarin-6 (C-6) fluorescence signals observed in case of C-6 loaded NPs, suggested enhanced cellular uptake via clathrin mediated endocytosis. Developed NPs demonstrated 4.8-fold higher AUC_(0-∞) value of GEM in comparison with Gemzar®. Tumor growth inhibition study demonstrated significant reduction in tumor volume and higher survival rate with NPs. Moreover, NPs demonstrated significantly lower hepato- and nephro-toxicity, evident from both histopathological sections and biochemical markers level estimation, and hemolytic toxicity. Data in hand suggest enhanced therapeutic efficacy and reduced toxicity of developed NPs over conventional drugs, resulting in efficient combinatorial chemotherapeutic-regimen and patient compliance, which is still an unmet task.     

Novel flavonoid-based biodegradable nanoparticles for effective oral delivery of etoposide by P-glycoprotein modulation: an in vitro,ex vivo and in vivo investigations

Abstract

A receptor level interaction of etoposide with P-glycoprotein (P-gp) and subsequent intestinal efflux has an adverse effect on its oral absorption. The present work is aimed to enhance the bioavailability of etoposide by co-administering it with quercetin (a P-gp inhibitor) in dual-loaded polymeric nanoparticle formulation. Poly-lactic-co-glycolic acid (PLGA) nanoparticles were optimized for various parameters like o/w phase volume ratio, poly-vinyl alcohol concentration, PLGA concentration and sonication time. The cytotoxicity studies (MTT assay) revealed a 9- and 11-fold decrease in the IC 50 values for etoposide-loaded nanoparticles (ENP) and etoposide?+?quercetin dual-loaded nanoparticles (EQNP) when compared to that of free etoposide, respectively, and the results were further supported by florescent-activated cell sorter studies. The confocal imaging of the intestinal sections treated with ENP and EQNP containing fluorescent probe (rhodamine) showed the superiority of the EQNP to permeate deeper. Furthermore, pharmacokinetic studies on rats revealed that EQNP exhibited a 2.4-fold increase in bioavailability of etoposide than ENP with no quercetin. The developed loaded nanoparticles have the high potential to enhance the bioavailability of the etoposide and sensitize the resistant cells.     

Targeted cancer drug delivery with aptamer-functionalized polymeric nanoparticles

Abstract

Based on exceptional advantages of aptamers, increasing attention has been presented in the utilise of them as targeted ligands for cancer drug delivery. Recently, the progress of aptamer-targeted nanoparticles has presented new therapeutic systems for several types of cancer with decreased toxicity and improved efficacy. We highlight some of the promising formulations of aptamer-conjugated polymeric nanoparticles for specific targeted drug delivery to cancer cells. This review paper focuses on the current progresses in the use of the novel strategies to aptamer-targeted drug delivery for chemotherapy. An extensive literature review was performed using internet database, mainly PubMed based on MeSH keywords. The searches included full-text publications written in English without any limitation in date. The abstracts, reviews, books as well as studies without obvious relating of aptamers as targeted ligands for cancer drug delivery were excluded from the study. The reviewed literature revealed that aptamers with ability to modify and conjugate to various molecules can be used as targeted cancer therapy agents. However, development of aptamers unique to each individual’s tumour to the development of personalised medicine seems to be needed.     

Co-delivery of gambogic acid and TRAIL plasmid by hyaluronic acid grafted PEI-PLGA nanoparticles for the treatment of triple negative breast cancer

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-based combination therapy and gene therapy are new strategies to potentially overcome the limitations of TRAIL, however, the lack of efficient and low toxic vectors remains the major obstacle. In this study, we developed a hyaluronic acid (HA)-decorated polyethylenimine-poly(d,l-lactide-co-glycolide) (PEI-PLGA) nanoparticle (NP) system for targeted co-delivery of TRAIL plasmid (pTRAIL) and gambogic acid (GA) in triple-negative breast cancer (TNBC) therapy. GA was encapsulated into the core of the PEI-PLGA NPs while pTRAIL was adsorbed onto the positive NP surface via charge adsorption. The coating of HA on PEI-PLGA NPs functions as a targeting ligand by binding to CD44 receptor of TNBC cells and a shell to neutralize the excess positive charge of inner NPs. The resultant pTRAIL and GA co-loaded HA-coated PEI-PLGA NPs exhibited spherical shape (121.5?nm) and could promote the internalization of loaded cargoes into TNBC cells through the CD44-dependent endocytic pathway. The dual drug-loaded NPs significantly augmented apoptotic cell death in vitro and inhibited TNBC tumor growth in vivo. This multifunctional NP system efficiently co-delivered GA and pTRAIL, thus representing a promising strategy to treat TNBC and bringing forth a platform strategy for co-delivery of therapeutic DNA and chemotherapeutic agents in combinatorial TNBC therapy.     

Development and in vivo evaluation of chitosan nanoparticles for the oral delivery of albumin

Albumin is used as a plasma expander in critically ill patients and for several other clinical applications mainly via intravenous infusion. Oral administration of albumin can improve patient compliance although limited oral bioavailability of proteins is still a major challenge. Although nanomaterials have been extensively utilized for improving oral delivery of proteins, albumin has been utilized only as either a model drug or as a carrier for drug delivery. In the current study, for the first time, chitosan nanoparticles have been developed and extensively optimized to improve oral bioavailability of albumin as a therapeutic protein. Several characterizations have been performed for the albumin-loaded nanoparticles (e.g. drug encapsulation efficiency, DSC, FTIR, particle size, zeta potential, morphology, release kinetics, and enzymatic stability). Nanosized spherical particles were prepared and demonstrated high stability over three months either in a powdered form or as suspensions. Sustained release of albumin over time and high enzymatic stability as compared to the free albumin were observed. In vivo, higher serum concentrations of albumin in normal rabbits and cirrhotic rats were attained following oral and intraperitoneal administrations of the albumin-loaded nanoparticles as compared to the free albumin. The nanoparticles developed in the current study might provide efficient nanovehicles for oral administration of therapeutic albumin.     

Formulation,characterization, and cellular toxicity assessment of tamoxifen-loaded silk fibroin nanoparticles in breast cancer

Silk fibroin (SF) is a natural polymeric biomaterial that is widely adopted for the preparation of drug delivery systems. Herein, we aimed to fabricate and characterize SF nanoparticles loaded with the selective estrogen receptor modulator; tamoxifen citrate (TC-SF-NPs) and to assess their in vitro efficacy against breast cancer cell lines (MCF-7 and MDA-MB-231). TC-loaded SF-NPs were characterized for particle size, morphology, entrapment efficiency, and release profile. In addition, we examined the in vitro cytotoxicity of TC-SF-NPs against human breast cancer cell lines and evaluated the anticancer potential of TC-SF-NPs through apoptosis assay and cell cycle analysis. Drug-loaded SF-NPs showed an average particle size of 186.1 ± 5.9 nm and entrapment efficiency of 79.08%. Scanning electron microscopy (SEM) showed the nanoparticles had a spherical morphology with smooth surface. Tamoxifen release from SF-NPs exhibited a biphasic release profile with an initial burst release within the first 6 h and sustained release for 48 h. TC-SF-NPs exerted a dose-dependent cytotoxic effect against breast cancer cell lines. In addition, flow cytometry analysis revealed that cells accumulate in G₀/G₁ phase, with a concomitant reduction of S- and G₂-M-phase cells upon treatment with TC-SF-NPs. Consequently, the potent anticancer activities of TC-SF-NPs against breast cancer cells were mainly attributed to the induction of apoptosis and cell cycle arrest. Our results indicate that SF nanoparticles may represent an attractive nontoxic nanocarrier for the delivery of anticancer drugs.     

新型辅助化疗在乳腺癌治疗中的临床应用

目的探讨新型辅助化疗法对乳腺癌特别是晚期乳腺癌的作用和疗效。方法选取我院2006年8月-2010年9月收治的160例乳腺癌疾病患者,并按照随机分配的原则分为实验组（80例）,对照组（80例）,实验组采用新型辅助化疗治疗方案（TAC）,对照组采用传统的化疗方法（CAF）,观察指标为腋窝淋巴结和肿瘤的大小、分化变化情况。结果实验组有效例数为63例（78．75％）,明显好于对照组有效例数42例（52．5％）,两组的治疗效果差异有极显著性（P〈0．01）。并且实验组抗癌药物细胞毒性（依照0-IV度毒性分级）也明显低于对照组（P〈0．01）,差异有极显著性。结论新型辅助化疗可以使腋窝淋巴结缩小、降低肿瘤分期、减小病灶、提高保乳手术和治性手术的成功率,值得临床推广。     

Preparation and characterization of letrozole-loaded poly(d,l-lactide) nanoparticles for drug delivery in breast cancer therapy

Letrozole (LTZ), an aromatase inhibitor used for the treatment of hormonally-positive breast cancer in postmenopausal women, has poor water solubility, rapid metabolism, and a range of side effects. In this study, polymer-based nanoparticles (NPs) incorporating the drug have been designed and characterized, aimed to control the release, potentially maximize the therapeutic efficiency, and minimize the side effects of the drug. LTZ was incorporated into poly(d,l-lactide) (PDLLA) NPs by employing the emulsion-solvent evaporation technique using a range of drug concentrations. Loaded drug and drug-polymer interactions were studied using X-ray diffraction and NPs morphology was evaluated using scanning electron microscopy (SEM). Particle size distribution (PSD) and zeta potential of the NPs were analyzed using dynamic light scattering (DLS) and laser Doppler velocimetry (LDV), respectively. Drug content and release profile studies were carried out and determined using ultra performance liquid chromatography (UPLC). The yield of LTZ-PDLLA NPs reached as high as 85%. The NPs were spherical and smooth, regardless of LTZ concentration in the formulation. However, particle size increased from 241.6?±?1.2 to 348.7?±?6.1?nm upon increasing LTZ concentration from 0 to 30% w/w, with entrapment efficiencies reaching up to 96.8%. Drug release from the polymeric matrix was best described by Higuchi model with a predominant diffusion-based mechanism. More than 15, 46, and 86% of LTZ was released in a controlled fashion over 30?d from the 10, 20, and 30% LTZ-PDLLA NPs, respectively. Overall, LTZ-PDLLA NPs were designed with appropriate size and surface charge, high drug loading, superior entrapment efficiency, and prolonged release profile.