智能响应型介孔二氧化硅抗肿瘤纳米递药系统的设计策略与研究应用

恶性肿瘤是危害人类健康的重大疾病,由于其微环境复杂多变,导致大多数抗肿瘤药物不能精准地到达病灶组织并可控释放。智能响应型纳米载体已成为抗肿瘤递药系统研究领域的热点。介孔二氧化硅作为一种优良的纳米材料,具有无毒、稳定、孔容孔径可调及表面易于功能化修饰等优势,凭借其对机体肿瘤微环境或生理变化的感知响应、实现递药系统在病灶组织定位释药或控制释药,使其成为智能响应型递药系统的理想载体。本文基于介孔二氧化硅的智能响应型递药系统的设计策略及研究应用展开综述,以期为抗肿瘤药物纳米制剂的研发提供参考。     

多孔微球在医药领域的应用

多孔微球作为一种药物新剂型,在药物新制剂的研发以及新剂型的改造方面应用广泛。多孔微球材料来源丰富,如天然高分子材料,无机材料,合成大分子聚合物等。作为一种新型缓/控释给药载体,微球具有保护药物免遭破坏、与某些细胞组织有特殊的亲和性、控制药物释放速度、延长药物作用时间、减少药物不良反应及降低用药量等优点,还可用于特定组织和器官的药物靶向释放等。由于多孔微球具有巨大的比表面积和孔体积,药物可吸附在多孔微球的表面或进入孔道内部,根据机体需要被做成速释或缓释制剂而发挥药效。该文综述了几种典型的多孔微球材料研究概况及其在生物医药领域中的应用,并对其发展前景进行展望。     

介孔二氧化硅纳米粒介导的药物传递系统及其生物安全性的研究进展

介孔二氧化硅纳米粒(MSNs)是一种新型无机纳米材料,因具有独特的网状孔道结构、巨大的比表面积、孔径分布窄且可调节及易于表面修饰等特性,已用于药物控释系统的研究.MSNs载体的药物负载量与其介孔容积相关,表面经修饰后可实现药物的控释和靶向传递.然而,随着MSNs载体与人体接触的机会和时间日益增加,其安全性也受到广泛关注.本文综合近10年来国内外的相关文献,归纳了MSNs在递药系统中的应用,并分析了其生物安全性的影响因素.     

手性介孔二氧化硅载体对地西泮溶出行为的改善

目的建立接枝L-酒石酸的手性介孔二氧化硅的药物释放系统,提升地西泮的体外溶出度,考察手性介孔硅对地西泮的体外释放特点。方法将L-酒石酸接枝硅烷偶联剂制备手性共结构导向剂,以共缩聚法制备手性介孔硅载体。将疏水性药物地西泮载入载体孔道构建药物释放系统,利用不同pH值的释放介质中的体外溶出测试评估载体对药物释放的调控能力。结果载体内部的介观孔道促使药物晶体发生无定型化转变,药物体外释放的速度和程度较原料药均得到显著提升,30 min内释放量提升4.6～6.4倍,24 h内释放量提升1.39～1.78倍,药物从载体中的释放速度随着载体比例的增加而变快。结论手性介孔硅具有良好的药物装载结合和控制释放能力,可以有效提高地西泮的体外溶出,将进一步提高药物的生物利用度,有利于其临床应用。     

介孔二氧化硅纳米粒的研究进展

介孔二氧化硅纳米粒(MSNs)具有良好生物相容性、有序介孔结构、比表面积大、表面易修饰性等特点,在很多生物医药领域显示出了极大的应用前景,尤其是基于MSNs的纳米药物输送体系被广泛用于各种药物的递送。主要介绍MSNs和可降解MSNs的制备,同时介绍了MSNs膜包被及官能团修饰在缓释控释药物中的应用,最后探讨了MSNs递进到中空介孔二氧化硅纳米粒(HMSNs)的更大的应用前景。     

介孔硅材料提高难溶性药物生物利用度的研究进展

介孔二氧化硅作为近年来比较热门的无机介孔载体材料,因其具有孔道排列规整、水热稳定性良好、生物相容性好,可以储存药物并保持药物的无定形态等特点,非常适合装载水难溶性药物。本文通过查阅国内外的相关文献,就难溶性药物口服生物利用度低的原因进行分析,并归纳总结了国内外关于介孔二氧化硅载体提高难溶性药物生物利用度方面的最新研究进展,为设计和制备具有特定结构和性能的介孔二氧化硅载体,提高难溶性药物的生物利用度及其临床应用提供参考。     

多功能介孔二氧化硅纳米粒在肿瘤治疗中的研究进展

介孔二氧化硅纳米粒由于较高的物理化学稳定性、易于官能化、低毒性以及对许多不同类型治疗剂的巨大负载能力,涉及了化学药物治疗、光热治疗、光动力治疗以及联合治疗,在肿瘤治疗方面受到极大的关注和广泛的研究探索。本文介绍了近年来基于介孔二氧化硅纳米粒作为载体在肿瘤治疗方面的一些研究报道,这些智能化的多功能性已经促使介孔二氧化硅纳米粒成为将来用于临床的非常有前途的药物纳米载体。     

两种介孔二氧化硅载体用于改善西洛他唑溶出度的比较

目的研究两种介孔二氧化硅(MCM-48和MCM-41)作为西洛他唑(cilostazol,CLT)的载体在改善药物溶出度方面的作用。方法分别采用3种方法制备CLT/MCM-48和CLT/MCM-41固体分散体,以紫外分光光度法测定样品的载药量。以溶出度为评价指标,对载药方法、药物与载体的质量比和固体分散体粒径等因素进行了优化,并应用氮气吸附和低温DSC法分析样品中药物的存在状态。结果当药物与载体质量比为1∶3时,以共沉淀法制备的CLT/MCM-48和CLT/MCM-41样品,经150μm孔径筛处理后,药物的溶出度最高,分别达到78%和85%。与以PEG4000为载体制备的CLT/PEG相比,显示了更加优良的药物溶出的稳定性。氮气吸附结果表明药物已经成功分散于载体孔道中;DSC分析显示,药物极有可能以无定形存在,且介孔孔道对药物向稳定型转变有延缓和阻滞作用。结论 MCM-48和MCM-41作为药物载体制备固体分散体能够不同程度地提高CLT的溶出度。     

多孔材料吸附技术改善中药挥发油稳定性的研究与应用

中药挥发油作为芳香类中药中的主要化学成分,具有显著的抗菌、抗炎、抗氧化等药理作用。然而,中药挥发油易挥发、易氧化变质等不稳定性问题严重限制了其制剂应用。多孔材料作为一种网格结构材料,具有高比表面积、孔体积大、孔径可调、吸附能力强及表面化学性能可控等特点,已被广泛应用于吸附分离、生物医学、工业催化、废水处理等领域。近年来利用多孔材料吸附挥发油,为改善中药挥发油的稳定性提供了新的策略方法,同时可实现中药挥发油的固化稳定与制剂应用。本文重点对介孔二氧化硅、介孔碳、介孔纳米羟基磷灰石、多孔金属有机框架、多孔淀粉等多孔材料的发展、特点及其在改善中药挥发油稳定性能的应用研究进行综述,并探讨了影响多孔介质对中药挥发油吸附稳定性能的研究策略,以期为中药挥发油的稳定化控制与应用提供参考与借鉴。     

介孔二氧化硅纳米药物缓控释系统影响药物释放因素研究进展

载体易于调控的结构对于药物实现缓控释放至关重要。本文将从孔尺寸、孔的连通性、介孔材料表面性质及壳层厚 度几个方面综述影响介孔二氧化硅纳米粒子药物释放速率的主要因素。最后，从介孔二氧化硅纳米粒子结构调控释药方面对纳 米药物药效提高的前景做了展望。本释药技术对抗生素新型制剂研发具有指导作用。     

Silica xerogels as pharmaceutical drug carriers

This review focuses on silica xerogels obtained by the sol-gel method and their application as drug delivery systems. SiO₂ xerogels are potential biomaterials to be used as matrix materials for the extended and controlled release of different kinds of biologically active agents administered by various routes. The article includes some representative examples that describe the encapsulation of bioactive molecules and model compounds inside a silica matrix produced by the conventional sol-gel method or by ultrasound hydrolysis. The drug release rate from xerogels could be modified by adjusting several parameters, such as the type of precursor, the concentration of the catalyst and drying temperature. In vitro and in vivo studies have shown the efficacy and biodegradability of these composites. The potential application of silica xerogels as drug carrier systems is critically analyzed and discussed.     

Rod-shaped mesoporous silica nanoparticles for nanomedicine: recent progress and perspectives

Introduction: Interest in mesoporous silica nanoparticles for drug delivery has resulted in a good understanding of the impact of size and surface chemistry of these nanoparticles on their performance as drug carriers. Shape has emerged as an additional factor that can have a significant effect on delivery efficacy. Rod-shaped mesoporous silica nanoparticles show improvements in drug delivery relative to spherical mesoporous silica nanoparticles.

Areas covered: This review summarises the synthesis methods for producing rod-shaped mesoporous silica nanoparticles for use in nanomedicine. The second part covers recent progress of mesoporous silica nanorods by comparing the impact of sphere and rod-shape on drug delivery efficiency.

Expert opinion: As hollow mesoporous silica nanorods are capable of higher drug loads than most other drug delivery vehicles, such particles will reduce the amount of mesoporous silica in the body for efficient therapy. However, the importance of nanoparticle shape on drug delivery efficiency is not well understood for mesoporous silica. Studies that visualize and quantify the uptake pathway of mesoporous silica nanorods in specific cell types and compare the cellular uptake to the well-studied nanospheres should be the focus of research to better understand the role of shape in uptake.     

A novel nanomatrix system consisted of colloidal silica and pH-sensitive polymethylacrylate improves the oral bioavailability of fenofibrate

A novel solid particle system with a nanomatrix structure and without surfactant for the oral delivery of insoluble drugs was prepared. This used a combination of pH-sensitive polymethylacrylate and nano-porous silica, in order to improve the drug absorption using only pharmaceutical excipients and a relative simple process. The in vitro drug dissolution and in vivo oral bioavailability of this formulation, using fenofibrate as the model drug, were compared with other reference formulations such as a suspension, micronized formulation or self microemulsion drug delivery system (SMEDDS). The supersaturation stabilizing effect of different polymers was evaluated and the physicochemical characterization of the optimal formulation was conducted by SEM, TEM, surface area analysis, DSC, and XRD. The optimized formulation prepared with polymethylacrylate (Eudragit®L100-55) and silica (Sylysia®350) markedly improved the drug dissolution compared with other reference preparations and displayed a comparative oral bioavailability to the SMEDDS. Fenofibrate existed in a molecular or amorphous state in the nanomatrix, and this state was maintained for up to 1 year, without obvious changes in drug release and absorption. In conclusion, the nanomatrix formulation described here is a promising system to enhance the oral bioavailability of water-insoluble drugs.     

Cell microenvironment stimuli-responsive controlled-release delivery systems based on mesoporous silica nanoparticles

To develop novel tumor cell microenvironment stimuli-responsive smart controlled-release delivery systems is one of the current common interests of materials science and clinical medicine. Meanwhile, mesoporous silica nanoparticles as a promising drug carrier have become the new area of interest in the field of biomedical application in recent years because of their unique characteristics and abilities to efficiently and specifically entrap cargo molecules. This review describes the more recent developments and achievements of mesoporous silica nanoparticles in drug delivery. In particular, we focus on the stimuli-responsive controlled-release systems that are able to respond to tumor cell environmental changes, such as pH, glucose, adenosine-5′-triphosphate (ATP), glutathione (GSH), and H₂O₂.     

Antibacterial and anti-inflammatory drug delivery properties on cotton fabric using betamethasone-loaded mesoporous silica particles stabilized with chitosan and silicone softener

In this study, mesoporous silica particles with a hexagonal structure (SBA-15) were synthesized and modified with (3-aminopropyl) triethoxysilane, and used as a carrier for anti-inflammatory drug, betamethasone sodium phosphate. Drug-loaded silica particles were grafted on the cotton fabric surface using chitosan and polysiloxane reactive softener as a soft and safe fixing agent to develop an antibacterial cotton fabric with drug delivery properties. Cytometry assays revealed that synthesized silica have no cytotoxicity against human peripheral blood mononuclear cells. Accordingly, the produced drug-loaded nanostructures can be applied via different routes, such as wound dressing. Drug delivery profile of the treated fabrics were investigated and compared. The drug release rate followed the conventional Higuchi model. The treated cotton fabrics were tested and evaluated using scanning electron microscope images, bending length, air permeability, washing durability and anti-bacterial properties. It was found that the chitosan-/softener-treated fabrics compounded with drug-loaded silica particles have a good drug delivery performance and exhibited a powerful antibacterial activity against both Escherichia coli and Staphylococcus aureus even after five washing cycles. The produced antibacterial cotton fabric with drug delivery properties could be proposed as a suitable material for many medical and hygienic applications.     

Controlled release using mesoporous materials containing gate-like scaffoldings

The use of gated mesoporous silica solids as suitable systems for controlled-release protocols is reviewed. These materials are based on mesoporous silica supports that can be prepared with tailor-made pores of around 2 – 10 nm and that show a very large specific surface area (up to 1200 m²/g), thus having a large load capacity. The solids can be additionally functionalised in the external surface with gate-like systems that can be opened on command to allow cargo release. Light, redox reactions, pH, temperature, polarity and enzyme-driven protocols are shown. The possible application in drug delivery protocols is discussed.     

微粉硅胶对固体自微乳化给药系统小肠吸收的影响

固体载体对固体自微乳化给药系统(solid self-microemulsifying drug delivery systems,S-SMEDDS)的体内外性质有重要影响。本文探讨微粉硅胶对S-SMEDDS药物吸收的影响,为选择适宜固体载体提供依据。通过研究微粉硅胶对小肠脂解和S-SMEDDS体外释放的影响,并采用新型体外脂解-吸收模型研究微粉硅胶对S-SMEDDS离体小肠吸收的影响。结果发现微粉硅胶既能提高脂解速率,增加脂解后水性分散相中药物分配,促进药物吸收;又会延缓S-SMEDDS体外释药,影响药物的吸收速度;最终导致对S-SMEDDS的离体小肠吸收没有显著性影响。而且微粉硅胶对脂解和释药的影响都与其用量有关,这提示微粉硅胶适合作为S-SMEDDS的固体载体,其用量需要进一步筛选优化。     

介孔二氧化硅阿霉素纳米粒的制备及体外释放考察

目的制备载阿霉素的介孔二氧化硅纳米粒(MSN),并对其体外释放进行初步研究。方法通过聚合法制备MSN,应用透射电镜表征纳米粒的形态,动态光散射粒径测定仪测定粒子的平均粒径及分布。紫外可见分光光度法评价载药量、包封率及体外释放。结果纳米粒分布均一,平均粒径约70 nm(PDI<0.1)。药物的载药量和包封率分别为(20.38±3.58)%和(55.29±5.17)%。纳米粒经24 h恒温振荡释放达平衡,在pH 5.5磷酸盐缓冲液中累积释放分数达到95%。结论 MSN具有较高的药物载药量,有望成为一种新型的化疗药物载体。     

Mesoporous silica formulation strategies for drug dissolution enhancement: a review

Introduction: Silica materials, in particular mesoporous silicas, have demonstrated excellent properties to enhance the oral bioavailability of poorly water-soluble drugs. Current research in this area is focused on investigating the kinetic profile of drug release from these carriers and manufacturing approaches to scale-up production for commercial manufacture.

Areas covered: This review provides an overview of different methods utilized to load drugs onto mesoporous silica carriers. The influence of silica properties and silica pore architecture on drug loading and release are discussed. The kinetics of drug release from mesoporous silica systems is examined and the manufacturability and stability of these formulations are reviewed. Finally, the future prospects of mesoporous silica drug delivery systems are considered.

Expert opinion: Substantial progress has been made in the characterization and development of mesoporous drug delivery systems for drug dissolution enhancement. However, more research is required to fully understand the drug release kinetic profile from mesoporous silica materials. Incomplete drug release from the carrier and the possibility of drug re-adsorption onto the silica surface need to be investigated. Issues to be addressed include the manufacturability and regulation status of formulation approaches employing mesoporous silica to enhance drug dissolution. While more research is needed to support the move of this technology from the bench to a commercial medicinal product, it is a realistic prospect for the near future.