Uniform mesoporous carbon as a carrier for poorly water soluble drug and its cytotoxicity study

Mesoporous silica nanoparticles-embedded hydrogel: A potential approach for transdermal delivery of carvedilol to pediatric population

Age-appropriate drug formulations, especially for children, are often limited. A beta-blocker, Carvedilol (CRV) has recently been reported as an off-label option for the management of cardiovascular disorders in pediatric patients. CRV exhibits a pH-dependent solubility and undergoes extensive hepatic metabolism, resulting in low oral bioavailability. Mesoporous silica nanoparticles (MSNs) of two types (MCM-41 and SBA-15) were loaded with CRV at three saturation levels to improve its dissolution rate. At high saturation level, CRV-loaded SBA-15 showed superior dissolution with a dissolution efficiency of 72.42 % and significant dissimilarity (f1 = 211.80, f2 = 16.89) compared to pure CRV, demonstrating enhanced solubility and dissolution rate due to its amorphous transformation and large pore diameter. Thermal and diffractometry analysis revealed the adsorption of CRV to MSNs in an amorphous state. CRV-loaded SBA-15 was incorporated into gel bases, and the amount of CRV released from triple-layer loaded gels was found to be higher than monolayer-loaded formulations. The ex vivo skin permeation study revealed a significant enhancement of drug release and permeation for CRV-loaded SBA-15 gel formulations (714.49 ± 38.49 µg/cm2) after 24 h, compared to the control (236.19 ± 18.93 µg/cm2), with flux increased by 62 %. Improving pediatric compliance by providing a convenient, non-invasive, and palatable drug delivery option that minimizes dosing errors and enhances treatment adherence. Our study suggests CRV-loaded SBA-15 transdermal gel as a pediatric-friendly alternative to oral delivery, addressing bitter taste, bypassing hepatic metabolism, and improving bioavailability while reducing side effects.

Nanotherapy for Neural Retinal Regeneration

Retinal diseases can severely impair vision and even lead to blindness, posing significant threats to both physical and mental health. Physical retinal regenerative therapies are poised to revolutionize the treatment of various disorders associated with blindness. However, these therapies must overcome the challenges posed by the protective inner and outer blood‒retinal barriers. Nanotechnology applications in ophthalmology have shown great potential in addressing the issue of drug delivery to the eye. Moreover, nanotechnology-based therapeutics can have profound clinical impacts on retinopathy, particularly retinal regeneration, thereby improving patient outcomes. Continuous advancements in nanotechnology are being applied to regenerate lost or damaged eye tissues and to treat vision loss and blindness caused by various retinal degenerative diseases. These approaches can be categorized into three main strategies: i) nanoparticles for delivering drugs, genes, and other essential substances; ii) nanoscaffolds for providing biocompatible support; and iii) nanocomposites for enhancing the functionality of primary or stem cells. The aim of this comprehensive review is to present the current understanding of nanotechnology-based therapeutics for retinal regeneration, with a focus on the perspective functions of nanomaterials.

Mesoporous Drug Delivery System: From Physical Properties of Drug in Solid State to Controlled Release

Mesoporous materials, which exhibit great potential in the control of polymorphs and delivery of poorly water-soluble drugs, have obtained considerable attention in the field of pharmaceutical science. The physical properties and release behaviors of amorphous or crystalline drugs may be affected by formulating them into mesoporous drug delivery systems. In the past few decades, an increasing amount of papers have been written about mesoporous drug delivery systems, which play a crucial role in improving the properties of drugs. Herein, mesoporous drug delivery systems are comprehensively reviewed in terms of their physicochemical characteristics, control of polymorphic forms, physical stability, in vitro performance, and in vivo performance. Moreover, the challenges and strategies of developing robust mesoporous drug delivery systems are also discussed.

Recent Biomedical Applications of Coupling Nanocomposite Polymeric Materials Reinforced with Variable Carbon Nanofillers

The hybridization between polymers and carbon materials is one of the most recent and crucial study areas which abstracted more concern from scientists in the past few years. Polymers could be classified into two classes according to the source materials synthetic and natural. Synthetic polymeric materials have been applied over a floppy zone of industrial fields including the field of biomedicine. Carbon nanomaterials including (fullerene, carbon nanotubes, and graphene) classified as one of the most significant sources of hybrid materials. Nanocarbons are improving significantly mechanical properties of polymers in nanocomposites in addition to physical and chemical properties of the new materials. In all varieties of proposed bio-nanocomposites, a considerable improvement in the microbiological performance of the materials has been explored. Various polymeric materials and carbon-course nanofillers were present, along with antibacterial, antifungal, and anticancer products. This review spots the light on the types of synthetic polymers-based carbon materials and presented state-of-art examples on their application in the area of biomedicine.

H2O2 generation enhancement by ultrasonic nebulisation with a zinc layer for spray disinfection

With the outbreak of COVID-19, microbial pollution has gained increasing attention as a threat to human health. Consequently, many research efforts are being devoted to the development of efficient disinfection methods. In this context, hydrogen peroxide (H₂O₂) stands out as a green and broad-spectrum disinfectant, which can be produced and sprayed in the air directly by cavitation in ultrasonic nebulisation. However, the yield of H₂O₂ obtained by ultrasonic nebulisation is too low to satisfy the requirements for disinfection by spraying and needs to be improved to achieve efficient disinfection of the air and objects. Herein, we report the introduction of a zinc layer into an ultrasonic nebuliser to improve the production of H₂O₂ and generate additional Zn²⁺ by self-corrosion, achieving good disinfecting performance. Specifically, a zinc layer was assembled on the oscillator plate of a commercial ultrasonic nebuliser, resulting in a 21-fold increase in the yield of H₂O₂ and the production of 4.75 μg/mL Zn²⁺ in the spraying droplets. When the generated water mist was used to treat a bottle polluted with Escherichia coli for 30 min, the sterilisation rate reached 93.53%. This ultrasonic nebulisation using a functional zinc layer successfully enhanced the production of H₂O₂ while generating Zn²⁺, providing a platform for the development of new methodologies of spray disinfection.

Towards principled design of cancer nanomedicine to accelerate clinical translation

Nanotechnology in medical applications, especially in oncology as drug delivery systems, has recently shown promising results. However, although these advances have been promising in the pre-clinical stages, the clinical translation of this technology is challenging. To create drug delivery systems with increased treatment efficacy for clinical translation, the physicochemical characteristics of nanoparticles such as size, shape, elasticity (flexibility/rigidity), surface chemistry, and surface charge can be specified to optimize efficiency for a given application. Consequently, interdisciplinary researchers have focused on producing biocompatible materials, production technologies, or new formulations for efficient loading, and high stability. The effects of design parameters can be studied in vitro, in vivo, or using computational models, with the goal of understanding how they affect nanoparticle biophysics and their interactions with cells. The present review summarizes the advances and technologies in the production and design of cancer nanomedicines to achieve clinical translation and commercialization. We also highlight existing challenges and opportunities in the field.

Biodistribution of Mesoporous Carbon Nanoparticles via Technetium-99m Radiolabelling after Oral Administration to Mice

The use of ordered mesoporous matrices, and in particular carbon-based mesoporous nanoparticles has shown great potential towards enhancing the bioavailability of orally administered drugs. Nevertheless, elucidation of the in vivo absorption, distribution, and excretion of such carriers is essential for understanding their behaviour, and radiolabelling provides a very useful way to track their occurrence inside the body. In this work, uniform spherical CMK-1-type ordered mesoporous carbon nanoparticles have been radiolabelled with Technetium-99m (99mTc) and traced after oral administration to mice. Ex vivo biodistribution studies showed that the radiolabelled nanoparticles accumulated almost exclusively in the gastrointestinal tract; complete elimination of the radiotracer was observed within 24 h after administration, with practically no uptake into other main organs. These findings along with the results from in vitro stability studies indicate that the spherical carbon nanoparticles examined could be safely used as drug carriers with minimal side effects, but also support the great value of radiolabelling methods for monitoring the particles' behaviour in vivo.

Carboxyl-functionalized mesoporous silica nanoparticles for the controlled delivery of poorly water-soluble non-steroidal anti-inflammatory drugs

The purpose of this study was to investigate the delivery of poorly water-soluble non-steroidal anti-inflammatory drugs (NSAIDs) by carboxyl-functionalized mesoporous silica nanoparticles (MSN-COOH) with high specific surface area (S_BET). In this study, MSN-COOH was prepared by collaborative self-assembly using cetyltrimethylammonium bromide (CTAB) as template and hydrolysis (3-triethoxyl-propyl) succinic anhydride (TESPSA) as co-structure auxiliary directing agent (CSDA). The drug delivery systems were constructed with NSAIDs including Nimesulide (NMS) and Indomethacin (IMC) as model drugs. Moreover, the characterization techniques, hemolysis and bio-adsorption testes, in vitro drug release and in vivo biological studies of MSN-COOH were also carried out. The characterization results showed that MSN-COOH is spheres with clearly visible irregular honeycomb nanopores and rough surface (S_BET: 1257 m²/g, pore volume (V_P): 1.17 cm³/g). After loading NMS/IMC into MSN-COOH with high drug loading efficiency (NMS: 98.7 and IMC: 98.2%), most crystalline NMS and IMC converted to amorphous phase confirmed using differential scanning calorimeter (DSC) and X-ray power diffraction (XRD) analysis. Meanwhile, MSN-COOH significantly increased the dissolution of NMS and IMC compared with non-functionalized mesoporous silica nanoparticles (MSN), which was also confirmed by wettability experiments. The results of in vivo biological effects showed that MSN-COOH had higher bioavailability of NMS and IMC than MSN, and exerted strong anti-inflammatory effects by delivering more NMS and IMC in vivo. STATEMENT OF SIGNIFICANCE: This study successfully prepared MSNs-COOH (mesoporous silica nanoparticles modified with negatively charged carboxyl groups on the surface and in the pores) with high specific surface area and pore volume by using the negatively charged carboxyl group (hyd-TESPSA) and the positively charged CTAB self-assembled through electrostatic attraction under alkaline conditions. The drug delivery systems were constructed with Nimesulide (NMS) and Indomethacin (IMC) as model drugs. The results showed MSNs-COOH had high drug loading capacity and also exhibited good in vitro drug release properties. Interestingly, NMS loaded MSNs-COOH also had a potential pH responsive release effect. In vivo biological studies revealed that NMS/IMC loaded MSNs-COOH could evidently improve the bioavailability and played the strong anti-inflammatory effects.

An updated review of mesoporous carbon as a novel drug delivery system

The nanotechnology approach has been recently adopted to provide more reliable, effective, controlled, and safe drug delivery systems. Nanostructured materials have gained great interest, including siliceous and carbonaceous nanoparticles. The effectiveness of mesoporous carbon nanoparticles (MCNs) in tumor imaging, targeting, and treatment is urging for more future studies. MCNs possess superior properties such as their biocompatibility, large surface area, large pore volume, tunability, and more responsive behavior to internal and external release triggers. These outstanding features make MCNs more applicable for stimuli-responsive drug delivery than the conventional forms of mesoporous silica nanoparticles (MSNs) and other carbon nanoparticles. In this review, we outlined the latest updates regarding the safety, benefits, and potential applications of MCNs.

Mesoporous Carbon: A Versatile Material for Scientific Applications

Mesoporous carbon is a promising material having multiple applications. It can act as a catalytic support and can be used in energy storage devices. Moreover, mesoporous carbon controls body's oral drug delivery system and adsorb poisonous metal from water and various other molecules from an aqueous solution. The accuracy and improved activity of the carbon materials depend on some parameters. The recent breakthrough in the synthesis of mesoporous carbon, with high surface area, large pore-volume, and good thermostability, improves its activity manifold in performing functions. Considering the promising application of mesoporous carbon, it should be broadly illustrated in the literature. This review summarizes the potential application of mesoporous carbon in many scientific disciplines. Moreover, the outlook for further improvement of mesoporous carbon has been demonstrated in detail. Hopefully, it would act as a reference guidebook for researchers about the putative application of mesoporous carbon in multidimensional fields.

Development and Characterization of a Glimepiride-Loaded Gelatin-Coated Mesoporous Hollow Silica Nanoparticle Formulation and Evaluation of Its Hypoglycemic Effect on Type-2 Diabetes Model Rats

In this study, we prepared gelatin-coated mesoporous hollow silica nanospheres (GSN) as a drug carrier to improve the water solubility and regulate the release rate of glimepiride (GLM). GLM was loaded into GSN by an absorption method, and drug-loaded samples (GLM-GSN) were characterized by differential scanning calorimeter (DSC) and X-ray diffraction (XRD). Cellular uptake and in vivo intestinal uptake experiments were performed in rats. In addition, the studies of in-vitro drug dissolution, pharmacokinetics, and pharmacodynamic experiments also were performed. GLM-GSN showed excellent drug loading (39.7% ± 0.7%) and sustained GLM release. The state of GLM in GSN was amorphous according to DSC and XRD results. Cellular uptake and in vivo intestinal uptake experiments indicated that GSN could be effectively absorbed, and an MTT experiment demonstrated that GSN had good biocompatibility. Furthermore, the GLM-GSN had a higher bioavailability in pharmacokinetics experiments and a prominent hypoglycemic effect on type-2 diabetes model rats in pharmacodynamic experiments. This study clearly shows that GSN is a promising platform for delivering GLM for the treatment of type-2 diabetes.

Fabrication of nanostructured mesoporous starch encapsulating soy-derived phytoestrogen (genistein) by well-tuned solvent exchange method

The present research was concerned with preparation of mesoporous starch (MPS) as a carrier for genistein, a model of poorly water-soluble phytoestrogen isoflavone; and exploration of the impact of different fabrication parameters on structural and loading properties. MPS is considered as a highly porous biomaterial which typically possesses nanometer-sized porous microstructure and low density, providing a large effective specific surface area (SSA) and hydrophilic surface to improve solubility, stability and bioavailability of poorly water-soluble active agents. To fabricate MPS, various concentrations (8-14% w/v) of starch from different sources (corn, potato and tapioca) was used for gel formation and the successive solvent exchange process was performed with use of various ethanol concentrations (40-70% v/v), which were then dried by different techniques (rotary vacuum evaporation, microwave and freeze drying). MPS quality attributes such as SSA, total porous volume, BJH pore diameter and swelling ratio were determined and effects of the fabrication parameters were investigated using L9-Taguchi orthogonal array design. The results indicate that second order polynomial regression models were well fitted for all response variables. Interestingly, the starch components greatly influenced physical properties of MPS. Also, the drying type and ethanol concentration altered significantly the model equations. The overall best fabrication condition (14% corn starch, 100% ethanol concentration in aging step and rotary vacuum drying) resulted in favorable MPS preparation with mean size of 105.4 nm and unimodal distribution. In the next step, genistein was encapsulated in MPS microstructure at different ratios, resulting in high loading capacity and efficiency (44.71% and 79.9%, respectively) at 1:1 weight ratio. Equilibrium adsorption isotherm of genistein was evaluated also by four different kinetics models including Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms. The experimental data were found to be fitted well to the Langmuir model (R2 = 0.989). According to the electron microscopy and XRD analysis, the degree of genistein crystallinity lowered remarkably after the impregnation in to MPS, indicating improved solubility. In-vitro release profile of genistein from MPS in the simulated gastrointestinal buffer solutions (pH 1.2 and 6.8) demonstrated that incorporating genistein into the MPS enhanced the dissolution rate compared with genistein powder. Release kinetic data were fitted to the Higuchi model (R2 = 0.98), indicating diffusion-controlled release mechanism. Altogether, well-tuned MPS fabrication method can be utilized for an efficient encapsulation and dissolution enhancement of poorly soluble phytochemicals, such as genistein.

Development of High-Drug-Loading Nanoparticles

Formulating drugs into nanoparticles offers many attractive advantages over free drugs including improved bioavailability, minimized toxic side effects, enhanced drug delivery, feasibility of incorporating other functions such as controlled release, imaging agents for imaging, targeting delivery, and loading more than one drug for combination therapies. One of the key parameters is drug loading, which is defined as the mass ratio of drug to drug-loaded nanoparticles. Currently, most nanoparticle systems have relatively low drug loading (<10 wt%), and developing methods to increase drug loading remains a challenge. This Minireview presents an overview of recent research on developing nanoparticles with high drug loading (>10 wt%) from the perspective of synthesis strategies, including post-loading, co-loading, and pre-loading. Based on these three different strategies, various nanoparticle systems with different materials and drugs are summarized and discussed in terms of their synthesis methods, drug loadings, encapsulation efficiencies, release profiles, stabilities, and their applications in drug delivery. The advantages and disadvantages of these strategies are presented with an objective of providing useful design rules for future development of high-drug-loading nanoparticles.

Influence of the Preparation Method on Some Characteristics of Alginate/Chitosan/Lovastatin Composites

This study investigates the effects of direct and indirect dispersion methods for lovastatin solid dispersion (LSD) in alginate (AG)/chitosan (CS) composites on the characteristics and properties of the AG/CS/LSD composites. The preparation method significantly influences the structure, morphology, and LSD size distribution of the composites as well as the drug release of LSD from the samples. The differences in dispersion methods for LSD lead to differences in the interaction between the components, the structure, and the control drug release of LSD. Lovastatin was released from the samples containing LSD in two stages (a fast release stage and a slow release stage), and the drug release content prepared using the indirect method is lower than that prepared using the direct method in the same buffer solution. After 32 h of testing, the released LSD content from the indirect and direct LSD dispersion methods in pH 2 and pH 7.4 buffer solutions was 87–94% and 41–61%, respectively. Drug release kinetics from the above samples in solutions with different pH values was also set up.

Resveratrol loaded oxidized mesoporous carbon nanoparticles: A promising tool to treat triple negative breast cancer

Currently, breast cancer has become the most commonly diagnosed malignancy among females and triple negative breast cancer (TNBC) is a highly aggressive and metastatic subtype. The natural polyphenolic compound, resveratrol (3, 4', 5-trihydroxy-trans-stilbene, RES), has drawn great attention for its potential against TNBC. However, due to the poor aqueous solubility, the bioactivity of RES against TNBC is extremely hampered. In this study, oxidized mesoporous carbon nanoparticles (oMCNs) with size below 200 nm and excellent water dispersibility were synthesized using mild oxidation method and RES was successfully encapsulated into the pores of oMCNs with high drug loading efficiency (24.8% w/w). oMCNs exhibited good biocompatibility and excellent cellular uptake efficiency. Compared to pure RES, oMCNs-RES greatly improved the saturated solubility and in vitro release property. In vitro cytoxicity assay and apoptosis analysis showed that oMCNs-RES induced enhanced cytotoxic effect and pro-apoptosis effect mediated via the PARP and Caspase-3 protein cleavage in TNBC cell line, respectively. These results demonstrate oMCNs have the potential to deliver hydrophobic drugs and oMCNs-RES are promising in treating TNBC.

Development of a tin oxide carrier with mesoporous structure for improving the dissolution rate and oral relative bioavailability of fenofibrate

Background

Biopharmaceutics classification system class II drugs have low solubility, which limits their extent and speed of absorption after oral administration. Over the years, mesoporous materials have been widely used to increase the dissolution rate and oral relative bioavailability of poorly water-soluble drugs.

Objectives

In order to improve the dissolution rate and increase oral relative bioavailability of the poorly water-soluble drugs, a tin oxide carrier (MSn) with a mesoporous structure was successfully synthesized.

Methods

In this study, MSn was synthesized using mesoporous silica material (SBA-15) as the template. Fenofibrate (FNB) was adsorbed into the channels of MSn by an adsorption method. Characterizations of the pure FNB, MSn, physical mixture of the drug and MSn (PM; 1:1) and FNB-loaded MSn (FNB-MSn) samples were carried out by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption/desorption, powder X-ray diffractometer (PXRD), differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. Cytotoxicity assay (MTT) was used to evaluate the cytotoxicity of MSn. In vitro dissolution studies were performed to investigate the dissolution rate of FNB-MSn. In vivo pharmacokinetic studies were used to investigate the changes of plasma drug concentrations of FNB-MSn tablets and commercial FNB tablets in rabbits.

Results

Detailed characterization showed that FNB in the channels of MSn was present in an amorphous state. The in vitro release tests demonstrated that MSn with a good biocompatibility could effectively enhance the dissolution rate of FNB. Pharmacokinetic results indicated that MSn significantly increased the oral relative bioavailability of FNB.

Conclusion

MSn can be regarded as a promising carrier for an oral drug delivery system.

Effect of Paclitaxel-Mesoporous Silica Nanoparticles with a Core-Shell Structure on the Human Lung Cancer Cell Line A549

A nanodrug delivery system of paclitaxel-mesoporous silica nanoparticles with a core-shell structure (PAC-csMSN) was used to increase the dissolution of paclitaxel (PAC) and improve its treatment of lung cancer. PAC was loaded into the core-shell mesoporous silica nanoparticles (csMSN) by the adsorption equilibrium method and was in an amorphous state in terms of its mesoporous structure. In vitro and in vivo studies showed that csMSN increased the dissolution rate of PAC and improved its lung absorption. The area under concentration-time curve (AUC) value of PAC-csMSN used for pulmonary delivery in rabbits was 2.678-fold higher than that obtained with the PAC. After continuous administration for 3 days, a lung biopsy showed no signs of inflammation. Cell apoptosis results obtained by flow cytometry indicated that PAC-csMSN was more potent than pure PAC in promoting cell apoptosis. An absorption investigation of PAC-csMSN in A549 cells was carried out by transmission electron microscopy (TEM) and laser scanning confocal microscopy (LSCM). The obtained results indicated that the cellular uptake was time-dependent and csMSN was uptaken into the cytoplasm. All these results demonstrate that csMSN have the potential to achieve pulmonary inhalation administration of poorly water-soluble drugs for the treatment of lung cancer.

Superiority of amino-modified chiral mesoporous silica nanoparticles in delivering indometacin

The present study established indometacin (IMC) delivery system with chiral mesoporous silica nanoparticles (CMSNs) and amino-modified chiral mesoporous silica nanoparticles (Amino-CMSNs) that previously reported as pharmaceutical excipients, and their systemic biological effects, mainly consisting of in vitro drug intestinal permeability, haemolysis assay, in vivo pharmacokinetics, anti-inflammation pharmacodynamics and gastric irritation, were addressed. It turned out that the two IMC delivery systems established by CMSN and Amino-CMSN significantly improved drug intestinal permeability due to the improved drug dissolution caused by conversion of drug crystalline state to amorphous phase. Further, IMC-loaded Amino-CMSN was the superior choice because of its higher dissolution rate. Furthermore, CMSN and Amino-CMSN were safe to be circulated in blood, and Amino-CMSN with significant lower haemolysis ratio than CMSN was better for the minimum haemolytic behaviour. Oral bioavailability and anti-inflammation effect of IMC delivery systems established by CMSN and Amino-CMSN were enhanced compared with IMC, which was attributed to the primary cause of the improvement of IMC dissolution, and Amino-CMSN exhibited better biological effect. As a result of these facts, it is believed that the effective delivery of IMC by Amino-CMSN will provide a new candidate to formulate poorly soluble drugs so as to significantly develop pharmaceutical application.

Porous Inorganic Drug Delivery Systems-a Review

Innovative methods and materials have been developed to overcome limitations associated with current drug delivery systems. Significant developments have led to the use of a variety of materials (as excipients) such as inorganic and metallic structures, marking a transition from conventional polymers. Inorganic materials, especially those possessing significant porosity, are emerging as good candidates for the delivery of a range of drugs (antibiotics, anticancer and anti-inflammatories), providing several advantages in formulation and engineering (encapsulation of drug in amorphous form, controlled delivery and improved targeting). This review focuses on key selected developments in porous drug delivery systems. The review provides a short broad overview of porous polymeric materials for drug delivery before focusing on porous inorganic materials (e.g. Santa Barbara Amorphous (SBA) and Mobil Composition of Matter (MCM)) and their utilisation in drug dosage form development. Methods for their preparation and drug loading thereafter are detailed. Several examples of porous inorganic materials, drugs used and outcomes are discussed providing the reader with an understanding of advances in the field and realistic opportunities.

High drug-loading nanomedicines: progress, current status, and prospects

Drug molecules transformed into nanoparticles or endowed with nanostructures with or without the aid of carrier materials are referred to as "nanomedicines" and can overcome some inherent drawbacks of free drugs, such as poor water solubility, high drug dosage, and short drug half-life in vivo. However, most of the existing nanomedicines possess the drawback of low drug-loading (generally less than 10%) associated with more carrier materials. For intravenous administration, the extensive use of carrier materials might cause systemic toxicity and impose an extra burden of degradation, metabolism, and excretion of the materials for patients. Therefore, on the premise of guaranteeing therapeutic effect and function, reducing or avoiding the use of carrier materials is a promising alternative approach to solve these problems. Recently, high drug-loading nanomedicines, which have a drug-loading content higher than 10%, are attracting increasing interest. According to the fabrication strategies of nanomedicines, high drug-loading nanomedicines are divided into four main classes: nanomedicines with inert porous material as carrier, nanomedicines with drug as part of carrier, carrier-free nanomedicines, and nanomedicines following niche and complex strategies. To date, most of the existing high drug-loading nanomedicines belong to the first class, and few research studies have focused on other classes. In this review, we investigate the research status of high drug-loading nanomedicines and discuss the features of their fabrication strategies and optimum proposal in detail. We also point out deficiencies and developing direction of high drug-loading nanomedicines. We envision that high drug-loading nanomedicines will occupy an important position in the field of drug-delivery systems, and hope that novel perspectives will be proposed for the development of high drug-loading nanomedicines.

Dissolution and physicochemical stability enhancement of artemisinin and mefloquine co-formulation via nano-confinement with mesoporous SBA-15

The objective of this study is to enhance the dissolution rate, supersaturation and physicochemical stability of combination of two poorly water-soluble anti-malarial drugs, artemisinin (ART) and mefloquine (MFQ), by encapsulating them inside mesoporous silica (SBA-15) via co-spray drying. Characteristic studies such as powder X-ray diffraction (PXRD), transmission electron microscopy (TEM) and scanning electron microscope (SEM) clearly indicate the amorphization of the crystalline drugs. ART/MQF/SBA-15 formulations show a superior dissolution enhancement with a burst release of more than 95% of drugs within 30min. In addition, the combination formulation exhibits a stable supersaturation enhancement by 2-fold higher than that of the untreated crystalline counterparts. ART/MQF/SBA-15 samples possess excellent physicochemical stability under 2 different moderate storage conditions for 6 months. The amorphization of ART and MFQ via nano-confinement using mesoporous SBA-15 is a potentially promising approach to enhance the solubility of poorly water-soluble anti-malarial drugs that co-formulated into a single dosage form.

Mesoporous carbon nanomaterials in drug delivery and biomedical application

Recent development of nano-technology provides highly efficient and versatile treatment methods to achieve better therapeutic efficacy and lower side effects of malignant cancer. The exploration of drug delivery systems (DDSs) based on nano-material shows great promise in translating nano-technology to clinical use to benefit patients. As an emerging inorganic nanomaterial, mesoporous carbon nanomaterials (MCNs) possess both the mesoporous structure and the carbonaceous composition, endowing them with superior nature compared with mesoporous silica nanomaterials and other carbon-based materials, such as carbon nanotube, graphene and fullerene. In this review, we highlighted the cutting-edge progress of carbon nanomaterials as drug delivery systems (DDSs), including immediate/sustained drug delivery systems and controlled/targeted drug delivery systems. In addition, several representative biomedical applications of mesoporous carbon such as (1) photo-chemo synergistic therapy; (2) delivery of therapeutic biomolecule and (3) in vivo bioimaging are discussed and integrated. Finally, potential challenges and outlook for future development of mesoporous carbon in biomedical fields have been discussed in detail.

Evaluation of mesoporous carbon aerogels as carriers of the non-steroidal anti-inflammatory drug ibuprofen

Towards the development of novel drug carriers for oral delivery of poorly soluble drugs mesoporous aerogel carbons (CAs), namely CA10 and CA20 with different pore sizes (10 and 20nm, respectively), were evaluated. The non-steroidal anti-inflammatory lipophilic compound ibuprofen was incorporated via passive loading. The drug loaded carbon aerogels were systemically investigated by means of High-Resolution Transmission Electron Microscopy (HR-TEM), Nitrogen physisorption studies, X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), X-ray photon electron spectroscopy (XPS) and ζ-potential studies. In vitro release studies were performed in simulated intestinal fluids reflecting both fasted (FaSSIF) and fed (FeSSIF) state conditions. Cytotoxicity studies were conducted with human intestinal cells (Caco-2). Drug was in an amorphous state in the pores of the carbon carrier as shown from the physicochemical characterization studies. The results showed marked differences in the release profiles for ibuprofen from the two aerogels in the media tested whereas in vitro toxicity profiles appear to be compatible with potential therapeutic applications at low concentrations.

Targeted Near-Infrared Fluorescent Turn-on Nanoprobe for Activatable Imaging and Effective Phototherapy of Cancer Cells

A novel and green multifunctional nanoplatform as a nanocarrier for drug delivery, cell imaging, and phototherapy has been engineered. The nanoplatform is composed of stabilized carbon spheres (CSs) as cores, a coated polydopamine (PDA) shell, targeted folic acid (FA), and the loaded anticancer drug indocyanine green (ICG), obtaining CSs@PDA-FA@ICG nanocomposites (NCs). The biocompatible PDA shell provided a high fluorescence quenching efficiency and a surface rich in functional groups for anchoring FA for targeting cancer cells. Aromatic ICG could be effectively loaded into the CSs@PDA-FA system via hydrophobic interactions and π-π stacking with a loading efficiency of 58.9%. Notably, the activated NIR fluorescence in an intracellular environment made CSs@PDA-FA@ICG a sensitive "OFF" to "ON" nanoprobe that can be used for NIR imaging. Moreover, compared to ICG alone, the CSs@PDA-FA@ICG NCs could induce efficient photoconversion for simultaneous synergetic photodynamic therapy (PDT) and photothermal therapy (PTT) under a single NIR laser irradiation. The results demonstrated that CSs@PDA-FA@ICG NCs as a targeted and activated nanoplatform provide new opportunities to facilitate the accurate diagnosis of cancer and enhanced treatment efficacy. This work stimulates more interest in the design of the facile surface functionalization strategy to construct other multifunctional nanocomposites, such as nanotubes and nanorods.

Controlled synthesis of N-doped carbon spheres with different morphologies for supercapacitors

A facile and general strategy has been developed to synthesize nitrogen doped mesoporous carbon nanospheres, newly nitrogen doped lychee exocarp-like mesoporous carbon spheres and nitrogen doped core–shell mesoporous carbon spheres.

The mechanism for increasing the oral bioavailability of poorly water-soluble drugs using uniform mesoporous carbon spheres as a carrier

Uniform mesoporous carbon spheres (UMCS) were used as a carrier to improve the bioavailability of the model drug, celecoxib (CEL). Furthermore, we investigated the mechanism responsible for the improved bioavailability of CEL. The association, adhesion and uptake of UMCS by intestinal epithelial cells were studied by transmission electron microscopy (TEM), fluorescence-activated cell sorting (FACS) and laser confocal scanning microscopy (LCSM). UMCS was found to promote cellular uptake of CEL. Drug transport in Caco-2 cell monolayers proved that UMCS can significantly reduce the rate of drug efflux and improve CEL permeability. The dissolution rate of CEL from drug-loaded samples was markedly improved compared with pure crystalline CEL; moreover, oral bioavailability of CEL loaded into UMCS was also markedly improved compared with that of commercially available capsules. UMCS indicates the advantages and potential of this method to achieve improved oral absorption by increasing the dissolution rate, cellular uptake and permeability of the drug.

Novel Nanostructured Solid Materials for Modulating Oral Drug Delivery from Solid-State Lipid-Based Drug Delivery Systems

Lipid-based drug delivery systems (LBDDS) have gained significant attention in recent times, owing to their ability to overcome the challenges limiting the oral delivery of poorly water-soluble drugs. Despite the successful commercialization of several LBDDS products over the years, a large discrepancy exists between the number of poorly water-soluble drugs displaying suboptimal in vivo performances and the application of LBDDS to mitigate their various delivery challenges. Conventional LBDDS, including lipid solutions and suspensions, emulsions, and self-emulsifying formulations, suffer from various drawbacks limiting their widespread use and commercialization. Accordingly, solid-state LBDDS, fabricated by adsorbing LBDDS onto a chemically inert solid carrier material, have attracted substantial interest as a viable means of stabilizing LBDDS whilst eliminating some of the various limitations. This review describes the impact of solid carrier choice on LBDDS performance and highlights the importance of appropriate solid carrier material selection when designing hybrid solid-state LBDDS. Specifically, emphasis is placed on discussing the ability of the specific solid carrier to modulate drug release, control lipase action and lipid digestion, and enhance biopharmaceutical performance above the original liquid-state LBDDS. To encourage the interested reader to consider their solid carrier choice on a higher level, various novel materials with the potential for future use as solid carriers for LBDDS are described. This review is highly significant in guiding future research directions in the solid-state LBDDS field and fostering the translation of these delivery systems to the pharmaceutical marketplace.

Micro-/mesoporous carbons for controlled release of antipyrine and indomethacin

We have demonstrated the potential of meso- and microporous carbons in controlled release applications and targeted oral drug delivery.

Packaging biological cargoes in mesoporous materials: opportunities for drug delivery

INTRODUCTION

Confinement of biomolecules in structured nanoporous materials offers several desirable features ranging from chemical and thermal stability, to resistance to degradation from the external environment. A new generation of mesoporous materials presents exciting new possibilities for the formulation and controlled release of biological agents. Such materials address niche applications in enteral and parenteral delivery of biologics, such as peptides, polypeptides, enzymes and proteins for use as therapeutics, imaging agents, biosensors, and adjuvants.

AREAS COVERED

Mesoporous silica Santa Barbara Amorphous-15 (SBA-15), with its unique, tunable pore diameter, and easily functionalized surface, provides a representative example of this new generation of materials. Here, we review recent advances in the design and synthesis of nanostructured mesoporous materials, focusing on SBA-15, and highlight opportunities for the delivery of biological agents to various organ and tissue compartments.

EXPERT OPINION

The SBA-15 platform provides a delivery carrier that is inherently separated from the active biologic due to distinct intra and extra-particle environments. This permits the SBA-15 platform to not require direct modification of the active biological therapeutic. Additionally, this makes the platform universal and allows for its application independent of the desired methods of discovery and development. The SBA-15 platform also directly addresses issues of targeted delivery and controlled release, although future challenges in the implementation of this platform reside in particle design, biocompatibility, and the tunability of the internal and external material properties. Examples illustrating the flexibility in the application of the SBA-15 platform are also discussed.

Biocompatibility of soft-templated mesoporous carbons

Soft-templated mesoporous carbon is morphologically a non-nano type of carbon. It is a relatively newer variety of biomaterial, which has already demonstrated its successful role in drug delivery applications. To investigate the toxicity and biocompatibility, we introduced three types of mesoporous carbons with varying synthesis conditions and pore textural properties. We compared the Brunauer-Emmett-Teller (BET) surface area and pore width and performed cytotoxicity experiments with HeLa cells, cell viability studies with fibroblast cells and hemocomapatibility studies. Cytotoxicity tests reveal that two of the carbons are not cytotoxic, with cell survival over 90%. The mesoporous carbon with the highest surface area showed slight toxicity (∼ 70% cell survival) at the highest carbon concentration of 500 μg/mL. Fibroblast cell viability assays suggested high and constant viability of over 98% after 3 days with no apparent relation with materials property and good visible cell-carbon compatibility. No hemolysis (<1%) was confirmed for all the carbon materials. Protein adsorption experiments with bovine serum albumin (BSA) and fibrinogen revealed a lower protein binding capacity of 0.2-0.6 mg/m(2) and 2-4 mg/m(2) for BSA and fibrinogen, respectively, with lower binding associated with an increase in surface area. The results of this study confirm the biocompatibility of soft-templated mesoporous carbons.

Enhanced bioavailability of apigenin via preparation of a carbon nanopowder solid dispersion

In this study, a novel carbon nanopowder (CNP) drug carrier was developed to improve the oral bioavailability of apigenin (AP). Solid dispersions (SDs) of AP with CNP were prepared, and their in vitro drug release and in vivo performance were evaluated. The physicochemical properties of the formulations were examined by differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. Drug release profiles showed that AP dissolution from the CNP-AP system (weight ratio, 6:1) after 60 minutes improved by 275% compared with that of pure AP. Moreover, the pharmacokinetic analysis of SD formulations in rats showed that the AP area under the curve_0–t value was 1.83 times higher for the CNP-AP system than for pure AP, indicating that its bioavailability was significantly improved. In addition, compared with pure AP, SDs had a significantly higher peak and shorter time to peak. Preliminary intestinal toxicity tests indicated that there was no significant difference in the tissues of the rats treated with the CNP-AP system, rats treated with the CNP alone, and controls. In conclusion, CNP-based SDs could be used for enhancing the bioavailability of poorly water-soluble drugs while also improving drug safety.

Poly dimethyl diallyl ammonium coated CMK-5 for sustained oral drug release

A new oral sustained drug delivery system (DDS) involving a combination of inorganic mesoporous material (CMK-5) and organic polymer poly dimethyl diallyl ammonium (PDDA) was established to determine its general suitability for use with poorly water soluble drugs. Nimodipine, carvedilol and fenofibrate, three different drugs with acidic or alkaline properties, were selected as model drugs and loaded into carriers. The physicochemical properties of the drug carriers were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption. The structural body changes of the composites in release medium, with or without additional salts, were also studied using particle sizing systems, nitrogen adsorption and zeta potential measurement in order to investigate the sustained release mechanism of the drugs. The results obtained showed that sustained release of drug from the designed DDS was mainly due to the blockage effect arising from the strong swelling of the coated polymers when in contact with release medium. Additional salts, when they reached a certain level, allowed a dramatic burst release. We believe that our designed sustained DDS provide a new option for water insoluble drugs and can be considered as fundamental for those more sophisticated DDS increasingly required in modern medical treatments.