Ligand decorated chitosan as an advanced nanocarrier for targeted delivery: a critical review

Multi-functional Chitosan Polymeric Micelles for improving the oral bioavailability of Paclitaxel based on synergistic effect

A novel multi-functional micelle delivery system was developed for enhancing the oral absorption of paclitaxel (PTX). The delivery carriers were constructed by modifying chitosan-stearic acid (CS-SA) micelles with L-carnitine (LC) and co-encapsulating quercetin (Que), and the PTX-loaded micelles were prepared by film-sonication dispersing technique. The as-prepared micelles showed homogeneous spherical shapes with a small particle size of 148.3 ± 1.7 nm, high drug loading of 7.05% and low critical micelle concentration (CMC) of 16.89 µg/ml. Compared to the in-house PTX formulation similar to the commercial injection Taxol™, the target PTX-loaded micelles had obvious sustained-release effects and exhibited an oral relative bioavailability of 168.08%. The cellular uptake studies of Caco-2 cells confirmed the micellar modification of LC and the co-loading of Que played important roles in promoting the absorption of drug loaded in micelles. The CYP3A4 enzyme test demonstrated the micelles had an inhibitory effect on the metabolic enzyme due to the presence of Que. These findings confirmed the potential of the multi-functional chitosan polymeric micelles based on synergistic effect as an effective oral delivery system.

Covalent Conjugates of Allylbenzenes and Terpenoids as Antibiotics Enhancers with the Function of Prolonged Action

The drug resistance of pathogenic bacteria is often due efflux pumps-specific proteins that remove foreign compounds from bacterial cells. To overcome drug resistance, adjuvants are often used that can inhibit efflux pumps or other systems that ensure the resistance of bacteria to the action of antibiotics. We assumed that a new level of effectiveness with the use of an antibiotic + an adjuvant pair could be achieved by their joint delivery into the pathogen. To test this hypothesis, we constructed a series of molecular carriers based on poly-(olygo-, dendry)mers based on cyclodextrin-grafted PEI or mannan, as well as glycol chitosan, covalently bound to antibiotic, adjuvant, and the oligosaccharide ligand to the macrophage mannose receptor (CD206), which we studied earlier and showed high efficiency and selectivity of delivery of a therapeutic "cargo" to macrophages. Moxifloxacin was used as an antibiotic, and terpenoid and allylbenzene compounds were used as adjuvants, for which we previously discovered the ability to inhibit bacterial efflux pumps. We show that: (a) the resulting structures were stable in vitro for a long time (up to 10 days); (b) they were adsorbed on bacterial cells, providing a local increase in the concentration of the antibiotic and adjuvant in pathogen cells; (c) they were internalized by bacterial cells, ensuring the accumulation of both antibiotic and adjuvant inside bacterial cells; (d) the adjuvant, after entering the bacterial cell, provided inhibition of the efflux pumps; (e) due to this action of the adjuvant, combined with the targeted delivery by the carrier, the antibiotic's half-life in rats increased by more than 2 times, the effective concentration of the drug in the blood plasma (AUC) increased up to 8-10 times; (f) a significant increase in the effectiveness of the antibacterial action against Gram+ and Gram- cells was achieved (up to 3 times). Potentially, such an approach would significantly increase the effectiveness of therapies for a number of infectious and other diseases, reduce the dosage of antibiotics, shorten the duration of treatment, and reduce the risk of developing bacterial resistance. Moreover, the use of a polymer carrier with covalently bound organic molecules of different structures will avoid problems linked to different (suboptimal) solubility and bio-distribution of the administered molecules, which would be almost inevitable when using the same compounds separately. It would be very difficult to find antibiotic/adjuvant pairs that simultaneously achieve optimal concentrations in the same target cells. In our case, terpenoids and alkylbenzenes used as adjuvants are practically insoluble as individual compounds, and their unacceptable pharmacological properties would not allow them to be used as efflux pump inhibitors.

Aggregation emission of AuNCs induced by chitosan self-assembled multilayers and sensitive sensing for water content in ethanol

AuNCs with chemical groups such as -NH₂ and -COOH were synthesized using glutathione as the stabilizer and reducing agent. The aggregation emission of AuNCs in solution-induced self-assembled multilayers (SAMs) were first studied. Scanning electron microscopy and quartz crystal microbalance were used to characterize the morphology and aggregation process of AuNCs. Further AuNC SAMs were used for the solid-liquid interface sensing of water content in ethanol, and the sensitivity is obviously improved as compared with that in the pure solution phase. This aggregation emission induced by SAMs would have a good application prospect in analysis.

Exploiting recent trends for the synthesis and surface functionalization of mesoporous silica nanoparticles towards biomedical applications

Rapid progress in developing multifunctional nanocarriers for drug delivery has been observed in recent years. Inorganic mesoporous silica nanocarriers (MSNs), emerged as an ideal candidate for gene/drug delivery with distinctive morphological features. These ordered carriers of porous nature have gained unique attention due to their distinctive features. Moreover, transformation can be made to these nanocarriers in terms of pores size, pores volume, and particle size by altering specific parameters during synthesis. These ordered porous materials have earned special attention as a drug carrier for treating multiple diseases. Herein, we highlight the strategies employed in synthesizing and functionalizing these versatile nanocarriers. In addition, the various factors that influence their sizes and morphological features were also discussed. The article also summarizes the recent advancements and strategies for drug and gene delivery by rendering smarter MSNs by incorporating functional groups on their surfaces. Averting off-target effects through various capping strategies is a massive milestone for the induction of stimuli-responsive nanocarriers that brings out a great revolution in the biomedical field.

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MSNs serve as an ideal candidate for gene/drug delivery with unique and excellent attributes.

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MSNs surface can be functionalized using specific materials to impart unique structural features.

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Functionalization of MSNs with stimuli-responsive molecules can act as gatekeepers by responding to the desired stimulus after uncapping.

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These capping agents act as vital targeting agents in developing MSNs being employed in various biomedical applications.

Targeted Co-Delivery of Gefitinib and Rapamycin by Aptamer-Modified Nanoparticles Overcomes EGFR-TKI Resistance in NSCLC via Promoting Autophagy

Acquired drug resistance decreases the efficacy of gefitinib after approximately 1 year of treatment in non-small-cell lung cancer (NSCLC). Autophagy is a process that could lead to cell death when it is prolonged. Thus, we investigated a drug combination therapy of gefitinib with rapamycin—a cell autophagy activator—in gefitinib-resistant NSCLC cell line H1975 to improve the therapeutic efficacy of gefitinib in advanced NSCLC cells through acute cell autophagy induction. Cell viability and tumor formation assays indicated that rapamycin is strongly synergistic with gefitinib inhibition, both in vitro and in vivo. Mechanistic studies demonstrated that EGFR expression and cell autophagy decreased under gefitinib treatment and were restored after the drug combination therapy, indicating a potential cell autophagy–EGFR positive feedback regulation. To further optimize the delivery efficiency of the combinational agents, we constructed an anti-EGFR aptamer-functionalized nanoparticle (NP-Apt) carrier system. The microscopic observation and cell proliferation assays suggested that NP-Apt achieved remarkably targeted delivery and cytotoxicity in the cancer cells. Taken together, our results suggest that combining rapamycin and gefitinib can be an efficacious therapy to overcome gefitinib resistance in NSCLC, and targeted delivery of the drugs using the aptamer-nanoparticle carrier system further enhances the therapeutic efficacy of gefitinib.

Development of an intelligent, stimuli-responsive transdermal system for efficient delivery of Ibuprofen against rheumatoid arthritis

The present study aimed to fabricate and evaluate the therapeutic efficacy of pH-responsive Ibuprofen (IB) nanoparticles (NPs) loaded transdermal hydrogel against rheumatoid arthritis (RA). The IB loaded Eudragit® L 100 (EL 100) nanoparticles were formulated through a modified nanoprecipitation technique and optimized using central composite design software. The optimized NPs were loaded into Carbopol® 934-based hydrogel by solvent evaporation method and were analyzed for physicochemical characteristics. The mean particle size of the prepared NPs was 48 nm with an entrapment efficiency of 90%. The transdermal hydrogel showed a pH-responsive sustained drug release and high penetration through the skin. Moreover, the prepared nanocarrier system exhibited therapeutic efficacy at inflamed joints' sites both in acute and chronic RA mice model. The therapeutic efficacy of the prepared formulation was confirmed through the results of various behavioral, biochemical, and cytokines-based assays. Similarly, the assessment of histopathological and radiological images, as well as the skin irritation studies further strengthens the potential use of the prepared formulation through the transdermal route. The current findings suggested that IB loaded pH-responsive NPs based transdermal hydrogel can be used as an efficient agent to manage RA.

Using Chitosan or Chitosan Derivatives in Cancer Therapy

Cancer is one of the major causes of death worldwide. Chemotherapeutic drugs have become a popular choice as anticancer agents. Despite the therapeutic benefits of chemotherapeutic drugs, patients often experience side effects and drug resistance. Biopolymers could be used to overcome some of the limitations of chemotherapeutic drugs, as well as be used either as anticancer agents or drug delivery vehicles. Chitosan is a biocompatible polymer derived from chitin. Chitosan, chitosan derivatives, or chitosan nanoparticles have shown their promise as an anticancer agent. Additionally, functionally modified chitosan can be used to deliver nucleic acids, chemotherapeutic drugs, and anticancer agents. More importantly, chitosan-based drug delivery systems improved the efficacy, potency, cytotoxicity, or biocompatibility of these anticancer agents. In this review, we will investigate the properties of chitosan and chemically tuned chitosan derivatives, and their application in cancer therapy.

Development of novel biopolymer-based nanoparticles loaded cream for potential treatment of topical fungal infections

OBJECTIVE

Biodegradable polymers are extensively used due to their efficient safety profiles. The aim of the current study was to fabricate, evaluate, and characterize biodegradable, biocompatible fluconazole (FLZ) loaded chitosan (CHS) chondroitin sulfate (CS) nanoparticles (NPs) for topical delivery. Polymers utilized in the formulation not only served as a carrier system but also aided in fighting with complex etiology of the disease due to their innate antifungal activities.

METHODS

NPs were prepared by the complex coacervation method, then were optimized for various parameters and subsequently loaded into a cream.

RESULTS

Scanning electron microscopic (SEM) analysis showed spherical morphology of the NPs. Prepared NPs showed an average particle size in the range of 350-450 nm and an encapsulation efficiency (EE) of 86%. The polydispersity index (PDI) was found to be 0.148 that showed a uniform distribution of NPs. Fourier transform infrared (FTIR) spectroscopy confirmed the absence of any electrostatic interaction between ingredients. In vitro drug release analyses exhibited a sustained release of the drug and higher antifungal activity than free FLZ. Ex vivo permeability and drug distribution in different skin layers ensured a site-specific delivery of the FLZ-NPs. As compared with free FLZ and other control groups, the prepared NPs also exhibited significantly higher antifungal activity against Candida albicans (p < .01).

CONCLUSION

It was concluded from the results that the FLZ-NPs laden cream could be a potential candidate for topical and site-specific delivery of the drug cargo for the potential treatment of fungal infections.

Modular synthesis of amphiphilic chitosan derivatives based on copper-free click reaction for drug delivery

Amphiphilic chitosan derivatives have attracted wide attention as drug carriers due to their physicochemical properties. However, obtaining a desired amphiphilic chitosan derivative by tuning the various functional groups was complex and time-consuming. Therefore, a facile and common synthesis strategy would be promising. In this study, a modular strategy based on strain-promoted azide-alkyne cycloaddition (SPAAC) click reaction was designed and applied in synthesizing deoxycholic acid- or octanoic acid-modified N-azido propionyl-N,O-sulfate chitosan through tuning the hydrophobic groups. Additionally, chitosan derivatives with the same substitute groups were prepared via amide coupling as controls. We demonstrated that these derivates via the two strategies showed no obvious difference in physicochemical properties, drug loading ability and biosafety, indicating the feasibility of modular strategy. Notably, the modular strategy exhibited advantages including high reactivity, flexibility and reproducibility. We believe that this modular strategy could provide varied chitosan derivatives in an easy and high-efficiency way for improving multifunctional drug carriers.

Plausible role of chitosan in drug and gene delivery against resistant breast cancer cells

Breast cancer is the highest global spread of invasive cancer in women. While significant progress has been made in breast cancer, diagnostic and therapeutic effective prevention and treatment options remain scarce. Concerning chitosan-based chemotherapeutic therapies, the studies reported cell migration resistance, improved drug absorption, membrane interaction and permeability, immune stimulating behavior, and extended in-vitro drug release. However, chitosan has been practically restricted mostly to unmodified forms. Targeted distribution is ensured by chitosan-based ligand conjugated carrier systems in conjunction with active moieties such as DNA, RNA, proteins, and therapeutic agents. The purpose of this context is to emphasize the efficient drug delivery to breast cancer cell lines using chitosan. Chitosan also exhibited excellent capabilities in gene packaging. For the interaction of bioactive molecules and the regulation of the drug release profile, chemical modification of chitosan is beneficial. This article discusses the various chitosan-based ligand conjugated carrier systems. From the studies reviewed it can be concluded that chitosan derivatives are promising materials for targeted and non-viral gene delivery in treatment of breast cancer.

Shield and sword nano-soldiers ameliorate rheumatoid arthritis by multi-stage manipulation of neutrophils

Rheumatoid arthritis (RA) is characterized by the outbreak of inflammation. Neutrophils, the main culprit of the outbreak of inflammation, are the first inflammatory cells to be recruited to inflamed joints and facilitate the recruitment of themselves by stimulating the release of chemokines. Here, based on neutrophils, a novel anti-inflammatory "shield and sword soldiers" strategy is established with LMWH-TOS nanoparticles (LT NPs). The hydrophilic fragment low molecular weight heparin (LMWH) acts as a shield which block the transvascular movement of neutrophils through inhibiting the adhesion cascade by binding to P-selectin on inflamed endothelium. Synergistically, MMP-9, which is secreted by the recruited neutrophils and degrade the main component of articular cartilage, is reduced by the hydrophobic fragment d-α-tocopheryl succinate (TOS), functioning as a sword. In collagen-induced arthritis (CIA) mouse model, LT NPs show significant targeting effect, and exhibit prominent therapeutic efficacy after enveloping the first-line anti-RA drug methotrexate. Our work proves that the multi-stage manipulation of neutrophils is feasible and effective, providing a new concept for RA treatment.

An efficient approach for development and optimisation of curcumin-loaded solid lipid nanoparticles' patch for transdermal delivery

This study aimed to develop and optimise a Curcumin-loaded SLNs (C-SLNs) patch through a new approach for transdermal delivery. C-SLNs were optimised through the response surface central composite design using the modified injection method. Optimised C-SLNs were loaded into a polyvinyl alcohol-based patch through the backing membrane method. Compatibility studies (FTIR, XRPD), in vitro release, ex vivo skin permeation, accelerated stability, and evaluation studies of the patch were also performed. Prepared C-SLNs exhibited average particle diameter of 170 ± 2 nm with an encapsulation efficiency of 90 ± 3.5% (w/w) while SEM illustrated spherical shape of particles. In vitro release data ensured a sustained release for up to 72 hours. The enhancement ratio of C-SLNs based patch with permeation enhancer (PE) was high up to 6.5 folds as compared to patch without PE. It is concluded that the modified injection method is simple, economical, and less time consuming for the development of C-SLNs patch for the transdermal route.

Recent trends, challenges and future outlook of transdermal drug delivery systems for rheumatoid arthritis therapy

At present, several drug molecules have been used for the treatment of rheumatoid arthritis (RA). However, the utilization of these compounds through the oral and parenteral route is limited due to low bioavailability, rapid metabolism, poor absorption, first-pass effect, and serious adverse effects. A transdermal delivery system is an appealing option in this scenario, as it possesses the proficiency to overcome drawbacks associated with the oral and parenteral route. With the innovation of several enhancement strategies, many therapeutic agents have been administered transdermally, proposing an exceptional approach to treat RA. The present article provides an insight into the etiology and pathophysiology of RA. The challenges of the transdermal route and the strategies to improve those problems are described. The current advances in increasing the transdermal efficiency of the therapeutics against RA are discussed. Limitations and advantages regarding the state of the art transdermal delivery system and future outlook are also summarized.

Exploiting proteases for cancer theranostic through molecular imaging and drug delivery

The measurement of biological processes at a molecular and cellular level serves as a basis for molecular imaging. As compared with traditional imaging approaches, molecular imaging functions to probe molecular anomalies that are the basis of a disease rather than the evaluation of end results of these molecular changes. Proteases play central role in tumor invasion, angiogenesis and metastasis thus can be exploited as a target for imaging probes in early diagnosis and treatment of tumors. Molecular imaging of protease has undergone tremendous breakthroughs in the field of diagnosis. It allows the clinicians not only to see the tumor location but also provides an insight into the expression and activity of different types of markers associated with the tumor microenvironment. These imaging techniques are expected to have a huge impact on early cancer detection and personalized cancer treatment. Effective development of protease imaging probes with the highest in vivo biocompatibility, stability and most appropriate pharmacokinetics for clinical translation will upsurge the success level of early cancer detection and treatment.

Surfactant-Free, Self-Assembled Nanomicelles-Based Transdermal Hydrogel for Safe and Targeted Delivery of Methotrexate against Rheumatoid Arthritis

Methotrexate (MTX) is the first line agent for therapy against rheumatoid arthritis (RA); however, orally its efficacy is hampered by poor solubility, less permeability, short plasma half-life, and reduced bioavailability. Meanwhile, parenteral formulations are associated with severe adverse effects. In an attempt to improve the efficacy of MTX, we synthesized polycaprolactone-polyethylene glycol-polycaprolactone (PCL-PEG-PCL) triblock copolymer by a ring-opening copolymerization reaction and used it as a carrier for the fabrication of MTX-loaded nanomicelles. Surfactant-free, self-assembled nanomicelles were prepared by nanoprecipitation technique and optimized through central composite design. The optimized nanomicelles exhibited a size distribution of 31 nm and an encapsulation efficiency of 91%. In vitro, the nanomicelles exhibited hemocompatibility, sustained release, and significantly high uptake in lipopolysaccharide activated macrophages. To facilitate application on the skin, optimized nanomicelles were loaded into a Carbopol 934-based hydrogel with eucalyptus oil as a penetration enhancer. Eucalyptus oil significantly improved the permeation of nanomicelles through the skin (p < 0.001). When the hydrogel was applied on the RA mice model, nanomicelles exhibited preferentially highest accumulation in the inflamed joints than other organs. As compared with the free MTX, MTX nanomicelles significantly improved the pharmacokinetic (4.34-fold greater half-life, 3.68-fold higher AUC_0-t, and 3.15-fold higher mean residence time) and pharmacodynamic profile ascertained through low inflammatory cytokines expression, improved oxidation protection, recovered behavioral responses, and radiological analysis. MTX nanomicelles-based hydrogel also significantly reduced the hepatotoxicity and did not activate the immune system. These results suggest that the MTX-loaded nanomicelles-based transdermal hydrogel can prove to be a promising agent against RA.

Development of novel pH-sensitive nanoparticle-based transdermal patch for management of rheumatoid arthritis

Aim: To formulate and evaluate a pH-responsive nanoparticle (NP)-based patch for efficient transdermal delivery of flurbiprofen against rheumatoid arthritis. Materials & methods: Nanoprecipitation technique was used for preparation of NPs and central composite design was employed for optimization purposes. Optimized NPs were loaded into the transdermal patch by the solvent evaporation method. Results: Prepared NPs exhibited an average size of 69 nm, while NPs loaded onto the transdermal patch showed sustained release and high permeation through the skin. In in vivo studies, the prepared carrier system elucidated high therapeutic potential in both acute and chronic inflammatory models as evident from the results of behavioral, radiological, histopathological and antioxidant analyses. Conclusion: The flurbiprofen-loaded pH-sensitive NP-based transdermal patch has the potential to manage rheumatoid arthritis effectively.