Cross-linked chitosan-dextran sulphate vehicle system for controlled release of ciprofloxaxin drug: An ophthalmic application

Absorption enhancement strategies in chitosan-based nanosystems and hydrogels intended for ocular delivery: Latest advances for optimization of drug permeation

Ophthalmic diseases can be presented as acute diseases like allergies, ocular infections, etc., or chronic ones that can be manifested as a result of systemic disorders, like diabetes mellitus, thyroid, rheumatic disorders, and others. Chitosan (CS) and its derivatives have been widely investigated as nanocarriers in the delivery of drugs, genes, and many biological products. The biocompatibility and biodegradability of CS made it a good candidate for ocular delivery of many ingredients, including immunomodulating agents, antibiotics, ocular hypertension medications, etc. CS-based nanosystems have been successfully reported to modulate ocular diseases by penetrating biological ocular barriers and targeting and controlling drug release. This review provides guidance to drug delivery formulators on the most recently published strategies that can enhance drug permeation to the ocular tissues in CS-based nanosystems, thus improving therapeutic effects through enhancing drug bioavailability. This review will highlight the main ocular barriers to drug delivery observed in the nano-delivery system. In addition, the CS physicochemical properties that contribute to formulation aspects are discussed. It also categorized the permeation enhancement strategies that can be optimized in CS-based nanosystems into four aspects: CS-related physicochemical properties, formulation components, fabrication conditions, and adopting a novel delivery system like implants, inserts, etc. as described in the published literature within the last ten years. Finally, challenges encountered in CS-based nanosystems and future perspectives are mentioned.

Exploring Hydrogel Nanoparticle Systems for Enhanced Ocular Drug Delivery

Drug delivery to the ocular system is affected by anatomical factors like the corneal epithelium, blinking reflex, aqueous blood barrier, and retinal blood barrier, which lead to quick removal from the site and inefficient drug delivery. Developing a drug delivery mechanism that targets specific eye tissue is a major hurdle for researchers. Our study examines the challenges of drug absorption in these pathways. Hydrogels have been researched as a suitable delivery method to overcome some obstacles. These are developed alone or in conjunction with other technologies, such as nanoparticles. Many polymer hydrogel nanoparticle systems utilizing both natural and synthetic polymers have been created and investigated; each has pros and cons. The complex release mechanism of encapsulated agents from hydrogel nanoparticles depends on three key factors: hydrogel matrix swelling, drug-matrix chemical interactions, and drug diffusion. This mechanism exists regardless of the type of polymer. This study provides an overview of the classification of hydrogels, release mechanisms, and the role of controlled release systems in pharmaceutical applications. Additionally, it highlights the integration of nanotechnology in ocular disease therapy, focusing on different types of nanoparticles, including nanosuspensions, nanoemulsions, and pharmaceutical nanoparticles. Finally, the review discusses current commercial formulations for ocular drug delivery and recent advancements in non-invasive techniques. The objective is to present a comprehensive overview of the possibilities for enhancing ocular medication delivery through hydrogel nanoparticle systems.

Polymers and their engineered analogues for ocular drug delivery: Enhancing therapeutic precision

Ocular drug delivery is constrained by anatomical and physiological barriers, necessitating innovative solutions for effective therapy. Natural polymers like hyaluronic acid, chitosan, and gelatin, alongside synthetic counterparts such as PLGA and PEG, have gained prominence for their biocompatibility and controlled release profiles. Recent strides in polymer conjugation strategies have enabled targeted delivery through ligand integration, facilitating tissue specificity and cellular uptake. This versatility accommodates combined drug delivery, addressing diverse anterior (e.g., glaucoma, dry eye) and posterior segment (e.g., macular degeneration, diabetic retinopathy) afflictions. The review encompasses an in-depth exploration of each natural and synthetic polymer, detailing their individual advantages and disadvantages for ocular drug delivery. By transcending ocular barriers and refining therapeutic precision, these innovations promise to reshape the management of anterior and posterior segment eye diseases.

A review on revolutionizing ophthalmic therapy: Unveiling the potential of chitosan, hyaluronic acid, cellulose, cyclodextrin, and poloxamer in eye disease treatments

Ocular disorders, encompassing both common ailments like dry eye syndrome and more severe situations for instance age-related macular degeneration, present significant challenges to effective treatment due to the intricate architecture and physiological barriers of the eye. Polysaccharides are emerging as potential solutions for drug delivery to the eyes due to their compatibility with living organisms, natural biodegradability, and adhesive properties. In this review, we explore not only the recent advancements in polysaccharide-based technologies and their transformative potential in treating ocular illnesses, offering renewed optimism for both patients and professionals but also anatomy of the eye and the significant obstacles hindering drug transportation, followed by an investigation into various drug administration methods and their ability to overcome ocular-specific challenges. Our focus lies on biological adhesive polymers, including chitosan, hyaluronic acid, cellulose, cyclodextrin, and poloxamer, known for their adhesive characteristics enhancing drug retention on ocular surfaces and increasing bioavailability. A detailed analysis of material designs used in ophthalmic formulations, such as gels, lenses, eye drops, nanofibers, microneedles, microspheres, and nanoparticles, their advantages and limitations, the potential of formulations in improving therapeutic outcomes for various eye conditions. Moreover, we underscore the discovery of novel polysaccharides and their potential uses in ocular drug delivery.

Investigating layer-by-layer chitosan-dextran sulfate-coated mesoporous silica as a pH-sensitive drug delivery system

Mesoporous silica nanoparticles (MSNPs) coated by chitosan (CS) were shown to be a proper candidate as a carrier for drug delivery purposes. However, choosing the suitable drug-containing complexes to be applied on MSNPs-CS is of much greater importance to evaluate the possible candidate for an efficient combination of cell viability, drug release kinetics, and atherosclerosis prevention. In this regard, this study concentrates on the synthesis and assessment of coated MSNPs-CS designed for drug delivery purposes. The MSNPs are coated with polyelectrolyte complexes (PEC) composed of CS and dextran sulfate (MSNPs-CS-DX), serving as a versatile drug carrier with favorable biological characteristics. CS-DX is applied to MSNPs without requiring complex or multi-step synthesis procedures. Rosuvastatin, a cholesterol-lowering medication, is chosen for its therapeutic relevance. Additionally, CS-DX is found to relatively impede the uptake of low-density lipoproteins (LDLs) by macrophages, enhancing their potential therapeutic utility. FTIR pattern, FESEM, and TEM images prove MSNPs-CS-DX formation. DLS measurement demonstrates the average particle size of 110 nm for MSNPs, with the combined thickness of CS and DX layers ranging from 10 to 15 nm. BET test is carried out to evaluate the pore size and porosity of structure, showing outstanding results that cause an entrapment efficiency of 57% for MSNPs-CS-DX. Furthermore, the findings demonstrate the pH sensitivity of MSNPs-CS-DX on drug release kinetics. Notably, the CS-DX layer exhibits a significant enhancement in cell viability of human umbilical vein endothelial cells (HUVEC) by approximately 24% within a 24 h timeframe compared to MSNPs lacking CS-DX.

Chitosan nanofibrous scaffold with graded and controlled release of ciprofloxacin and BMP-2 nanoparticles for the conception of bone regeneration

The repair of bone defects using grafts is commonly employed in clinical practice. However, the risk of infection poses a significant concern. Tissue engineering scaffolds with antibacterial functionalities offer a better approach for bone tissue repair. In this work, firstly, two kinds of nanoparticles were prepared using chitosan to complex with ciprofloxacin and BMP-2, respectively. The ciprofloxacin complex nanoparticles improved the dissolution efficiency of ciprofloxacin achieving a potent antibacterial effect and cumulative release reached 95 % in 7 h. For BMP-2 complexed nanoparticles, the release time points can be programmed at 80 h, 100 h or 180 h by regulating the number of coating chitosan layers. Secondly, a functional scaffold was prepared by combining the two nanoparticles with chitosan nanofibers. The microscopic nanofiber structure of the scaffold with 27.28 m2/g specific surface area promotes cell adhesion, high porosity provides space for cell growth, and facilitates drug loading and release. The multifunctional scaffold exhibits programmed release function, and has obvious antibacterial effect at the initial stage of implantation, and releases BMP-2 to promote osteogenic differentiation of mesenchymal stem cells after the antibacterial effect ends. The scaffold is expected to be applied in clinical bone repair and graft infection prevention.

Poly-ε-caprolactone (PCL)/poly-l-lactic acid (PLLA) nanofibers loaded by nanoparticles-containing TGF-β1 with linearly arranged transforming structure as a scaffold in cartilage tissue engineering

This study aimed to present a novel three-dimensional nanocomposite scaffold using poly-ε-caprolactone (PCL), containing transforming growth factor-beta 1 (TGF-β1)-loaded chitosan-dextran nanoparticles and poly-l-lactic acid (PLLA), to make use of nanofibers and nanoparticles simultaneously. The electrospinning method fabricated a bead-free semi-aligned nanofiber composed of PLLA, PCL, and chitosan-dextran nanoparticles containing TGF-β1. A biomimetic scaffold was constructed with the desired mechanical properties, high hydrophilicity, and high porosity. Transmission electron microscopy findings showed a linear arrangement of nanoparticles along the core of fibers. Based on the results, burst release was not observed. The maximum release was achieved within 4 days, and sustained release was up to 21 days. The qRT-PCR results indicated an increase in the expression of aggrecan and collagen type Ι genes compared to the tissue culture polystyrene group. The results indicated the importance of topography and the sustained release of TGF-β1 from bifunctional scaffolds in directing the stem cell fate in cartilage tissue engineering.

Controlled release of silica-coated insulin-loaded chitosan nanoparticles as a promising oral administration system

BACKGROUND

Oral insulin administration has recently become one of the most exciting research subjects. Different approaches have been carried out to get an effective oral insulin delivery system using nanotechnology. The development of a delivery system that overcomes the difficulties of oral insulin administration, achieving high stability and minimal side effects, is still an urgent need. Therefore, this study is considered one of the efforts to design a new prospective drug delivery nano-composite (silica-coated chitosan-dextran sulfate nanoparticles).

METHODS

Chitosan-dextran sulfate nanoparticles (CS-DS NPs) were prepared via a complex coacervation method and then coated with silica. Uncoated and silica-coated CS-DS NPs were physically characterized via different techniques. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, and atomic force microscopy (AFM) have been used to investigate the chemical elements, size, morphology, and surface properties of the prepared formulations. Differential scanning calorimetry (DSC) to assess the thermal properties of formed nano-formulations. Fourier transform infrared (FT-IR) spectroscopy investigated the silica coat and chitosan interaction. The encapsulation efficiency was evaluated using high-performance liquid chromatography (HPLC) analysis. The insulin release profile of nano-formulations was performed with and without silica coat at two different pHs (5.5,7), nearly simulating the environment of the gastrointestinal tract (GIT).

RESULTS

The silica-coated CS-DS NPs revealed interesting physicochemical properties exemplified by suitable core particle size obtained by TEM images (145.31 ± 33.15 nm), hydrodynamic diameter (210 ± 21 nm), high stability indicated by their zeta potential value (-32 ± 3.2 mV), and adequate surface roughness assessed by AFM. The encapsulation efficiency of insulin-loaded chitosan nanoparticles (ICN) was (66.5%) higher than that of insulin-chitosan complex nanoparticles (ICCN). The silica-coated ICN demonstrated a controlled insulin release profile at pHs (5.5 and 7) compared with uncoated ICN.

CONCLUSION

The silica-coated ICN can be an efficient candidate as a desired oral delivery system, overcoming the common obstacles of peptides and proteins delivery and achieving high stability and controlled release for further applications.

Engineering of inhalable nano-in-microparticles for co-delivery of small molecules and miRNAs

In this study, novel Trojan particles were engineered for direct delivery of doxorubicin (DOX) and miR-34a as model drugs to the lungs to raise local drug concentration, decrease pulmonary clearance, increase lung drug deposition, reduce systemic side effects, and overcome multi-drug resistance. For this purpose, targeted polyelectrolyte nanoparticles (tPENs) developed with layer-by-layer polymers (i.e., chitosan, dextran sulfate, and mannose-g-polyethyleneimine) were spray dried into a multiple-excipient (i.e., chitosan, leucine, and mannitol). The resulting nanoparticles were first characterized in terms of size, morphology, in vitro DOX release, cellular internalization, and in vitro cytotoxicity. tPENs showed comparable cellular uptake levels to PENs in A549 cells and no significant cytotoxicity on their metabolic activity. Co-loaded DOX/miR-34a showed a greater cytotoxicity effect than DOX-loaded tPENs and free drugs, which was confirmed by Actin staining. Thereafter, nano-in-microparticles were studied through size, morphology, aerosolization efficiency, residual moisture content, and in vitro DOX release. It was demonstrated that tPENs were successfully incorporated into microspheres with adequate emitted dose and fine particle fraction but low mass median aerodynamic diameter for deposition into the deep lung. The dry powder formulations also demonstrated a sustained DOX release at both pH values of 6.8 and 7.4.

Dextran Sulfate Nanocarriers: Design, Strategies and Biomedical Applications

Dextran sulfate (DXS) is a hydrophilic, non-toxic, biodegradable, biocompatible and safe biopolymer. These biomedically relevant characteristics make DXS a promising building block in the development of nanocarrier systems for several biomedical applications, including imaging and drug delivery. DXS polyanion can bind with metal oxide nanomaterials, biological receptors and therapeutic drug molecules. By taking advantage of these intriguing properties, DXS is used to functionalize or construct nanocarriers for specific applications. In particular, the diagnostic or therapeutic active agent-loaded DXS nanoparticles are prepared by simple coating, formation of polyelectrolyte complexes with other positively charged polymers or through self-assembly of amphiphilic DXS derivatives. These nanoparticles show a potential to localize the active agents at the pathological site and minimize undesired side effects. As DXS can recognize and be taken up by macrophage surface receptors, it is also used as a targeting ligand for drug delivery. Besides as a nanocarrier scaffold material, DXS has intrinsic therapeutic potential. DXS binds to thrombin, acts as an anticoagulant and exhibits an inhibitory effect against coagulation, retrovirus, scrapie virus and human immunodeficiency virus (HIV). Herein, biomedical applications involving the use of DXS as nanocarriers for drugs, biomolecules, and imaging agents have been reviewed. A special focus has been made on strategies used for loading and delivering of drugs and biomolecules meant for treating several diseases, including cancer, inflammatory diseases and ocular disease.

Novel Drug Delivery Systems to Improve the Treatment of Keratitis

Keratitis is a disease characterized by inflammation of the cornea caused by different pathogens. It can cause serious visual morbidity if not treated quickly. Depending on the pathogen causing keratitis, eye drops containing antibacterial, antifungal, or antiviral agents such as besiloxacin, moxifloxacin, ofloxacin, voriconazol, econazole, fluconazole, and acyclovir are used, and these drops need to be applied frequently due to their low bioavailability. Studies are carried out on formulations with extended residence time in the cornea and increased permeability. These formulations include various new drug delivery systems such as inserts, nanoparticles, liposomes, niosomes, cubosomes, microemulsions, in situ gels, contact lenses, nanostructured lipid carriers, carbon quantum dots, and microneedles. Ex vivo and in vivo studies with these formulations have shown that the residence time of the active substances in the cornea is prolonged, and their ocular bioavailability is increased. In addition, in vivo studies have shown that these formulations successfully treat keratitis. However, it has been observed that fluoroquinolones are used in most of the studies; similar drug delivery systems are generally preferred for antifungal drugs, and studies for viral and acanthameba keratitis are limited. There is a need for new studies on different types of keratitis and different drug active substances. At the same time, proving the efficacy of drug delivery systems, which give promising results in in vivo animal models, with clinical studies is of great importance for progress in the treatment of keratitis.

Multiple Roles of Chitosan in Mucosal Drug Delivery: An Updated Review

Chitosan (CS) is a linear polysaccharide obtained by the deacetylation of chitin, which, after cellulose, is the second biopolymer most abundant in nature, being the primary component of the exoskeleton of crustaceans and insects. Since joining the pharmaceutical field, in the early 1990s, CS attracted great interest, which has constantly increased over the years, due to its several beneficial and favorable features, including large availability, biocompatibility, biodegradability, non-toxicity, simplicity of chemical modifications, mucoadhesion and permeation enhancer power, joined to its capability of forming films, hydrogels and micro- and nanoparticles. Moreover, its cationic character, which renders it unique among biodegradable polymers, is responsible for the ability of CS to strongly interact with different types of molecules and for its intrinsic antimicrobial, anti-inflammatory and hemostatic activities. However, its pH-dependent solubility and susceptibility to ions presence may represent serious drawbacks and require suitable strategies to be overcome. Presently, CS and its derivatives are widely investigated for a great variety of pharmaceutical applications, particularly in drug delivery. Among the alternative routes to overcome the problems related to the classic oral drug administration, the mucosal route is becoming the favorite non-invasive delivery pathway. This review aims to provide an updated overview of the applications of CS and its derivatives in novel formulations intended for different methods of mucosal drug delivery.

Effect of Different Molecular Weights of Chitosan on Formulation and Evaluation of Allopurinol-Loaded Nanoparticles for Kidney Targeting and in Management of Hyperuricemic Nephrolithiasis

Present research study was conducted to formulate kidney-targeted allopurinol (AO)-loaded chitosan nanoparticles (ANPs) for management of hyperuricemic related nephrolithiasis. Different molecular weights of chitosan were used for fabricating ANP formulation by adopting modified ionotropic gelation method. The prepared batches were than evaluated for particle size analysis, entrapment efficiency, transmission electron microscopy, X-ray diffraction, Differential Scanning Calorimetry, in vitro release and in vivo animal study. The in vivo study depicted that post 2 h of administration of different formulations and pure drug; ANPs prepared from low molecular weight chitosan showed maximum concentration of AO in kidney signifying successful kidney targeting of drug (25.92 fold) whereas no or very less amount of AO was seen in other animal groups. Effectiveness (p < 0.01) of formulation in management of hyperuricemia-associated nephrolithiasis was also evaluated via estimation of urine pH and serum and urine uric acid levels of mice. Further histological study was also performed on kidney samples which again affirmed these results. Present investigation demonstrated that ANPs prepared from low MW chitosan depicted maximum kidney-targeting ability that might be due to its specific uptake by the kidneys as well as its higher solubility than other two polymers, which results in enhanced release rate from the formulation and also offers an efficient strategy for the management of hyperuricemic nephrolithiasis.

Reactive oxygen species-scavenging hollow MnO2 nanozymes as carriers to deliver budesonide for synergistic inflammatory bowel disease therapy

Inflammatory bowel disease (IBD) is related to excessive reactive oxygen species (ROS) and high expression of proinflammatory cytokines. An enzymatically active drug carrier that can simultaneously scavenge excessive ROS and deliver anti-inflammatory drugs to inhibit the production of inflammatory cytokines may lead to improved therapeutic effects. Herein, nanoparticles (NPs) that can target activated macrophages, remove ROS and release anti-inflammatory drugs are fabricated by loading budesonide (Bud) into dextran sulfate sodium (DSS)-coated hollow mesoporous manganese dioxide (hMnO₂) NPs. This strategy can treat IBD better through the synergistic effect of the ROS-scavenging hMnO₂ carriers and anti-inflammatory drug by blocking the amplification effect of inflammation. In addition, compared with free Bud, the drug delivery system can reduce side effects of Bud and improve its treatment outcome at the same dosage. Therefore, this study provides a new method for the design of highly effective synergistic anti-inflammatory nanomedicines.

Chitosan Nanoparticles Inactivate Alfalfa Mosaic Virus Replication and Boost Innate Immunity in Nicotiana glutinosa Plants

Plant viral infection is one of the most severe issues in food security globally, resulting in considerable crop production losses. Chitosan is a well-known biocontrol agent against a variety of plant infections. However, research on combatting viral infections is still in its early stages. The current study investigated the antiviral activities (protective, curative, and inactivation) of the prepared chitosan/dextran nanoparticles (CDNPs, 100 µg mL-1) on Nicotiana glutinosa plants. Scanning electron microscope (SEM) and dynamic light scattering analysis revealed that the synthesized CDNPs had a uniform, regular sphere shapes ranging from 20 to 160 nm in diameter, with an average diameter of 91.68 nm. The inactivation treatment was the most effective treatment, which resulted in a 100% reduction in the alfalfa mosaic virus (AMV, Acc# OK413670) accumulation level. On the other hand, the foliar application of CDNPs decreased disease severity and significantly reduced viral accumulation levels by 70.43% and 61.65% in protective and curative treatments, respectively, under greenhouse conditions. Additionally, the induction of systemic acquired resistance, increasing total carbohydrates and total phenolic contents, as well as triggering the transcriptional levels of peroxidase, pathogen-related protein-1, and phenylalanine ammonia-lyase were observed. In light of the results, we propose that the potential application of CDNPs could be an eco-friendly approach to enhance yield and a more effective therapeutic elicitor for disease management in plants upon induction of defense systems.

Smart co-delivery of miR-34a and cytotoxic peptides (LTX-315 and melittin) by chitosan based polyelectrolyte nanocarriers for specific cancer cell death induction

A novel polyelectrolyte nanocarrier was synthesized via layer-by-layer self-assembly of polycationic and polyanionic chains. The nanocarrier is composed of polyglutamate grafted chitosan core, dextran sulfate as a complexing agent, and polyethyleneimine shell decorated with folic acid. This polyelectrolyte complex has unique physicochemical properties so that the core is considered as an efficient carrier for LTX-315 and melittin peptides, and the shell is suitable for delivery of miR-34a. The spherical nanocarriers with an average size of 123 ± 5 nm and a zeta potential of -36 ± 1 mV demonstrated controlled-release of gene and peptides ensured a synergistic effect in establishing multiple cell death pathways on chemoresistance human breast adenocarcinoma cell line, MDA-MB-231. In vitro cell viability assays also revealed no cytotoxicity for the nanocarriers, and an IC50 of 15 μg/mL and 150 μg/mL for melittin and LTX-315, respectively, after 48 h, whereas co-delivery of melittin with miR-34a increased smart death induction by 54%.

Broad-Spectrum Reactive Oxygen Species Scavenging and Activated Macrophage-Targeting Microparticles Ameliorate Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a refractory chronic inflammatory disease. An excessively high level of reactive oxygen species (ROS) in the colon is one of the characteristics and pathogenic factors of IBD. Therefore, scavenging excessive ROS is a feasible method to treat IBD. Because ROS include many types of species, scavenging a single kind of ROS is not enough to reduce the ROS level and cure IBD effectively. Herein, broad-spectrum ROS scavenging and activated macrophage-targeting microparticles (MPs) are successfully fabricated by coprecipitation of catalase (CAT) and bovine serum albumin into a MnCO₃ template followed by deposition of polydopamine (PDA), assembly of targeting molecules on the surface, and finally removal of MnCO₃. The CAT content of MPs is about 34.1%. The obtained MPs can effectively scavenge the broad spectrum of ROS and retain 88% of the radical scavenging activity even after the treatment of simulated gastric fluid. The surface-modified dextran sulfate endows MPs with the targeting ability toward activated macrophages, achieving a better therapeutic effect. The MPs with components mostly derived from natural substances exhibit good biocompatibility and can show excellent ROS scavenging ability in cell experiments. In animal experiments, oral administration of a proper dosage of MPs can substantially mitigate colonic inflammation, as evidenced by disease activity index scores reduced by ∼40%, reduced body weight loss, and the production of typical proinflammatory cytokines in the inflammatory colon. This kind of MP can also be utilized for the treatment of other inflammatory diseases.

Nanoparticle-Based Rifampicin Delivery System Development

The alkaline milieu of chronic wounds severely impairs the therapeutic effect of antibiotics, such as rifampicin; as such, the development of new drugs, or the smart delivery of existing drugs, is required. Herein, two innovative polyelectrolyte nanoparticles (PENs), composed of an amphiphilic chitosan core and a polycationic shell, were synthesized at alkaline pH, and in vitro performances were assessed by ¹H NMR, elemental analysis, FT-IR, XRD, DSC, DLS, SEM, TEM, UV/Vis spectrophotometry, and HPLC. According to the results, the nanostructures exhibited different morphologies but similar physicochemical properties and release profiles. It was also hypothesized that the simultaneous use of the nanosystem and an antioxidant could be therapeutically beneficial. Therefore, the simultaneous effects of ascorbic acid and PENs were evaluated on the release profile and degradation of rifampicin, in which the results confirmed their synergistic protective effect at pH 8.5, as opposed to pH 7.4. Overall, this study highlighted the benefits of nanoparticulate development in the presence of antioxidants, at alkaline pH, as an efficient approach for decreasing rifampicin degradation.

Low molecular weight chitosan-cyanocobalamin nanoparticles for controlled delivery of ciprofloxacin: Preparation and evaluation

This study was carried out to project a safe nano-drug carrier composed of chitosan and cyanocobalamin (CNCbl) to improve oral delivery of ciprofloxacin hydrochloride (CIP). CIP is classified in class IV of the biopharmaceutical classification system with low solubility and permeabilityA, so it has some problems if given orally. Novel conjugate of low molecular weight chitosan, as a natural biopolymer, and CNCbl was synthesized, and then drug loading and in-vitro drug release were assessed. The loading of CIP was optimized by the Design-Expert software and the central composite design method, and that the optimal drug loading efficiency (57%) was obtained via analysis of variance (ANOVA). In-vitro drug release studies showed controlled release patterns in two various conditions, namely phosphate buffer saline (pH = 7.4) and 0.1 N HCl. Functionalized nano-drug-loaded carrier showed cytotoxicity as much as that of free drug, particle size less than 100 nm as well as positive zeta potential. Due to the beneficial properties of the chitosan-based drug carrier and the suitable features of the CIP-loaded carrier, this chitosan-based nano-drug delivery system can be regarded as an ideal candidate for oral delivery of the CIP as a drug model.

Chitosan and its Derivatives for Ocular Delivery Formulations: Recent Advances and Developments

Chitosan (CS) is a hemi-synthetic cationic linear polysaccharide produced by the deacetylation of chitin. CS is non-toxic, highly biocompatible, and biodegradable, and it has a low immunogenicity. Additionally, CS has inherent antibacterial properties and a mucoadhesive character and can disrupt epithelial tight junctions, thus acting as a permeability enhancer. As such, CS and its derivatives are well-suited for the challenging field of ocular drug delivery. In the present review article, we will discuss the properties of CS that contribute to its successful application in ocular delivery before reviewing the latest advances in the use of CS for the development of novel ophthalmic delivery systems. Colloidal nanocarriers (nanoparticles, micelles, liposomes) will be presented, followed by CS gels and lenses and ocular inserts. Finally, instances of CS coatings, aiming at conferring mucoadhesiveness to other matrixes, will be presented.

Ampicillin-mediated functionalized gold nanoparticles against ampicillin-resistant bacteria: strategy, preparation and interaction studies

Antibiotic resistance is a highly challenging concern of infectious diseases, and it requires a rational approach to overcome. Through this work, we have synthesized ampicillin-capped gold nanoparticles (Amp-Au NPs) and studied its interaction with bacterial cells. In this process of synthesis, the primary amine group of ampicillin acts as both reducing as well as capping agent. In addition to synthesized gold nanoparticles, the β-lactam ring remains free to interact with bacteria. This approach not only utilizes the maximum efficiency of nanoparticles and antibiotics towards ampicillin sensitive bacterial cells but also proves to be effective against ampicillin resistance bacteria. Our results illustrate that the optimized system of Amp-Au NPs was formulated by taking 1.25 mM ampicillin and 10^-2 of gold ions concentration. UV-vis spectrum of gold nanoparticles and the presence of ampicillin were recorded at around 540 nm and 259 nm, respectively. Microscopic images indicate that particles are nearly spherical and are in size range between 25 and 50 nm. Moreover, formulated Amp-Au NPs show successful accumulation onto the surface of the bacterial cell as a result of which pores were formed into the bacterial membrane. The entry of nanoparticles into bacterial cells was validated through both atomic force microscopy and fluorescent microscopy. The adhesive properties of this coating material and its stability in various pH, i.e. pH 3, pH 7 and pH 10 conditions, could make them a good candidate in the prevention of biofilm formation. Amp-Au NPs show promising antimicrobial activity against ampicillin resistance Escherichia coli bacteria. Furthermore, antimicrobial studies indicate that the efficacy of Amp-Au NPs increased against both ampicillin sensitive and ampicillin resistance bacteria up to sixteen folds and four folds respectively.

Surgical applications of intracorporal tissue adhesive agents: current evidence and future development

Introduction: Traditional mechanical closure techniques pose many challenges including the risk of infection, tissue reaction, and injury to both patients and clinicians. There is an urgent need to develop tissue adhesive agents to reform closure technique. This review examined a variety of tissue adhesive agents available in the market in an attempt to gain a better understanding of intracorporal tissue adhesive agents as medical devices.Areas covered: Fundamental principles and clinical determinants of the tissue adhesives were summarized. The available tissue adhesives for intracorporal use and their relevant clinical evidence were then presented. Lastly, the perspective of future development for intracorporal tissue adhesive were discussed. Clinical evidence shows current agents are efficacious as adjunctive measures to mechanical closure and these agents have been trialed outside of clinical indications with varied results.Expert opinion: Despite some advancements in the development of tissue adhesives, there is still a demand to develop novel technologies in order to address unmet clinical needs, including low tensile strength in wet conditions, non-controllable polimerization and sub-optimal biocompatibility. Research trends focus on producing novel adhesive agents to remit these challenges. Examples include the development of biomimetic adhesives, externally activated adhesives, and multiple crosslinking strategies. Economic feasibility and biosafety are limiting factors for clinical implementation.

Nanomedicine Fight against Antibacterial Resistance: An Overview of the Recent Pharmaceutical Innovations

Based on the recent reports of World Health Organization, increased antibiotic resistance prevalence among bacteria represents the greatest challenge to human health. In addition, the poor solubility, stability, and side effects that lead to inefficiency of the current antibacterial therapy prompted the researchers to explore new innovative strategies to overcome such resilient microbes. Hence, novel antibiotic delivery systems are in high demand. Nanotechnology has attracted considerable interest due to their favored physicochemical properties, drug targeting efficiency, enhanced uptake, and biodistribution. The present review focuses on the recent applications of organic (liposomes, lipid-based nanoparticles, polymeric micelles, and polymeric nanoparticles), and inorganic (silver, silica, magnetic, zinc oxide (ZnO), cobalt, selenium, and cadmium) nanosystems in the domain of antibacterial delivery. We provide a concise description of the characteristics of each system that render it suitable as an antibacterial delivery agent. We also highlight the recent promising innovations used to overcome antibacterial resistance, including the use of lipid polymer nanoparticles, nonlamellar liquid crystalline nanoparticles, anti-microbial oligonucleotides, smart responsive materials, cationic peptides, and natural compounds. We further discuss the applications of antimicrobial photodynamic therapy, combination drug therapy, nano antibiotic strategy, and phage therapy, and their impact on evading antibacterial resistance. Finally, we report on the formulations that made their way towards clinical application.

Stabilization of chitosan-based polyelectrolyte nanoparticle cargo delivery biomaterials by a multiple ionic cross-linking strategy

PolyElectrolyte Nanoparticles (PENs) obtained by layer-by-layer self-assembly of polycations/polyanions suffer from a lack of colloidal stability in physiological conditions. We report a simple innovative approach for increasing their stability by multiple ionic cross-linkers. Herein, a chitosan-based core was stabilized by polyanions such as tripolyphosphate and dextran sulfate at pHs of 3 (aPENs) and 8 (bPENs) to improve the quality of electrostatic interactions in the core and manage self-assembly of polyethyleneimine shell onto the core. The physicochemical properties of the particles were characterized by DLS, SEM, TEM, FT-IR, and TGA. TEM micrographs showed visible core/shell structures of bPENs. From particle size and polydispersity indices, the bPENs stability was salt concentration-dependent. The release profiles of PENs using nicotinic acid demonstrated sustained release in a pH-independent manner with a good fit of Korsmeyer-Peppas model. These results suggest that multiple ionic cross-linkers can be an efficient approach to increase the colloidal stability of PENs.

Targeting kidneys by superparamagnetic allopurinol loaded chitosan coated nanoparticles for the treatment of hyperuricemic nephrolithiasis

PURPOSE

The major short coming of conventional therapy system is that they can't deliver the therapeutics specifically to a site within the body without producing nonspecific toxicity. Present research aimed at developing kidney targeted allopurinol (AP) loaded chitosan coated magnetic nanoparticles (A-MNPs) for the management of hyperuricemic nephropathy manifested in the form of nephrolithiasis.

METHODS

The work includes preparation of magnetic nanoparticles by chemical co-precipitation method and evaluation of the prepared batches for particle size analysis, Transmission electron microscopy, entrapment efficiency, in-vitro release study etc. Further, FTIR spectroscopy, X-ray diffraction, Differential Scanning Calorimetry, Vibrational sample magnetometer (VSM) and in-vivo animal studies were also performed.

RESULTS

VSM analysis demonstrates that the prepared nanoparticles exhibit superparamagnetic magnetic behaviour which was retained even after coating by chitosan. In-vivo studies of A-MNPs showed 19.07-fold increase in kidney uptake of AP as compared to serum post 2 h of administration in mice whereas no drug was detected in kidney and serum post 2 h administration of pure drug (free-form) indicating successful targeting to kidney as well as sustained release of AP from the formulated A-MNPs. The significant (p < 0.01) effectiveness of A-MNPs in management of hyperuricemic nephrolithiasis was observed through estimating pH and uric acid levels in urine and serum samples of mice. These findings were also confirmed by histological examination of isolated kidney samples.

CONCLUSION

Present investigation signifies that a simple external magnetic field is enough for targeting allopurinol to kidneys by formulating A-MNPs which further offers an effective approach for management of hyperuricemic nephrolithiasis. Graphical Abstract.

Losartan-chitosan/dextran sulfate microplex as a carrier to lung therapeutics: Dry powder inhalation, aerodynamic profile and pulmonary tolerability

This study aims to obtain an inhalation powder with meaningful aerodynamic and safety profiles for the lung delivery of losartan (LS). For this, the capacity of self-assembly of chitosan (CS) and dextran sulfate (DS) to form CS/DS microplex (MC), incorporating high payload of hydrophilic LS was harnessed. Dry powder inhaler (LS-MC-DPI), prepared via spray drying of the best achieved LS-MC, was proposed to impart precise engineered inhalation characteristics. Micrometric robust CS/DS MC was revealed to offer the opportunity to heighten LS encapsulation, accounting for ~75%. LS-MC-DPI was successfully developed with high yield, flowability, respirable aerodynamic size and morphology which formed swellable and mucoadhesive network, facilitating intra-pulmonary delivery. Moreover, sustained release pattern, augmented deep lung deposition and safe histological profile were realized. Overall, the newly developed LS-MC DPI shows promises as an inhalation system. The aerodynamic performance and safety of LS-MC-DPI verify its suitability for further in vivo lung therapeutics.

Utility of nanomedicine targeting scar-forming myofibroblasts to attenuate corneal scarring and haze

Corneal scarring refers to the loss of normal corneal tissue, replaced by fibrotic tissue (during wound repair) thereby affecting corneal transparency and vision quality. The corneal wound healing process involves a complex series of physiological events resulting in the transformation of transparent keratocytes into opaque myofibroblasts; the prominent cause of irregular extracellular matrix synthesis leading to the development of corneal opacity/hazy vision. Globally, corneal scarring/haze is one of the most prevalent causes of blindness. Ocular trauma (physical and chemical) and microbial infections induce corneal tissue damage. Although great progress has been made in the clinical management of ocular diseases, the global rates of corneal blindness remain high, nonetheless. The topical conventional modalities treating corneal wounds/injuries have inherent limitations/side effects such as low bioavailability of a therapeutic agent, upregulation of the intraocular pressure and the toxicity/allergy of the drug. These limitations/side effects rather than treating the wound, often negatively affect the healing process, especially, when applied frequently for longer periods. Recently, there has been an increasing evidence provided by the preclinical studies that nanotechnology-based drug-delivery systems can improve drug bioavailability, through controlled drug release and targeted delivery. After reviewing the epidemiology, risk factors of corneal scarring/haze and the conventional ocular medicines, we review here the different nanodrug-delivery systems and potential drug candidates including nanoherbal formulations investigated for their efficacy to heal the damaged cornea. Finally, we discuss the challenges of using these nanomedicinal platforms.

SR-A-Targeted Phase-Transition Nanoparticles for the Detection and Treatment of Atherosclerotic Vulnerable Plaques

Atherosclerosis is a major cause of sudden death and myocardial infarction, instigated by unstable plaques. Thus, the early detection of unstable plaques and corresponding treatment can improve the prognosis and reduce mortality. In this study, we describe a protocol for the preparation of nanoparticles (NPs) combined with the phase transitional material perfluorohexane (PFH) and with dextran sulfate (DS) targeting class A scavenger receptors (SR-A) for the diagnosis and treatment of atherosclerotic vulnerable plaques. The results showed that the Fe-PFH-poly(lactic- co-glycolic acid) (PLGA)/chitosan (CS)-DS NPs were fabricated successfully, with the ability to undergo phase transition by low-intensity focused ultrasound (LIFU) irradiation to achieve ultrasound imaging; a high carrier rate of Fe₃O₄ had a good negative enhancement effect on magnetic resonance imaging (MRI). The NPs had a high binding affinity for activated macrophages and could be endocytosed by the macrophages and notably induced apoptosis under LIFU irradiation by an acoustic droplet vaporization effect in vitro. Furthermore, in an ex vivo atherosclerotic plaque model of apolipoprotein E knockout (KO) (apoE^-/-) mice induced by high cholesterol, the NPs selectively accumulated at the sites of SR-A expressed on the activated macrophages of the aortic region. This result was also confirmed by MRI in vivo, where the NPs could be targeted to the aortic plaque and reduced the T₂* signal. The LIFU-induced phase transition could lead to the apoptosis of macrophages on plaques in vivo. In summary, Fe-PFH-PLGA/CS-DS NPs may be applied as multimodal and multifunctional probes and are expected to enable the specific diagnosis and targeted therapy of vulnerable plaques.

Chitosan-Based In Situ Gels for Ocular Delivery of Therapeutics: A State-of-the-Art Review

Ocular in situ gels are a promising alternative to overcome drawbacks of conventional eye drops because they associate the advantages of solutions such as accuracy and reproducibility of dosing, or ease of administration with prolonged contact time of ointments. Chitosan is a natural polymer suitable for use in ophthalmic formulations due to its biocompatibility, biodegradability, mucoadhesive character, antibacterial and antifungal properties, permeation enhancement and corneal wound healing effects. The combination of chitosan, pH-sensitive polymer, with other stimuli-responsive polymers leads to increased mechanical strength of formulations and an improved therapeutic effect due to prolonged ocular contact time. This review describes in situ gelling systems resulting from the association of chitosan with various stimuli-responsive polymers with emphasis on the mechanism of gel formation and application in ophthalmology. It also comprises the main techniques for evaluation of chitosan in situ gels, along with requirements of safety and ocular tolerability.