Chondroitin sulfate-chitosan nanoparticles for ocular delivery of bromfenac sodium: Improved permeation, retention, and penetration

Design, optimization and characterization of atorvastatin loaded chitosan-based polyelectrolyte complex nanoparticles based transdermal patch

AIM

Atorvastatin (ATO) loaded chitosan-based polyelectrolyte complex nanoparticles (PECN) incorporated transdermal patch was developed to enhance its skin permeability and bioavailability.

METHODOLOGY

The ATO loaded PECN were prepared by ionic gelation method and optimized by Box-Behnken design. The optimized batches were evaluated for physicochemical characteristics, in vitro, ex vivo, cell line and stability studies. The optimized ATO-PECN were incorporated into transdermal patches by solvent evaporation method and evaluated for their physicochemical properties, ex vivo skin permeation, in vivo pharmacokinetics and stability study.

RESULTS

The optimized batch of ATO-PECN had average size of 219.2 ± 5.98 nm with 82.68 ± 2.63 % entrapment and 25.41 ± 3.29 mV zeta potential. ATO-PECN showed sustained drug release and higher skin permeation. The cell line study showed that ATO-PECN increased the cell permeability of ATO as compared to ATO suspension. ATO-PECN loaded transdermal patch showed higher skin permeation. The in vivo pharmacokinetic study revealed that the ATO-PECN transdermal patch showed significant (p < 0.05) increase in pharmacokinetic parameters as compared to marketed oral tablet, confirming enhancement in bioavailability of ATO.

CONCLUSIONS

The results of the present work concluded that the ATO-PECN loaded transdermal patch is a promising novel drug delivery system for poorly bioavailable drugs.

Chondroitin Sulphate-Chitosan polyelectrolyte complexes for etorocoxib transdermal delivery: in silico, in vitro and in vivo studies

Rheumatoid arthritis (RA) is a chronic autoimmune disease which affects around 1% globally leading to joint inflammation and disability. Etorocoxib (ETR) is a potent COX-2 inhibitor traditionally used orally to alleviate RA induced inflammation, yet it causes hepatic side effects on prolonged use. This study aims for in silico optimization of ETR polyelectrolyte complex (PEC) utilizing chondroitin sulphate (CS) and chitosan (CH) for transdermal delivery to RA-inflamed joints with a synergistic anti-inflammatory action owing to CS. An artificial neural network (ANN) combined with 22 factorial design was used to optimize the PEC formula according to particle size (PS) and entrapment efficiency (%EE) by varying CS and CH concentrations. The optimum ETR PEC was incorporated in a gel and examined for its in vitro release, ex vivo permeation, in vivo inflammatory biomarkers, and histopathological evaluation in rats. The optimized formula (F3) with 0.1 CH% w/w and 0.5 CS %w/w showed a PS of 214.98 ± 17.24 nm, %EE 75.31 ± 1.67%, and enhanced in vitro release profile, ex vivo permeation and in vivo anti-inflammatory effect compared to ETR gel via suppressing the expression of IL-6, TNF-α, and TGF-β pro-inflammatory cytokines as well as the additional anti-inflammatory effect of CS. In conclusion, ETR-PEC gel holds promise as transdermal therapy for managing RA-induced inflammation.

Next-generation nanomaterials: advancing ocular anti-inflammatory drug therapy

Ophthalmic inflammatory diseases, including conjunctivitis, keratitis, uveitis, scleritis, and related conditions, pose considerable challenges to effective management and treatment. This review article investigates the potential of advanced nanomaterials in revolutionizing ocular anti-inflammatory drug interventions. By conducting an exhaustive analysis of recent advancements and assessing the potential benefits and limitations, this review aims to identify promising avenues for future research and clinical applications. The review commences with a detailed exploration of various nanomaterial categories, such as liposomes, dendrimers, nanoparticles (NPs), and hydrogels, emphasizing their unique properties and capabilities for accurate drug delivery. Subsequently, we explore the etiology and pathophysiology of ophthalmic inflammatory disorders, highlighting the urgent necessity for innovative therapeutic strategies and examining recent preclinical and clinical investigations employing nanomaterial-based drug delivery systems. We discuss the advantages of these cutting-edge systems, such as biocompatibility, bioavailability, controlled release, and targeted delivery, alongside potential challenges, which encompass immunogenicity, toxicity, and regulatory hurdles. Furthermore, we emphasize the significance of interdisciplinary collaborations among material scientists, pharmacologists, and clinicians in expediting the translation of these breakthroughs from laboratory environments to clinical practice. In summary, this review accentuates the remarkable potential of advanced nanomaterials in redefining ocular anti-inflammatory drug therapy. We fervently support continued research and development in this rapidly evolving field to overcome existing barriers and improve patient outcomes for ophthalmic inflammatory disorders.

Structure and drug delivery relationship of acidic polysaccharides: A review

Scientists from across the world are being inspired by recent development in polysaccharides and their use in medical administration. Due to their extraordinary physical, chemical, and biological characteristics, polysaccharides are excellent materials for use in medicine. Acidic polysaccharides, which include Pectin, Xanthan gum, Carrageenan, Alginate, and Glycosaminoglycan, are natural polymers with carboxyl groups that are being researched for their potential as drug delivery systems. Most publications do not discuss how the different polysaccharides interact structurally in terms of drug delivery, which limits the scope of their use. The purpose of this review is to inform readers about the structural activity correlations between acidic polysaccharides, their different modification process and effects of combination of various acidic polysaccharides which have been used in drug delivery systems and expanding their potential applications, and bringing new perspectives to the fore.

Nanoparticles Based on Chondroitin Sulfate from Tuna Heads and Chitooligosaccharides for Enhanced Water Solubility and Sustained Release of Curcumin

This study aimed to separate chondroitin sulfate (CS) from the heads of skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacares), by-products derived from canned tuna processing, via a biological process. The use of 1% w/w papain and an incubation time of 48 h resulted in a degree of hydrolysis of 93.75 ± 2.94% and a CS content of 59.53 ± 1.77 mg/100 g. The FTIR spectra of extracted CS products exhibited identical functional groups found in commercially available CS. The molecular weights of CS extracted from skipjack and yellowfin tuna heads were 11.0 kDa and 7.7 kDa, respectively. Subsequently, a CH:CS ratio of 3:2 for CS and chitooligosaccharides (CH) was chosen as the optimal ratio for the preparation of spherical nanoparticles, with %EE, mean particle size, PDI, and zeta potential values of 50.89 ± 0.66%, 128.90 ± 3.29 nm, 0.27 ± 0.04, and -12.47 ± 2.06, respectively. The CU content was enhanced to 127.21 ± 1.66 μg/mL. The release of CU from this particular nanosystem involved mainly a drug diffusion mechanism, with a burst release in the first 3 h followed by a sustained release of CU over 24 h. The DPPH and ABTS scavenging activity results confirmed the efficient encapsulation of CU into CHCS nanoparticles. This study will provide a theoretical basis for CS derived from tuna head cartilages to be used as a functional component with specific functional properties in food and biomedical applications.

Chondroitin sulfate-based composites: a tour d'horizon of their biomedical applications

Chondroitin sulfate (CS), a natural anionic mucopolysaccharide, belonging to the glycosaminoglycan family, acts as the primary element of the extracellular matrix (ECM) of diverse organisms. It comprises repeating units of disaccharides possessing β-1,3-linked N-acetyl galactosamine (GalNAc), and β-1,4-linked D-glucuronic acid (GlcA), and exhibits antitumor, anti-inflammatory, anti-coagulant, anti-oxidant, and anti-thrombogenic activities. It is a naturally acquired bio-macromolecule with beneficial properties, such as biocompatibility, biodegradability, and immensely low toxicity, making it the center of attention in developing biomaterials for various biomedical applications. The authors have discussed the structure, unique properties, and extraction source of CS in the initial section of this review. Further, the current investigations on applications of CS-based composites in various biomedical fields, focusing on delivering active pharmaceutical compounds, tissue engineering, and wound healing, are discussed critically. In addition, the manuscript throws light on preclinical and clinical studies associated with CS composites. A short section on Chondroitinase ABC has also been canvassed. Finally, this review emphasizes the current challenges and prospects of CS in various biomedical fields.

Degradable and Non-Degradable Chondroitin Sulfate Particles with the Controlled Antibiotic Release for Bacterial Infections

Non-degradable, slightly degradable, and completely degradable micro/nanoparticles derived from chondroitin sulfate (CS) were synthesized through crosslinking reactions at 50%, 40%, and 20% mole ratios, respectively. The CS particles with a 20% crosslinking ratio show total degradation within 48 h, whereas 50% CS particles were highly stable for up to 240 h with only 7.0 ± 2.8% weight loss in physiological conditions (pH 7.4, 37 °C). Tobramycin and amikacin antibiotics were encapsulated into non-degradable CS particles with high loading at 250 g/mg for the treatment of corneal bacterial ulcers. The highest release capacity of 92 ± 2% was obtained for CS-Amikacin particles with sustainable and long-term release profiles. The antibacterial effects of CS particles loaded with 2.5 mg of antibiotic continued to render a prolonged release time of 240 h with 24 ± 2 mm inhibition zones against Pseudomonas aeruginosa. Furthermore, as a carrier, CS particles significantly improved the compatibility of the antibiotics even at high particle concentrations of 1000 g/mL with a minimum of 71 ± 7% fibroblast cell viability. In summary, the sustainable delivery of antibiotics and long-term treatment of bacterial keratitis were shown to be afforded by the design of tunable degradation ability of CS particles with improved biocompatibility for the encapsulated drugs.

Effect of Saccharides Coating on Antibacterial Potential and Drug Loading and Releasing Capability of Plasma Treated Polylactic Acid Films

More than half of the hospital-associated infections worldwide are related to the adhesion of bacteria cells to biomedical devices and implants. To prevent these infections, it is crucial to modify biomaterial surfaces to develop the antibacterial property. In this study, chitosan (CS) and chondroitin sulfate (ChS) were chosen as antibacterial coating materials on polylactic acid (PLA) surfaces. Plasma-treated PLA surfaces were coated with CS either direct coating method or the carbodiimide coupling method. As a next step for the combined saccharide coating, CS grafted samples were immersed in ChS solution, which resulted in the polyelectrolyte complex (PEC) formation. Also in this experiment, to test the drug loading and releasing efficiency of the thin film coatings, CS grafted samples were immersed into lomefloxacin-containing ChS solution. The successful modifications were confirmed by elemental composition analysis (XPS), surface topography images (SEM), and hydrophilicity change (contact angle measurements). The carbodiimide coupling resulted in higher CS grafting on the PLA surface. The coatings with the PEC formation between CS-ChS showed improved activity against the bacteria strains than the separate coatings. Moreover, these interactions increased the lomefloxacin amount adhered to the film coatings and extended the drug release profile. Finally, the zone of inhibition test confirmed that the CS-ChS coating showed a contact killing mechanism while drug-loaded films have a dual killing mechanism, which includes contact, and release killing.

Chitosan-coated bovine serum albumin nanoparticles for topical tetrandrine delivery in glaucoma: in vitro and in vivo assessment

Glaucoma is one of the leading causes of blindness. Therapies available suffer from several drawbacks including low bioavailability, repeated administration and poor patient compliance with adverse effects thereafter. In this study, bovine serum albumin nanoparticles (BSA-NPs) coated with chitosan(CS) were developed for the topical delivery of tetrandrine (TET) for glaucoma management. Optimized nanoparticles were prepared by desolvation. pH, BSA, CS and cross-linking agent concentrations effects on BSA-NPs colloidal properties were investigated. CS-BSA-NPs with particle size 237.9 nm and zeta potential 24 mV was selected for further evaluation. EE% exceeded 95% with sustained release profile. In vitro mucoadhesion was evaluated based on changes in viscosity and zeta potential upon incubation with mucin. Ex vivo transcorneal permeation was significantly enhanced for CS coated formulation. In vitro cell culture studies on corneal stromal fibroblasts revealed NPs biocompatibility with enhanced cellular uptake and improved antioxidant and anti-proliferative properties for the CS-coated formulation. Moreover, BSA-NPs were nonirritant as shown by HET-CAM test. Also, bioavailability in rabbit aqueous humor showed 2-fold increase for CS-TET-BSA-NPs compared to TET with a sustained reduction in intraocular pressure in a rabbit glaucoma model. Overall, results suggest CS-BSA-NPs as a promising platform for topical ocular TET delivery in the management of glaucoma.

Pharmacokinetic and pharmacodynamic evaluation of gemifloxacin chitosan nanoparticles as an antibacterial ocular dosage form

Ocular infections are classified into superficial keratitis, conjunctivitis or deep infections such as corneal abscesses and blepharitis. Herein, we focused on the development of formulation approaches that could prolong the residence time of gemifloxacin (GM) and enhance its corneal penetration to facilitate GM effects both superficially and at the deep tissues. Ionic gelation method was used to prepare eight forms of GM nanoparticles (NPs) formulated from chitosan polymer using sodium tripolyphosphate (TPP)-induced precipitation method. Differential scanning colorimetry (DSC) and X-ray diffraction (XRD) demonstrated the interaction between the chitosan and GM. Particle size, entrapment efficiency and cumulative in vitro release were used to select the optimal formula using Design Expert® software. The mean diameter of the selected NPs was 158. 4 nm. The average entrapment efficiency and cumulative release exhibited by the formulated NPs were 46.6% and 74.9%, respectively. Pharmacokinetics studies carried out on rabbits revealed that the ocularly-administered NPs significantly increased the loaded GM concentration in the tear and aqueous humour samples that suggested enhancement of precorneal retention and transcorneal permeation, respectively. Furthermore, ocular pharmacodynamic studies conducted on rabbits following ocular infection with Staphylococcus aureus or Pseudomonas aeruginosa showed that the administered NPs augmented the antibacterial activity of the delivered GM. This was demonstrated via the histopathological examination of the dissected corneas that showed preserved histological features and reduced bacterial keratitis on using the GM NPs rather than GM solution. Moreover, the GM NPs-treated corneas showed lower viable bacterial counts than the GM solution-treated corneas. Accordingly, our study illustrated the capability of the chitosan NPs to promote the antibacterial activity of GM against eye infections via ocular administration.

Formulation and development of tacrolimus-gellan gum nanoformulation for treatment of dry eye disease

The present study aimed at the development and evaluation of tacrolimus gellan gum nanoparticles (TGNPs) for the effective management of dry eye disease (DED) following topical application. TGNPs were developed by ionotropic gelation between gellan gum and aluminum chloride. Developed TGNPs were nanosized (274.46 ± 8.90 nm) with high % encapsulation efficiency (74.2 ± 2.4%) and loading capacity (36.14 ± 1.7%). The nanosize and spherical morphology of TGNPs was confirmed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) revealed no interaction between drug and GG. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) confirms the conversion of crystalline tacrolimus to amorphous post encapsulation in the nanoparticle. TGNPs showed prolonged drug release throughout 12 h and higher pre-corneal retention compared to tacrolimus solution. HET-CAM studies, histopathological evaluation, and Draize test confirmed the safety of the formulation for ocular use. Further, the pharmacodynamic studies using experimental DED in rabbits showed that TGNPs are effective in treating symptoms of DED. In conclusion, topical delivery of TGNPs could hold potential for efficient management of DED.

Hyaluronic Acid-Based Nanoparticles for Protein Delivery: Systematic Examination of Microfluidic Production Conditions

Hyaluronic acid-based nanoparticles (HA NPs) can be used to deliver a protein cargo to cells overexpressing HA receptors such as CD44 since they combine the low toxicity of the carrier and the retention of the protein integrity with the receptor-mediated internalization. HA properties play a crucial but sometimes unclear role in managing the formation and stability of the meshwork, cell interactions, and ultimately the protein entrapment efficacy. Nowadays, microfluidic is an innovative technology that allows to overcome limits linked to the NPs production, guaranteeing reproducibility and control of individual batches. Taking advantage of this technique, in this research work, the role of HA weight average molecular weight (Mw) in NPs formation inside a microfluidic device has been specifically faced. Based on the relationship between polymer Mw and solution viscosity, a methodological approach has been proposed to ensure critical quality attributes (size of 200 nm, PDI ≤ 0.3) to NPs made by HA with different Mw (280, 540, 710 and 820 kDa). The feasibility of the protein encapsulation was demonstrated by using Myoglobin, as a model neutral protein, with an encapsulation efficiency always higher than 50%. Lastly, all NPs samples were successfully internalized by CD44-expressing cells.

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.

Nanodelivery of triamcinolone acetonide with PLGA-chitosan nanoparticles for the treatment of ocular inflammation

Triamcinolone acetonide (TA) is widely indicated in the treatment of several ocular disorders, but the free drug suspension limits its clinical benefits and commercial compositions cause adverse ocular effects. In this study, TA was formulated in poly(d,l-lactide-co-glycolide) (PLGA)-chitosan (PLC) nanoparticles (NPs) for the treatment of ocular inflammatory diseases. TA-loaded PLC NPs exhibited excellent anti-inflammatory activity against human corneal epithelial (HCE) cells and significantly reduced the secretion of interleukin (IL)-6 in tumour necrosis factor (TNF)-α activated cells. In a rabbit model, TA-loaded PLC NPs did not show any typical clinical signs of eye inflammation and significantly alleviated inflammatory signs, compared with free TA suspension, at 24 h after a single dose. TA-loaded PLC NPs exhibited a greater aqueous humour transparency (%AHT), compared with that of normal saline (NS) or free TA suspension, indicating reduction in anterior chamber fogginess. Pharmacokinetic analysis of rabbit eyes revealed that TA-loaded PLC NPs peaked at 6 h. Substantial concentrations of TA were observed until 24 h, indicating the superiority of this PLC-based nanocarrier system. Overall, PLC-based NP formulations offer a new approach for the treatment of ocular inflammatory diseases.

Developed simvastatin chitosan nanoparticles co-crosslinked with tripolyphosphate and chondroitin sulfate for ASGPR-mediated targeted HCC delivery with enhanced oral bioavailability

Simvastatin (SV) repurposing has emerged as an alternative approach for the treatment of cancer. In this study, SV chitosan nanoparticles co-crosslinked with tripolyphosphate and chondroitin sulfate (SVCSChSNPs) were developed in order to maximize SV therapeutic efficiency. The hepatic targeting was realized using N-acetylgalactosamine (GalNAc) residues of ChS, which can be identified by the ASGPR receptors specifically expressed in hepatocytes. SV was repurposed as an anticancer agent against hepatocellular carcinoma (HCC). NPs were fabricated by the ionic gelation method, and the formulation variables (CS concentration, CS:ChS ratio, and CS solution pH) were optimized using a three-factor, three-level Box-Behnken design. The optimized NPs were investigated for particle size, size distribution, zeta potential, morphology, in vitro cytotoxicity, apoptotic effects against human hepatocellular carcinoma HepG2 cells, and detection of intracellular localization. The NPs were further evaluated for in vitro release behavior of SV and pharmacokinetics using Wister albino rats. Transmission electron microscopy (TEM) imaging showed a spherical shape with regular surface NPs of < 100 nm diameter. In vitro cytotoxicity testing showed that the SVCSChSNPs exhibited greater inhibition of proliferation in HepG2 cells and high cellular uptake through ASGPR-mediated endocytosis. The in vitro dissolution profile was 2.1-fold greater than that of pure SV suspension. Furthermore, in vivo oral pharmacokinetics revealed that the obtained NPs enhanced the bioavailability of SV by up to 2- and 1.6-fold for SV and SVA, respectively, compared to the pure SV suspension. These findings demonstrated that hepatic-targeted CSChSNPs delivering SV could potentially serve as a promising platform for HCC and other liver-related diseases.

Biomedical application of chondroitin sulfate with nanoparticles in drug delivery systems: systematic review

Chondroitin sulphate captured an increasing amount of attention in the field of drug delivery systems. Nanoparticles and chondroitin sulphate were combined in different ways to form effective target nanocarriers. The study aimed to evaluate the biomedical application of chondroitin sulphate with nanoparticles in drug delivery systems. We searched PubMed, Google Scholar, and MEDLINE for studies that included data for the application of chondroitin sulphate and nanoparticles in targeting drug delivery published in English up to 25 February 2020. OHAT (Office of Health Assessment and Translation) Risk-of-Bias Tool was used to assessing the quality and risk of bias of each study. We performed a qualitative synthesis of findings from included studies. The toxicity of developed drugs has been evaluated using cell viability percentage and 50% inhibitory concentration of drugs. Twenty original articles reported the application of chondroitin sulphate on drug delivery systems were selected. Drug loading and encapsulation efficiency were from 2% to 16.1% and from 39.50% to 93.97%, respectively. The drug release was fast at start time and followed by a slow and sustain released stage. The risk of bias was rated as high in two out of twenty studies. Most of the studies presented baseline characteristics and outcomes appropriately.

Clarithromycin-Loaded Ocular Chitosan Nanoparticle: Formulation, Optimization, Characterization, Ocular Irritation, and Antimicrobial Activity

Purpose

The topically administered drugs through conventional delivery systems have low bioavailability. Henceforth, the present study was designed to prepare and optimize clarithromycin (CTM)-loaded chitosan nanoparticles (CHNPs) to demonstrate the efficacy against microorganisms.

Methods

Clarithromycin-loaded chitosan nanoparticles (CTM-CHNPs) were prepared by ionotropic gelation method. The formulation was optimized by box-Behnken design using the formulation variables like CH (A), STPP concentration (B), and stirring speed (C). Their effects were evaluated on the independent variables like particle size (Y₁) and entrapment efficiency (Y₂). Further, CTM-CHNPs were evaluated for physicochemical parameters, in-vitro drug release, ex-vivo permeation, bioadhesive study, corneal hydration, histopathology, HET-CAM, and antibacterial study.

Results

The optimized formulation (CTM-CHNPopt) showed the low particle size (152±5 nm), which is desirable for ocular delivery. It also showed high encapsulation (70.05%), zeta potential (+35.2 mV), and was found in a spherical shape. The drug release study revealed a sustained drug release profile (82.98±3.5% in 12 hours) with Korsmeyer peppas kinetic (R²=0.996) release model. It showed a 2.7-fold higher corneal permeation than CTM-solution. CHNPs did not exhibit any sign of damage to excised goat cornea, which is confirmed by hydration, histopathology, and HET-CAM test. It exhibited significant (P<0.05) higher antibacterial susceptibility than CTM-solution.

Conclusion

The finding of the study concluded that CTM-CHNPs can be used for effective management of bacterial conjunctivitis by increasing the precorneal residence time.

Biofabrication of Chitosan-Based Nanomedicines and Its Potential Use for Translational Ophthalmic Applications

Drug delivery to the anterior and posterior segment of eye remains a challenge. Nanoparticle-mediated drug delivery has indicated some promise. The presented review aims to summarize recent advancements in chitosan-based nanotherapies for ocular drug delivery and the challenges encountered during the process. Significant research using chitosan, a cationic linear polymer, is being conducted for ocular drug delivery. A vast number of publications exploit the mucoadhesive properties of the polymer, which arise due to interactions between the amino acids of chitosan and the sialic acid residues in mucous. The high degree of crosslinking in chitosan nanoparticles facilitates a dramatic increase in ocular drug retention of the desired drug, which subsequently helps in ocular penetration and improving the bioavailability of the drugs. A noted decrease in the initial burst of the drug is the basis for developing sustained drug release formulation using biodegradable and biocompatible chitosan polymer. In vitro as well as in vivo studies have indicated enhancement in the uptake, accumulation, and removal of chitosan nanoparticles from the site of delivery. In summary, chitosan- or modified-chitosan-based nanoparticles are being widely tested as drug carriers for treatment of bacterial and viral infections, glaucoma, age-related macular degeneration, and diabetic retinopathy.

Carbohydrate-based nanomaterials for biomedical applications

Carbohydrates are abundant biomolecules, with a strong tendency to form supramolecular networks. A host of carbohydrate-based nanomaterials have been exploited for biomedical applications. These structures are based on simple mono- or disaccharides, as well as on complex, polymeric systems. Chemical modifications serve to tune the shapes and properties of these materials. In particular, carbohydrate-based nanoparticles and nanogels were used for drug delivery, imaging, and tissue engineering applications. Due to the reversible nature of the assembly, often based on a combination of hydrogen bonding and hydrophobic interactions, carbohydrate-based materials are valuable substrates for the creations of responsive systems. Herein, we review the current research on carbohydrate-based nanomaterials, with a particular focus on carbohydrate assembly. We will discuss how these systems are formed and how their properties are tuned. Particular emphasis will be placed on the use of carbohydrates for biomedical applications. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Strategies for Improving Ocular Drug Bioavailability and Corneal Wound Healing with Chitosan-Based Delivery Systems

The main inconvenience of conventional eye drops is the rapid washout of the drugs due to nasolacrimal drainage or ophthalmic barriers. The ocular drug bioavailability can be improved by either prolonging retention time in the cul-de-sac or by increasing the ocular permeability. The focus of this review is to highlight some chitosan-based drug delivery approaches that proved to have good clinical efficacy and high potential for use in ophthalmology. They are exemplified by recent studies exploring in-depth the techniques and mechanisms in order to improve ocular bioavailability of the active substances. Used alone or in combination with other compounds with synergistic action, chitosan enables ocular retention time and corneal permeability. Associated with other stimuli-responsive polymers, it enhances the mechanical strength of the gels. Chitosan and its derivatives increase drug permeability through the cornea by temporarily opening tight junctions between epithelial cells. Different types of chitosan-based colloidal systems have the potential to overcome the ocular barriers without disturbing the vision process. Chitosan also plays a key role in improving corneal wound healing by stimulating the migration of keratinocytes when it is used alone or in combination with other compounds with synergistic action.

Preparation and in vitro evaluation of novel cross-linked chondroitin sulphate nanoparticles by aluminium ions for encapsulation of green tea flavonoids

Chondroitin sulphate is a sulphated glycosaminoglycan biopolymer composed over 100 individual sugars. Chondroitin sulphate nanoparticles (NPs) loaded with catechin were prepared by an ionic gelation method using AlCl₃ and optimised for polymer and cross-linking agent concentration, curing time and stirring speed. Zeta potential, particle size, loading efficiency, and release efficiency over 24 h (RE₂₄%) were evaluated. The surface morphology of NPs was investigated by scanning electron microscopy and their thermal behaviour by differential scanning calorimetric. Antioxidant effect of NPs was determined by chelating activity of iron ions. The cell viability of mesenchymal stem cells was determined by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide assay and the calcification of osteoblasts was studied by Alizarin red staining. The optimised NPs showed particle size of 176 nm, zeta potential of -20.8 mV, loading efficiency of 93.3% and RE₂₄% of 80.6%. The chatechin loaded chondroitin sulphate NPs showed 70-fold more antioxidant activity, 3-fold proliferation effect and higher calcium precipitation in osteoblasts than free catechin.

Recent advance of nanoparticle-based topical drug delivery to the posterior segment of the eye

INTRODUCTION

Considering that the number of patients afflicted by posterior eye diseases is increasing, effective drug delivery is currently in high clinical demand. Topical administration has been identified as the preferred option, while sufferingfrom multiple barriers. The development of nanoparticle-based drug delivery system provides an option, which would enhance the drug permeability across the barriers and achieve the desired drug level in the targeted tissue.

AREAS COVERED

This review highlights the barrier to the posterior segment of the eye via topical administration. The up-to-date development of lipid nanoparticles, liposomes, emulsions, spanlastics, micelles, polymeric nanoparticles, layered double hydroxides (LDH), dendrimers, cyclodextrins(CDs), and prodrugs are summarized. Moreover, nanocarriers currently in clinical trials for posterior segment diseases have been discussed.

EXPERT OPINION

Topical nanoparticle-based drug delivery systems have demonstrated significant progress. An ideal formulation should prolong retention time on the surface, enhance drug permeability through the ocular tissues, and efficiently deliver drugs to the targeted site. To design the rational targeting nanoparticle-based drug delivery system, a better understanding of the distribution of transporters and receptors on the eye is required. Ultimately, there is an urgent need to develop targeting hybrid drug delivery systems with the combination of the advantages of several nanocarriers.

Biodegradable Ingredient-Based Emulgel Loaded with Ketoprofen Nanoparticles

Biodegradable materials are extensively employed to design nanocarriers that mimic extracellular environment in arthritis. The aim of this study was to formulate and characterize biocompatible, biodegradable ketoprofen-loaded chitosan-chondroitin sulfate (CHS-CS) nanoparticles with natural ingredients for transdermal applications. Polymers used in the design of nanocarriers are biodegradable and produce synergistic anti-inflammatory effect for the treatment of arthritis. For transdermal application, argan oil-based emulgel is utilized to impart viscosity to the formulation. Furthermore, naturally occurring argan oil synergizes anti-inflammatory effect of formulation and promotes skin penetration. CHS and CS form nanoparticles by polyelectrolyte complex formation or complex coacervation at pH 5.0. These particles were loaded into argan oil-based emulgel. Employing this method, nanoparticles were formulated with particle size in the range of 300-500 nm. These nanocarriers entrapped ketoprofen and showed more than 76% encapsulation efficiency and 77% release of the ketoprofen at pH 7.4 within 72 h. Drug releases from CHS-CS nanoparticles by mechanism of simple diffusion. Nanoparticle-loaded argan oil emulgel significantly enhanced skin penetration of ketoprofen as compared to marketed gel (p < 0.05). Nanocarriers prepared successfully delivered drug through transdermal route using natural ingredients. Graphical abstract ᅟ.

Smart Carriers and Nanohealers: A Nanomedical Insight on Natural Polymers

Biodegradable polymers are popularly being used in an increasing number of fields in the past few decades. The popularity and favorability of these materials are due to their remarkable properties, enabling a wide range of applications and market requirements to be met. Polymer biodegradable systems are a promising arena of research for targeted and site-specific controlled drug delivery, for developing artificial limbs, 3D porous scaffolds for cellular regeneration or tissue engineering and biosensing applications. Several natural polymers have been identified, blended, functionalized and applied for designing nanoscaffolds and drug carriers as a prerequisite for enumerable bionano technological applications. Apart from these, natural polymers have been well studied and are widely used in material science and industrial fields. The present review explains the prominent features of commonly used natural polymers (polysaccharides and proteins) in various nanomedical applications and reveals the current status of the polymer research in bionanotechnology and science sectors.

Novel nanosystems for the treatment of ocular inflammation: Current paradigms and future research directions

Ocular discomforts involve anterior/posterior-segment diseases, symptomatic distress and associated inflammations and severe retinal disorders. Conventionally, the formulations such as eye drops, eye solutions, eye ointments and lotions, etc. were used as modalities to attain relief from such ocular discomforts. However, eye allows limited access to these traditional formulations due to its unique anatomical structure and dynamic ocular environment and therefore calls for improvement in disease intervention. To address these challenges, development of nanotechnology based nanomedicines and novel nanosystems (liposomes, cubosomes, polymeric and lipidic nanoparticles, nanoemulsions, spanlastics and nano micelles) are currently in progress (some of them are already marketed such as Eye-logic liposomal eye spray@Naturalife, Ireland). Today, it is one of the central concept in designing more accessible formulations for deeper segments of the eyes. These nanosystems has largely enabled the availability of medicaments at required site in a required concentration without inversely affecting the eye tissues; and therefore, attaining the excessive considerations from the formulation scientists and pharmacologists worldwide. The entrapment of drugs, genes, and proteins inside these novel systems is the basis that works at the bio-molecular level bestows greater potential to eradicate disease causatives. In this review, we highlighted the recent attempts of nanotechnology-based systems for treating and managing various ocular ailments. The progress described herein may pave the way to new, highly effective and vital ocular nanosystems.

Development of Timolol-Loaded Galactosylated Chitosan Nanoparticles and Evaluation of Their Potential for Ocular Drug Delivery

This study was conducted to develop timolol maleate (TM)-loaded galactosylated chitosan (GC) nanoparticles (NPs) (TM-GC-NPs) followed by optimization via a four-level and three-factor Box-Behnken statistical experimental design. The optimized nanoparticles showed a particle size of 213.3 ± 6.83 nm with entrapment efficiency of 38.58 ± 1.31% and drug loading of 17.72 ± 0.28%. The NPs were characterized with respect to zeta potential, pH, surface morphology, and differential scanning calorimetry (DSC). The determination of the oil-water partition coefficient demonstrated that the TM-GC-NPs had a high liposolubility at pH 6 as compared to timolol-loaded chitosan nanoparticles (TM-CS-NPs) and commercial TM eye drops. The in vitro release study indicated that TM-GC-NPs had a sustained release effect compared with the commercial TM eye drops. Ocular tolerance was studied by the hen's egg chorioallantoic membrane (HET-CAM) assay and the formulation was non-irritant and could be used for ophthalmic drug delivery. The in vitro transcorneal permeation study and confocal microscopy showed enhanced penetration, and retention in the cornea was achieved with TM-GC-NPs compared with the TM-CS-NPs and TM eye drops. Preocular retention study indicated that the retention of TM-GC-NPs was significantly longer than that of TM eye drops. The in vivo pharmacodynamic study suggested TM-GC-NPs had a better intraocular pressure (IOP) lowering efficacy and a prolonged working time compared to commercial TM eye drops (P ≤ 0.05). The optimized TM-GC-NPs could be prepared successfully promising their use as an ocular delivery system.

Improving the topical ocular pharmacokinetics of an immunosuppressant agent with mucoadhesive nanoemulsions: Formulation development, in-vitro and in-vivo studies

Topical ocular conditions such as cornea transplant rejection and keratoconjunctivitis sicca (so called dry eye disease) require therapeutic concentration of immunosuppressant onto the ocular surface for prolonged period. Based on this rational, we optimized cyclosporine A (Cy-A) loaded polymeric mucoadhesive nanoemulsion (Cy-A-mN) with higher Cy-A payload, improved ocular retention, corneal and conjunctival bioavailability. The concentrations of oil, surfactant and co-surfactant needed for the stable nanoemulsion were screened followed by phase behavior study of the formulations components by the construction of pseudo-ternary phase diagrams. The concentration of chitosan was optimized according to the blinking force of eyelids. The size distribution, surface charge, mucoadhesiveness and Cy-A release were studied for Cy-A-mN along with other formulations. The corneal retention of Cy-A-mN was evaluated by gamma scintigraphy, revealing that the clearance was slowest in the case of Cy-A-mN. Biodistribution performed in rabbits showed that Cy-A-mN was able to maintain the therapeutic concentrations (≥50-300ng/g) of Cy-A in the cornea and conjunctiva over the period of 24h. The safety of formulation was confirmed by Draize's test and by measuring the ocular surface temperature.