Encapsulating curcumin in ethylene diamine-β-cyclodextrin nanoparticle improves topical cornea delivery

Functionalization of β-cyclodextrin metal-organic frameworks with gelatin and glutamine for drug delivery of curcumin to cancerous cells

Beta-cyclodextrin Metal-Organic Framework (β-CD-MOF) is a unique class of porous materials that merges the inherent properties of cyclodextrins with the structural advantages of metal-organic frameworks (MOFs). When combined with the concept of MOFs, which are crystalline structures composed of metal ions or clusters linked by organic ligands, the resulting β-CD-MOF holds immense potential for various applications, especially in the field of drug delivery. In this study, biocompatible metal-organic frameworks (MOFs) synthesized using β-Cyclodextrin (β-CD) and potassium enabled drug delivery of curcumin (CCM) to cancerous cells. Functionalizing β-CD-MOF with l-glutamine (glutamine-β-CD-MOF) enhanced cancer cell-specific targeting due to glutamine's essential role in cancer cell proliferation and energy pathways. Amino group functionalization provided further functionalization opportunities. Gelatin coating (gelatin@β-CD-MOF) facilitated controlled drug release in an acidic medium. High drug loading capacities (52.38-55.63 %) were achieved for β-CD-MOF@CCM and glutamine-β-CD-MOF@CCM, leveraging the high porosity and affinity of amine and phenol groups of curcumin. The MTT assay highlighted the specificity and differentiation of glutamine-β-CD-MOF in targeting cancerous over normal cells. These functionalized β-CD MOFs efficiently encapsulate curcumin, ensuring controlled drug release and enhanced therapeutic efficacy, particularly in cancer therapy.

The potential benefits of polyphenols for corneal diseases

The cornea functions as the primary barrier of the ocular surface, regulating temperature and humidity while providing protection against oxidative stress, harmful stimuli and pathogenic microorganisms. Corneal diseases can affect the biomechanical and optical properties of the eye, resulting in visual impairment or even blindness. Due to their diverse origins and potent biological activities, plant secondary metabolites known as polyphenols offer potential advantages for treating corneal diseases owing to their anti-inflammatory, antioxidant, and antibacterial properties. Various polyphenols and their derivatives have demonstrated diverse mechanisms of action in vitro and in vivo, exhibiting efficacy against a range of corneal diseases including repair of tissue damage, treatment of keratitis, inhibition of neovascularization, alleviation of dry eye syndrome, among others. Therefore, this article presents a concise overview of corneal and related diseases, along with an update on the research progress of natural polyphenols in safeguarding corneal health. A more comprehensive understanding of natural polyphenols provides a novel perspective for secure treatment of corneal diseases.

Ocular immunosuppressive microenvironment and novel drug delivery for control of uveitis

Ocular immune privilege is a phenomenon described by Peter Medawar in relation to the indefinite survival of the placement of foreign tissue grafts into the eye. Several mechanisms have been described that contribute to ocular immune privilege, such as a blood-ocular barrier and lack of lymphatics in the eye, the production of immune-suppressing molecules inside the ocular microenvironment, and the induction of systemic regulatory immunity against antigens found in the eye. Because ocular immune privilege is not absolute, failure of it can result in uveitis. Uveitis is a group of inflammatory disorders that can lead to vision loss if not treated properly. The current uveitis treatments involve the use of immunosuppressive and anti-inflammatory medications. Researching mechanisms of ocular immune privilege and the development of novel treatments for uveitis is ongoing. This review discusses mechanisms of ocular immune privilege, followed by an overview of uveitis treatments and ongoing clinical trials.

Carbohydrate polymer-based bioadhesive formulations and their potentials for the treatment of ocular diseases: A review

Eyes are directly exposed to the outer environment and susceptible to infections, leading to various ocular disorders. Local medication is preferred to treat eye diseases due to its convenience and compliance. However, the rapid clearance of the local formulations highly limits the therapeutic efficacy. In the past decades, several carbohydrate bioadhesive polymers (CBPs), such as chitosan and hyaluronic acid, have been used in ophthalmology for sustained ocular drug delivery. These CBP-based delivery systems have improved the treatment of ocular diseases to a large extent but also caused some undesired effects. Herein, we aim to summarize the applications of some typical CBPs (including chitosan, hyaluronic acid, cellulose, cyclodextrin, alginate and pectin) in treating ocular diseases from the general view of ocular physiology, pathophysiology and drug delivery, and to provide a comprehensive understanding of the design of the CBP-based formulations for ocular use. The patents and clinical trials of CBPs for ocular management are also discussed. In addition, a discussion on the concerns of CBPs in clinical use and the possible solutions is presented.

Curcumin-Loaded Mesenchymal Stem Cell-Derived Exosomes Efficiently Attenuate Proliferation and Inflammatory Response in Rheumatoid Arthritis Fibroblast-Like Synoviocytes

This study aimed to evaluate the potential of mesenchymal stem cell-derived exosomes loaded with curcumin (Curc-Exos) as an effective therapeutic strategy for rheumatoid arthritis through modulation of proliferation and inflammatory response in HIG-82 synovial cells. For this purpose, Exos were isolated and characterized with BCA protein assay, DLS, FE-SEM, and TEM. The Curc was embedded by mixing it with Exos in a 1:4 ratio. It was found that the Curc stability has improved after loading on Exos compared to the free Curc. Besides, the in vitro studies using LPS-stimulated HIG-82 synovial cells indicated the efficiency of Curc-Exos in enhancing cytotoxicity and apoptosis compared to the free Curc treatment. It was also revealed that Curc-Exos significantly could reduce the expression levels of anti-apoptotic proteins IAP1 and IAP2 and inflammatory mediators including IL-6, TNF-α, MMP1, and PGE2. This preliminary study confirmed the suitability of Curc-Exos in counteracting the proliferation and inflammatory response of rheumatoid arthritis synovial fibroblasts in vitro.

Guest-host Relationship of Cyclodextrin and its Pharmacological Benefits

Many methods, including solid dispersion, micellization, and inclusion complexes, have been employed to increase the solubility of potent drugs. Beta-cyclodextrin (βCD) is a cyclic oligosaccharide consisting of seven glucopyranoside molecules, and is a widely used polymer for formulating soluble inclusion complexes of hydrophobic drugs. The enzymatic activity of Glycosyltransferase or α-amylase converts starch or its derivatives into a mixture of cyclodextrins. The βCD units are characterized by α -(1-4) glucopyranose bonds. Cyclodextrins possess certain properties that make them very distinctive because of their toroidal or truncated cage-like supramolecular configurations with multiple hydroxyl groups at each end. This allowed them to encapsulate hydrophobic compounds by forming inclusion complexes without losing their solubility in water. Chemical modifications and newer derivatives, such as methylated βCD, more soluble hydroxyl propyl methyl βCD, and sodium salts of sulfobutylether-βCD, known as dexolve® or captisol®, have envisaged the use of CDs in various pharmaceutical, medical, and cosmetic industries. The successful inclusion of drug complexes has demonstrated improved solubility, bioavailability, drug resistance reduction, targeting, and penetration across skin and brain tissues. This review encompasses the current applications of β-CDs in improving the disease outcomes of antimicrobials and antifungals as well as anticancer and anti-tubercular drugs.

A Review of Cyclodextrin Encapsulation and Intelligent Response for the Release of Curcumin

To overcome the low water solubility and low bioavailability of curcumin (CUR), multiple delivery strategies have been proposed. Among these, cyclodextrin-based carriers have been widely used for the encapsulation and delivery of CUR. Cyclodextrins (CDs), as natural oligosaccharides, have been well known for their biodegradability, biocompatibility, non-toxicity, and internal hydrophobic and external hydrophilic structural features. This paper summarizes the recently reported CD-based carriers for encapsulating CUR. Particularly, the polymerization properties of CD self-assembly to enhance the encapsulation of CUR are discussed. In addition, the current progress on stimuli-responsive CD carriers for controlled release of CUR is described, which laid an important foundation for the development of CUR-based precision therapy in clinical practice. In conclusion, this review may provide ideas for the future development of a CD-based encapsulant for CUR.

ROS-responsive resveratrol-loaded cyclodextrin nanomicelles reduce inflammatory osteolysis

Bone loss in inflammatory disorders such as osteomyelitis, septic arthritis, and periodontitis is caused by excessive osteoclastic activity. Meanwhile, reactive oxygen species (ROS) have been identified as contributors to osteoclast differentiation, and the application of ROS scavengers has emerged as a promising strategy to protect against bone loss. Recently, resveratrol (RSV), a polyphenolic phytoalexin, has been demonstrated to inhibit osteoclastogenesis by scavenging ROS; however, the application of RSV as an antioxidant is limited by its low water solubility, structural instability, and short elimination half-life. In this study, we developed a PEGylated cyclodextrin (CD)-based nanoplatform (PCP) for local delivery of RSV as nanomicelles (RSV-NMs). In addition, polymer functionalization with phenylboronic acid ester in RSV-NMs successfully achieved ROS-responsive release of RSV. The RSV-NMs in a well-dispersed state possessed good biocompatibility as well as improved solubility and stability compared with RSV compound. In vitro, RSV-NMs significantly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells and suppressed F-actin (filamentous actin) ring formation. Additionally, the mRNA expressions of osteoclastic marker genes, including matrix metalloprotein-9 (MMP-9), nuclear factor of activated T cells 1 (NFATc1), TRAP, and cathepsin K, were consequently downregulated in the presence of RSV-NMs. In vivo, RSV-NMs provided protection against LPS-induced bone destruction, as evidenced by a decreased number of osteoclasts, increased bone density, and reduced area of bone resorption. Taken together, these results indicate that our ROS-responsive RSV-NMs can be employed as a potential therapeutic agent for the treatment of inflammatory osteolysis.

Multifunctional magnetic nanocarriers for delivery of siRNA and shRNA plasmid to mammalian cells: Characterization, adsorption and release behaviors

Nucleic acids are promising candidates for treating various diseases. Nucleic acid is negatively charged and hydrophilic; therefore, it is not efficiently taken up by cells. Successful gene therapy requires the development of carriers for efficient delivery of gene-expressing DNA plasmid and small interfering RNA (siRNA) duplex. In this study, we developed MNP-CA-PEI, a citric acid (CA)-modified magnetic nanoparticle (MNP) cross-linked with polyethyleneimine (PEI), using carbonyldiimidazole as the crosslinker. The physical properties of MNP-CA-PEI (particle size, morphologies, surface coating, surface potentials, magnetic hystereses, superparamagnetic behaviors, and infrared spectra) were systematically characterized by transmission electron microscopy imaging, dynamic light scattering, thermogravimetric analysis, superconducting quantum interference device, and Fourier transform infrared spectroscopy. The adsorption isotherm and kinetics were determined by the Langmuir model, the Freundlich model, a pseudo-first-order equation, and a pseudo-second-order equation. MNP-CA-PEI could form polyelectrolyte complexes with negatively charged nucleic acids, enabling the efficient delivery of nucleic acids into cells. Using MNP-CA-PEI nanoparticles, we magnetically triggered the intracellular delivery of green fluorescence protein (GFP)-expressing DNA plasmid, plasmid-expressing short hairpin RNA (shRNA) against GFP, or siRNA targeting GFP into different cell lines. Nucleic acid/MNP-CA-PEI displayed the enhanced cellular uptake of GFP-expressing DNA plasmid, and it improved the silencing efficiency of shRNA and siRNA, determined by fluorescence imaging. Gene knockdowns mediated by shRNA and siRNA were also confirmed by a quantitative real-time polymerase chain reaction. MNP-CA-PEI delivered nucleic acids into cytosol through caveolae-mediated endocytosis. This study introduces a new MNP functionalization that can be used for the magnetically driven intracellular delivery of nucleic acids.

Ocular Drug Delivery: Advancements and Innovations

Ocular drug delivery has been significantly advanced for not only pharmaceutical compounds, such as steroids, nonsteroidal anti-inflammatory drugs, immune modulators, antibiotics, and so forth, but also for the rapidly progressed gene therapy products. For conventional non-gene therapy drugs, appropriate surgical approaches and releasing systems are the main deliberation to achieve adequate treatment outcomes, whereas the scope of “drug delivery” for gene therapy drugs further expands to transgene construct optimization, vector selection, and vector engineering. The eye is the particularly well-suited organ as the gene therapy target, owing to multiple advantages. In this review, we will delve into three main aspects of ocular drug delivery for both conventional drugs and adeno-associated virus (AAV)-based gene therapy products: (1) the development of AAV vector systems for ocular gene therapy, (2) the innovative carriers of medication, and (3) administration routes progression.

Enzyme-responsive nano-drug delivery system for combined antitumor therapy

Efficient drug loading, tumor targeting, intratumoral penetration, and cellular uptake are the main factors affecting the effectiveness of drug delivery systems in oncotherapy. Based on the tumor microenvironment, we proposed to develop Curcumin (Cur)-loaded matrix metalloproteinase (MMP)-responsive nanoparticles (Cur-P-NPs) by static electricity, to enhance tumor targeting, cellular uptake, and drug loading efficiency. These nanoparticles combine the properties of both PEG-peptides (cleaved peptide + penetrating peptide) and star-shaped polyester (DPE-PCL) nanoparticles. Cur-P-NPs displayed good entrapment efficiency, drug loading and biocompatibility. Additionally, they showed an enhanced release rate, cellular uptake, and anti-proliferative activity by activating peptides under the simulated tumor microenvironment. Furthermore, intraperitoneal injection of losartan (LST) successfully enhanced intratumoral drug penetration by collagen I degradation. In vivo studies based on the systematic administration of the synergistic LST + Cur-P-NPs combination to mice confirmed that combined antitumor therapy with LST and Cur-P-NPs could further improve intratumor distribution, enhance anticancer efficacy, and reduce the toxicity and side effects. Therefore, LST + Cur-P-NPs represent a new and efficient system for clinical oncotherapy.

TGFBR3 supports anoikis through suppressing ATF4 signaling

Epithelial morphogenesis and oncogenic transformation can cause loss of cell adhesion, and detached cells are eliminated by anoikis. Here, we reveal that transforming growth factor beta receptor 3 (TGFBR3) acts as an anoikis mediator through the coordination of activating transcription factor 4 (ATF4). In breast cancer, TGFBR3 is progressively lost, but elevated TGFBR3 is associated with a histologic subtype characterized by cellular adhesion defects. Dissecting the impact of extracellular matrix (ECM) deprivation, we demonstrate that ECM loss promotes TGFBR3 expression, which in turn differentiates cell aggregates to a prosurvival phenotype and drives the intrinsic apoptotic pathway. We demonstrate that inhibition of TGFBR3 impairs epithelial anoikis by activating ATF4 signaling. These preclinical findings provide a rationale for therapeutic inhibition of ATF4 in the subgroup of breast cancer patients with low TGFBR3 expression.

Antimicrobial Peptide Expression at the Ocular Surface and Their Therapeutic Use in the Treatment of Microbial Keratitis

Microbial keratitis is a common cause of ocular pain and visual impairment worldwide. The ocular surface has a relatively paucicellular microbial community, mostly found in the conjunctiva, while the cornea would be considered relatively sterile. However, in patients with microbial keratitis, the cornea can be infected with multiple pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, and Fusarium sp. Treatment with topical antimicrobials serves as the standard of care for microbial keratitis, however, due to high rates of pathogen resistance to current antimicrobial medications, alternative therapeutic strategies must be developed. Multiple studies have characterized the expression and activity of antimicrobial peptides (AMPs), endogenous peptides with key antimicrobial and wound healing properties, on the ocular surface. Recent studies and clinical trials provide promise for the use of AMPs as therapeutic agents. This article reviews the repertoire of AMPs expressed at the ocular surface, how expression of these AMPs can be modulated, and the potential for harnessing the AMPs as potential therapeutics for patients with microbial keratitis.

Recent Developments of Nanostructures for the Ocular Delivery of Natural Compounds

Ocular disorders comprising various diseases of the anterior and posterior segments are considered as the main reasons for blindness. Natural products have been identified as potential treatments for ocular diseases due to their anti-oxidative, antiangiogenic, and anti-inflammatory effects. Unfortunately, most of these beneficial compounds are characterised by low solubility which results in low bioavailability and rapid systemic clearance thus requiring frequent administration or requiring high doses, which hinders their therapeutic applications. Additionally, the therapeutic efficiency of ocular drug delivery as a popular route of drug administration for the treatment of ocular diseases is restricted by various anatomical and physiological barriers. Recently, nanotechnology-based strategies including polymeric nanoparticles, micelles, nanofibers, dendrimers, lipid nanoparticles, liposomes, and niosomes have emerged as promising approaches to overcome limitations and enhance ocular drug bioavailability by effective delivery to the target sites. This review provides an overview of nano-drug delivery systems of natural compounds such as thymoquinone, catechin, epigallocatechin gallate, curcumin, berberine, pilocarpine, genistein, resveratrol, quercetin, naringenin, lutein, kaempferol, baicalin, and tetrandrine for ocular applications. This approach involves increasing drug concentration in the carriers to enhance drug movement into and through the ocular barriers.

Tetraethylenepentamine-Coated β Cyclodextrin Nanoparticles for Dual DNA and siRNA Delivery

Nucleic acid reagents, including plasmid-encoded genes and small interfering RNA (siRNA), are promising tools for validating gene function and for the development of therapeutic agents. Native β-cyclodextrins (BCDs) have limited efficiency in gene delivery due to their instable complexes with nucleic acid. We hypothesized that cationic BCD nanoparticles could be an efficient carrier for both DNA and siRNA. Tetraethylenepentamine-coated β-cyclodextrin (TEPA-BCD) nanoparticles were synthesized, characterized, and evaluated for targeted cell delivery of plasmid DNA and siRNA. The cationic TEPA coating provided ideal zeta potential and effective nucleic acid binding ability. When transfecting plasmid encoding green fluorescent protein (GFP) by TEPA-BCD, excellent GFP expression could be achieved in multiple cell lines. In addition, siRNA transfected by TEPA-BCD suppressed target GFP gene expression. We showed that TEPA-BCD internalization was mediated by energy-dependent endocytosis via both clathrin-dependent and caveolin-dependent endocytic pathways. TEPA-BCD nanoparticles provide an effective means of nucleic acid delivery and can act as potential carriers in future pharmaceutical application.

A topical fluorometholone nanoformulation fabricated under aqueous condition for the treatment of dry eye

Fluorometholone (FMT) is a frequently prescribed drug for the alleviation of dry eye. However, due to low aqueous solubility, it has been routinely used as an ophthalmic suspension, which is characterized by low bioavailability, inconvenience of administration, and difficulty in delivering accurate dose. Furthermore, the opaque appearance of the ophthalmic suspension is not desirable for optical purpose. In the present study, a transparent FMT nanoformulation (FMT-CD NPs) was fabricated by the cyclodextrin (CD) nanoparticle technology without organic solvents. It was demonstrated that FMT was encapsulated in an amorphous form, which was associated with increased release rate and enhanced corneal penetration efficiency. The biocompatibility of FMT-CD NPs was confirmed by the Live/Dead assay, CCK-8 assay and the wound healing assay. Most importantly, FMT-CD NPs alleviated dry eye signs more efficiently than the commercial eye drop, with one-fifth the dosage of FMT in the latter. Collectively, our study provides a promising FMT formulation for improved management of dry eye while reducing drug related side effects.

Development of oral curcumin based on pH-responsive transmembrane peptide-cyclodextrin derivative nanoparticles for hepatoma

Herein, a pH-responsive cyclodextrin derivative (R6H4-CMβCD) with cell-penetrating ability was successfully synthesized, and curcumin-loaded nanoparticles (R6H4-CMβCD@CUR NPs, RCCNPs) were developed to improve its efficacy in hepatoma. RCCNPs could improve the cell uptake compared with CMβCD@CUR NPs (CCNPs) and were internalized into cells mainly through endocytosis mediated by reticulin and macropinocytosis. Furthermore, the accumulation of RCCNPs in hepatoma cells at pH 6.4 was higher than that at pH 7.4, indicating a pH-responsive uptake. Additionally, RCCNPs could escape from the lysosomes via the "proton sponge effect", and a high apoptosis rate was detected. Importantly, in vivo experiments revealed that orally administered RCCNPs could exert excellent anti-cancer effects in tumor-bearing mice. Hematoxylin-eosin staining did not show significant histological changes in the major organs. Thus, our findings indicate the potential of R6H4-CMβCD as a nanopharmaceutical material, and RCCNPs as an effective delivery system for oral curcumin in cancer management.

Modification of cyclodextrin and use in environmental applications

Water pollution, which has become a global problem in parallel with environmental pollution, is a problem that needs to be solved urgently, considering the gradual depletion of water resources. The inadequacy of the water treatment methods and the materials used somehow directed the researchers to look for dual character structures such as biocompatible and biodegradable β-cyclodextrin (β-CD). β-CD, which is normally insoluble in water, is used in demanding wastewater applications by being modified with the help of different agents to be water soluble or transformed into polymeric adsorbents as a result of co-polymerization via cross-linkers. In this way, in addition to the host-guest interactions offered by β-CD, secondary forces arising from these interactions provide advantages in terms of regeneration and reusability. However, the adsorption efficiency and synthesis steps need to be improved. Based on the current studies presented in this review, in which cross-linkers and modification methods are also mentioned, suggestions for novel synthesis methods of new-generation β-CD-based materials, criticisms, and recent methods of removal of micropollutants such as heavy metals, industrial dyes, harmful biomolecules, and pharmaceutics wastes are mentioned.

Molecular encapsulation of andrographolide in 2-hydroxypropyl-β-cyclodextrin cavity: synthesis, characterization, pharmacokinetic and in vitro antiviral activity analysis against SARS-CoV-2

In present investigation, AND-2-HyP-β-CYD (Andrographolide-2-Hydroxypropyl-β-cyclodextrin) complex was synthesized and characterized for antiviral and pharmacokinetic profile. The linear host-guest relation suggested synthesis of a 1:1 complex of AND with 2-HyP-β-CYD by inclusion mode. The Kc, stability constant of the two phase system of AND with 2-HyP-β-CYD computed to be 38.60 x 10⁻³M. ¹H NMR spectrum of AND indicated the presence of triplet at 6.63-ppm which was up-fielded in AND-2-HyP-β-CYD complex at 6.60-ppm (doublet) confirmed the insertion of AND in cavity of 2-HyP-β-CYD through lactone ring. AND-2-HyP-β-CYD complex exhibited the IC₅₀ of 0.1-μg.mL⁻¹ (E gene) and 0.29-μg.mL⁻¹ (N gene) against SARS-CoV-2 infected Vero6 cells. Moreover, a 1.5-fold increment in extent of absorption of AND was noticed post complexation. The bioavailability was estimated to be 15.87 ± 3.84% and 23.84 ± 5.46%, respectively for AND and AND-2-HyP-β-CYD complex. AND-2-HyP-β-CYD complex may be a prospective candidate for further studies to evolve as a clinically viable formulation against SARS-CoV-2.

Therapeutic Effects of Curcumin against Bladder Cancer: A Review of Possible Molecular Pathways

There are concerns about the increased incidence of cancer both in developing and developed countries. In spite of recent progress in cancer therapy, this disease is still one of the leading causes of death worldwide. Consequently, there have been rigorous attempts to improve cancer therapy by looking at nature as a rich source of naturally occurring anti-tumor drugs. Curcumin is a well-known plant-derived polyphenol found in turmeric. This compound has numerous pharmacological effects such as antioxidant, anti-inflammatory, antidiabetic and anti-tumor properties. Curcumin is capable of suppressing the growth of a variety of cancer cells including those of bladder cancer. Given the involvement of various signaling pathways such as PI3K, Akt, mTOR and VEGF in the progression and malignancy of bladder cancer, and considering the potential of curcumin in targeting signaling pathways, it seems that curcumin can be considered as a promising candidate in bladder cancer therapy. In the present review, we describe the molecular signaling pathways through which curcumin inhibits invasion and metastasis of bladder cancer cells.

Zoudani E, Daliri R, Aghamirsalim M, Raahemifar K. Biodegradable Nanoparticle for Cornea Drug Delivery: Focus Review

During recent decades, researchers all around the world have focused on the characteristic pros and cons of the different drug delivery systems for cornea tissue change for sense organs. The delivery of various drugs for cornea tissue is one of the most attractive and challenging activities for researchers in biomaterials, pharmacology, and ophthalmology. This method is so important for cornea wound healing because of the controllable release rate and enhancement in drug bioavailability. It should be noted that the delivery of various kinds of drugs into the different parts of the eye, especially the cornea, is so difficult because of the unique anatomy and various barriers in the eye. Nanoparticles are investigated to improve drug delivery systems for corneal disease. Biodegradable nanocarriers for repeated corneal drug delivery is one of the most attractive and challenging methods for corneal drug delivery because they have shown acceptable ability for this purpose. On the other hand, by using these kinds of nanoparticles, a drug could reside in various part of the cornea for longer. In this review, we summarized all approaches for corneal drug delivery with emphasis on the biodegradable nanoparticles, such as liposomes, dendrimers, polymeric nanoparticles, niosomes, microemulsions, nanosuspensions, and hydrogels. Moreover, we discuss the anatomy of the cornea at first and gene therapy at the end.

Polysaccharide-Based Nanomaterials for Ocular Drug Delivery: A Perspective

Ocular drug delivery is one of the most challenging issues in ophthalmology because of the complex physiological structure of the eye. Polysaccharide-based nanomaterials have been extensively investigated in recent years as ideal carriers for enhancing the bioavailability of drugs in the ocular system because of their biocompatibility and drug solubilization. From this perspective, we discuss the structural instability of polysaccharides and its impact on the synthesis process; examine the potential for developing bioactive polysaccharide-based ocular drug nanocarriers; propose four strategies for designing novel drug delivery nanomaterials; and suggest reviewing the behavior of nanomaterials in ocular tissues.

Therapies Based on Nanoparticles for Eye Drug Delivery

Eye drug delivery, particularly to the retina, is a technical hurdle that needs to be solved and represents an ongoing current important medical field. Posterior segment eye diseases are a major cause of visual impairment worldwide. Age-related macular degeneration, glaucoma, and diabetic retinopathy are the major causes of blindness. To achieve efficient drug delivery and drug retention time in the posterior segment of the eye, novel delivery systems based on nanoparticles have been developed in the last few years. Nowadays, liposomes represent the most utilized nanoparticles for eye drug delivery and, recently, a broad spectrum of diverse nanoparticles continue to emerge with special characteristics representing ideal candidates for eye drug delivery.