Ocular Drug Research Articles

Nano-based ocular drug delivery systems: an insight into the preclinical/clinical studies and their potential in the treatment of posterior ocular diseases.

Numerous novel nano-based ocular drug delivery systems have been developed to overcome the limitations of conventional drug delivery systems, which have demonstrated promising results in ocular disease models and clinical practice. Of all the nano-based drug delivery systems approved or under clinical investigation, topical instillation of eye drops is the most common route for administering therapeutics to the eye. Although this pathway is a viable way of ocular drug delivery to treat many ocular diseases because of its potential to eliminate the risks of intravitreal injection and the toxicity of systemic drug delivery, it remains a major challenge to efficiently treat posterior ocular diseases through topical administration of eye drops. So far, relentless efforts have been dedicated to the development of novel nano-based drug delivery systems with the aim of possible clinical translation. They are designed or modified to facilitate drug delivery to the retina by increasing the retention time, promoting drug penetration across barriers, and targeting specific cells or tissues. In this paper, we provided a snapshot of nano-based drug delivery systems that are currently marketed and under investigation in clinical trials for the treatment of ocular diseases and highlighted some examples of recent preclinical research on novel nano-based systems as eye drops to the posterior segment of the eye.

Management of Sjogren’s Dry Eye Disease—Advances in Ocular Drug Delivery Offering a New Hope

Sjögren's syndrome is a chronic and insidious autoimmune disease characterized by lymphocyte infiltration of exocrine glands. Patients typically present with dry eye, dry mouth, and other systemic manifestations. Currently, the available molecules and drug-delivery systems for the treatment of Sjögren's syndrome dry eye (SSDE) have limited efficacy since they are not specific to SSDE but to dry eye disease (DED) in general. The current treatment modalities are based on a trial-and-error approach using primarily topical agents. However, this approach gives time for the vicious cycle of DED to develop which eventually causes permanent damage to the lacrimal functional unit. Thus, there is a need for more individualized, specific, and effective treatment modalities for SSDE. The purpose of this article is to describe the current conventional SSDE treatment modalities and to expose new advances in ocular drug delivery for treating SSDE. A literature review of the pre-clinical and clinical studies published between 2016 and 2022 was conducted. Our current understanding of SSDE pathophysiology combined with advances in ocular drug delivery and novel therapeutics will allow the translation of innovative molecular therapeutics from the bench to the bedside.

Short-term outcomes of micropulse transscleral cyclophotocoagulation as a primary versus additional therapy in eyes with uncontrolled glaucoma.

To study the safety and efficacy outcomes of Micropulse Transscleral Cyclophotocoagulation (MP-TSCPC) as a primary versus additional therapy in eyes with uncontrolled glaucoma. This was a prospective, interventional, comparative study. All patients with advanced and refractory glaucoma treated with MP-TSCPC from April 2020 to December 2020 were recruited in this study. A total of 77 eyes of 77 patients were analyzed. Group A (n = 33), included patients with advanced glaucoma at high risk for invasive surgery, who underwent MP-TSCPC as the primary intervention, and group B (n = 44) included patients who had undergone previous surgical intervention and MP-TSCPC was used additionally to control the intraocular pressure (IOP). Mean IOP and mean number of antiglaucoma medications were 34.06 (13.9) mmHg and 3.64 (0.7), respectively, in group A and 35.61 (11.5) mmHg and 3.73 (0.9), respectively, in Group B. Postoperatively, the mean IOP and percentage of IOP reduction were significantly lower at 1, 3, and 6 months, that is, 20.78 (32%), 22.07 (30%), and 19.09 (37%), respectively, in group A and 23.68 (35%), 19.50 (44%), and 19.61 (42%), respectively, in group B, but there was no difference between the groups at all visits. Postoperative need for ocular hypotensive drugs did not differ in group A (P = 0.231); however, it was significantly lower in group B (P = 0.027). Group A had 87%, 77%, and 74% success rates at 1, 3, and 6 months, respectively, whereas group B had 91%, 86%, and 77% success rates at 1, 3, and 6 months, respectively. Postoperative complications and intervention did not reveal any statistical difference between the two groups. MP-TSCPC may be considered as a temporizing measure both as a primary or as an additional intervention to control the IOP in eyes with refractory and advanced glaucoma that have a high risk of vision-threatening complications with invasive surgery.

Exploring the advancement of polymer-based nano-formulations for ocular drug delivery systems: an explicative review

Exploring the advancement of polymer-based nano-formulations for ocular drug delivery systems: an explicative review

Design and Evaluation of Solid Lipid Nanoparticle Eye Drops Containing VRN for Ocular Drug Delivery

As a well-known oral and intravenous antifungal, voriconazole (VRN) has an extensive history of usage in the medical field. Solid lipid nanoparticles (SLNs) have been produced to treat ocular fungal keratitis in the eye. A 32Box-behnken design was used to produce a variety of new formulas for hot-melt extrusion. The SLNs were evaluated by entrapment efficiency (EE percent), particle size (PS), polydispersity index (PDI), and zeta potential (ZP). A series of in-vitro and in-vivo studies were carried out on the new formula. The produced vesicles’ EE, PS, PDI, and ZP values were all good. SLNs eye drops were numerically adjusted to include carbopol, a stabilizer, lipids, and a surfactant, among other substances. ZP of -36.5 ± 0.20 mV, 80.9 ± 1.02 % EE, 205 ± 9.1 nm PS, and 0.015 PDI were all included in the data. For example, by differential scanning calorimetry (DSC) and fourier-transform infrared (FTIR), it was discovered that the crystallinity of the drug had been reduced. The in-vitro release study and the SLNs and carbopol-based eye drops prepared with ultrasonication method demonstrated sustained release up to 48 hours. Comparing VRN-SLNs pharmacokinetics to that of pure drug solution, researchers discovered an area under the curve (AUC) and Cmax three times higher and a factor of five times higher, respectively (both P 0.01). By functioning as a carrier, SLNs may increase the bioavailability of VRN in the eye. The in-vivo studies were performed by infecting the rats with candida species. It was observed that VRN-loaded SLNs eye drops were more efficient in treating candidiasis. Results indicate that VRN-loaded SLNs eye drops provide a sustaining VRN topical effect and quick relief from fungal infection.

Polydopamine-based nanospheres as nanoplatforms to kill Staphylococcus aureus and to promote wound healing by photothermal therapy.

Bacterial infections have always been a threat when it comes to public health accounting for increased morbidity and mortality rates around the world. For the first time, Polydopamine is often used as an ocular surface drug delivery medium to treat some ocular surface diseases based on its good tissue affinity. Mesoporous polydopamine nanospheres (MPDA NPs) under photothermal therapy (PTT) are demonstrated as efficient therapeutic nanoplatforms for Staphylococcus aureus (S. aureus) infection and wound healing. MPDA NPs were found to exhibit excellent photothermal performance, significantly causing an increase in temperature within a short period of NIR-I exposure (808nm, 1Wcm-2, 6min). The MPDA NPs under the NIR irradiation remarkably eliminated S. aureus in vitro. Moreover, these synergistic effects turnouts to be phenomenal in vivo, effectively killing and healing S. aureus-infected abscesses in mice. These revealed the combined effect of the intrinsic antibacterial activity of MPDA NPs enhanced upon NIR-I exposure. Hence, MPDA NPs under NIR-I could prove excellent therapeutic nanoplatforms for bacteria-related infections and other biomedical applications.

Microfluidic contact lenses for ocular diagnostics and drug delivery

AbstractThe human eye and tear provide essential physiological information for the detection of ocular dysfunctions and therapy monitoring. The measurements of biomarkers in tear composition are critical for disease diagnosis and early interventions. Hence, significant efforts are dedicated to the development of functional contact lenses that can quantify tear analytes and ocular physiological condition. The combination of microfluidics and contact lens technologies offer real‐time monitoring of ocular physiology and timely detection of eye disorders through wireless components. This review discusses the fundamentals of microfluidic contact lenses and their diverse applications in ophthalmic diagnostics and drug delivery. It also elucidates the strategies for the commercialization of microfluidic contact lenses to create clinical and point‐of‐care products.

Framework Nucleic Acids as Blood-Retinal-Barrier-Penetrable Nanocarrier for Periocular Administration.

Designing an ocular drugs delivery system that can permeate the outer blood-retinal barrier (oBRB) is crucial for the microinvasive or noninvasive treatment of ocular fundus diseases. However, due to the lack of a nanocarrier that can maintain structure and composition at the oBRB, only intravitreal injection at the eyeball can deliver therapeutics directly to the ocular fundus via paracellular and intercellular routes, despite the intraocular operations risks. Here, we demonstrated tetrahedral framework nucleic acids (tFNAs) can penetrate the oBRB and deliver therapeutic nucleic acids to the retina of the rat eye in vivo following subconjunctival injection. We also discovered that tFNAs were transported via a paracellular route across the intercellular tight junctions at the oBRB. The histology analysis for ocular layers indicated that individual and aptamer/doxorubicin-loaded tFNAs penetrated all layers of the posterior segment of the eyeball to reach the innermost retina and persisted for over 3 days with minimal systemic biodistribution. We expect that the programmability and penetrability of tFNAs will provide a promising method for drug delivery across oBRB and long-term sustenance at the target site via periocular administration to various tissues.

DCZ19931, a novel multi-targeting kinase inhibitor, inhibits ocular neovascularization

Neovascularization is a prominent cause of irreversible blindness in a variety of ocular diseases. Current therapies for pathological neovascularization are concentrated on the suppression of vascular endothelial growth factors (VEGF). Despite the remarkable efficacy of anti-VEGF drugs, several problems still exist, including ocular complications and drug resistance. Thus, it is still required to design novel drugs for anti-angiogenic treatment. This study aimed to investigate the anti-angiogenic effects of a small molecule multi-target tyrosine kinase inhibitor, DCZ19931, on ocular neovascularization. The results showed that administration of DCZ19931 at the tested concentrations did not cause obvious cytotoxicity and tissue toxicity. DCZ19931 could reduce the size of choroidal neovascularization (CNV) lesions in laser-induced CNV model and suppress ocular neovascularization in oxygen-induced retinopathy (OIR) model. DCZ19931 could suppress VEGF-induced proliferation, migration, and tube formation ability of endothelial cells, exhibiting similar anti-angiogenic effects as Ranibizumab. DCZ19931 could reduce the levels of intercellular cell adhesion molecule-1 (ICAM-1) expression in vivo and in vitro. Network pharmacology prediction and western blots revealed that DCZ19931 exerted its anti-angiogenic effects through the inactivation of ERK1/2-MAPK signaling and p38-MAPK signaling. In conclusion, this study indicates that DCZ19931 is a promising drug for anti-angiogenic therapy for ocular diseases.

Both non-coated and polyelectrolytically-coated intraocular collagen-alginate composite gels enhanced photoreceptor survival in retinal degeneration

Treatments of vision-threatening retinal diseases are often hampered by drug delivery difficulties. Polyelectrolytically-coated alginate encapsulated-cell therapy (ECT) systems have shown therapeutic efficacy through prolonged in vivo drug delivery but still face various biocompatibility, viability, drug delivery and mechanical stability issues in clinical trials. Here, novel, injectable alginate-poly-l-lysine (AP)-coated composite alginate-collagen (CAC) ECT gels were developed for sustained ocular drug delivery, and their long-term performance was compared with non-coated CAC ECT gels. All optimised AP-coated gels (AP1- and AP5.5-CAC ECT: 2 mg/ml collagen, 1.5% high molecular weight alginate, 50,000 cells/gel, with 0.01% or 0.05% poly-l-lysine coating for 5 min, followed by 0.15% alginate coating) and non-coated gels showed effective cell proliferation control, cell viability support and continuous delivery of bioactive glial cell-derived neurotrophic factor (GDNF) with no significant gel degradation in vitro and in rat vitreous. Most importantly, intravitreally injected gels demonstrated therapeutic efficacy in Royal College of Surgeons rats with retinal degeneration, resulting in reduced photoreceptor apoptosis and retinal function loss. At 6 months post-implantation, no host-tissue attachment or ingrowth was detected on the retrieved gels. Non-coated gels were mechanically more stable than AP5.5-coated ones under the current cell loading. This study demonstrated that both coated and non-coated ECT gels can serve as well-controlled, sustained drug delivery platforms for treating posterior eye diseases without immunosuppression.

Viability studies of hydrogel contact lens on a 3D printed platform as ocular drug delivery carrier for diabetic retinopathy

Diabetic retinopathy (DR) is a microvascular disease that damages retinal layers. Avastin loaded PHEMA hydrogel lens as a topical implant is presented here for DR therapy. The lens is fabricated upon a novel, cost-effective and simple to design 3D printed platform. It has contours similar to a commercial contact lens for patient comfort and added characteristics of a drug delivery vehicle. The lens swelling properties are comparable to the commercial lens. The percentage of cumulative drug released between 0 and 1500 min is 60 %, and the release kinetics follows the Korsmeyer- Pappas (KP) release model with 40–60% anti-VEGF effects.

Chitosan/dialdehyde starch hybrid in situ forming hydrogel for ocular delivery of betamethasone

Ocular drug therapy remains to be a major pharmaceutical challenge due to the presence of ocular barriers. The development of novel ophthalmic delivery systems is an immense necessity to overcome such biological and physiological barriers. Hydrophilic gels are considered an ideal candidate for such purposes owing to their favorable characteristics such as rapid in situ gelation, biodegradability, biocompatibility, and high encapsulation capacity. In the current study, we report on the development of an in situ forming composite hydrogel formulated using natural polymers, including dialdehyde starch (DAS) and chitosan (CS), to deliver betamethasone to the eye. The modification of starch and composite hydrogel structure was evaluated by FT-IR spectroscopy. The effect of the different ratios of CS to DAS on the gelation time, surface microstructure morphology, swelling ratio, rheological behavior, and in vitro degradation was evaluated. Our findings demonstrated that the high content of DAS could result in fast gelation, improved mechanical strength, larger pore size, and optimized degradation with a fast in vitro and ex vivo release rate. Furthermore, the developed composite hydrogel displayed excellent biocompatibility in cell models in vitro. Altogether, the obtained data suggest that the developed hydrogel-based delivery system could be well suited for local administration of betamethasone to control ocular inflammation and consequent complications.

Ex vivo model for the measurement of intraocular pressure and force of injection during the administration of hollow microneedles in porcine sclera

AbstractPurpose: The current gold standard treatment option for posterior segment diseases such as age‐related macular degeneration is the delivery of drug into the vitreous cavity by intravitreal injection. This method is, however, associated with several issues including low patient compliance and the risk of adverse effects [1]. Microneedles (MNs), designed to deliver their payload into the sclera, offer a minimally invasive means of providing localized drug delivery to the eye, providing a potentially more patient‐friendly alternative. MNs for ocular drug delivery have gained significant interest in recent years; however, for clinical acceptability, safe values for parameters such the injection force and changes in intraocular pressure (IOP) are critical. This work investigated the effects that changing MN design parameters (e.g., bevel angle, needle length and needle gauge) had on both the force of penetration (FoP) and depth of penetration (DoP) achieved in ex vivo porcine sclera at clinically relevant locations. The model used a pressure transducer to allow for real‐time monitoring of IOP over the injection procedure.Methods: Stainless steel hollow microneedles (ssHMNs) were fabricated from conventional hypodermic needles, with a range of bevel angles (30–75°) cut in triplicate using Wire Electrical Discharge Machining. Needle heights were adjusted as required using 3D‐printed adapters. To assess FoP and DoP, ssHMNs were inserted into ex vivo porcine sclera with images being captured using optical coherence topography. IOP changes during the injection procedure were monitored in real‐time using a pressure transducer.Results: ssHMNs were shown to partially penetrate the ex vivo porcine sclera. Average values obtained for FoP and DoP were shown to be dependent on sclera location. Peak IOP values were observed upon scleral penetration, with these being lower with smaller needle sizes. Similarly, average FoP values were found to decrease for higher gauge needles and smaller bevel angles.Conclusions: This work demonstrates the effects of changing design parameters of ssHMNs on the FoP and DOP achieved in ex vivo porcine sclera, as well as changes in IOP.Reference1. “Stimuli sensitive ocular drug delivery systems,” in Drug Targeting and Stimuli Sensitive Drug Delivery Systems, 2018, pp. 211–270.

Novel episcleral implants of sunitinib can depress ocular neovascularization under ex‐vivo conditions

AbstractBackground: Current management of posterior segment disease such as Age‐related Macular degeneration (AMD) and Diabetic Macular Edema (DME) is by monthly Intravitreal injections of Anti‐VEGF agents (IVT). IVT therapy suffers from various serious drawbacks such as highly invasive procedure and risk of ocular tissue damage. Moreover, Lower response rate of Anti‐VEGF agents in patients also demands development of novel alternative therapies. One of the major challenge of posterior segment drug delivery is selection of suitable in‐vivo models for pharmacokinetic and therapeutic screening due to highly localized nature of eye leading limited choices animals that resemble human ocular anatomy. Hence we aim to novel episcleral implant platform for posterior segment drug delivery along with using suitable ex‐vivo assays for therapeutic estimation of developed drug delivery systems.Methods: The Implants loaded with sunitinib malate were fabricated using a polymeric blend of gelatin and polyglycerol sebacate (PGS) by electrospinning technique. The effect of polymer blending and drug loading on morphology and in‐vitro drug release profile by scanning electron microscopy and shaking incubator drug release method. Further, the effect of electrospinning and polymer blending on mucoadhesion was studied by mucin agar plate method. Transscleral drug permeation and the secondary depot formation of sunitinib following episcleral application were studies Franz diffusion cell experiment. The biocompatibility of implant was tested on ARPE‐19 cells and the effect of treatment on cell morphology was studied by crystal violet staining. The therapeutic efficacy of episcleral implants was tested by ex‐vivo choroidal angiogenesis assay.Results: The electrospinning process lead to development of highly porous and flexible implants. It was found that polymer blending has profound effect on the morphology as well as in vitro drug release of implants. The addition of PGS lead to thinner fibres within implant and it also lead to sustained release of sunitinib over the period of one week. The drug loading did not has proficient effect on the morphology of implants; however, higher loading lead to sustained release of sunitinib over the release period. The electrospinning process lead to enhanced mucoadhesion that could possibly due to increased surface area and improved contact angle. The implants were found to be biocompatible and did not alter the morphology of ARPE‐19 cells upon treatment as observed by crystal violet staining. The drug release samples of implants in cell culture media were tested upon ex‐vivo rat choroidal angiogenesis assay where it was observed that the release samples were able to suppress the ocular neovascularization significantly when compared with untreated samples.Conclusions: We can conclude that sunitinib loaded episcleral implants could be a promising alternative for management of disease with posterior segment neovascularization such as AMD and DME. The polymer blending of different polymers along with electrospinning technique could aid in development of novel episcleral implants with sustained release of medicinal agents. The electrospun implant platform could also be used for anterior segment drug delivery as well. Finally ex‐vivo rat choroidal angiogenesis assay could be a great tool for therapeutic screening of ocular drug delivery systems.

Micellar solutions of Pluronic F127 for ocular drug delivery

AbstractThe goal of this research was to prepare drug‐encapsulated polymeric micelles for delivery to the posterior segment of the eye. Solutions of surface active PF127 at the critical micellar concentration (CMC) were prepared in deionized water (DI water) and phosphate buffer (PBS). The CMC of PF127 solution in DI water and PBS solution were found to 0.21 ± 0.04 and 0.16 ± 0.05% (w/v), respectively. In addition, the micellization of the PF127 was observed around 25 and 21°C in DI water and PBS solution, respectively by DSC analysis. The hydrodynamic diameter of the PF127 micelles were found to range between 3 and 4 nm with polydispersity indices ranging between 0.35 ± 0.22 and 0.96 ± 1.52.Curcumin (CUR), a natural dietary compound having an anti‐VEGF properties, was successfully loaded into PF127 copolymers by the thin‐film hydration method. The CUR‐loaded PF127 micelles were confirmed by several characterization techniques including DLS and HPLC. A detailed study of the effect of experimental conditions on both the particle size and drug encapsulation efficiency (%EE) of the CUR micelles was also carried out. CUR‐loaded PF127 micelles with small particle sizes (around 15 nm, PDI = 0.19 ± 0.13) and %EE around 10% were observed at high centrifugation speed. Also, increasing the copolymer‐to‐drug ratio resulted in higher %EE (>90%). Additionally, the CUR‐loaded PF127 micelles were easy to reconstitute in water by manual shaking after lyophilization. These results suggest that PF127 micelles are a promising carrier for delivery of CUR to the eye. Future work will study in more detail about the physicochemical properties and the ability of these micelles to transport CUR across ocular barriers in ex vivo and in vivo trials.

OCULAR DRUG DELIVERY SYSTEMS: AN OVERVIEW

The treatment for the ophthalmic diseases are topical route because of the various ocular barrier. Ocular drug delivery systems are considered as major challenges by today’s pharmacologist and formulation scientist. Topical eye drop is the most convenient and patient compliant route of drug administration, especially for the treatment of anterior segment diseases. tissues. In the past two decades, ocular drug delivery research acceleratedly advanced towards developing a novel, safe and patient compliant formulation and drug delivery techniques, which may surpass these barriers and maintain drug levels in tissues. There are many eye ailments which affected to eye and one can loss the eye sight also. Therefore, many ophthalmic drug delivery systems are available. These are classified as conventional and non- conventional (newer) drug delivery systems. Most commonly available ophthalmic preparations are eye drops and ointments about 70% of the eye dosage formulations in market. So overcome to these problems newer pharmaceutical ophthalmic formulation such as in-situ gel, nanoparticle, liposome, nanosuspension, microemulsion, intophoresis and ocular inserts have been developed in last three decades increase the bioavailability of the drug as a sustained and controlled manner.

Controlling the Adsorption and Release of Ocular Drugs in Metal-Organic Frameworks: Effect of Polar Functional Groups.

A series of UiO-66 materials with different functional groups (-H, -NH2, and -NO2) have been evaluated for the adsorption and release of a common ocular drug such as brimonidine tartrate. UiO-66 samples were synthesized under solvothermal conditions and activated by solvent exchange with ethanol. Experimental results suggest that the incorporation of surface functionalities gives rise to the development of structural defects (missing linker defects) but without altering the basic topology of the UiO-66 framework. These defects improve the adsorption performance of the parent metal-organic framework (MOF), while the bulkier functionalities infer slower release kinetics, with the associated benefits for prolonged delivery of brimonidine. Among the evaluated MOFs, defective UiO-66-NO2 can be proposed as the most promising candidate due to the combination of a larger brimonidine volumetric uptake (680 mg/cm3), a prolonged delivery (period of up to 25 days), a small particle size, and a larger instability. Contrariwise, at high concentrations UiO-66-NO2 has higher toxicity toward human retinal pigment epithelium cells (ARPE-19) compared to the pure and NH2-functionalized UiO-66.

Maleimide-Decorated PEGylated Mucoadhesive Liposomes for Ocular Drug Delivery.

Liposomes are promising spherical vesicles for topical drug delivery to the eye. Several types of vesicles were formulated in this study, including conventional, PEGylated, and maleimide-decorated PEGylated liposomes. The physicochemical characteristics of these liposomes, including their size, zeta potential, ciprofloxacin encapsulation efficiency, loading capacity, and release, were evaluated. The structure of these liposomes was examined using dynamic light scattering, transmission electron microscopy, and small angle neutron scattering. The ex vivo corneal and conjunctival retention of these liposomes were examined using the fluorescence flow-through method. Maleimide-decorated liposomes exhibited the best retention performance on bovine conjunctiva compared to other types of liposomes studied. Poor retention of all liposomal formulations was observed on bovine cornea.

Corneal endothelial protection during manual small-incision cataract surgery: A narrative review.

Cataract causes bilateral blindness in 20 million people globally, the vast majority of whom live in developing countries. Manual small-incision cataract surgery (MSICS) has emerged as an efficient and economical alternative to phacoemulsification, giving comparable results in terms of final visual gain. One of the important determinants of postoperative visual gain is the status of the corneal endothelium. Multiple factors such as corneal distortion, irrigation solution turbulence, mechanical trauma by instruments, nuclear fragments, intraocular lens contact, and free oxygen radicals, all have been implicated in causing corneal damage during cataract surgery. MSICS with posterior chamber intraocular lens implantation has been reported to cause an endothelial cell loss of 15.83%, which is comparable with other modes of cataract surgery like extracapsular cataract extraction and phacoemulsification. Thorough preoperative assessment of endothelial status and taking necessary steps for endothelial protection during surgery can decrease the endothelial cell loss and overall burden of pseudophakic bullous keratopathy. In addition to surgical techniques, the type of irrigating solutions, ocular viscoelastic devices, intracameral dyes, and drugs all affect the endothelial cell status. This review presents a summary of available literature on the protection of endothelial cells during different steps of MSICS. This is especially relevant for developing countries where large-scale MSICS cataract surgeries are performed to decrease the cataract blindness burden.

Nanogel Development and its Importance in Ophthalmic Drug Delivery System

Background: The current review focuses on ophthalmic nanogels, their applications, their benefits over traditional gels, and the challenges and opportunities of nanogels. The major goal is to investigate ophthalmic nanogels from preparation through characterization and how nanogels are the future of the ophthalmic drug delivery system compared to traditional gels, eye drops, and ointments. Objective: Because of the ophthalmic bioavailability, delivery to the eye is crucial. The lacrimal flu-id in the eye clears the eye surface, and the ocular sight is washed away as a result of this medicine. The limited ocular bioavailability was also due to the different obstacles present. Drug nano-gelling systems are effective in improving ocular bioavailability and corneal permeation time. Nanoparti-cles abound in these nanogels. Various natural polymers, such as Chitosan and Alginate, and syn-thetic polymers, such as PLA and PLGA, can be used to make nanogels. The use of nanotechnology improves medicine bioavailability and penetration in the eye. However, nanotechnology has some limits, such as large-scale manufacturing, restricting medicine doses, and so forth. Conclusion: Nanotechnology offers much clinical potential when it comes to treating eye issues. Although ophthalmic nanogels are suited for effective drug delivery, they must meet several re-quirements. First, the drug component must be encapsulated adequately in a stable polymer com-plex. In ocular drug delivery, nanogels are a preferable option since they can improve patient com-pliance and therapeutic impact. In addition, the nanogel has a faster corneal penetration time and higher bioavailability.