Formulation Development, Optimization, and In Vitro–In Vivo Characterization of Natamycin-Loaded PEGylated Nano-Lipid Carriers for Ocular Applications

Nanomicelles empower natamycin in treating fungal keratitis: An in vitro, ex vivo and in vivo study

Fungal infections of cornea are important causes of blindness especially in developing nations with tropical climate. However, the challenges associated with current treatments are responsible for poor outcome. Natamycin is the only FDA-approved antifungal drug to treat fungal keratitis, but unfortunately due to its poor water solubility, it is available as suspension. The marketed suspension (5% Natamycin) has rapid precorneal clearance, poor corneal permeability, a higher frequency of administration, and corneal irritation due to undissolved suspended drug particles. In our study, we developed clear and stable natamycin-loaded nanomicelles (1% Natcel) to overcome the above challenges. We demonstrated that 1% Natcel could permeate the cornea better than 5% suspension. The developed 1% Natcel was able to provide sustained release for up to 24 h. Further, it was found to be biocompatible and also improved the mean residence time (MRT) than 5% suspension in tears. Therefore, the developed 1% Natcel could be a potential alternative treatment for fungal keratitis.

Novel Drug Delivery Systems for the Management of Fungal Keratitis

Fungal keratitis (FK) is a dangerous corneal infection that is common in tropical and subtropical areas. Its incidence is extremely high, and ocular trauma and contact lenses can lead to FK, but its common treatment such as using topical antifungal eye drop instillation is often less effective because of several drawbacks of the drugs typically used, including limited ocular penetration, high frequency of dosing, poor biocompatibility, and the potential for severe drug reactions. Therefore, the development of novel drug delivery devices for the treatment of FK is urgent. The urgent need for novel drug delivery devices to treat FK has led to the development of several techniques, including nanoparticles (NPs), in situ forming hydrogels, contact lenses, and microneedles (MNs). However, it is important to note that the main mechanisms differ between these techniques. NPs can transport large amounts of drugs and be taken up by cells owing to their large surface area and small size. In situ forming hydrogels can significantly extend the residence time of drugs because of their strong adhesive properties. Contact lenses, with their comfortable shape and drug-carrying capacity, can also act as drug delivery devices. MNs can create channels in the cornea, bypassing its barrier and enhancing drug bioavailability. This article will go over novel medication delivery techniques for treating FK and make a conclusion about their advantages and limitations in anticipation to serve the best option for the individual therapy of FK.

Novel nanomicelle butenafine formulation for ocular drug delivery against fungal keratitis: In Vitro and In Vivo study

Fungal keratitis (FK) is a serious infectious corneal disease that leads to blindness. Butenafine (BTF) is an allylamine drug with high antifungal activity, but its poor water solubility and low bioavailability limit its clinical application in ophthalmology. To increase its aqueous solubility and corneal permeability, butenafine was encapsulated in d-ɑ-tocopheryl polyethylene glycol succinate (TPGS) polymeric nanomicelles to improve the bioavailability of the drug for the treatment of FK. Butenafine was successfully fabricated into nanomicelles with a high EE of 96.34 ± 1.65 % and DL of 6.71 ± 0.099 %. The BTF-NM showed an average particle size of 13.12 ± 0.24 nm, a zeta potential of -0.56 ± 0.44 mV and a narrow PDI of 0.12 ± 0.02 with a nearly spherical shape. The characterization results of FTIR, XRD and DSC indicated that BTF was encapsulated in the TPGS nanomicelles. The BTF-NM formulation also showed high storage stability, and the in vitro drug release study showed typical biphasic-release characteristics. In addition, the BTF-NM formulation displayed good cellular tolerance and excellent ocular tolerance in rabbits. Significantly elevated in vitro antifungal activity was also observed in the BTF-NM formulation, and remarkable improvements regarding in vivo corneal permeation were observed compared with the BTF suspension formulation. Finally, the in vivo antifungal activity studies indicated that the BTF-NM formulation had a good therapeutic effect on FK and had similar efficacy to that of commercial natamycin suspension eye drops. These results suggest that the BTF-NM ophthalmic formulation could be a promising ocular drug delivery system for the treatment of FK.

Improved Topical Ophthalmic Natamycin Suspension for the Treatment of Fungal Keratitis

Purpose: Natamycin (NT) is used as a first-line antifungal prescription in the treatment of fungal keratitis (FK) and is commercially available as a 5% w/v ophthalmic suspension. NT shows poor water solubility and light sensitivity. Thus, the present investigation is aimed to enhance the fraction of NT in solution in the commercial formulation by adding cyclodextrins (CDs), thereby improving the delivery of the drug into deeper ocular tissues. Methods: The solubility of NT in different CDs, the impact of ultraviolet (UV) light exposure, stability at 4°C and 25°C, in vitro release, and ex vivo transcorneal permeation studies were performed. Results: NT exhibited the highest solubility (66-fold) in randomly methylated-β-cyclodextrin (RM-βCD) with hydroxypropyl-βCD (HP-βCD) showing the next highest solubility (54-fold) increase in comparison to market formulation Natacyn® as control. The stability of NT-CD solutions was monitored for 2 months (last-time point) at both storage conditions. The degradation profile of NT in NT-RM-βCD and NT-HP-βCD solutions under UV-light exposure followed first-order kinetics exhibiting half-lives of 1.2 h and 1.4 h, respectively, an almost 3-fold increase over the control solutions. In vitro release/diffusion studies revealed that suspensions containing RM-βCD and HP-βCD increased transmembrane flux significantly (3.1-fold) compared to the control group. The transcorneal permeability of NT from NT-RM-βCD suspension exhibited an 8.5-fold (P < 0.05) improvement compared to Natacyn eyedrops. Furthermore, the addition of RM-βCD to NT suspension increases the solubilized fraction of NT and enhances transcorneal permeability. Conclusion: Therefore, NT-RM-βCD formulations could potentially lead to a decreased frequency of administration and significantly improved therapeutic outcomes in FK treatment.

Recent advances in nanotechnology for the treatment of fungal keratitis

Fungal keratitis (FK) is a serious pathogenic disease usually associated with serious ocular complications. The current mainstay of treatment for FK is topical eye drops; however, poor corneal penetration, low bioavailability of the drug and the need to administer high and frequent doses due to the presence of an effective clearance mechanism in the eye result in poor patient compliance. Nanocarriers can extend the duration of drug action through sustained and controlled release of the drug, protect the drug from ocular enzymes and help overcome ocular barriers. In this review, we discussed the mechanisms of action of antifungal drugs, the theoretical basis for the treatment of FK, and recent advances in the clinical treatment of FK. We have summarized the results of research into the most promising nanocarriers for ocular drug delivery and highlight their efficacy and safety in the therapy.

Nanomedicine for the Detection and Treatment of Ocular Bacterial Infections

Ocular bacterial infection is a prevalent cause of blindness worldwide, with substantial consequences for normal human life. Traditional treatments for ocular bacterial infections areless effective, necessitating the development of novel techniques to enable accurate diagnosis, precise drug delivery, and effective treatment alternatives. With the rapid advancement of nanoscience and biomedicine, increasing emphasis has been placed on multifunctional nanosystems to overcome the challenges posed by ocular bacterial infections. Given the advantages of nanotechnology in the biomedical industry, it can be utilized to diagnose ocular bacterial infections, administer medications, and treat them. In this review, the recent advancements in nanosystems for the detection and treatment of ocular bacterial infections are discussed; this includes the latest application scenarios of nanomaterials for ocular bacterial infections, in addition to the impact of their essential characteristics on bioavailability, tissue permeability, and inflammatory microenvironment. Through an in-depth investigation into the effect of sophisticated ocular barriers, antibacterial drug formulations, and ocular metabolism on drug delivery systems, this review highlights the challenges faced by ophthalmic medicine and encourages basic research and future clinical transformation based on ophthalmic antibacterial nanomedicine.

Design and Optimization of Solid Lipid Nanoparticles Loaded with Triamcinolone Acetonide

Principles of quality by design and design of experiments are acquiring more importance in the discovery and application of new drug carriers, such as solid lipid nanoparticles. In this work, an optimized synthesis of solid lipid nanoparticles loaded with Triamcinolone Acetonide is presented using an approach that involves Stearic Acid as a lipid, soy PC as an ionic surfactant, and Tween 80 as a nonionic surfactant. The constructed circumscribed Central Composite Design considers the lipid and nonionic surfactant quantities and the sonication amplitude in order to optimize particle size and Zeta potential, both measured by means of Dynamic Light Scattering, while the separation of unentrapped drug from the optimized Triamcinolone Acetonide-loaded solid lipid nanoparticles formulation is performed by Size Exclusion Chromatography and, subsequently, the encapsulation efficiency is determined by HPLC-DAD. The proposed optimized formulation-with the goal of maximizing Zeta potential and minimizing particle size-has shown good accordance with predicted values of Zeta potential and dimensions, as well as a high value of encapsulated Triamcinolone Acetonide. Experimental values obtained from the optimized synthesis reports a dimension of 683 ± 5 nm, which differs by 3% from the predicted value, and a Zeta potential of -38.0 ± 7.6 mV (12% difference from the predicted value).

Formulation and processing of solid self-emulsifying drug delivery systems (HME S-SEDDS): A single-step manufacturing process via hot-melt extrusion technology through response surface methodology

The objective of the current study is the formulation development and manufacturing of solid self-emulsifying drug delivery systems (HME S-SEDDS) via a single-step continuous hot-melt extrusion (HME) process. For this study, poorly soluble fenofibrate was selected as a model drug. From the results of pre-formulation studies, Compritol® HD5 ATO, Gelucire® 48/16, and Capmul® GMO-50 were selected as oil, surfactant and co-surfactant respectively for manufacturing of HME S-SEDDS. Neusilin® US2 was selected as a solid carrier. The design of experiments (response surface methodology) was employed to prepare formulations via a continuous HME process. The formulations were evaluated for emulsifying properties, crystallinity, stability, flow properties and drug release characteristics. The prepared HME S-SEDDS showed excellent flow properties, and the resultant emulsions were stable. The globule size of the optimized formulation was 269.6 nm. The DSC and XRD studies revealed the amorphous nature of the formulation and FTIR studies showed no significant interaction between fenofibrate and excipients. The drug release studies showed significant (p < 0.05) improvement in solubility compared to the pure drug (DE15 = 45.04 for the optimized formulation), as >90% of drug release was observed within 15 min. The stability studies for the optimized formulation were conducted for 3 months at 40 °C/75% RH.

Recent Progress of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers as Ocular Drug Delivery Platforms

Sufficient ocular bioavailability is often considered a challenge by the researchers, due to the complex structure of the eye and its protective physiological mechanisms. In addition, the low viscosity of the eye drops and the resulting short ocular residence time further contribute to the observed low drug concentration at the target site. Therefore, various drug delivery platforms are being developed to enhance ocular bioavailability, provide controlled and sustained drug release, reduce the number of applications, and maximize therapy outcomes. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) exhibit all these benefits, in addition to being biocompatible, biodegradable, and susceptible to sterilization and scale-up. Furthermore, their successive surface modification contributes to prolonged ocular residence time (by adding cationic compounds), enhanced penetration, and improved performance. The review highlights the salient characteristics of SLNs and NLCs concerning ocular drug delivery, and updates the research progress in this area.

Novel Drug Delivery Systems to Improve the Treatment of Keratitis

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

Development of α-Tocopherol Succinate-Based Nanostructured Lipid Carriers for Delivery of Paclitaxel

The management of retinoblastoma (RB) involves the use of invasive treatment regimens. Paclitaxel (PTX), an effective antineoplastic compound used in the treatment of a wide range of malignant tumors, poses treatment challenges due to systemic toxicity, rapid elimination, and development of resistance. The goal of this work was to develop PTX-loaded, α-tocopherol succinate (αTS)-based, nanostructured lipid carrier (NLCs; αTS-PTX-NLC) and PEGylated αTS-PTX-NLC (αTS-PTX-PEG-NLC) to improve ocular bioavailability. The hot homogenization method was used to prepare the NLCs, and repeated measures ANOVA analysis was used for formulation optimization. αTS-PTX-NLC and αTS-PTX-PEG-NLC had a mean particle size, polydispersity index and zeta potential of 186.2 ± 3.9 nm, 0.17 ± 0.03, −33.2 ± 1.3 mV and 96.2 ± 3.9 nm, 0.27 ± 0.03, −39.15 ± 3.2 mV, respectively. The assay and entrapment efficiency of both formulations was >95.0%. The NLC exhibited a spherical shape, as seen from TEM images. Sterilized (autoclaved) formulations were stable for up to 60 days (last time point checked) under refrigerated conditions. PTX-NLC formulations exhibited an initial burst release and 40% drug release, overall, in 48 h. The formulations exhibited desirable physicochemical properties and could lead to an effective therapeutic option in the management of RB.

Dual Drug Loaded Lipid Nanocarrier Formulations for Topical Ocular Applications

Introduction

Untreated ocular infections can damage the unique fine structures of the eye with possible visual impairments and blindness. Ciprofloxacin (CIP) ophthalmic solution is prescribed as first-line therapy in ocular bacterial infections. Natamycin (NT) ophthalmic suspension is one of the progenitors in ocular antifungal therapy. Nanostructured lipid carriers (NLCs) have been widely examined for ocular penetration enhancement and distribution to deeper ocular tissues. The objective of the current study was to prepare NLCs loaded with a combination of CIP and NT (CIP-NT-NLCs) and embed them in an in-situ gelling system (CIP-NT-NLCs-IG). This novel formulation will target the co-delivery of CIP and NT for the treatment of mixed ocular infections or as empirical treatment in case of limited access to healthcare diagnostic services.

Methods

CIP-NT-NLC and CIP-NT-NLC-IG formulations were evaluated based on physicochemical characteristics, in vitro release, and ex vivo transcorneal permeation studies and compared against commercial CIP and NT ophthalmic eye drops.

Results and Discussion

NLCs formulation (0.1% CIP and 0.3% NT) showed particle size, polydispersity index, and zeta potential of 196.2 ± 1.2 nm, 0.43 ± 0.06, and −28.1 ± 1.4 mV, respectively. Moreover, CIP-NT-NLCs showed entrapment efficiency of 80.9 ± 2.9 and 98.7 ± 1.9% for CIP and NT, respectively. CIP-NT-NLCs-IGformulation with 0.2% w/v gellan gum demonstrated the most favorable viscoelastic characteristics for ocular application. CIP-NT-NLCs and CIP-NT-NLCs-IG formulations exhibited a sustained release pattern for both drugs over 24 h. Moreover, CIP-NT-NLCs and CIP-NT-NLC-IG formulations showed 4.0- and 2.2-folds, and 5.0- and 2.5-folds enhancement in ex vivo transcorneal permeability of CIP and NT, respectively, compared to the control formulations.

Conclusion

The results suggest that this dual nanoparticulate-based in-situ gelling drug delivery system can serve as a promising topical delivery platform for the treatment of ocular infections.

Drug-loaded mesoporous carbon with sustained drug release capacity and enhanced antifungal activity to treat fungal keratitis

Fungal keratitis is a severe infectious corneal disease with a high rate of incidence and blindness. Since traditional treatments natamycin (NATA) eye drops, exhibit poor dissolution and bioavailability, and the efficacy of current therapeutic approaches remains limited. In this study, we innovatively utilized mesoporous carbon (Meso-C) and microporous carbon (Micro-C) as nanocarriers loaded with the antifungal drug NATA and silver nanoparticles (Ag-NPs). Porous carbon loaded with NATA and Ag-NPs has not previously been studied in fungal keratitis. Due to the mesoporous structure, high surface area and larger pore volume of Meso-C, it displayed greater superiority in sustained drug release and drug dispersity than Micro-C. Moreover, Meso-C could adsorb inflammatory cytokines during fungal infection. In vitro, Meso-C/NATA/Ag showed excellent antifungal effects. In vivo, compared with pure NATA treatment, Meso-C/NATA/Ag exhibited significantly improved therapeutic effects and reduced dosing frequency when treating fungal keratitis. Our study is the first to report the sustained drug release and improved drug dispersity of Meso-C/NATA and demonstrates that NATA and Ag-NPs-loaded Meso-C has therapeutic effects against fungal keratitis.

Thermosensitive Tri-Block Polymer Nanoparticle-Hydrogel Composites as Payloads of Natamycin for Antifungal Therapy Against Fusarium Solani

Purpose

Fusarium Solani is the principal pathogen associated with fungal keratitis. As a sensitive drug to F. Solani, natamycin (NAT) was limited by the poor penetration and low bioavailability in clinical application. The aim of this study was to develop a new type of tri-block polymer nanoparticle-gel complex (Gel@PLGA-PEI-PEG@NAT) for delivering NAT and evaluate its physicochemical properties, antifungal activity, safety, penetrability, adhesion, and efficacy in treating fungal keratitis.

Methods

PLGA-PEI-PEG@NAT was prepared and characterized with a nano-particle size analyzer, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The minimum inhibitory concentration (MIC), cytotoxicity, penetrability of NAT (Natacyn^® 5% ophthalmic suspension; Alcon) and PLGA-PEI-PEG@NAT with different concentrations were assessed. The eye surface retention time, ocular irritation, and curative effect of the NAT ophthalmic suspension and Gel@PLGA-PEI-PEG@NAT on a rabbit fungal keratitis model were evaluated.

Results

PLGA-PEI-PEG@NAT had a particle size of 150 nm, a positive surface charge, and a sustained-release effect. The MIC for F. Solani was 2 μg/mL. A cytotoxicity test and ocular irritation test showed that PLGA-PEI-PEG@NAT and Gel@PLGA-PEI-PEG@NAT had good biocompatibility and no obvious irritation for rabbit corneas. Penetration experiments confirmed that PLGA-PEI-PEG@NAT can successfully enter corneal epithelial cells and through the cornea to enter the anterior chamber. Compared with NAT ophthalmic suspension, Gel@PLGA-PEI-PEG@NAT had stronger cornea permeation at the same concentration. The therapeutic effect and precorneal retention ability of the NAT ophthalmic suspension and Gel@PLGA-PEI-PEG@NAT on the fungal keratitis rabbit model were compared. Gel@PLGA-PEI-PEG@NAT achieved a better therapeutic effect at a lower drug concentration, and its eye surface retention time was significantly longer than that of the NAT ophthalmic suspension.

Conclusion

Gel@PLGA-PEI-PEG@NAT was shown to be a safe and effective nanodrug delivery system for NAT. It has great potential to improve the cure rate of fungal keratitis, reduce the administration frequency during the treatment process, and improve patient compliance.

Advanced Nano-Carriers for Anti-Tumor Drug Loading

Chemotherapy is one of the important means of tumor therapy. However, most of the anti-tumor drugs that currently used in clinic are hydrophobic non-specific drugs, which seriously affect the efficacy of drugs. With the development of nanotechnology, drug efficacy can be improved by selecting appropriate biodegradable nanocarriers for achieving the controlled release, targeting and higher bioavailability of drugs. This paper reviewed the research progress of anti-tumor drug nanoparticle carriers, which mainly summarized the materials used for anti-tumor drug nanoparticle carriers and their effects in anti-tumor drugs, as well as the targeted drug delivery methods of anti-tumor drugs based on nanocarriers.

HPLC-MS/MS studies of brimonidine in rabbit aqueous humor by microdialysis

Aim: The pharmacokinetic study of the brimonidine tartrate in situ gel in the anterior chamber of the rabbit eye was studied by microdialysis technique, and samples were analyzed by HPLC-MS/MS. Materials & methods: It was monitored in ESI mode at transition 291.9→212.0 and 296.0→216.0 for brimonidine and internal standard, respectively. Acetonitrile and 0.1% aqueous formic acid (50:50, v/v) were used as the mobile phase at 0.4 ml/min. Results & conclusion: It showed a good linear correlation between 5 and 5000 ng/ml in microdialysis solution, and the inter- and intra-day precision (relative standard deviation) was less than 4.0%. The pharmacokinetic study showed that the AUC(0-t) of in situ gel was 3.5-times than that of eyedrops, which significantly improve the bioavailability of brimonidine.

Nanocubosomal based in situ gel loaded with natamycin for ocular fungal diseases: development, optimization, in-vitro, and in-vivo assessment

Natamycin (NT) is a synthetic broad-spectrum antifungal used in eye drops. However, it has low solubility and high molecular weight, limiting its permeation, and generally causes eye discomfort or irritation when administered. Therefore, the present study aimed to develop an ophthalmic in situ gel formulation with NT-loaded cubosomes to enhance ocular permeation, improve antifungal activity, and prolong the retention time within the eye. The NT-loaded cubosome (NT-Cub) formula was first optimized using an I-optimal design utilizing phytantriol, PolyMulse, and NT as the independent formulation factors and particle size, entrapment efficiency %, and inhibition zone as responses. Phytantriol was found to increase particle size and entrapment efficiency %. Higher levels of PolyMulse slightly increased the inhibition zone whereas a decrease in particle size and EE% was observed. Increasing the NT level initially increased the entrapment efficiency % and inhibition zone. The optimized NT-Cub formulation was converted into an in situ gel system using 1.5% Carbopol 934. The optimum formula showed a pH-sensitive increase in viscosity, favoring prolonged retention in the eye. The in vitro release of NT was found to be 71 ± 4% in simulated tear fluid. The optimum formulation enhanced the ex vivo permeation of NT by 3.3 times compared to a commercial formulation and 5.2 times compared to the NT suspension. The in vivo ocular irritation test proved that the optimum formulation is less irritating than a commercial formulation of NT. This further implies that the developed formulation produces less ocular irritation and can reduce the required frequency of administration.

In vitro dissolution testing models of ocular implants for posterior segment drug delivery

The delivery of drugs to the posterior segment of the eye remains a tremendously difficult task. Prolonged treatment in conventional intravitreal therapy requires injections that are administered frequently due to the rapid clearance of the drug molecules. As an alternative, intraocular implants can offer drug release for long-term therapy. However, one of the several challenges in developing intraocular implants is selecting an appropriate in vitro dissolution testing model. In order to determine the efficacy of ocular implants in drug release, multiple in vitro test models were emerging. While these in vitro models may be used to analyse drug release profiles, the findings may not predict in vivo retinal drug exposure as this is influenced by metabolic and physiological factors. This review considers various types of in vitro test methods used to test drug release of ocular implants. Importantly, it discusses the challenges and factors that must be considered in the development and testing of the implants in an in vitro setup.

Ocular drug delivery to the anterior segment using nanocarriers: A mucoadhesive/mucopenetrative perspective

There is a growing demand for effective treatments for ocular conditions that improve patient compliance and reduce side-effects. While methods such as implants and injections have proven effective, topical administration remains the method of choice for the delivery of therapeutics to the anterior segment of the eye. However, topical administration suffers from multiple drawbacks including low bioavailability of the target therapeutic, systemic toxicity, and the requirement for high therapeutic doses due to the effective clearance mechanisms that exist in the eye. Nanoparticles that have tunable mucoadhesion and/or mucopenetration offer outstanding potential to overcome the anatomical and physiological barriers present to improve ocular bioavailability, reduce toxicity, and increase ocular retention, among other benefits. The current review highlights recent advances in the field of developing nanocarriers with tunable mucoadhesion and mucopenetration for drug delivery to the eye.

Nanosuspension as an Efficient Carrier for Improved Ocular Permeation of Voriconazole

BACKGROUND

The present limitations related to the ocular administration of antifungal drugs for the treatment of fungal keratitis include poor ocular bioavailability, limited retention time, and low ocular tissue penetration.

METHODS

This study aimed to prepare a novel ophthalmic voriconazole-loaded nanosuspension based on Eudragit RS 100. Pharmasolve® was explored as a corneal permeation enhancer in voriconazole ophthalmic formulation using in vitro and in vivo experiments. Briefly, 1% voriconazole-loaded nanosuspension was prepared using the quasi-emulsion solvent evaporation process.

RESULTS

Characterizations of the voriconazole-loaded nanosuspension by Zetasizer Nano ZS and Transmission Electron Microscope (TEM) showed a uniform spherical shape without any agglomeration. The well-discreted nanoparticle with a size of 138 ± 1.3 nm was achieved with high entrapment efficiency (98.6 ± 2.5%) and positive zeta potential in the range of 22.5-31.2mV, indicating excellent physical stability.

DISCUSSION

Voriconazole-loaded nanosuspension containing the penetration enhancer displayed good permeability both in vitro and in vivo compared with the commercial voriconazole injection. The voriconazole-loaded nanosuspension exhibited good antifungal activity, significantly inhibiting the growth of Candida albicans at a lower concentration of voriconazole (2.5μg/mL, p < 0.05).

CONCLUSION

In conclusion, the voriconazole-loaded nanosuspension containing Pharmasolve® can be used as an effective ophthalmic formulation for the topical ocular delivery of voriconazole.

Lipid-Based Nanocarriers for Ophthalmic Administration: Towards Experimental Design Implementation

Nanotherapeutics based on biocompatible lipid matrices allow for enhanced solubility of poorly soluble compounds in the treatment of ophthalmic diseases, overcoming the anatomical and physiological barriers present in the eye, which, despite the ease of access, remains strongly protected. Micro-/nanoemulsions, solid lipid nanoparticles (SLN) or nanostructured lipid carriers (NLC) combine liquid and/or solid lipids with surfactants, improving drug stability and ocular bioavailability. Current research and development approaches based on try-and-error methodologies are unable to easily fine-tune nanoparticle populations in order to overcome the numerous constraints of ocular administration routes, which is believed to hamper easy approval from regulatory agencies for these systems. The predictable quality and specifications of the product can be achieved through quality-by-design (QbD) implementation in both research and industrial environments, in contrast to the current quality-by-testing (QbT) framework. Mathematical modelling of the expected final nanoparticle characteristics by variation of operator-controllable variables of the process can be achieved through adequate statistical design-of-experiments (DoE) application. This multivariate approach allows for optimisation of drug delivery platforms, reducing research costs and time, while maximising the understanding of the production process. This review aims to highlight the latest efforts in implementing the design of experiments to produce optimised lipid-based nanocarriers intended for ophthalmic administration. A useful background and an overview of the different possible approaches are presented, serving as a starting point to introduce the design of experiments in current nanoparticle research.

Recent developments on solid-state fermentation for production of microbial secondary metabolites: Challenges and solutions

Microbial secondary metabolites (SMs) are the intermediate or the product of metabolism produced during fermentation process. SMs are produced during stationary phase and play a major role in competition, antagonism and self defence mechanisms. These metabolites finds application in the pharmaceuticals, food, cosmetics etc. These are produced besides primary key metabolites (e.g., amino acids, lipids, carbohydrates etc.). Growth condition in solid-state fermentation (SSF) resembles microorganism's own native environment allowing the microorganisms to adapt best. Recent developments in bioprocessing has identified specific SSF practices that have a significant impact on SMs production. The practice of SSF, representing new opportunities to design better bioprocessing with potential genetic development goals for expanding the list of exciting SMs. Current updates cover advanced techniques on SSF to improve microbial SMs production and their ease of operation and cost-effective production strategies. Various factors affecting the SSF have been discussed with respect to sustainable development of novel SSF strategies for SMs production.

Polymeric Nanoparticles for Drug Delivery: Recent Developments and Future Prospects

The complexity of some diseases—as well as the inherent toxicity of certain drugs—has led to an increasing interest in the development and optimization of drug-delivery systems. Polymeric nanoparticles stand out as a key tool to improve drug bioavailability or specific delivery at the site of action. The versatility of polymers makes them potentially ideal for fulfilling the requirements of each particular drug-delivery system. In this review, a summary of the state-of-the-art panorama of polymeric nanoparticles as drug-delivery systems has been conducted, focusing mainly on those applications in which the corresponding disease involves an important morbidity, a considerable reduction in the life quality of patients—or even a high mortality. A revision of the use of polymeric nanoparticles for ocular drug delivery, for cancer diagnosis and treatment, as well as nutraceutical delivery, was carried out, and a short discussion about future prospects of these systems is included.

Ciprofloxacin Loaded Nanostructured Lipid Carriers Incorporated into In-Situ Gels to Improve Management of Bacterial Endophthalmitis

Bacterial endophthalmitis (BE) is a potentially sight-threatening inflammatory reaction of the intraocular fluids or tissues caused by bacteria. Ciprofloxacin (CIP) eye drops are prescribed as first-line therapy in BE. However, frequent administration is necessary due to precorneal loss and poor ocular bioavailability. The objective of the current research was to prepare CIP containing nanostructured lipid carriers (CIP-NLCs) loaded an in situ gel system (CIP-NLC-IG) for topical ocular administration for enhanced and sustained antibacterial activity in BE treatment. CIP-NLCs were prepared by the hot homogenization method and optimized based on physicochemical characteristics and physical stability. The optimized CIP-NLC formulation was converted into CIP-NLC-IG with the addition of gellan gum as a gelling agent. Furthermore, optimized CIP-NLC and CIP-NLC-IG were evaluated for in vitro release and ex vivo transcorneal permeation studies, using commercial CIP ophthalmic solution (CIP-C) as the control. The optimized CIP-NLC formulation showed particle size, polydispersity index, zeta potential, assay and entrapment efficiency of 193.1 ± 5.1 nm, 0.43 ± 0.01, -32.5 ± 1.5 mV, 99.5 ± 5.5 and 96.3 ± 2.5%, respectively. CIP-NLC-IG with 0.2% w/v gellan gum showed optimal viscoelastic characteristics. The in vitro release studies demonstrated sustained release of CIP from CIP-NLC and CIP-NLC-IG formulations over a 24 h period. Transcorneal flux and permeability increased 4 and 3.5-fold, and 2.2 and 1.9-fold from CIP-NLC and CIP-NLC-IG formulations, respectively, when compared to CIP-C. The results demonstrate that CIP-NLC-IG could be considered as an alternate delivery system to prolong the residence time on the ocular surface after topical administration. Thus, the current CIP ophthalmic formulations may exhibit improved ocular bioavailability and prolonged antibacterial activity, which may improve therapeutic outcomes in the treatment of BE.

Carboxyvinyl Polymer and Guar-Borate Gelling System Containing Natamycin Loaded PEGylated Nanolipid Carriers Exhibit Improved Ocular Pharmacokinetic Parameters

Purpose: Natamycin (NTM) ophthalmic suspension is the only FDA-approved formulation commercially available for treating ocular fungal infections. However, precorneal residence times and losses/drainage remain the foremost challenges associated with current ocular antifungal pharmacotherapy. In our previous investigations, NTM loaded polyethylene glycol nanolipid carriers (NTM-PNLCs) showed enhanced corneal permeation, both in vitro and in vivo. To further improve the corneal retention of NTM-PNLCs, this study aimed to develop a gelling system composed of carboxyvinyl polymer, guar gum, and boric acid in which the NTM-PNLCs were loaded. Methods: A 2³ factorial design was employed in formulating and optimizing the gelling system for NTM-PNLCs, where the independent factors were the gelling excipients (guar gum, boric acid, and Carbopol^® 940) and dependent variables were gelling time, gel depot collapse time, rheology, firmness, and work of adhesion. Optimized gel was evaluated for transcorneal permeation using rabbit cornea, in vitro; and tear pharmacokinetics and ocular biodistribution in male New Zealand White rabbits, in vivo. Results: Optimized NTM-PNLC-GEL was found to exhibit shear thinning rheology, adequate firmness, and spreadability, and formed a depot that did not collapse immediately. In addition, the in vitro transcorneal evaluation studies indicated that the NTM-PNLC-GEL exhibited a lower/slower flux and rate in comparison to Natacyn^® suspension. NTM-PNLC-GEL (0.3%), at a 16-fold lower dose, exhibited mean residence time and elimination half-life comparable to Natacyn (5%), and provided similar in vivo concentrations in the innermost tissues of the eye. Conclusion: The data indicate that the NTM-PNLC-GEL formulation could serve as an alternative during ophthalmic antifungal therapy.

Nanocarriers for ocular drug delivery: current status and translational opportunity

Ocular diseases have a significant effect on vision and quality of life. Drug delivery to ocular tissues is a challenge to formulation scientists. The major barriers to delivering drugs to the anterior and posterior segments include physiological barriers (nasolacrimal drainage, blinking), anatomical barriers (static and dynamic), efflux pumps and metabolic barriers. The static barriers comprise the different layers of the cornea, sclera, and blood–aqueous barriers whereas dynamic barriers involve conjunctival blood flow, lymphatic clearance and tear drainage. The tight junctions of the blood–retinal barrier (BRB) restrict systemically administered drugs from entering the retina. Nanocarriers have been found to be effective at overcoming the issues associated with conventional ophthalmic dosage forms. Various nanocarriers, including nanodispersion systems, nanomicelles, lipidic nanocarriers, polymeric nanoparticles, liposomes, niosomes, and dendrimers, have been investigated for improved permeation and effective targeted drug delivery to various ophthalmic sites. In this review, various nanomedicines and their application for ophthalmic delivery of therapeutics are discussed. Additionally, scale-up and clinical status are also addressed to understand the current scenario for ophthalmic drug delivery.

Ocular diseases have a significant effect on vision and quality of life.

Improving Topical Skin Delivery of Monocrotaline Via Liposome Gel-based Nanosystems

Background:

In this study, a liposomal gel based on a pH-gradient method was used to increase the skin-layer retention of monocrotaline (MCT) for topical administration.

Methods:

Using the Box-Behnken design, different formulations were designed to form liposome suspensions with optimal encapsulation efficiency (EE%) and stability factor (KE). In order to keep MCT in liposomes and accumulate in skin slowly and selectively, MCT liposome suspensions were engineered into gels.

Results:

A pH-gradient method was used to prepare liposome suspensions. The optimal formulation of liposome suspensions (encapsulation efficiency: 83.10 ± 0.21%) was as follows: MCT 12 mg, soybean phosphatidyl choline (sbPC) 200 mg, cholesterol (CH) 41 mg, vitamin E (VE) 5 mg, and citric acid buffer solution (CBS) 4.0 10 mL (pH 7.0). The final formulation of liposomal gels consisted of 32 mL liposome suspensions, 4.76 mL deionized water, 0.40 g Carbopol-940, 1.6 g glycerol, 0.04 g methylparaben, and a suitable amount of triethanolamine for pH value adjustment. The results of in vitro drug release showed that MCT in liposomal gels could be released in 12 h constantly in physiological saline as a Ritger-Peppas model. Compared with plain MCT in gel form, liposomal MCT in gel had higher skin retention in vitro.

Conclusion:

In this study, liposomal gels were formed for greater skin retention of MCT. It is potentially beneficial for reducing toxicities of MCT by topical administration with liposomal gel.

Optimization, stabilization, and characterization of amphotericin B loaded nanostructured lipid carriers for ocular drug delivery

The current study sought to formulate, optimize, and stabilize amphotericin B (AmB) loaded PEGylated nanostructured lipid carriers (NLC) and to study its ocular biodistribution following topical instillation. AmB loaded PEGylated NLC (AmB-PEG-NLC) were fabricated by hot-melt emulsification followed by high-pressure homogenization (HPH) technique. 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)] (mPEG-2K-DSPE) was used for surface PEGylation. mPEG-DSPE with different PEG molecular weight, 1 K, 2 K, 5 K, 10 K, and 20 K, were screened for formulation stability. Furthermore, the AmB loaded PEGylated (2K) NLC (AmB-PEG2K-NLC) was optimized using Box-Behnken design with respect to the amount of AmB, castor oil, mPEG-2K-DSPE, and number of high-pressure homogenization cycles as the factors; particle size, zeta potential, PDI, entrapment efficiency, and loading efficiency as responses. Stability of the optimized AmB-PEG2K-NLC was assessed over 4 weeks, at 4 °C as well as 25 °C and effect of autoclaving was also evaluated. AmB-PEG2K-NLC were tested for their in vitro antifungal activity against Candida albicans (ATCC 90028), AmB resistant Candida albicans (ATCC 200955) and Aspergillus fumigatus (ATCC 204305). Cytotoxicity of AmB-PEG2K-NLC was studied in human retinal pigmented epithelium cells. In vivo ocular biodistribution of AmB was evaluated in rabbits, following topical application of PEGylated NLCs or marketed AmB preparations. PEGylation with mPEG-2K-DSPE prevented leaching of AmB and increased the drug load significantly. The optimized formulation was prepared with a particle size of 218 ± 5 nm; 0.3 ± 0.02 PDI, 4.6 ± 0.1% w/w drug loading, and 92.7 ± 2.5% w/w entrapment efficiency. The optimized colloidal dispersions were stable for over a month, at both 4 °C and 25 °C. AmB-PEG2K-NLCs showed significantly (p < 0.05) better antifungal activity in both wild-type and AmB resistant Candida strains and, was comparable to, or better than, commercially available parenteral AmB formulations like Fungizone™ and AmBisome®. AmB-PEG2K-NLC did not show any toxicity up to a highest concentration of 1% (v/v) (percent formulation in medium). Following topical instillation, AmB was detected in all the ocular tissues tested and statistically significant (p > 0.05) difference was not observed between the formulations tested. An optimized autoclavable and effective AmB-PEG2K-NLC ophthalmic formulation with at least one-month stability, in the reconstituted state, has been developed.

Δ9-Tetrahydrocannabinol Derivative-Loaded Nanoformulation Lowers Intraocular Pressure in Normotensive Rabbits

PURPOSE

Δ9-Tetrahydrocannabinol-valine-hemisuccinate, a hydrophilic prodrug of Δ9-tetrahydrocannabinol, synthesized with the aim of improving the ocular bioavailability of the parent molecule, was investigated in a lipid-based nanoparticle dosage form for ocular delivery.

METHODS

Solid lipid nanoparticles (SLNs) of Δ9-tetrahydrocannabinol-valine-hemisuccinate and Δ9-tetrahydrocannabinol, along with a nanoemulsion of Δ9-tetrahydrocannabinol-valine-hemisuccinate, were tested for glaucoma management in a normotensive rabbit model by using a multiple-dosing protocol. Marketed formulations of timolol maleate and pilocarpine HCl were also tested for their pharmacodynamic profile, post-single dose administration.

RESULTS

A peak intraocular pressure (IOP) drop of 30% from baseline was observed in rabbits treated with SLNs loaded with Δ9-tetrahydrocannabinol-valine-hemisuccinate at 90 minutes. Treated eyes of rabbits receiving Δ9-tetrahydrocannabinol-valine-hemisuccinate SLNs had significantly lower IOP than untreated eyes until 360 minutes, whereas the group receiving the emulsion formulation showed a drop in IOP until 90 minutes only. In comparison to marketed pilocarpine and timolol maleate ophthalmic solutions, Δ9-tetrahydrocannabinol-valine-hemisuccinate SLNs produced a greater effect on IOP in terms of both intensity and duration. In terms of tissue concentrations, significantly higher concentrations of Δ9-tetrahydrocannabinol-valine-hemisuccinate were observed in iris-ciliary bodies and retina-choroid with SLNs.

CONCLUSION

Δ9-Tetrahydrocannabinol-valine-hemisuccinate formulated in a lipid-based nanoparticulate carrier shows promise in glaucoma pharmacotherapy.

TRANSLATIONAL RELEVANCE

Glaucoma therapies usually focus on decreased aqueous humor production and increased outflow. However, such therapy is not curative, and there lies a need in preclinical research to focus efforts on agents that not only affect the aqueous humor dynamics but also provide neuroprotection. Historically, there have been bench-scale studies looking at retinal ganglion cell death post-axonal injury. However, for a smooth translation of this in vitro activity to the clinic, animal models examining IOP reduction, i.e., connecting the neuroprotective activity to a measurable outcome in glaucoma management (IOP), need to be investigated. This study investigated the IOP reduction efficacy of cannabinoids for glaucoma pharmacotherapy in a normotensive rabbit model, bringing forth a new class of agents with the potential of IOP reduction and improved permeation to the back of the eye, possibly providing neuroprotective benefits in glaucoma management.

Cyclodextrin⁻Amphiphilic Copolymer Supramolecular Assemblies for the Ocular Delivery of Natamycin

Natamycin is the only drug approved for fungal keratitis treatment, but its low water solubility and low ocular penetration limit its efficacy. The purpose of this study was to overcome these limitations by encapsulating the drug in single or mixed micelles and poly(pseudo)rotaxanes. Soluplus and Pluronic P103 dispersions were prepared in 0.9% NaCl and pH 6.4 buffer, with or without α-cyclodextrin (αCD; 10% w/v), and characterized through particle size, zeta potential, solubilization efficiency, rheological properties, ocular tolerance, in vitro drug diffusion, and ex vivo permeation studies. Soluplus micelles (90–103 nm) and mixed micelles (150–110 nm) were larger than Pluronic P103 ones (16–20 nm), but all showed zeta potentials close to zero. Soluplus, Pluronic P103, and their mixed micelles increased natamycin solubility up to 6.00-fold, 3.27-fold, and 2.77-fold, respectively. Soluplus dispersions and poly(pseudo)rotaxanes exhibited in situ gelling capability, and they transformed into weak gels above 30 °C. All the formulations were non-irritant according to Hen’s Egg Test on the Chorioallantoic Membrane (HET-CAM) assay. Poly(pseudo)rotaxanes facilitated drug accumulation into the cornea and sclera, but led to lower natamycin permeability through the sclera than the corresponding micelles. Poly(pseudo)rotaxanes made from mixed micelles showed intermediate natamycin diffusion coefficients and permeability values between those of Pluronic P103-based and Soluplus-based poly(pseudo)rotaxanes. Therefore, the preparation of mixed micelles may be a useful tool to regulate drug release and enhance ocular permeability.

Analog Derivatization of Cannabidiol for Improved Ocular Permeation

Purpose: Cannabidiol (CBD), active component of plant Cannabis sativa, has anti-inflammatory properties that could potentially help treat diabetic retinopathy-induced pain and inflammation. However, CBD is a lipophilic molecule making its topical delivery to back of the eye challenging. This study aims at improving ocular penetration of CBD by means of analog derivatization. Methods: Analogs were designed using various ligands, such as amino acids (AAs) and dicarboxylic acids (DCAs) and their combinations. Select analogs were screened in vitro with respect to their stability in ocular tissue homogenates. Based on in vitro stability, analogs were selected for in rabbits testing. Formulations containing these compounds were tested in rabbits to determine ocular tissue disposition of CBD and the analogs after topical application. The rabbits were sacrificed 90 min post-topical application and the aqueous humor, vitreous humor (VH), iris-ciliary bodies (IC), and retina-choroid (RC) were analyzed for CBD and analog content. Results: CBD-divalinate-dihemisuccinate (CBD-Di-VHS) and CBD-divalinate (CBD-Di-Val) were stable in the ocular tissue homogenates. Post-topical application, CBD and CBD-Di-Val analog levels were detected only in RC. Dosing of CBD-Di-VHS nanoemulsion generated analog levels both in the VH and in the RC, respectively. In contrast, post dosing of CBD-monovalinate-monohemisuccinate (CBD-Mono-VHS), both the analog and CBD were detected in the IC and RC. Conclusion: The analogs demonstrated superior penetration into ocular tissues in comparison with CBD. CBD-Di-VHS and CBD-Mono-VHS exhibited better permeation properties, possibly due to improved stability and physicochemical characteristics imparted by AA and DCA combination derivatives.

Natamycin solid lipid nanoparticles - sustained ocular delivery system of higher corneal penetration against deep fungal keratitis: preparation and optimization

Background

Fungal keratitis (FK) is a serious pathogenic condition usually associated with significant ocular morbidity. Natamycin (NAT) is the first-line and only medication approved by the Food and Drug Administration for the treatment of FK. However, NAT suffers from poor corneal penetration, which limits its efficacy for treating deep keratitis.

Purpose

The objective of this work was to prepare NAT solid lipid nanoparticles (NAT-SLNs) to achieve sustained drug release and increased corneal penetration.

Methods

NAT-SLNs were prepared using the emulsification-ultrasonication technique. Box– Behnken experimental design was applied to optimize the effects of independent processing variables (lipid concentration [X₁], surfactant concentration [X₂], and sonication frequency [X₃]) on particle size (R₁), zeta potential (ZP; R₂), and drug entrapment efficiency (EE%) (R₃) as responses. Drug release profile, ex vivo corneal permeation, antifungal susceptibility, and cytotoxicity of the optimized formula were evaluated.

Results

The optimized formula had a mean particle size of 42 r.nm (radius in nanometers), ZP of 26 mV, and EE% reached ~85%. NAT-SLNs showed an extended drug release profile of 10 hours, with enhanced corneal permeation in which the apparent permeability coefficient (P_app) and steady-state flux (J_ss) reached 11.59×10⁻² cm h⁻¹ and 3.94 mol h⁻¹, respectively, in comparison with 7.28×10⁻² cm h⁻¹ and 2.48 mol h⁻¹ for the unformulated drug, respectively. Antifungal activity was significantly improved, as indicated by increases in the inhibition zone of 8 and 6 mm against Aspergillus fumigatus ATCC 1022 and a Candida albicans clinical isolate, respectively, and minimum inhibitory concentration values that were decreased 2.5-times against both of these pathogenic strains. NAT-SLNs were found to be non-irritating to corneal tissue. NAT-SLNs had a prolonged drug release rate^, that improved corneal penetration, and increased antifungal activity without cytotoxic effects on corneal tissues.

Conclusion

Thus, NAT-SLNs represent a promising ocular delivery system for treatment of deep corneal keratitis.

Effects of formulation composition on the characteristics of mucoadhesive films prepared by hot-melt extrusion technology

OBJECTIVES

To investigate the effects of formulation composition on the physico-chemical and drug release properties of mucoadhesive buccal films prepared by melt extrusion technology, using a response surface methodology.

METHODS

Salbutamol sulphate, an antiasthmatic drug was used for this study. Klucel hydroxypropylcellulose (HPC) EF (film-forming polymer), Benecel hydroxypropylmethylcellulose (HPMC) K-15M (drug release retardant) and polyethylene glycol (PEG) 4500 (plasticiser) were the three independent factors utilised for the study. The responses were fitted to a full quadratic model and P-values for each of the factors were used to determine their significance on the film characteristics.

KEY FINDINGS

Films were successfully extruded using the corotating twin-screw extruder. The torque during extrusion was found to be significantly affected by all the three factors and no interaction between factors was observed. A significant interaction was observed between HPC and PEG 4500 for stiffness of films. For disintegration time and swelling index, a significant interaction was found between HPC and HPMC. The in vitro % drug release was directly correlated with HPMC content and not with other factors and varied from 69-89% at 4 h.

CONCLUSIONS

The influence of extrusion process and formulation parameters on salbutamol sulphate films was elucidated, indicating the use of melt extrusion as a feasible method for film preparation.

Challenges in the Polyene- and Azole-Based Pharmacotherapy of Ocular Fungal Infections

Polyenes and azoles constitute 2 major drug classes in the antifungal armamentarium used to treat fungal infections of the eye such as fungal keratitis, endophthalmitis, conjunctivitis, and blepharitis. These classes of drugs have come to occupy an important niche in ophthalmic antifungal therapy due to their broad spectrum of activity against a variety of filamentous and yeast-like fungi. Natamycin suspension (Natacyn^®), a polyene antifungal drug, is currently the only US FDA-approved formulation for treating ophthalmic fungal infections, whereas the other polyene and azole antifungals such as amphotericin B, fluconazole, itraconazole, ketoconazole, miconazole, voriconazole, and posaconazole are routinely used off-label in the clinical setting. Despite potent antifungal activity, the clinical utility of these agents in ophthalmic infections has been challenged by their physicochemical properties, the unique ocular anatomy and physiology, selective antifungal activity, ocular and systemic toxicity, emergence of resistance and cross-resistance, and absence of reliable techniques for developing a robust in vitro-in vivo correlation. This review discusses the aforementioned challenges and the common approaches undertaken to circumnavigate the difficulties associated with the polyene- and azole-based pharmacotherapy of ophthalmic fungal infections.

Curcumin-loaded Nanostructured Lipid Carriers for Ocular Drug Delivery: Design Optimization and Characterization

The current study sought to formulate, optimize, and evaluate curcumin-loaded Nanostructured Lipid Carriers (NLCs) for their in vitro and ex vivo characteristics. NLCs, prepared using hot-melt emulsification and ultrasonication techniques, were optimized using a Central Composite Design (CCD) and evaluated for their in vitro physicochemical characteristics. Their stability over a 3 month period and transcorneal permeation across excised rabbit corneas (ex vivo) were assessed for the optimized NLCs. The optimized NLC, with a particle size of 66.8 ± 2 nm, polydispersity index of 0.17±0.05, entrapment efficiency of 96 ± 1.6%, and drug loading of 3.1 ± 0.05% w/w, was chosen using CCD. The optimized NLCs showed optimum ex vivo stability at 4°C for the study period and demonstrated a significant increase in curcumin permeation (~2.5-fold) across the rabbit cornea in comparison to the control. Overall, these studies indicated the successful development of NLCs using the design of experiment approach; the formulation enhanced curcumin permeation across excised corneas and did not show any harmful side effects.