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

Chitosan-based xerogel film incorporating Nystatin: Synthesis, structural Analysis, and biological evaluation

Wound infections are challenging to manage, requiring innovative wound dressing systems with prescribed properties. Active wound dressings should provide a moist environment, protect from secondary infections, and remove wound exudate to accelerate tissue regeneration. Hydrogels are encouraging matrices for bioactive compound encapsulation in pharmaceutical applications. The aim of the present study is to design chitosan/gelatin /polyvinyl alcohol-based xerogel film containing nystatin for wound dressing applications with antifungal properties. The xerogel film is developed using a film-casting method and evaluated for its chemical and physical characteristics using FTIR, SEM, AFM, and tensile analysis. Water barrier properties of the film, such as the moisture content (17.84 ± 3.62 %), water solubility (44.50 ± 5.55 %), gel fraction (55.50 ± 5.55 %), and water vapour transmission rate (1912.25 ± 248.12 g m-2 per day), suggest a humid microenvironment suitable for wound. The xerogel film, characterized by its robust mechanical strength, substantial swelling capacity (∼120-400 %) across various pH levels, and acceptable bio-adhesive properties, reveals as a potential antifungal wound dressing material. In vitro toxicity assessments confirm its biocompatibility towards both RBCs and NIH-3 T3 fibroblast cells. The findings confirm that the film formulation has strong antifungal properties, with a minimum inhibitory concentration of 2-8 μL/mL against Candida species, as well as outstanding antibiofilm effectiveness (∼85 %) and a significant reduction of the fungal colony count (∼100 %). Moreover, its controlled drug release capabilities, along with antifungal properties, offer it as an appealing dressing for the localized treatment of superficial fungal infections. As a result, this xerogel film can be used as a versatile platform for advanced wound care and therapeutic applications.

Enhanced Natamycin production in Streptomyces gilvosporeus through phosphate tolerance screening and transcriptome-based analysis of high-yielding mechanisms

BACKGROUND

Natamycin is a natural antibiotic with broad-spectrum antifungal activity, widely used in food preservation, medicine, and biological control. However, the relatively low biosynthetic capacity of producing strains limits further industrialization and broader applications of natamycin. Due to the complexity of cellular metabolism, evolutionary engineering is required for developing strains with enhanced natamycin biosynthetic capacity.

RESULTS

Here, protoplast fusion combined with phosphate tolerance screening was employed for the first time to enhance natamycin production of Streptomyces gilvosporeus. A high-yielding strain, GR-2, was obtained, with natamycin production twice that of the original strain. Transcriptomic analysis revealed that the natamycin biosynthetic gene cluster and several primary metabolic pathways were significantly upregulated in GR-2, likely contributing to its high production performance. Further experiments, including amino acid addition and reverse engineering, confirmed that branched-chain amino acid, nitrogen, and phosphate metabolism play crucial roles in promoting natamycin production. Silencing of the phosphate metabolism transcriptional regulators PhoP and PhoR led to a decreased expression of natamycin biosynthetic genes and significantly reduced natamycin production, highlighting the key role of these regulators in S. gilvosporeus. Based on omics data, co-expression of phoP and phoR in GR-2 resulted in the engineered strain GR2-P3, which exhibited a 25% increase in natamycin production in shake flasks. In a 5 L fermenter, GR2-P3 achieved a natamycin production of 12.2 ± 0.6 g·L⁻¹, the highest yield reported for S. gilvosporeus to date.

CONCLUSIONS

Our findings suggest that the high production performance of GR-2 is primarily due to the upregulation of the natamycin biosynthetic gene cluster and genes related to precursor supply. Increasing the intracellular supply of valine and glutamate significantly enhanced natamycin production. Additionally, the natamycin biosynthetic gene cluster is likely positively regulated by PhoP and PhoR. Our work presents a novel strategy for strain screening and evolution to improve natamycin production and identifies novel molecular targets for metabolic engineering.

Formulation Advances in Posterior Segment Ocular Drug Delivery

Posterior segment ocular diseases, such as diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion, are leading causes of vision impairment and blindness worldwide. Effective management of these conditions remains a formidable challenge due to the unique anatomical and physiological barriers of the eye, including the blood-retinal barrier and rapid drug clearance mechanisms. To address these hurdles, nanostructured drug delivery systems are proposed to overcome ocular barriers, target the retina, and enhance permeation while ensuring controlled release. Traditional therapeutic approaches, such as intravitreal injections, pose significant drawbacks, including patient discomfort, poor compliance, and potential complications. Therefore, understanding the physiology and clearance mechanism of eye could aid in the design of novel formulations that could be noninvasive and deliver drugs to reach the target site is pivotal for effective treatment strategies. This review focuses on recent advances in formulation strategies for posterior segment ocular drug delivery, highlighting their potential to overcome these limitations. Furthermore, the potential of nanocarrier systems such as in-situ gel, niosomes, hydrogels, dendrimers, liposomes, nanoparticles, and nanoemulsions for drug delivery more effectively and selectively is explored, and supplemented with illustrative examples, figures, and tables. This review aims to provide insights into the current state of posterior segment drug delivery, emphasizing the need for interdisciplinary approaches to develop patient-centric, minimally invasive, and effective therapeutic solutions.

Drug delivery strategies to improve the treatment of corneal disorders

Anterior eye disorders including dry eye syndrome, keratitis, chemical burns, and trauma have varying prevalence rates in the world. Classical dosage forms based-topical ophthalmic drugs are popular treatments for managing corneal diseases. However, current dosage forms of ocular drugs can be associated with major challenges such as the short retention time in the presence of ocular barriers. Developing alternative therapeutic methods is required to overcome drug bioavailability from ocular barriers. Nanocarriers are major platforms and promising candidates for the administration of ophthalmic drugs in an adjustable manner. This paper briefly introduces the advantages, disadvantages, and characteristics of delivery systems for the treatment of corneal diseases. Additionally, advanced technologies such as 3D printing are being considered to fabricate ocular drug carriers and determine drug dosages for personalized treatment. This comprehensive review is gathered through multiple databases such as Google Scholar, PubMed, and Web of Science. It explores information around "ocular drug delivery systems'', "nano-based drug delivery systems'', "engineered nanocarriers'', and "advanced technologies to fabricate personalized drug delivery systems''.

Network pharmacology, molecular docking-driven, Qbd-Engineered antifungal in-situ gel loaded with voriconazole nanostructured lipid carriers

Fungal infections (FIs) affect majority of the population, but the current treatments face challenges in terms of their effectiveness. This study focused on specific fungal targets, including dihydrofolate reductase (DHFR), acetohydroxy-acid synthase (AHAS), farnesyltransferase and endoglucanase. The docking studies were conducted with the drug voriconazole (VCZ), comparing it with Fluconazole (FCZ) and Amphotericin B (ATB) against 11 protein data bank (PDB) IDs (IDYR, 3NZB, 6DEQ, 1KS5, 7T0C, 1FY4, 5AJH, 7R79, 6TZ6 and 6IDY). Molecular dynamics (MD) analysis, including RMSD, RMSF, PCA and FEL, confirmed the stability of VCZ. The solubility of VCZ was a problem, so nanostructured lipid carriers (NLCs) were developed to improve ocular penetration. VCF5 was the optimized formulation by using 32 full factorial design. VCZF5-NLCs were the best in terms of nanoparticle size (126.6 nm), Zeta potential (33.5 mV), drug content (DC; 97.38 ± 0.210), encapsulation efficiency (EE; 88.01 ± 0.272) and extended drug release. The results of the ex-vivo corneal diffusion study indicate that VCZ-NLC-loaded in-situ gel (VCZ-NLC-IG3) exhibited DC of 88.25% and drug entrapment (DE) of 74.2%. The results of the zone of inhibition indicated that VCZ-NLC-IG3 had superior efficacy compared to ATB. Network pharmacology showed VCZ interacts with the genes which are responsible for fungus ergosterol biosynthesis, including lanosterol 14-alpha demethylase inhibitors (ERG11), ergosterol biosynthesis protein 5 (ERG5), dimethylallyltransferase 2 (DIT2), ketosynthase (KCN), methylsterol monooxygenase (MSMO1), lamin B receptor (LBR), squalene epoxidase (SQLE), 3-hydroxy-3-methylglutaryl-coenzyme A Reductase (MGCR), 3-hydroxy-3-methylglutaryl-coenzyme A Synthase (HMGCS) and 3-keto-steroid reductase (HSD17B7). In conclusion, the optimized VCZ-loaded NLCs present a promising approach to treat ocular FIs.Communicated by Ramaswamy H. Sarma.

Recent Advancements in Nanopharmaceuticals for Novel Drug Delivery Systems

Nanoparticles have found applications across diverse sectors, including agriculture, food, cosmetics, chemicals, mechanical engineering, automotive, and oil and gas industries. In the medical field, nanoparticles have garnered considerable attention due to their great surface area, high solubility, rapid dissolution, and enhanced bioavailability. Nanopharmaceuticals are specifically designed to precisely deliver drug substances to targeted tissues and cells, aiming to optimize therapeutic efficacy while minimizing potential adverse effects. Furthermore, nanopharmaceuticals offer advantages, such as expedited therapeutic onset, reduced dosages, minimized variability between fed and fasted states, and enhanced patient compliance. The increasing interest in nanopharmaceuticals research among scientists and industry stakeholders highlights their potential for various medical applications from disease management to cancer treatment. This review examines the distinctive characteristics of ideal nanoparticles for efficient drug delivery, explores the current types of nanoparticles utilized in medicine, and delves into the applications of nanopharmaceuticals, including drug and gene delivery, as well as transdermal drug administration. This review provides insights into the nanopharmaceuticals field, contributing to the development of novel drug delivery systems and enhancing the potential of nanotechnology in healthcare.

From Preformulative Design to In Vivo Tests: A Complex Path of Requisites and Studies for Nanoparticle Ocular Application. Part 1: Design, Characterization, and Preliminary In Vitro Studies

Ocular pathologies are widely diffused worldwide, and their effective treatment, combined with a high patient compliance, is sometimes challenging to achieve due to the barriers of the eye; in this context, the use of nanoparticles for topical ophthalmic application could represent a successful strategy. Aiming to develop nanoplatforms with potential clinical applications, great attention has to be paid to their features, in relation to the route of administration and to the pharmacopoeial requirements. This review (part 1) thus embraces the preliminary steps of nanoparticle development and characterization. At the beginning, the main barriers of the eye and the different administration routes are resumed, followed by a general description of the advantages of the employment of nanoparticles for ocular topical administration. Subsequently, the preformulative steps are discussed, deepening the choice of raw materials and determining the quantitative composition. Then, a detailed report of the physicochemical and technological characterization of nanoparticles is presented, analyzing the most relevant tests that should be performed on nanoparticles to verify their properties and the requisites (both mandatory and suggested) demanded by regulatory agencies. In conclusion, some preliminary noncellular in vitro evaluation methods are described. Studies from in vitro cellular assays to in vivo tests will be discussed in a separate (part 2) review paper. Hence, this overview aims to offer a comprehensive tool to guide researchers in the choice of the most relevant studies to develop a nanoplatform for ophthalmic drug administration.

Multifunctional natamycin modified chondroitin sulfate eye drops with anti-inflammatory, antifungal and tissue repair functions possess therapeutic effects on fungal keratitis in mice

Fungal keratitis (FK) is recognized as a stubborn ocular condition, caused by intense fungal invasiveness and heightened immune reaction. The glycosaminoglycan chondroitin sulfate exhibits properties of immunomodulation and tissue regeneration. In prior investigations, oxidized chondroitin sulfate (OCS) ameliorated the prognosis of FK in murine models. To further improve the curative efficacy, we used the antifungal drug natamycin to functionalize OCS and prepared oxidized chondroitin sulfate-natamycin (ON) eye drops. The structure of ON was characterized by FTIR, UV-vis, and XPS, revealing that the amino group of natamycin combined with the aldehyde group in OCS through Schiff base reaction. Antifungal experiments revealed that ON inhibited fungal growth and disrupted the mycelium structure. ON exhibited exceptional biocompatibility and promoted the proliferation of corneal epithelial cells. Pharmacokinetic analysis indicated that ON enhanced drug utilization by extending the mean residence time in tears. In murine FK, ON treatment reduced the clinical score and corneal fungal load, restored corneal stroma conformation, and facilitated epithelial repair. ON effectively inhibited neutrophil infiltration and decreased the expression of TLR-4, LOX-1, IL-1β, and TNF-α. Our research demonstrated that ON eye drops achieved multifunctional treatment for FK, including inhibiting fungal growth, promoting corneal repair, enhancing drug bioavailability, and controlling inflammatory reactions.

Improving antifungal lipid-based drug delivery against Candida: a review

INTRODUCTION

Fungal infections, particularly those caused by Candida spp. have increased in recent years. A primary contributor to this surge was the COVID-19 pandemic, where many hospitalized patients had secondary fungal infections. Additionally, the emergence of resistant and multi-resistant fungal strains has become increasingly problematic due to the limited therapeutic options available in antifungal treatments.

AREAS COVERED

This review presents a comprehensive analysis of recent studies focused on the development and characterization of lipid-based nanosystems as an emerging and promising therapeutic alternative. These systems have been evaluated for their potential to deliver antifungal agents specifically targeting resistant Candida spp. strains, offering a controlled and sustained release of drugs.

EXPERT OPINION

Lipid-based nanomaterials are promising tools for the controlled and sustained release of drugs, particularly in treating Candida spp. infections. Although substantial research has been dedicated to development of these nanomaterials, only a few have reached clinical application, such as liposomal amphotericin B, for example. Therefore, it is critical to push forward with advancements to bring these nanomedicines into clinical practice, where they can contribute meaningfully to mitigating the challenge of resistant and lethal fungal strains.

Formulation and characterization of cholesterol-based nanoparticles of gabapentin protecting from retinal injury

Introduction

This study aimed to prepare cholesterol and stearic acid-based solid lipid nanoparticles of gabapentin (GAB-SLNs) for protection against streptozotocin (STZ)-induced retinal injury in rats.

Methods

We prepared four preparations of GAB-SLNs using a hot high-shear homogenization ultrasonication process, and the best formulation was selected and tested for biological activity. The retinal injury was brought in male adult albino rats while gabapentin doses continued for 6 weeks. Six groups of rats were assigned as the vehicle, diabetic, diabetic + gabapentin (10-20 mg/kg), and diabetic + GAB-SLNs (10-20 mg/kg). GAB-SLN#2 was selected as the optimized formulation with high entrapment efficacy (EE%, 98.64% ± 1.97%), small particle size (185.65 ± 2.41 nm), high negative Zeta potential (-32.18 ± 0.98 mV), low polydispersity index (0.28 ± 0.02), and elevated drug release (99.27% ± 3.48%). The TEM image of GAB-SLN#2 revealed a smooth surface with a spherical shape.

Results

GAB-SLNs provided greater protection against retinal injury than free gabapentin as indicated by the histopathology data which demonstrated more organization of retinal layers and less degeneration in ganglion cell layer in rats treated with GAB-SLN#2. Further, GAB-SLN#2 reduced the inflammatory proteins (IL-6/JAK2/STAT3) and vascular endothelial growth factor (VEGF).

Conclusion

The preparation of GAB-SLNs enhanced the physical properties of gabapentin and improved its biological activity as a neuroprotectant. Further studies are warranted to validate this technique for the use of oral gabapentin in other neurological disorders.

Fostering the unleashing potential of nanocarriers-mediated delivery of ocular therapeutics

Ocular delivery is the most challenging aspect in the field of pharmaceutical research. The major hurdle for the controlled delivery of drugs to the eye includes the physiological static barriers such as the complex layers of the cornea, sclera and retina which restrict the drug from permeating into the anterior and posterior segments of the eye. Recent years have witnessed inventions in the field of conventional and nanocarrier drug delivery which have shown considerable enhancement in delivering small to large molecules across the eye. The dynamic challenges associated with conventional systems include limited drug contact time and inadequate ocular bioavailability resulting from solution drainage, tear turnover, and dilution or lacrimation. To this end, various bioactive-based nanosized carriers including liposomes, ethosomes, niosomes, dendrimer, nanogel, nanofibers, contact lenses, nanoprobes, selenium nanobells, nanosponge, polymeric micelles, silver nanoparticles, and gold nanoparticles among others have been developed to circumvent the limitations associated with the conventional dosage forms. These nanocarriers have been shown to achieve enhanced drug permeation or retention and prolong drug release in the ocular tissue due to their better tissue adherence. The surface charge and the size of nanocarriers (10-1000 nm) are the important key factors to overcome ocular barriers. Various nanocarriers have been shown to deliver active therapeutic molecules including timolol maleate, ampicillin, natamycin, voriconazole, cyclosporine A, dexamethasone, moxifloxacin, and fluconazole among others for the treatment of anterior and posterior eye diseases. Taken together, in a nutshell, this extensive review provides a comprehensive perspective on the numerous facets of ocular drug delivery with a special focus on bioactive nanocarrier-based approaches, including the difficulties and constraints involved in the fabrication of nanocarriers. This also provides the detailed invention, applications, biodistribution and safety-toxicity of nanocarriers-based therapeutcis for the ophthalmic delivery.

Drug Release from Lipid Microparticles-Insights into Drug Incorporation and the Influence of Physiological Factors

The aim of this study was to assess the impact of physiological factors, namely tear fluid and lysozyme enzyme, as well as surfactant polysorbate, on the release profile from solid lipid microparticles (SLM), in the form of dispersion intended for ocular application. Indomethacin (Ind) was used as a model drug substance and a release study was performed by applying the dialysis bag method. Conducting release studies taking into account physiological factors is expected to improve development and screening studies, as well as support the regulatory assessment of this multi-compartment lipid dosage form. The effect of the lysozyme was directly related to its effect on lipid microparticles, as it occurred only in their presence (no effect on the solubility of Ind). Polysorbate also turned out to be an important factor interacting with the SLM surface, which determined the release of Ind from SLM. However, in study models without tear fluid or lysozyme, the release of Ind did not exceed 60% within 96 h. Ultimately, only the simultaneous application of artificial tear fluid, lysozyme, and polysorbate allowed for the release of 100% of Ind through the SLM dispersion. The examination of the residues after the release studies indicated the possibility of releasing 100% of Ind from SLM without complete degradation of the microparticles' matrix. The incubation of SLM with tear fluid confirmed a similar influence of physiological factors contained in tear fluid on the surface structure of SLM as that observed during the in vitro studies.

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.

Deoxynivalenol Damages Corneal Epithelial Cells and Exacerbates Inflammatory Response in Fungal Keratitis

BACKGROUND

Fungal keratitis (FK) is a kind of infectious keratopathy with a high rate of blindness worldwide. Deoxynivalenol (DON) has been proven to have multiple toxic effects on humans and animals.

OBJECTIVES

The aim of this study was to explore a possible pathogenic role of DON in FK.

METHODS

We first made an animal model of FK in New Zealand white rabbits, and then attempted to detect DON in a culture medium in which Fusarium solani had been grown and also in the corneal tissue of the animal model of Fusarium solani keratitis. Next, a model of DON damage in human corneal epithelial cells (HCECs) was constructed to evaluate effects of DON on the activity, migration ability, cell cycle, and apoptosis in the HCECs. Then, putative the toxic damaging effects of DON on rabbit corneal epithelial cells and the impact of the repair cycle were studied. The expression levels of inflammatory factors in the corneas of the animal model and in the model of DON-damaged HCECs were measured.

RESULTS

The Fusarium solani strain used in this study appeared to have the potential to produce DON, since DON was detected in the corneal tissue of rabbits which had been inoculated with this Fusarium solani strain. DON was found to alter the morphology of HCECs, to reduce the activity and to inhibit the proliferation and migration of HCECs. DON also induced the apoptosis and S-phase arrest of HCECs. In addition, DON was found to damage rabbit corneal epithelial cells, to prolong the corneal epithelial regeneration cycle, and to be associated with the upregulated expression of inflammatory factors in HCECs and rabbit corneas.

CONCLUSIONS

DON appears to have a toxic damaging effect on HCECs in FK, and to induce the expression of inflammatory factors, leading to the exacerbation of keratitis and the formation of new blood vessels. Future studies will explore the possibility of developing a test to detect DON in ophthalmic settings to aid the rapid diagnosis of FK, and to develop DON neutralizers and adsorbents which have the potential to improve keratocyte status, inhibit apoptosis, and alleviate inflammation, therein providing new thinking for therapy of clinical FK.

Repaglinide-Solid Lipid Nanoparticles in Chitosan Patches for Transdermal Application: Box-Behnken Design, Characterization, and In Vivo Evaluation

Background

Repaglinide (REP) is an antidiabetic drug with limited oral bioavailability attributable to its low solubility and considerable first-pass hepatic breakdown. This study aimed to develop a biodegradable chitosan-based system loaded with REP-solid lipid nanoparticles (REP-SLNs) for controlled release and bioavailability enhancement via transdermal delivery.

Methods

REP-SLNs were fabricated by ultrasonic hot-melt emulsification. A Box-Behnken design (BBD) was employed to explore and optimize the impacts of processing variables (lipid content, surfactant concentration, and sonication amplitude) on particle size (PS), and entrapment efficiency (EE). The optimized REP-SLN formulation was then incorporated within a chitosan solution to develop a transdermal delivery system (REP-SLN-TDDS) and evaluated for physicochemical properties, drug release, and ex vivo permeation profiles. Pharmacokinetic and pharmacodynamic characteristics were assessed using experimental rats.

Results

The optimized REP-SLNs had a PS of 249±9.8 nm and EE of 78%±2.3%. The developed REP-SLN-TDDS demonstrated acceptable characteristics without significant aggregation of REP-SLNs throughout the casting and drying processes. The REP-SLN-TDDS exhibited a biphasic release pattern, where around 36% of the drug load was released during the first 2 h, then the drug release was sustained at around 80% at 24 h. The computed flux across rat skin for the REP-SLN-TDDS was 2.481±0.22 μg/cm2/h in comparison to 0.696±0.07 μg/cm2/h for the unprocessed REP, with an enhancement ratio of 3.56. The REP-SLN-TDDS was capable of sustaining greater REP plasma levels over a 24 h period (p<0.05). The REP-SLN-TDDS also reduced blood glucose levels compared to unprocessed REP and commercial tablets (p<0.05) in experimental rats.

Conclusion

Our REP-SLN-TDDS can be considered an efficient therapeutic option for REP administration.

Nanotechnology-based fungal detection and treatment: current status and future perspective

Fungal infections impose a significant impact on global health and encompass major expenditures in medical treatments. Human mycoses, a fungal co-infection associated with SARS-CoV-2, is caused by opportunistic fungal pathogens and is often overlooked or misdiagnosed. Recently, there is increasing threat about spread of antimicrobial resistance in fungus, mostly in hospitals and other healthcare facilities. The diagnosis and treatment of fungal infections are associated with several issues, including tedious and non-selective detection methods, the growth of drug-resistant bacteria, severe side effects, and ineffective drug delivery. Thus, a rapid and sensitive diagnostic method and a high-efficacy and low-toxicity therapeutic approach are needed. Nanomedicine has emerged as a viable option for overcoming these limitations. Due to the unique physicochemical and optical properties of nanomaterials and newer biosensing techniques, nanodiagnostics play an important role in the accurate and prompt differentiation and detection of fungal diseases. Additionally, nano-based drug delivery techniques can increase drug permeability, reduce adverse effects, and extend systemic circulation time and drug half-life. This review paper is aimed at highlighting recent, promising, and unique trends in nanotechnology to design and develop diagnostics and treatment methods for fungal diseases.

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.

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.

Natamycin-Loaded Ethyl Cellulose/PVP Films Developed by Microfluidic Spinning for Active Packaging

The preparation of active packaging loaded with antimicrobial, antioxidant, and other functional agents has become a hot topic for food preservation in recent years. In this field, active fiber films based on spinning methods have attracted the interest of researchers owing to their high specific surface area, high porosity, high loading capacity, and good controlled release capacity. In the present work, neatly arranged ethyl cellulose (EC)/polyvinyl-pyrrolidone (PVP) fibrous films loaded with natamycin as an antimicrobial agent were prepared by microfluidic spinning. The encapsulation efficiency of natamycin was more than 90% in each group and the loading increased with increasing natamycin content. According to the characterization results of the natamycin-loaded EC/PVP fibrous films, hydrogen bonding was formed between natamycin and EC and PVP in the fibrous films. Meanwhile, the water contact angle of the fibrous films was increased, suggesting the improved hydrophobicity of the films. In the in vitro bacterial inhibition experiments, the active fiber films loaded with natamycin showed good antimicrobial activity, which could significantly inhibit the growth of gray mold. In conclusion, N-EC/PVP fibrous films with antimicrobial activity prepared by microfluidic spinning showed good potential in the field of active packaging.

Progress in the application of nanoparticles for the treatment of fungal infections: A review

The burden of fungal infections on human health is increasing worldwide. Aspergillus, Candida, and Cryptococcus are the top three human pathogenic fungi that are responsible for over 90% of infection-related deaths. Moreover, effective antifungal therapeutics are lacking, primarily due to host toxicity, pathogen resistance, and immunodeficiency. In recent years, nanomaterials have proved not only to be more efficient antifungal therapeutic agents but also to overcome resistance against fungal medication. This review will examine the limitations of standard antifungal therapy as well as focus on the development of nanomaterials.

Physicochemical properties and micro-interaction between micro-nanoparticles and anterior corneal multilayer biological interface film for improving drug delivery efficacy: the transformation of tear film turnover mode

Recently, various novel drug delivery systems have been developed to overcome ocular barriers in order to improve drug efficacy. We have previously reported that montmorillonite (MT) microspheres (MPs) and solid lipid nanoparticles (SLNs) loaded with the anti-glaucoma drug betaxolol hydrochloride (BHC) exhibited sustained drug release and thus intraocular pressure (IOP) lowering effects. Here, we investigated the effect of physicochemical particle parameters on the micro-interactions with tear film mucins and corneal epithelial cells. Results showed that the MT-BHC SLNs and MT-BHC MPs eye drops significantly prolonged the precorneal retention time due to their higher viscosity and lower surface tension and contact angle compared with the BHC solution, with MT-BHC MPs exhibiting the longest retention due to their stronger hydrophobic surface. The cumulative release of MT-BHC SLNs and MT-BHC MPs was up to 87.78% and 80.43% after 12 h, respectively. Tear elimination pharmacokinetics study further confirmed that the prolonged precorneal retention time of the formulations was due to the micro-interaction between the positively charged formulations and the negatively charged tear film mucins. Moreover, the area under the IOP reduction curve (AUC) of MT-BHC SLNs and MT-BHC MPs was 1.4 and 2.5 times that of the BHC solution. Accordingly, the MT-BHC MPs also exhibit the most consistent and long-lasting IOP-lowering effect. Ocular irritation experiments showed no significant toxicity of either. Taken together, MT MPs may have the potential for more effective glaucoma treatment.

Role of Polymeric Micelles in Ocular Drug Delivery: An Overview of Decades of Research

Local drug delivery to the eye through conventional means has faced many challenges due to three essential barriers: (a) the complex structure of the cornea limiting drug absorption, (b) the capacity of ocular absorptive cells in drug metabolism, and (c) the washing effect of eye tears. Polymeric micelles (PMs) have been the focus of much interest for ocular drug delivery due to several advantages they provide for this application, including the capacity for the solubilization of hydrophobic drugs, nonirritability, nanoscopic diameter, and the clarity of their aqueous solution not interfering with vision. The potential to increase the release and residence time of incorporated medication at the site of absorption is also a bonus advantage for these delivery systems. This Review covers research conducted on single or mixed micelles prepared from small amphiphilic molecules, copolymers (diblock, triblock, and graft), and gel systems containing micelles. The purpose of this review is to provide an update on the status of micellar ocular delivery systems for different indications, with a focus on preclinical and clinical drug development. In this context, we are discussing the anatomy of the eye, various ocular barriers, different micellar formulations, and their benefits in ocular drug delivery, as well as the role of PMs in the management of ocular diseases both in preclinical models and in clinic. The encouraging preclinical effectiveness findings from experiments conducted in both laboratory settings and live animals have paved the way for the advancement of micellar systems in clinical trials for ocular administration and the first nanomicallar formulation approved for clinical use by the United States Food and Drug Administration (marketed as Cequa by Sun Pharmaceuticals).

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.

Overview of Recent Advances in Nano-Based Ocular Drug Delivery

Ocular diseases profoundly impact patients' vision and overall quality of life globally. However, effective ocular drug delivery presents formidable challenges within clinical pharmacology and biomaterial science, primarily due to the intricate anatomical and physiological barriers unique to the eye. In this comprehensive review, we aim to shed light on the anatomical and physiological features of the eye, emphasizing the natural barriers it presents to drug administration. Our goal is to provide a thorough overview of various characteristics inherent to each nano-based drug delivery system. These encompass nanomicelles, nanoparticles, nanosuspensions, nanoemulsions, microemulsions, nanofibers, dendrimers, liposomes, niosomes, nanowafers, contact lenses, hydrogels, microneedles, and innovative gene therapy approaches employing nano-based ocular delivery techniques. We delve into the biology and methodology of these systems, introducing their clinical applications over the past decade. Furthermore, we discuss the advantages and challenges illuminated by recent studies. While nano-based drug delivery systems for ophthalmic formulations are gaining increasing attention, further research is imperative to address potential safety and toxicity concerns.

Lipid-based nanocarriers challenging the ocular biological barriers: Current paradigm and future perspectives

Eye is the most specialized and sensory body organ and treating eye diseases efficiently is necessary. Despite various attempts, the design of a consummate ophthalmic drug delivery system remains unsolved because of anatomical and physiological barriers that hinder drug transport into the desired ocular tissues. It is important to advance new platforms to manage ocular disorders, whether they exist in the anterior or posterior cavities. Nanotechnology has piqued the interest of formulation scientists because of its capability to augment ocular bioavailability, control drug release, and minimize inefficacious drug absorption, with special attention to lipid-based nanocarriers (LBNs) because of their cellular safety profiles. LBNs have greatly improved medication availability at the targeted ocular site in the required concentration while causing minimal adverse effects on the eye tissues. Nevertheless, the exact mechanisms by which lipid-based nanocarriers can bypass different ocular barriers are still unclear and have not been discussed. Thus, to bridge this gap, the current work aims to highlight the applications of LBNs in the ocular drug delivery exploring the different ocular barriers and the mechanisms viz. adhesion, fusion, endocytosis, and lipid exchange, through which these platforms can overcome the barrier characteristics challenges.

Enhancement of ocular anti-glaucomic activity of agomelatine through fabrication of hyaluronic acid modified-elastosomes: formulation, statistical optimisation, in vitro characterisation, histopathological study, and in vivo assessment

AIM

The aim of this manuscript was to fabricate agomelatine (AGM) loaded elastosomes to improve its corneal permeation and ocular bioavailability. AGM is a biopharmaceutical classification system (BCS) class II with low water solubility and high membrane permeability. It has a potent agonistic action on melatonin receptors, so it is used for glaucoma treatment.

METHODS

Elastosomes were made using modified ethanol injection technique according to a 22 × 41 full factorial design. The chosen factors were: edge activators (EAs) type, surfactant percent (SAA %w/w), and cholesterol:surfactant ratio (CH:SAA ratio). The studied responses were encapsulation efficiency percent (EE%), mean diameter, polydispersity index (PDI), zeta potential (ZP), percentage of drug released after two hours (Q2h%), and 24 hours (Q24h%).

RESULTS

The optimum formula with the desirability of 0.752 was composed of Brij98 as EA type, 15%w/w SAA%, and 1:1 CH:SAA ratio. It revealed EE% of 73.22%w/v and mean diameter, PDI, ZP, Q2h%, and Q24h% values of 484.25 nm, 0.31, -30.75 mV, 32.7%w/v, and 75.6%w/v, respectively. It demonstrated acceptable stability for three months and superior elasticity than its conventional liposome. The histopathological study ensured the tolerability of its ophthalmic application. Also, it was proven to be safe from the results of the pH and refractive index tests. The in vivo pharmacodynamic parameters of the optimum formula revealed dominance in a maximum % decrease in intraocular pressure (IOP), the area under the IOP response curve, and mean residence time with the value of 82.73%w/v, 820.69%h, and 13.98 h compared to that of the AGM solution (35.92%w/v, 181.30%h, and 7.52 h).

CONCLUSIONS

Elastosomes can be a promising option to improve AGM ocular bioavailability.

A systematic review of emerging technologies to enhance the treatment of ovarian cancer

The efficacy and safety of chemotherapy are two major challenges when it comes to treating ovarian cancer. The associated undesirable side effects of chemotherapy agents jeopardize the clinical intent and the efficiency of the therapy. Multiple studies have been published describing new developments and novel strategies utilizing the latest therapeutic and drug delivery technologies to address the efficacy and safety of chemotherapeutics in ovarian cancers. We have identified five novel technologies that are available and, if used, have the potential to mitigate the above-mentioned challenges. Nanocarriers in different forms (Nano-gel, Aptamer, peptide medicated formulations, Antibody-drug conjugation, surface charge, and nanovesicle technologies) are developed and available to be employed to target the cancerous tissue. These strategies are promising to improve clinical efficacy and reduce side effects. We have systematically searched and analyzed published data, as well as the authors intent for the described technology on each publication. We narrowed to 81 key articles and extracted their data to be discussed in this review. In summary, the selected articles investigated the pharmacokinetic properties of drugs combined with nanocarriers and found significant improvement in efficacy and safety by reducing the IC50 values and drug doses. These key papers described promising novel technologies in anti-cancer therapeutic approaches to enable sustained drug release and achieve prolonged drug performance near the tumor site or target tissue.

Statistical optimization of tetrahydrocurcumin loaded solid lipid nanoparticles using Box Behnken design in the management of streptozotocin-induced diabetes mellitus

In the past, curcumin was the go-to medication for diabetes, but recent studies have shown that tetrahydrocurcumin is more effective. The problem is that it's not very soluble in water or very bioavailable. So, our research aims to increase the bioavailability and anti-diabetic efficacy of tetrahydrocurcumin in streptozotocin-induced diabetic rats by synthesizing tetrahydrocurcumin-loaded solid lipid nanoparticles. Box Behnken Design was employed for the optimization of tetrahydrocurcumin-loaded solid lipid nanoparticles (THC-SLNs). The optimal formulation was determined by doing an ANOVA to examine the relationship between the independent variables (drug-to-lipid ratio, surfactant concentration, and co-surfactant concentration) and the dependent variables (particle size, percent entrapment efficiency, and PDI). Particle size, PDI, and entrapment efficiency all showed statistical significance based on F-values and p-values. The optimized batch was prepared using a drug-to-lipid ratio (1:4.16), 1.21% concentration of surfactant, and 0.4775% co-surfactant (observed with a particle size of 147.1 nm, 83.58 ± 0.838 % entrapment efficiency, and 0.265 PDI, and the values were found very close with the predicted ones. As the THC peak vanishes from the DSC thermogram of the improved formulation, this indicates that the drug has been transformed from its crystalline form into its amorphous state. TEM analysis of optimized formulation demonstrated mono-dispersed particles with an average particle size of 145 nm which are closely related to zetasizer's results. In-vitro release study of optimized formulation demonstrated burst release followed by sustained release up to 71.04% throughout 24 hrs. Increased bioavailability of the adjusted THC-SLN was found in an in vivo pharmacokinetics research with 9.47 folds higher AUC(0-t) compared to plain THC-suspension. Additionally, pharmacodynamic experiments of optimized formulation demonstrated a marked decrease in blood glucose level to 63.7% and increased body weight from 195.8 ± 7.223 to 231.2 ± 7.653 on the 28th day of the study and showed a better anti-diabetic effect than plain drug suspension. Results of stability studies revealed that formulation can be stored for longer periods at room temperature. Tetrahydrocurcumin can be effectively administered by SLN for the treatment of diabetes.

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).

Ocular Delivery of Bimatoprost-Loaded Solid Lipid Nanoparticles for Effective Management of Glaucoma

Glaucoma is a progressive optic neuropathy characterized by a rise in the intraocular pressure (IOP) leading to optic nerve damage. Bimatoprost is a prostaglandin analogue used to reduce the elevated IOP in patients with glaucoma. The currently available dosage forms for Bimatoprost suffer from relatively low ocular bioavailability. The objective of this study was to fabricate and optimize solid lipid nanoparticles (SLNs) containing Bimatoprost for ocular administration for the management of glaucoma. Bimatoprost-loaded SLNs were fabricated by solvent evaporation/ultrasonication technique. Glyceryl Monostearate (GMS) was adopted as solid lipid and poloxamer 407 as surfactant. Optimization of SLNs was conducted by central composite design. The optimized formulation was assessed for average particle size, entrapment efficiency (%), zeta potential, surface morphology, drug release study, sterility test, isotonicity test, Hen's egg test-chorioallantoic membrane (HET-CAM) test and histopathology studies. The optimized Bimatoprost-loaded SLNs formulation had an average size of 183.3 ± 13.3 nm, zeta potential of -9.96 ± 1.2 mV, and encapsulation efficiency percentage of 71.8 ± 1.1%. Transmission electron microscopy (TEM) study revealed the nearly smooth surface of formulated particles with a nano-scale size range. In addition, SLNs significantly sustained Bimatoprost release for up to 12 h, compared to free drug (p < 005). Most importantly, HET-CAM test nullified the irritancy of the formulation was verified its tolerability upon ocular use, as manifested by a significant reduction in mean irritation score, compared to positive control (1% sodium dodecyl sulfate; p < 0.001). Histopathology study inferred the absence of any signs of cornea tissue damage upon treatment with Bimatoprost optimized formulation. Collectively, it was concluded that SLNs might represent a viable vehicle for enhancing the corneal permeation and ocular bioavailability of Bimatoprost for the management of glaucoma.

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.

Unroasted Green Coffee Extract-Loaded Solid Lipid Nanoparticles for Enhancing Intestinal Permeation

Green coffee bean extract (GCBE) provides diversified health benefits. However, its reported low bioavailability impeded its utilization in various applications. In this study, GCBE-loaded solid lipid nanoparticles (SLNs) were prepared to improve the bioavailability through enhanced intestinal absorption of GCBE. During the preparation of promising GCBE-loaded SLNs, the lipid concentration, surfactant concentration, and co-surfactant amount are crucial that were optimized using the Box-Behnken design, while particle size, polydispersity index (PDI), ζ-potential, entrapment efficiency, and cumulative drug release were the measured responses. GCBE-SLNs were successfully developed by a high shear homogenization technique using geleol as a solid lipid, tween 80 as a surfactant, and propylene glycol as Co-SAA. The optimized SLNs contained 5.8% geleol, 5.9% tween 80, and 80.4 mg PG resulting in a small particle size of 235.7 ± 12.5 nm, reasonably acceptable PDI of 0.417 ± 0.023, and ζ-potential of -15 ± 0.14 mV, with a high entrapment efficiency of 58.3 ± 0.85% and cumulative release of 7575 ± 0.78%. Furthermore, the performance of the optimized GCBE-SLN was evaluated using an ex vivo everted sac model where the intestinal permeation of GCBE was improved due to nanoencapsulation using SLN. Consequently, the results enlightened the auspicious potential of exploiting oral GCBE-SLNs for boosting intestinal absorption of chlorogenic acid.

Influence of Surface-Modification via PEGylation or Chitosanization of Lipidic Nanocarriers on In Vivo Pharmacokinetic/Pharmacodynamic Profiles of Apixaban

Nanostructured lipid carriers (NLCs) have been proven to significantly improve the bioavailability and efficacy of many drugs; however, they still have many limitations. These limitations could hinder their potential for enhancing the bioavailability of poorly water-soluble drugs and, therefore, require further amendments. From this perspective, we have investigated how the chitosanization and PEGylation of NLCs affected their ability to function as a delivery system for apixaban (APX). These surface modifications could enhance the ability of NLCs to improve the bioavailability and pharmacodynamic activity of the loaded drug. In vitro and in vivo studies were carried out to examine APX-loaded NLCs, chitosan-modified NLCs, and PEGylated NLCs. The three nanoarchitectures displayed a Higuchi-diffusion release pattern in vitro, in addition to having their vesicular outline proven via electron microscopy. PEGylated and chitosanized NLCs retained good stability over 3 months, versus the nonPEGylated and nonchitosanized NLCs. Interestingly, APX-loaded chitosan-modified NLCs displayed better stability than the APX-loaded PEGylated NLCs, in terms of mean vesicle size after 90 days. On the other hand, the absorption profile of APX (AUC_0-inf) in rats pretreated with APX-loaded PEGylated NLCs (108.59 µg·mL^-1·h^-1) was significantly higher than the AUC_0-inf of APX in rats pretreated with APX-loaded chitosan-modified NLCs (93.397 µg·mL^-1·h^-1), and both were also significantly higher than AUC_0-inf of APX-Loaded NLCs (55.435 µg·mL^-1·h^-1). Chitosan-coated NLCs enhanced APX anticoagulant activity with increased prothrombin time and activated partial thromboplastin time by 1.6- and 1.55-folds, respectively, compared to unmodified NLCs, and by 1.23- and 1.37-folds, respectively, compared to PEGylated NLCs. The PEGylation and chitosanization of NLCs enhanced the bioavailability and anticoagulant activity of APX over the nonmodified NLCs; this highlighted the importance of both approaches.

Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) Prepared by Microwave and Ultrasound-Assisted Synthesis: Promising Green Strategies for the Nanoworld

Many pharmaceutically active molecules are highly lipophilic, which renders their administration and adsorption in patients extremely challenging. Among the countless strategies to overcome this problem, synthetic nanocarriers have demonstrated superb efficiency as drug delivery systems, since encapsulation can effectively prevent a molecules' degradation, thus ensuring increased biodistribution. However, metallic and polymeric nanoparticles have been frequently associated with possible cytotoxic side effects. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), which are prepared with physiologically inert lipids, therefore emerged as an ideal strategy to bypass toxicities issues and avoid the use of organic solvents in their formulations. Different approaches to preparation, using only moderate amounts of external energy to facilitate a homogeneous formation, have been proposed. Greener synthesis strategies have the potential to provide faster reactions, more efficient nucleation, better particle size distribution, lower polydispersities, and furnish products with higher solubility. Particularly microwave-assisted synthesis (MAS) and ultrasound-assisted synthesis (UAS) have been utilized in the manufacturing of nanocarrier systems. This narrative review addresses the chemical aspects of those synthesis strategies and their positive influence on the characteristics of SLNs and NLCs. Furthermore, we discuss the limitations and future challenges for the manufacturing processes of both types of nanoparticles.

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.

Application of Convergent Science and Technology toward Ocular Disease Treatment

Eyes are one of the main critical organs of the body that provide our brain with the most information about the surrounding environment. Disturbance in the activity of this informational organ, resulting from different ocular diseases, could affect the quality of life, so finding appropriate methods for treating ocular disease has attracted lots of attention. This is especially due to the ineffectiveness of the conventional therapeutic method to deliver drugs into the interior parts of the eye, and the also presence of barriers such as tear film, blood-ocular, and blood-retina barriers. Recently, some novel techniques, such as different types of contact lenses, micro and nanoneedles and in situ gels, have been introduced which can overcome the previously mentioned barriers. These novel techniques could enhance the bioavailability of therapeutic components inside the eyes, deliver them to the posterior side of the eyes, release them in a controlled manner, and reduce the side effects of previous methods (such as eye drops). Accordingly, this review paper aims to summarize some of the evidence on the effectiveness of these new techniques for treating ocular disease, their preclinical and clinical progression, current limitations, and future perspectives.

Breaking Barriers in Eye Treatment: Polymeric Nano-Based Drug-Delivery System for Anterior Segment Diseases and Glaucoma

The eye has anatomical structures that function as robust static and dynamic barriers, limiting the penetration, residence time, and bioavailability of medications administered topically. The development of polymeric nano-based drug-delivery systems (DDS) could be the solution to these challenges: it can pass through ocular barriers, offering higher bioavailability of administered drugs to targeted tissues that are otherwise inaccessible; it can stay in ocular tissues for longer periods of time, requiring fewer drug administrations; and it can be made up of polymers that are biodegradable and nano-sized, minimizing the undesirable effects of the administered molecules. Therefore, therapeutic innovations in polymeric nano-based DDS have been widely explored for ophthalmic drug-delivery applications. In this review, we will give a comprehensive overview of polymeric nano-based drug-delivery systems (DDS) used in the treatment of ocular diseases. We will then examine the current therapeutic challenges of various ocular diseases and analyze how different types of biopolymers can potentially enhance our therapeutic options. A literature review of the preclinical and clinical studies published between 2017 and 2022 was conducted. Thanks to the advances in polymer science, the ocular DDS has rapidly evolved, showing great promise to help clinicians better manage patients.

Polymer- and lipid-based nanocarriers for ocular drug delivery: Current status and future perspectives

Ocular diseases seriously affect patients' vision and life quality, with a global morbidity of over 43 million blindness. However, efficient drug delivery to treat ocular diseases, particularly intraocular disorders, remains a huge challenge due to multiple ocular barriers that significantly affect the ultimate therapeutic efficacy of drugs. Recent advances in nanocarrier technology offer a promising opportunity to overcome these barriers by providing enhanced penetration, increased retention, improved solubility, reduced toxicity, prolonged release, and targeted delivery of the loaded drug to the eyes. This review primarily provides an overview of the progress and contemporary applications of nanocarriers, mainly polymer- and lipid-based nanocarriers, in treating various eye diseases, highlighting their value in achieving efficient ocular drug delivery. Additionally, the review covers the ocular barriers and administration routes, as well as the prospective future developments and challenges in the field of nanocarriers for treating ocular diseases.

Solid lipid-based nanoparticulate system for sustained release and enhanced in-vitro cytotoxic effect of 5-fluorouracil on skin Melanoma and squamous cell carcinoma

The present study aimed to prepare solid lipid-based nanoparticles (SLNs) using Precirol® ATO 5 as solid lipid and Poloxamer 188 and Tween 80 as surfactant and co-surfactant respectively, and SLNs-derived gel for sustained delivery, enhanced in-vitro cytotoxicity, enhanced cellular uptake of 5-FU and enhanced permeation of 5-FU across the skin. The 5-FU-loaded SLNs were prepared by the hot melt encapsulation method and converted into SLN-derived gel using a gelling agent (Carbopol 940). The 5-FU-loaded SLNs had a particle size in the range of 76.82±1.48 to 327±4.46 nm, zeta potential between -11.3±2.11 and -28.4±2.40 mV, and entrapment efficiency (%) in range of 63.46±1.13 and 76.08±2.42. The FTIR analysis depicted that there was no chemical interaction between 5-FU and formulation components. Differential scanning calorimetric analysis showed thermal stability of 5-FU in the nanoparticles and powdered X-ray diffraction analysis revealed successful incorporation of 5-FU in nanoparticles. The in-vitro release study of 5-FU-loaded SLNs showed biphasic release behavior with initial burst release followed by sustained release over 48 hr. The 5-FU-loaded SLNs showed a greater cytotoxic effect on skin melanoma (B16F10 cells) and squamous cell carcinoma (A-431 cells) as compared to free 5-FU drug solution after 48 hr. Flow cytometry and fluorescence microscopy displayed enhanced quantitative and qualitative cellular uptake of SLNs. The SLNs formulation showed acceptable safety and biocompatible profile after an acute toxicity study in Wistar rats. Moreover, ex-vivo permeation studies depicted 2.13±0.076 folds enhanced flux of 5-FU-loaded SLN derived gel compared to 5-FU plain gel, and skin retention studies revealed target efficiency (%) 2.54±0.03 of 5-FU-loaded SLN derived gel compared to 5-FU plain gel.

Tailoring Apixaban in Nanostructured Lipid Carrier Enhancing Its Oral Bioavailability and Anticoagulant Activity

Apixaban (Apx), an oral anticoagulant drug, is a direct factor Xa inhibitor for the prophylaxis against venous thromboembolism. Apx has limited oral bioavailability and poor water solubility. The goal of this study was to improve the formulation of an Apx-loaded nanostructured lipid carrier (NLC) to increase its bioavailability and effectiveness. As solid lipid, liquid lipid, hydrophilic, and lipophilic stabilizers, stearic acid, oleic acid, Tween 80, and lecithin were used, respectively. Utilizing Box-Behnken design, the effects of three factors on NLC particle size (Y1), zeta potential (Y2), and entrapment efficiency percent (Y3) were examined and optimized. The optimized formula was prepared, characterized, morphologically studied, and pharmacokinetically and pharmacodynamically assessed. The observed responses of the optimized Apx formula were 315.2 nm, -43.4 mV, and 89.84% for Y1, Y2, and Y3, respectively. Electron microscopy revealed the homogenous spherical shape of the NLC particles. The in vivo pharmacokinetic study conducted in male Wistar rats displayed an increase in AUC and Cmax by 8 and 2.67 folds, respectively, compared to oral Apx suspension. Moreover, the half-life was increased by 1.94 folds, and clearance was diminished by about 8 folds, which makes the NLC formula a promising sustained release system. Interestingly, the pharmacodynamic results displayed the superior effect of the optimized formula over the drug suspension with prolongation in the cuticle bleeding time. Moreover, both prothrombin time and activated partial thromboplastin time are significantly increased. So, incorporating Apx in an NLC formula significantly enhanced its oral bioavailability and pharmacodynamic activity.

Quality by Design Based Formulation of Xanthohumol Loaded Solid Lipid Nanoparticles with Improved Bioavailability and Anticancer Effect against PC-3 Cells

Many natural products with greater therapeutic efficacy are limited to target several chronic diseases such as cancer, diabetes, and neurodegenerative diseases. Among the natural products from hops, i.e., Xanthohumol (XH), is a prenylated chalcone. The present research work focuses on the enhancement of the poor oral bioavailability and weak pharmacokinetic profile of XH. We exemplified the development of a Xanthohumol-loaded solid lipid nanoparticles (XH-SLNs) cargo system to overcome the limitations associated with its bioavailability. The XH-SLNs were prepared by a high-shear homogenization/ultrasonication method and graphical, numerical optimization was performed by using Box-Behnken Design. Optimized XH-SLNs showed PS (108.60 nm), PDI (0.22), ZP (-12.70 mV), %EE (80.20%) and an amorphous nature that was confirmed by DSC and PXRD. FE-SEM and HRTEM revealed the spherical morphology of XH-SLNs. The results of release studies were found to be 9.40% in 12 h for naive XH, whereas only 28.42% of XH was released from XH-SLNs. The slow release of drugs may be due to immobilization of XH in the lipid matrix. In vivo pharmacokinetic study was performed for the developed XH-SLNs to verify the enhancement in the bioavailability of XH than naive XH. The enhancement in the bioavailability of the XH was confirmed from an increase in Cmax (1.07-folds), AUC0-t (4.70-folds), t1/2 (6.47-folds) and MRT (6.13-folds) after loading into SLNs. The relative bioavailability of XH loaded in SLNs and naive XH was found to be 4791% and 20.80%, respectively. The cytotoxicity study of naive XH, XH-SLNs were performed using PC-3 cell lines by taking camptothecin as positive control. The results of cytotoxicity study revealed that XH-SLNs showed good cell inhibition in a sustained pattern. This work successfully demonstrated formulation of XH-SLNs with sustained release profile and improved oral bioavailability of XH with good anticancer properties against PC-3 cells.

Recent advancements in polymeric nanofibers for ophthalmic drug delivery and ophthalmic tissue engineering

Nanofibers due to their unique properties such as high surface-to-volume ratio, porous structure, mechanical strength, flexibility and their resemblance to the extracellular matrix, have been researched extensively in the field of ocular drug delivery and tissue engineering. Further, different modifications considering the formulation and process parameters have been carried out to alter the drug release profile and its interaction with the surrounding biological environment. Electrospinning is the most commonly used technique for preparing nanofibers with industrial scalability. Advanced techniques such as co-axial electrospinning and combined system such as embedding nanoparticles in nanofiber provide an alternative approach to enhance the performance of the scaffold. Electrospun nanofibers offers a matrix like structure for cell regeneration. Nanofibers have been used for ocular delivery of various drugs like antibiotics, anti-inflammatory and various proteins. In addition, lens-coated medical devices provide new insights into the clinical use of nanofibers. Through fabricating the nanofibers researchers have overcome the issues of low bioavailability and compatibility with ocular tissue. Therefore, nanofibers have great potential in ocular drug delivery and tissue engineering and have the capacity to revolutionize these therapeutic areas in the field of ophthalmology. This review is mainly focused on the recent advances in the preparation of nanofibers and their applications in ocular drug delivery and tissue engineering. The authors have attempted to emphasize the processing challenges and future perspectives along with an overview of the safety and toxicity aspects of nanofibers.

Development of a Luliconazole Nanoemulsion as a Prospective Ophthalmic Delivery System for the Treatment of Fungal Keratitis: In Vitro and In Vivo Evaluation

Luliconazole (LCZ), a novel imidazole drug, has broad-spectrum and potential antifungal effects, which makes it a possible cure for fungal keratitis; nevertheless, its medical use in ocular infections is hindered by its poor solubility. The purpose of this study was to design and optimize LCZ nanoemulsion (LCZ-NE) formulations using the central composite design-response surface methodology, and to investigate its potential in improving bioavailability following ocular topical administration. The LCZ-NE formulation was composed of Capryol 90, ethoxylated hydrogenated castor oil, Transcutol® P and water. The shape of LCZ-NE was spherical and uniform, with a droplet size of 18.43 ± 0.05 nm and a low polydispersity index (0.070 ± 0.008). The results of an in vitro release of LCZ study demonstrated that the LCZ-NE released more drug than an LCZ suspension (LCZ-Susp). Increases in the inhibition zone indicated that the in vitro antifungal activity of the LCZ-NE was significantly improved. An ocular irritation evaluation in rabbits showed that the LCZ-NE had a good tolerance in rabbit eyes. Ocular pharmacokinetics analysis revealed improved bioavailability in whole eye tissues that were treated with LCZ-NE, compared with those treated with LCZ-Susp. In conclusion, the optimized LCZ-NE formulation exhibited excellent physicochemical properties, good tolerance, enhanced antifungal activity and bioavailability in eyes. This formulation would be safe, and shows promise in effectively treating ocular fungal infections.

New Approach for Preparing Solid Lipid Nanoparticles with Volatile Oil-Loaded Quercetin Using the Phase-Inversion Temperature Method

Quercetin (QCT), a natural flavonoid, is of research interest owing to its pharmacological properties. However, its pharmacokinetic limitations could hinder its widespread therapeutic use. Nanocarriers, especially solid lipid nanoparticles (SLNs), might overcome this constraint. This study aimed to investigate QCT-loaded SLNs prepared via a new approach using a volatile oil. The phase-inversion temperature method was used to incorporate rosemary oil (RMO) into SLNs prepared using solid lipids possessing different chemical structures. Among the solid lipids used in the formulations, trilaurin (TLR) exhibited the smallest particle size and good stability after a temperature cycling test. SLNs prepared with a ratio of RMO to TLR of 1:3 could load QCT with an entrapment efficiency of >60% and drug loading of ~2% w/w. The smallest particle size was achieved using the polyoxyethylene-hydrogenated castor oil RH40, and the particle size depended on the concentration. The drug-release profile of QCT_TLR exhibited prolonged biphasic release for >24 h. QCT_TLR was a safe formulation, as indicated by a cell viability percentage of >75% at <2% v/v. In a computer simulation, the system with RMO enabled smaller sized SLNs than those without RMO. This new discovery shows great promise for producing SLNs via the phase-inversion temperature method with incorporation of volatile oil, particularly for delivering compounds with limited water solubility.

Current Advances in Nano-Based and Polymeric Stimuli-Responsive Drug Delivery Targeting the Ocular Microenvironment: A Review and Envisaged Future Perspectives

Optimal vision remains one of the most essential elements of the sensory system continuously threatened by many ocular pathologies. Various pharmacological agents possess the potential to effectively treat these ophthalmic conditions; however, the use and efficacy of conventional ophthalmic formulations is hindered by ocular anatomical barriers. Recent novel designs of ophthalmic drug delivery systems (DDS) using nanotechnology show promising prospects, and ophthalmic formulations based on nanotechnology are currently being investigated due to their potential to bypass these barriers to ensure successful ocular drug delivery. More recently, stimuli-responsive nano drug carriers have gained more attention based on their great potential to effectively treat and alleviate many ocular diseases. The attraction is based on their biocompatibility and biodegradability, unique secondary conformations, varying functionalities, and, especially, the stimuli-enhanced therapeutic efficacy and reduced side effects. This review introduces the design and fabrication of stimuli-responsive nano drug carriers, including those that are responsive to endogenous stimuli, viz., pH, reduction, reactive oxygen species, adenosine triphosphate, and enzymes or exogenous stimuli such as light, magnetic field or temperature, which are biologically related or applicable in clinical settings. Furthermore, the paper discusses the applications and prospects of these stimuli-responsive nano drug carriers that are capable of overcoming the biological barriers of ocular disease alleviation and/or treatment for in vivo administration. There remains a great need to accelerate the development of stimuli-responsive nano drug carriers for clinical transition and applications in the treatment of ocular diseases and possible extrapolation to other topical applications such as ungual or otic drug delivery.

Sodium alginate/gum arabic/glycerol multicomponent edible films loaded with natamycin: Study on physicochemical, antibacterial, and sweet potatoes preservation properties

Sweet potato (Ipomonea batatas Lam) is easily damaged due to its thin skin, which is limited in shelf life and causes enormous economic losses in the food industry. A new type of safe, non-toxic, and edible antibacterial functional film was developed with sodium alginate (2.5 %), gum arabic (1 %), glycerol (2 %), and natamycin as an antimicrobial agent in this study. The physical and antibacterial properties of films, such as thickness, chromaticity, water vapor permeability, tensile strength, and elongation at break, were studied. Furthermore, the antibacterial film was applied in the preservation of sweet potatoes. The results showed that natamycin emulsion had good compatibility with sodium alginate. Besides reducing the transparency of the composite membrane, the mechanical properties, barrier properties, and thermal stability of the composite film were significantly enhanced by the addition of natamycin prepared by a pH-cycle method. When the concentration of natamycin in the membrane solution reached 40 μg/mL or more, the antibacterial film had a noticeable inhibitory effect on the growth of molds, and yeasts, significantly enhancing the bacteriostatic effect of the base film. During the sweet potatoes storage, the water content, total starch content, Vc content, and flavonoid glycoside content of sweet potato showed a downward trend. However, the treatment of antibacterial film containing natamycin could slow down the physiological and quality changes of sweet potatoes during conventional storage, and the sweet potatoes still had good processing quality after 120 days of storage.

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.