Preparation and in vitro-in vivo evaluation of ofloxacin loaded ophthalmic nano structured lipid carriers modified with chitosan oligosaccharide lactate for the treatment of bacterial keratitis

Unveiling the potential of chitosan-coated lipid nanoparticles in drug delivery for management of critical illness: a review

Chitosan (CT), a natural, cationic, chemically stable molecule, biocompatible, biodegradable, nontoxic, polysaccharide derived from the deacetylation of chitin, has very uniquely surfaced as a material of promise for drug delivery and biomedical applications. For the oral, ocular, cutaneous, pulmonary, and nose-to-brain routes, CT-coated nanoparticles (CTCNPs) have numerous advantages, consisting of improved controlled drug release, physicochemical stability, improved cell and tissue interactions, and increased bioavailability and efficacy of the active ingredient. CTCNPs have a broad range of therapeutic properties including anticancer, antiviral, antifungal, anti-inflammatory, antibacterial properties, treating neurological disorders, and other diseases. This has led to substantial research into the many potential uses of CT as a drug delivery vehicle. CT has also been employed in a wide range of biomedical processes, including bone and cartilage tissue regeneration, ocular tissue regeneration, periodontal tissue regeneration, heart tissue regeneration, and wound healing. Additionally, CT has been used in cosmeceutical, bioimaging, immunization, and gene transfer applications. CT exhibits a number of biological activities, which are the basis for its remarkable potential for use as a drug delivery vehicle, and these activities are covered in detail in this article. The alterations applied to CT to obtain the necessary properties have been described.

Chitosan-coated nanoparticles in innovative cancer bio-medicine

In the recent decade, nanoparticles (NPs) have had enormous implications in cancer biomedicine, including research, diagnosis, and therapy. However, their broad application still faces obstacles due to some practical limitations and requires further development. Recently, there has been more interest in the coated class of nanoparticles to address those challenges. Chitosan-coated NPs are simple to produce, biodegradable, biocompatible, exhibit antibacterial activity, and have less cytotoxicity. This study provides an updated and comprehensive overview of the application of chitosan-coated NPs as a promising class of NPs in cancer biomedicine. Additionally, we discussed chitosan-coated lipid, metal, and polymer-based nanoparticles in biomedical applications. Furthermore, different coating methods and production/characterization procedures were reviewed. Moreover, the biological and physicochemical advantages of chitosan-coated NPs, including facilitated controlled release, greater physicochemical stability, improved cell/tissue interaction, and enhanced bioavailability of medications, were highlighted. Finally, the prospects of chitosan-coated NPs in cancer biomedicine were discussed.

Chitosan oligosaccharide/pluronic F127 micelles exhibiting anti-biofilm effect to treat bacterial keratitis

Mono or dual chitosan oligosaccharide lactate (COL)-conjugated pluronic F127 polymers, FCOL1 and FCOL2 were prepared, self-assembled to form micelles, and loaded with gatifloxacin. The Gati@FCOL1/Gati@FCOL2 micelles preparation process was optimized by QbD analysis. Micelles were characterized thoroughly for size, CMC, drug compatibility, and viscosity by GPC, DLS, SEM, IR, DSC, and XRD. The micelles exhibited good cellular uptake in both monolayers and spheroids of HCEC. The antibacterial and anti-biofilm activities of the micelles were evaluated on P. aeruginosa and S. aureus. The anti-quorum sensing activity was explored in P. aeruginosa by analyzing micelles' ability to produce virulence factors, including AHLs, pyocyanin, and the motility behavior of the organism. Gati@FCOL2 Ms was mucoadhesive, cornea-penetrant, antibacterial, and inhibited the biofilm formation by P. aeruginosa and S. aureus significantly more than Gati@FCOL1. A significant reduction in bacterial load in mice cornea was observed after Gati@FCOL2 Ms-treatment to the P. aeruginosa-induced bacterial keratitis-infected mice.

Emphasis on Nanostructured Lipid Carriers in the Ocular Delivery of Antibiotics

BACKGROUND

Drug distribution to the eye is still tricky because of the eye's intricate structure. Systemic delivery, as opposed to more traditional methods like eye drops and ointments, is more effective but higher doses can be harmful.

OBJECTIVE

The use of solid lipid nanoparticles (SLNPs) as a method of drug delivery has been the subject of research since the 1990s. Since SLNPs are derived from naturally occurring lipids, they pose no health risks to the user. To raise the eye's absorption of hydrophilic and lipophilic drugs, SLNs can promote corneal absorption and improve the ocular bioavailability of SLNPs.

METHODS

To address problems related to ocular drug delivery, many forms of nano formulation were developed. Some of the methods developed are, emulsification and ultra-sonication, high-speed stirring and ultra-sonication, thin layer hydration, adapted melt-emulsification, and ultrasonication techniques, hot o/w micro-emulsion techniques, etc. Results: Nanostructured lipid carriers are described in this review in terms of their ocular penetration mechanism, structural characteristic, manufacturing process, characterization, and advantages over other nanocarriers.

CONCLUSION

Recent developments in ocular formulations with nanostructured bases, such as surfacemodified attempts have been made to increase ocular bioavailability in both the anterior and posterior chambers by incorporating cationic chemicals into a wide variety of polymeric systems.

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.

mPEG-CS-modified flexible liposomes-reinforced thermosensitive sol-gel reversible hydrogels for ocular delivery of multiple drugs with enhanced synergism

Non-invasive drug delivery offers a safe treatment while improving patient compliance. However, due to the particular physiological structure of the ocular, long-term retention and sustained drug release of the drug delivery system is crucial. Herein, this study aimed to design mPEG-CS-modified flexible liposomes-reinforced thermosensitive sol-gel reversible hydrogels (mPEG-CS-FL-TSG) for the delivery of astragaloside IV (AS-IV) and tetramethylpyrazine (TMP) to treat age-related macular degeneration. In vitro biological properties of mPEG-CS-FL and mPEG-CS-FL-TSG showed that they could be successfully taken up by ARPE-19 cells, and the uptake rate of mPEG-CS-FL-TSG was higher. Not only that, the release rate of mPEG-CS-FL-TSG was slower. More significantly, the results showed that the cytotoxicity of mPEG-CS-FL-TSG was lower than that of mPEG-CS-FL. In vivo result revealed that the drug delivery system could prominently enhance the ocular bioavailability of AS-IV and TMP, which is the enhanced synergism of well-permeable liposome and slow-releasing hydrogel. In summary, the mPEG-CS-FL-TSG can compensate for the short retention time and sudden release of liposome, as well as the low drug penetration of hydrogel, in order to show great promise in the non-invasive delivery of multiple drugs for the treatment of posterior ocular diseases.

Chitosan-Coated SLN: A Potential System for Ocular Delivery of Metronidazole

Ophthalmic drops for ocular delivery exhibit inadequate residence time, which often requires multiple daily dosing that may result in patient non-adherence. In this study, the development of a once-daily-dosed chitosan-coated metronidazole (MTZ)-loaded solid lipid nanoparticles (SLNs) for ocular delivery was undertaken. Melt emulsification and ultrasonication were used to manufacture MTZ-loaded SLN, which were subsequently coated with chitosan (CS) by mechanical stirring using a 0.1% w/v solution. Gelucire^® 48/16 and Transcutol^® HP were used as the solid lipid and synthetic solvent, respectively, with Tween^® 20 included as a stabilizing agent. The critical quality attributes (CQA) of the optimized CS-coated SLN that was monitored included particle size, polydispersity index, Zeta potential, % entrapment efficiency, % MTZ loading, pH, and osmolarity. The optimized coated nanocarriers were evaluated using laser Doppler anemometry (LDA) and were determined to be stable, with particle sizes in the nanometre range. In vitro mucoadhesion, MTZ release and short-term stability, in addition to the determination of the shape of the optimized CS-coated SLN, were undertaken. The mucoadhesive properties of the optimized CS-coated MTZ-loaded SLN demonstrated increased ocular availability, which may allow dose reduction or longer intervals between doses by improving precorneal retention and ocular availability. Overall, our findings suggest that CS-coated MTZ-loaded SLNs have the potential for clinical application, to enhance ocular delivery through the release of MTZ.

The effect of charges on the corneal penetration of solid lipid nanoparticles loaded econazole after topical administration in rabbits

Fungal keratitis is an infectious disease caused by pathogenic fungi with a high blindness rate. Econazole (ECZ) is an imidazole antifungal drug with insoluble ability. Econazole-loaded solid lipid nanoparticles (E-SLNs) were prepared by microemulsion method, then modified with positive and negative charge. The mean diameter of cationic E-SLNs, nearly neutral E-SLNs and anionic E-SLNs were 18.73±0.14, 19.05±0.28, 18.54±0.10 nm respectively. The Zeta potential of these different charged SLNs formulations were 19.13±0.89, -2.20±0.10, -27.40±0.67 mV respectively. The Polydispersity Index (PDI) of these three kinds of nanoparticles were about 0.2. The Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetry (DSC) analysis showed that the nanoparticles were a homogeneous system. Compared with Econazole suspension (E-Susp), SLNs exhibited sustained release capability, stronger corneal penetration and enhanced inhibition of pathogenic fungi without irritation. The antifungal ability was further improved after cationic charge modification compared with E-SLNs. Studies on pharmacokinetics showed that the order of the AUC and t_1/2 of different preparations was cationic E-SLNs > nearly neutral E-SLNs > anionic E-SLNs > E-Susp in cornea and aqueous humor. It was shown that SLNs could increase corneal penetrability and ocular bioavailability while these capabilities were further enhanced with positive charge modification compared with negative charge ones.

Ocular Drug Delivery: a Comprehensive Review

The human eye is a sophisticated organ with distinctive anatomy and physiology that hinders the passage of drugs into targeted ophthalmic sites. Effective topical administration is an interest of scientists for many decades. Their difficult mission is to prolong drug residence time and guarantee an appropriate ocular permeation. Several ocular obstacles oppose effective drug delivery such as precorneal, corneal, and blood-corneal barriers. Routes for ocular delivery include topical, intravitreal, intraocular, juxtascleral, subconjunctival, intracameral, and retrobulbar. More than 95% of marketed products exists in liquid state. However, other products could be in semi-solid (ointments and gels), solid state (powder, insert and lens), or mixed (in situ gel). Nowadays, attractiveness to nanotechnology-based carries is resulted from their capabilities to entrap both hydrophilic and lipophilic drugs, enhance ocular permeability, sustain residence time, improve drug stability, and augment bioavailability. Different in vitro, ex vivo, and in vivo characterization approaches help to predict the outcomes of the constructed nanocarriers. This review aims to clarify anatomy of the eye, various ocular diseases, and obstacles to ocular delivery. Moreover, it studies the advantages and drawbacks of different ocular routes of administration and dosage forms. This review also discusses different nanostructured platforms and their characterization approaches. Strategies to enhance ocular bioavailability are also explained. Finally, recent advances in ocular delivery are described.

Nanotechnology based drug delivery systems for the treatment of anterior segment eye diseases

Diseases affecting the anterior segment of the eye are the primary causes of vision impairment and blindness globally. Drug administration through the topical ocular route is widely accepted because of its user/patient friendliness - ease of administration and convenience. However, it remains a significant challenge to efficiently deliver drugs to the eye through this route because of various structural and physiological constraints that restrict the distribution of therapeutic molecules into the ocular tissues. The bioavailability of topically applied ocular medications such as eye drops is typically less than 5%. Developing novel delivery systems to increase the retention time on the ocular surfaces and permeation through the cornea is one of the approaches adopted to boost the bioavailability of topically administered medications. Drug delivery systems based on nanotechnology such as micelles, nanosuspensions, nanoparticles, nanoemulsions, liposomes, dendrimers, niosomes, cubosomes and nanowafers have been investigated as effective alternatives to conventional ocular delivery systems in treating diseases of the anterior segment of the eye. This review discussed different nanotechnology-based delivery systems that are currently investigated for treating and managing diseases affecting the anterior ocular tissues. We also looked at the challenges in translating these systems into clinical use and the prospects of nanocarriers as a vehicle for the delivery of phytoactive compounds to the anterior segment of the eye.

Targeted Nanotherapies for the Posterior Segment of the Eye: An Integrative Review on Recent Advancements and Challenges

The eye is a one-of-a-kind sensory organ with intricate anatomy and physiology. It is protected by a variety of barriers, ranging from static barriers to dynamic barriers. Although these barriers are very effective at protecting the eye from exogenous substances and external stress, they are highly compromised by various vision-impairing diseases of both the anterior and the posterior segment of the eye. Due to ocular elimination systems and intricate obstacles that selectively limit drug entry into the eye, effective drug delivery to the posterior segment of the eye (PSE) continues to be a challenge in ophthalmology. Since more than half of the most debilitating eye illnesses are thought to originate in the posterior segment (PS), understanding the physiology and clearance mechanism of the eye could help design improved formulations that could be noninvasive and intended for targeted posterior segment therapeutics. Moreover, the major drawback associated with the conventional drug delivery system to PSE is minimal therapeutic drug concentration in the desired ocular tissue and life-threatening ophthalmic complications. One possible approach that can be implemented to overcome these ocular barriers for efficient ocular therapy, non-invasive and targeted drug action to the posterior tissues is by designing nanomedicines. This review summarizes the recent non-invasive and patient compliant advances in designing nanomedicines targeting PSE. The various routes and pathways of drug administration to the ocular tissue are also summarized.

Chitosan-functionalized nanostructured lipid carriers containing chloroaluminum phthalocyanine for photodynamic therapy of skin cancer

The objective of this study was to obtain optimized nanostructured lipid carriers (NLC) functionalized with chitosan containing chloroaluminum phthalocyanine (ClAlPc) as a photosensitizer. Initially, the optimization of the preparation method of the NLC was performed, where the influence of different surfactants such as PVA and Tween 80, as well as different solid lipids such as stearic acid and Glycerol Monostearate (GM) was evaluated. The formulation containing GM and PVA (NLC10) was considered promising. Following, by the adsorption method (NLC10q), the formulation was functionalized with chitosan and characterized. NLC10 and NLC10q presented sizes of 131.5 and 231.5 nm, and ZP of -24.30 and + 19.96 mV, respectively. The encapsulation efficiency of NLC10q was 96 %, higher than NLC10 (79 %). The formulations were able to promote significant cutaneous retention of ClAlPc, after 2 h and 4 h of the study, and showed to be non-toxic to fibroblasts (biocompatible). PDT in BF16-F10 melanoma resulted in reduced cell viability to 70 % and 50 % for NLC10 and NLCq, respectively. In view of the results obtained, NLC showed to be promising in the treatment of skin cancer through PDT. NLC10q showed higher encapsulation efficiency and stability than NLC10, but, contrary to what was expected, it presented lower photodynamic efficiency.

Optimization and Characterization of Low-Molecular-Weight Chitosan-Coated Baicalin mPEG-PLGA Nanoparticles for the Treatment of Cataract

The present study was to evaluate the potential effectiveness of low-molecular-weight chitosan-coated baicalin methoxy poly(ethylene glycol)-poly(d,l-lactic-co-glycolic acid) (mPEG-PLGA) nanoparticles (BA LCH NPs) for the treatment of cataract. mPEG-PLGA NPs were optimized by the Box-Behnken design and the central composite design based on the encapsulation efficiency and drug loading. Then, the BA LCH NPs were characterized based on morphology, particle size, and zeta potentials. The analytical data of differential scanning calorimetry, X-ray diffraction, and transmission electron microscopy depicted the drug excipient compatibility. In vitro, we evaluated cell viability, cellular uptake, potential ocular irritation, transcorneal permeability, and the precorneal retention of BA LCH NPs. In vivo, the chronic selenium cataract model was selected to assess the therapeutic effect of BA LCH NPs. The size of BA LCH NPs was within the range from 148 to 219 nm and the zeta potential was 19-25 mV. Cellular uptake results showed that the fluorescence intensity of the preparations in each group increased with time, and the fluorescence intensity of the LCH NP group was significantly higher than that of the solution group. The optimized BA LCH NPs improved precorneal residence time without causing eye irritation and also showed a sustained release of BA through the cornea for effective management of cataract. Also, fluorescence tracking on the rabbit cornea showed increased corneal retention of the LCH NPs. In addition, the results of therapeutic efficacy demonstrated that BA LCH NPs can significantly reduce the content of malondialdehyde and enhanced the activities of catalase, superoxide dismutase, and glutathione peroxidase, which was comparable to positive control and better than the BA solution group. Thus, it can be inferred that the BA LCH NPs are a promising drug delivery system for enhancing the ophthalmic administration of BA to the posterior segment of the eye and improving cataract symptoms.

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.

Design of Besifloxacin HCl-Loaded Nanostructured Lipid Carriers: In Vitro and Ex Vivo Evaluation

Objective: In the treatment of severe cases of bacterial keratitis, conventional eye drops containing antibiotics should be applied daily and very frequently. The aim of this study is to develop low-dose high-effect formulations with the prepared nanostructured lipid carrier (NLC) formulations to reduce antibiotic resistance and increase patient compliance. Methods: NLC formulations were loaded with besifloxacin HCl (BHL) and the besifloxacin HCl: sulfobutyl ether beta-cyclodextrin (SBE-CD) complex. Positive charge was gained with chitosan, and corneal permeation and resolubility were increased with SBE-CD. In vitro characterization studies, permeability studies, and cytotoxicity and ex vivo transport studies were carried out. Results: In this study, it was found that SBE-CD increased BHL's solubility by 8-fold based on phase solubility studies. The optimized NLCs were small in size (13.63-16.09 nm) with a low polydispersity index (0.107-0.181) and adequate BHL drug loading efficiency. In vitro release studies showed that formulations were released approximately for 8 h and at levels over the minimum inhibitory concentration of Pseudomonas aeruginosa and Staphylococcus aureus. NLC formulations had a better corneal permeation rate than the marketed product during 6 h of ex vivo studies. Conclusions: According to in vitro and ex vivo data, it was determined that the most favorable NLC formulation was the formulation containing BHL/SBE-CD that was covered with chitosan. It has the highest drug loading capacity and one of the highest ex vivo corneal passage levels, along with desired drug release. The formulation containing BHL/SBE-CD and chitosan can be a potential alternative for the treatment of bacterial keratitis.

Targeting foodborne pathogens via surface-functionalized nano-antimicrobials

The incorporation of antibiotics and bioactive compounds into non-toxic nanoparticles has been popularly used to produce effective antimicrobial nanocarriers against foodborne pathogens. These systems can protect antimicrobials against harsh environments, control their release, and increase their antimicrobial activities; however, their functions can be decreased by some major barriers. Intracellular localization of bacteria protects them from the host immune system and antimicrobial agents. Also, bacteria can cause constant infection by nestling in professional phagocytic cells. In the last years, surface functionalization of nanocarriers by passive and active modification methods has been applied for their protection against clearance from the blood, increasing both circulation time and uptake by target cells. For achieving this objective, different functional agents such as specifically targeted peptides internalize ligands, saccharide ligands, or even therapeutic molecules (e.g., antibodies or enzymes) are used. In this review, techniques for functionalizing the surface of antimicrobial-loaded nanocarriers have been described. This article offers a comprehensive review of the potential of functional nanoparticles to increase the performance of antimicrobials against foodborne pathogens through targeting delivery.

Taking leads out of nature, can nano deliver us from COVID-like pandemics?

The COVID-19 crisis has alerted the research community to re-purpose scientific tools that can effectively manage emergency pandemic situations. Researchers were never so desperate to discover a 'magic bullet' that has significant clinical benefits with minimal or no side effects. At the beginning of the pandemic, due to restricted access to traditional laboratory techniques, many research groups delved into computational screening of thousands of lead molecules that could inhibit SARS-CoV-2 at one or more stages of its infectious cycle. Several in silico studies on natural derivatives point out their potency against SARS-CoV-2 proteins. However, theoretical predictions and existing knowledge on related molecules reflect their poor oral bioavailability due to biotransformation in the gut and liver. Nanotechnology has evolved into a key field for precise and controlled delivery of various drugs that lack aqueous solubility, have low oral bioavailability and possess pronounced toxicity in their native form. In this review, we discuss various nanoformulations of natural products with favorable ADME properties, and also briefly explore nano-drug delivery to lungs, the primary site of SARS-CoV-2 infection. Natural products are also envisioned to augment nanotechnology-based 1) personnel protective equipment for ex vivo viral inactivation and 2) wearable sensors that perform rapid and non-invasive analysis of volatile organic compounds in exhaled breath of the infected person after therapeutic food consumption.

Nanostructured Lipid Carriers-Hydrogels System for Drug Delivery: Nanohybrid Technology Perspective

Advanced hybrid component development in nanotechnology provides superior functionality in the application of scientific knowledge for the drug delivery industry. The purpose of this paper is to review important nanohybrid perspectives in drug delivery between nanostructured lipid carriers (NLC) and hydrogel systems. The hybrid system may result in the enhancement of each component's synergistic properties in the mechanical strength of the hydrogel and concomitantly decrease aggregation of the NLC. The significant progress in nanostructured lipid carriers-hydrogels is reviewed here, with an emphasis on their preparation, potential applications, advantages, and underlying issues associated with these exciting materials.

Compritol solid lipid nanoparticle formulations enhance the protective effect of betulinic acid derivatives in human Müller cells against oxidative injury

Müller cells maintain homeostatic functions in the retina. Their dysfunction leads to irreversible retinal diseases. Oxidative injury is a leading cause of retinal cytotoxicity. Our previous studies reported several betulinic acid (BA) derivatives can protect Müller cells from oxidative injury but achieving pharmacologically effective concentrations in the Müller cells could be a limitation. To optimise cellular delivery, we encapsulated the BA analogues H3, H5 and H7 into the clinically approved Compritol 888 and HD5 ATO solid lipid nanoparticles (SLNs) using the micro-emulsion method. The cytoprotective effects of these SLN-formulations were determined in human MIO-M1 cells. We found cytoprotection by H3 and H5 SLN-formulations was significantly enhanced, which was evident at concentrations much lower than those required with the free agents. Both SLN-formulations prolonged the duration of action of these agents. The most effective agent H5 delivered in 888 ATO SLNs attenuated glutamate-induced ROS formation and the associated necrosis in MIO-M1 cells. Overall, SLNs have emerged as promising delivery carriers for BA derivatives enhancing their protective effects against oxidative injury in human Müller cells. Our study is the first to show SLNs can be a viable route to delivery agents with improved efficacy and stability into human Müller cells favoring the treatment/prevention of retinal diseases.

Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis

Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the "anti-biotic era". Although, we are expeditiously developing our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins. In this review article, we have provided an overview of the established classical diagnostic techniques and therapeutics for keratitis caused by various bacteria. We have extensively reported our recent in-roads through novel tools for accurate diagnosis of mono- and poly-bacterial corneal infections. Furthermore, we outlined the recent progress by our group and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discussed in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.

Tissue Engineering Meets Nanotechnology: Molecular Mechanism Modulations in Cornea Regeneration

Nowadays, tissue engineering is one of the most promising approaches for the regeneration of various tissues and organs, including the cornea. However, the inability of biomaterial scaffolds to successfully integrate into the environment of surrounding tissues is one of the main challenges that sufficiently limits the restoration of damaged corneal tissues. Thus, the modulation of molecular and cellular mechanisms is important and necessary for successful graft integration and long-term survival. The dynamics of molecular interactions affecting the site of injury will determine the corneal transplantation efficacy and the post-surgery clinical outcome. The interactions between biomaterial surfaces, cells and their microenvironment can regulate cell behavior and alter their physiology and signaling pathways. Nanotechnology is an advantageous tool for the current understanding, coordination, and directed regulation of molecular cell-transplant interactions on behalf of the healing of corneal wounds. Therefore, the use of various nanotechnological strategies will provide new solutions to the problem of corneal allograft rejection, by modulating and regulating host-graft interaction dynamics towards proper integration and long-term functionality of the transplant.

Development of ritonavir-loaded nanostructured lipid carriers employing quality by design (QbD) as a tool: characterizations, permeability, and bioavailability studies

The objective of the present work was to optimize ritonavir (RTV)-loaded nanostructured lipid carriers (NLCs) to improve bioavailability using a quality by design (QbD)-based technique. Risk assessment was studied using "cause and effect" diagram followed by failure mode effect analysis (FMEA) to identify the effective high-risk variables for the formulation development. Quality target product profile (QTPP) and critical quality attributes (CQAs) were initially assigned for the proposed product. Central composite rotatable design (CCRD) was used to identify the individual and combined interactions of formulation variables. RTV-loaded NLC (RTV-NLC) was prepared using emulsification-ultrasonication method. The effect of formulation variables like ultrasound amplitude, lipid concentration, surfactant concentration on their responses like particle size, polydispersity index (PDI), and entrapment efficiency (EE) were studied by CCRD. The optimized formulation was subjected to lyophilization to obtain dry NLCs for solid-state analysis. DSC and PXRD investigations showed that RTV was molecularly dispersed in lipid matrix indicating amorphous form present in the formulation. FESEM and AFM depicted the spherical and uniform particles. The increase in solubility and dissolution rate is expected to be related to the molecular dispersion, amorphous state, of the drug in the nanoparticle. The optimized NLCs showed good physical stability during storage for 6 months. RTV-NLC was further subjected to in vitro studies and found a successful sustained release rate of 92.37 ± 1.03%. The parallel artificial membrane permeability assay (PAMPA) and everted gut sac model have demonstrated the permeation enhancement of RTV. In vivo study observed the enhanced bioavailability with 2.86-fold suggesting optimized NLC successfully overcome the issue of solubility.

Topical ocular delivery of vancomycin loaded cationic lipid nanocarriers as a promising and non-invasive alternative approach to intravitreal injection for enhanced bacterial endophthalmitis management

Vancomycin (VCM) is a drug of choice for treating infections caused by Staphylococcus species, reported being the most causative agent of bacterial endophthalmitis. However, the ocular bioavailability of topically applied VCM is low due to its high molecular weight and hydrophilicity. The current study sought to explore whether the nanostructured lipid carriers (NLCs) fabricated via cold homogenization technique could improve ocular penetration and prolong the ophthalmic residence of VCM. A 2³ full factorial design was adopted to evaluate the influence of different process and formulation variables on VCM-loaded NLC formulae. The optimized formula with the particle size of 96.4 ± 0.71 nm and narrow size distribution showed spherical morphology obtained by AFM and represented sustained drug release up to 67% in 48 h fitted to the Korsmeyer-Peppas model with probably non-Fickian diffusion kinetic. FTIR studies visualized the drug-carrier interactions in great detail. High encapsulation of VCM (74.8 ± 4.3% w/w) in NLC has been established in DSC and PXRD analysis. The optimal positively charged (+ 29.7 ± 0.47 mV) colloidal dispersion was also stable for 12 weeks at both 4 °C and 25 °C. According to in vivo studies, incorporation of VCM in NLC resulted in a nearly 3-fold increase in the intravitreal concentration of VCM after eye-drop instillation over control groups. Besides, microbiological evaluation admitted its therapeutic effect within five days is comparable to intravitreal injection of VCM. Further, the optimized formula was found to be nonirritant and safe for ophthalmic administration in RBC hemolytic assay. Also, fluorescent tracking of NLCs on rabbit's cornea showed an increase in corneal penetration of nanoparticles. Thus, it is possible to infer that the evolved NLCs are promising drug delivery systems with superior attainments for enhanced Vancomycin ophthalmic delivery to the eye's posterior segment and improved bacterial endophthalmitis management.

Alternative Therapeutic Interventions: Antimicrobial Peptides and Small Molecules to Treat Microbial Keratitis

Microbial keratitis is a leading cause of blindness worldwide and results in unilateral vision loss in an estimated 2 million people per year. Bacteria and fungus are two main etiological agents that cause corneal ulcers. Although antibiotics and antifungals are commonly used to treat corneal infections, a clear trend with increasing resistance to these antimicrobials is emerging at rapid pace. Extensive research has been carried out to determine alternative therapeutic interventions, and antimicrobial peptides (AMPs) are increasingly recognized for their clinical potential in treating infections. Small molecules targeted against virulence factors of the pathogens and natural compounds are also explored to meet the challenges and growing demand for therapeutic agents. Here we review the potential of AMPs, small molecules, and natural compounds as alternative therapeutic interventions for the treatment of corneal infections to combat antimicrobial resistance. Additionally, we have also discussed about the different formats of drug delivery systems for optimal administration of drugs to treat microbial keratitis.

"Kill-release" antibacterial polysaccharides multilayer coating based therapeutic contact lens for effective bacterial keratitis treatment

Contact lenses (CLs) are an important medical device for ophthalmic disease treatment. They can be used not only to correct refractive errors, such as myopia, but also can serve as a drug carrier for ocular surface disease treatment. In this study, a therapeutic CL was designed for bacterial keratitis treatment by constructing an antibacterial surface coating via a layer-by-layer (LbL) electrostatic self-assembly method. Vancomycin-incorporated chitosan nanoparticles were firstly prepared by ionic condensation of sodium tripolyphosphate (abbreviated as CTVNP). The positively charged CTVNP were then used for LbL deposition with negatively charged heparin (HEP), obtaining a (HEP/CTVNP)_n polyelectrolyte multilayer on the CL surface. It is shown that such antibiotic incorporated surface coating doesn't influence the light transmittance of the CL, so it should not affect the patients' visual acuity when wearing them. The in vitro bacteriostatic effect evaluation was performed via live and dead bacteria staining and scanning electron microscope (SEM), which demonstrated the effective antibacterial property of such a surface. The fabricated therapeutic CL was then used to treat bacterial keratitis on a rabbit model. The results showed that such CL could effectively control the development of the bacteria-infected cornea and had a significant therapeutic effect.

Therapeutic contact lenses fabricated by polysaccharides multilayer surface modification, shows “kill-release” antibacterial performance, can serve as an effective treatment for bacterial keratitis.

Effective Ocular Delivery of Eplerenone Using Nanoengineered Lipid Carriers in Rabbit Model

Background

Eplerenone (Epl) is a selective mineralocorticoid-receptor antagonist used for chronic central serous chorioretinopathy treatment. Our goal was to enhance the corneal performance of Epl-loaded nanostructured lipid carriers (NLCs) through surface modification using different coating polymers.

Methods

Epl-loaded modified NLCs (Epl-loaded MNLCs) were prepared by coating the surface of Epl-loaded NLCs using different polymers, namely hyaluronic acid, chitosan oligosaccharide lactate, and hydrogenated collagen. A 3¹×4¹ full factorial design was used to evaluate the effect of the surface modification on the properties of the prepared systems. Selected optimal Epl-loaded MNLCs were further evaluated for in vitro drug release, morphology, pH, rheological properties, corneal mucoadhesion, irritation, and penetration.

Results

Epl-loaded MNLCs were successfully prepared with high drug-entrapment efficiency and nanosized particles with low size distribution. Transmission electron microscopy revealed nanosized spherical particles surrounded by a coating layer of the surface modifier. The pH, refractive index, and viscosity results of the Epl-loaded MNLCs confirmed the ocular compatibility of the systems with no blurring of vision. The safety and ocular tolerance of the optimal MNLCs were confirmed using the hen’s egg test on chorioallantoic membrane and by histopathological evaluation of rabbit eyes treated with the optimal systems. Confocal laser-scanning microscopy of corneal surfaces confirmed successful transcorneal permeation of the Epl-loaded MNLCs compared to the unmodified Epl-loaded NLCs, revealed by higher corneal fluorescence intensity at all time intervals.

Conclusion

Overall, the results confirmed the potential of Epl-loaded MNLCs as a direct approach for Epl ocular delivery.

A diffusion cell adapted to nuclear imaging instruments for the measurement of molecular release and pharmacokinetics across membranes

Diffusion cells are routinely used in pharmacology to measure the permeation of pharmaceutical compounds and contaminants across membranes (biological or synthetic). They can also be used to study drug release from excipients. The device is made of a donor (DC) and an acceptor (AC) compartment, separated by a membrane. Usually, permeation of molecules across membranes is measured by sampling from the AC at different time points. However, this process disturbs the equilibrium of the cell. Furthermore, analytical techniques used in association with diffusion cells sometimes lack either accuracy, sensitivity, or both. This work reports on the development of nuclear imaging - compatible diffusion cells. The cell is made of a polymer transparent to high-energy photons typically detected in positron emission tomography (PET). It was tested in a finite-dose set-up experiment with a pre-clinical PET system. Porous cellulose membranes (3.5, 25 and 300 kDa), a common excipient in pharmacology, as well as for dialysis membranes, were used as test membranes. The radioisotope ⁸⁹Zr chelated with deferoxamine B (DFO; 0.65 kDa), was used as an imaging probe (7-10 MBq; 0.2-0.3 nMol ⁸⁹Zr-DFO). In medicine, DFO is also commonly used for iron removal treatments and pharmacological formulations often require the association of this molecule with cellulose. Permeation profiles were obtained by measuring the radioactivity in the DC and AC for up to 2 weeks. The kinetic profiles were used to extract lag time, influx, and diffusion coefficients of DFO across porous cellulose membranes. A sensitivity threshold of 0.005 MBq, or 3.4 fmol of ⁸⁹Zr-DFO, was revealed. The lag time to permeation (τ) measured in the AC compartment, was found to be 1.33, 0.5, and 0.19 h with 3.5, 25, and 300 kDa membranes, respectively. Diffusion coefficients of 3.65 × 10^-6, 8.33 × 10^-6, and 4.74 × 10^-5 cm² h^-1 where revealed, with maximal pseudo steady-state influx values (J_pss) of 6.55 × 10^-6, 1.76 × 10^-5, and 1.29 × 10^-5 nmol cm^-2 h^-1. This study confirms the potential of the technology for monitoring molecular diffusion and release processes at low concentrations, high sensitivities, in real time and in a visual manner.

Colloidal nanosystems with mucoadhesive properties designed for ocular topical delivery

Over the last years, the scientific interest about topical ocular delivery targeting the posterior segment of the eye has been increasing. This is probably due to the fact that this is a non-invasive administration route, well tolerated by patients and with fewer local and systemic side effects. However, it is a challenging task due to the external ocular barriers, tear film clearance, blood flow in the conjunctiva and choriocapillaris and due to the blood-retinal barriers, amongst other features. An enhanced intraocular bioavailability of drugs can be achieved by either improving corneal permeability or by improving precorneal retention time. Regarding this last option, increasing residence time in the precorneal area can be achieved using mucoadhesive polymers such as xyloglucan, poly(acrylate), hyaluronic acid, chitosan, and carbomers. On the other hand, colloidal particles can interact with the ocular mucosa and enhance corneal and conjunctival permeability. These nanosystems are able to deliver a wide range of drugs, including macromolecules, providing stability and improving ocular bioavailability. New pharmaceutical approaches based on nanotechnology associated to bioadhesive compounds have emerged as strategies for a more efficient treatment of ocular diseases. Bearing this in mind, this review provides an overview of the current mucoadhesive colloidal nanosystems developed for ocular topical administration, focusing on their advantages and limitations.

Nanostructured lipid carrier-incorporated gel for efficient topical delivery of fluconazole

Background: Nanostructured lipid carriers (NLCs) of fluconazole were prepared to improve permeability and thereby effective topical drug delivery. Materials and methods: NLCs were prepared and evaluated, and then the optimized NLC suspension was incorporated into a gel that was further evaluated for topical drug delivery. Results and discussion: F-2 NLC formulation was optimized based on results of particle size (161.3 ± 1.385 nm), polydispersity index (0.401), zeta potential (-33 ± 0.46), entrapment efficiency (82.26 ± 0.91%) and in vitro drug release (76.40 ± 0.21%). Ex vivo skin permeation studies showed flux of F-2 gel and the comparison marketed gel as 0.21 and 0.18 mg/cm²/h, respectively. The in vitro antifungal study revealed significantly better activity compared with the marketed gel. Conclusion: Fluconazole NLCs increase drug permeability and proved to be effective in topical drug delivery.

Challenges in Oral Drug Delivery and Applications of Lipid Nanoparticles as Potent Oral Drug Carriers for Managing Cardiovascular Risk Factors

BACKGROUND

The oral application of drugs is the most popular route through which the systemic effect can be achieved. Nevertheless, oral administration is limited by difficulties related to the physicochemical properties of the drug molecule, including low aqueous solubility, instability, low permeability, and rapid metabolism, all of which result in low and irregular oral bioavailability.

OBJECTIVE

The enhancement of oral bioavailability of drug molecules with such properties could lead to extreme complications in drug preparations. Oral lipid-based nanoparticles seem to possess extensive advantages due to their ability to increase the solubility, simplifying intestinal absorption and decrease or eradicate the effect of food on the absorption of low soluble, lipophilic drugs and therefore improving the oral bioavailability.

METHODS

The present review provides a summary of the general theory of lipid-based nanoparticles, their preparation methods, as well as their oral applications. Moreover, oral drug delivery challenges are discussed.

RESULTS

According to this review, the most frequent types of lipid-based nanoparticle, the solid lipid nanoparticles and nanostructured lipid carriers are potent oral carriers due to their ability to penetrate the oral drug adsorption barriers. Moreover, such lipid nanoparticles can be beneficial drug carriers against cardiovascular risk disorders as diabetes, hypertension, etc. Conclusion: In this review, the most current and promising studies involving Solid Lipid Nanoparticles and Nanostructured Lipid Carriers as oral drug carriers are reported aiming to assist researchers who focus their research on lipid-based nanoparticles.

Quality by design (QbD)-based fabrication of atazanavir-loaded nanostructured lipid carriers for lymph targeting: bioavailability enhancement using chylomicron flow block model and toxicity studies

Atazanavir (ATV) is widely used as anti-HIV agent having poor aqueous solubility needs to modulate novel drug delivery system to enhance therapeutic efficiency and safety. The main objective of the present work was to fabricate ATV-loaded nanostructured lipid carriers (NLCs) employing quality by design (QbD) approach to address the challenges of bioavailability and their safety after oral administration. Herein, the main objective was to identify the influencing variables for the production of quality products. Considering this objective, quality target product profile (QTPP) was assigned and a systematic risk assessment study was performed to identify the critical material attributes (CMAs) and critical process parameter (CPP) having an influence on critical quality attributes (CQAs). Lipid concentrations, surfactant concentrations, and pressure of high-pressure homogenizer were identified as CMAs and CPP. ATV-NLCs were prepared by emulsification-high pressure homogenization method and further lyophilized to obtain solid-state NLCs. The effect of formulation variables (CMAs and CPP) on responses like particle size (Y₁), polydispersity index (Y₂), and zeta potential (Y₃) was observed by central composite rotatable design (CCRD). The data were statistically evaluated by ANOVA for confirmation of a significant level (p < 0.05). The optimal conditions of NLCs were obtained by generating design space and desirability value. The lyophilized ATV-NLCs were characterized by DSC, powder X-ray diffraction, and FT-IR analysis. The morphology of NLCs was revealed by TEM and FESEM. In vitro study suggested a sustained release pattern of drug (92.37 ± 1.03%) with a mechanism of Korsmeyer-Peppas model (r² = 0.925, and n = 0.63). In vivo evaluation in Wistar rats showed significantly higher (p < 0.001) plasma drug concentration of ATV-NLCs as compared to ATV-suspension using chylomicron flow block model. The relative bioavailability of ATV-NLCs was obtained to be 2.54 folds. Thus, a safe and promising drug targeting system was successfully developed to improve bioavailability and avoiding first-pass effect ensures to circumvent the acute-toxicity of liver.

Polyvinyl Alcohol/Chitosan Single-Layered and Polyvinyl Alcohol/Chitosan/Eudragit RL100 Multi-layered Electrospun Nanofibers as an Ocular Matrix for the Controlled Release of Ofloxacin: an In Vitro and In Vivo Evaluation

A novel nanofiber insert was prepared with a modified electrospinning method to enhance the ocular residence time of ofloxacin (OFX) and to provide a sustained release pattern by covering hydrophilic polymers, chitosan/polyvinyl alcohol (CS/PVA) nanofibers, with a hydrophobic polymer, Eudragit RL100 in layers, and by glutaraldehyde (GA) cross-linking of CS-PVA nanofibers for the treatment of infectious conjunctivitis. The morphology of the prepared nanofibers was studied using scanning electron microscopy (SEM). The average fiber diameter was found to be 123 ± 23 nm for the single electrospun nanofiber with no cross-linking (OFX-O). The single nanofibers, cross-linked for 10 h with GA (OFX-OG), had an average fiber diameter of 159 ± 30 nm. The amount of OFX released from the nanofibers was measured in vitro and in vivo using UV spectroscopy and microbial assay methods against Staphylococcus aureus, respectively. The antimicrobial efficiency of OFX formulated in cross-linked and non-cross-linked nanofibers was affirmed by observing the inhibition zones of Staphylococcus aureus and Escherichia coli. In vivo studies using the OFX nanofibrous inserts on a rabbit eye confirmed a sustained release pattern for up to 96 h. It was found that the cross-linking of the nanofibers by GA vapor could reduce the burst release of OFX from OFX-loaded CS/PVA in one layer and multi-layered nanofibers. In vivo results showed that the AUC_0–96 for the nanofibers was 9–20-folds higher compared to the OFX solution. This study thus demonstrates the potential of the nanofiber technology is being utilized to sustained drug release in ocular drug delivery systems.

Nanotechnology approaches for delivery and targeting of Amphotericin B in fungal and parasitic diseases

Amphotericin B (AMB), with widespread antifungal and anti-parasitic activities and low cross-resistance with other drugs, has long been identified as a potent antimicrobial drug. However, its clinical toxicities, especially nephrotoxicity, have limited its use in clinical practice. Lately, nano-based systems have been the subject of serious research and becoming an effective strategy to improve toxicity and antimicrobial potency. Commercial AMB lipid formulations have been developed in order to improve the therapeutic index and nephrotoxicity, while limited use is mainly due to their high cost. The review aimed to highlight the updated information on nanotechnology-based approaches to the development of AMB delivery and targeting systems for treatment of fungal diseases and leishmaniasis, regarding therapeutic challenges and achievements of various delivery systems.

Nanochitosan: Commemorating the Metamorphosis of an ExoSkeletal Waste to a Versatile Nutraceutical

Chitin (poly-N-acetyl-D-glucosamine) is the second (after cellulose) most abundant organic polymer. In its deacetylated form-chitosan-becomes a very interesting material for medical use. The chitosan nano-structures whose preparation is described in this article shows unique biomedical value. The preparation of nanochitosan, as well as the most vital biomedical applications (antitumor, drug delivery and other medical uses), have been discussed in this review. The challenges confronting the progress of nanochitosan from benchtop to bedside clinical settings have been evaluated. The need for inclusion of nano aspects into chitosan research, with improvisation from nanotechnological inputs has been prescribed for breaking down the limitations. Future perspectives of nanochitosan and the challenges facing nanochitosan applications and the areas needing research focus have been highlighted.

Promising nanogels loaded with usnic acid for oral ulcer treatment: development, characterization, and in vivo evaluation in rabbits

This study aimed to present an effective formulation targeting oral ulcers that will remain in the application site for a longer period, reducing the frequency of administration. As a candidate formulation, usnic acid (UA) was loaded into the optimum nanogels. The characterization studies included physical, rheological, and bioadhesive properties as well as in vitro release and ex vivo studies. The rheological results revealed that the nanogels present pseudoplastic flow behavior. In vitro drug release showed a prolonged pattern. In further, the chosen UA nanogels showed very low percentages of penetration and permeation. F13, which showed the highest release, suitable bioadhesive properties (0.475 ± 0.033 N/cm²) and eligible particle size (250.22 ± 4.11 nm), PDI (0.089 ± 0.052), and zeta potential (20.56 ± 0.330 mV) values were chosen for in vivo experiments. The selected UA nanogels showed effective antimicrobial activity against Bacillus Cereus and great in vivo wound healing properties. The results indicated that suitable UA nanogels with desired properties could be prepared. The therapeutic potential of the nanogels for oral ulcers was assessed using an animal model and the histopathological findings suggested that the optimized formulation is a good choice for oral ulcer treatment. Nonetheless, further research is recommended to support its efficacy by applying pharmacodynamic and pharmacokinetic studies in human individuals.

Strategies to prolong the residence time of drug delivery systems on ocular surface

Ocular diseases may be treated via different routes of administration, such as topical, intracameral, intravitreal, oral and parenteral. Among them the topical route is most accepted by patients, although it provides in many cases the lowest bioavailability. Indeed, when a topical formulation reaches the precorneal area, i.e., the drug absorption and/or action site, it is rapidly eliminated due to eye protection mechanisms such as blinking, basal and reflex tearing, and naso-lacrimal draining. To avoid this and to reduce the frequency of dosing, various strategies have been developed to prolong drug residence time after topical administration. These strategies include the use of viscosity increasing and mucoadhesive excipients as well as combinations thereof. From the drug delivery system point of view, liquid and semisolid formulations are preferred over solid formulations such as ocular inserts and contact lenses. Furthermore, liquid and semisolid formulations can contain nano- and microcarrier systems that contribute to a prolonged residence time. Within this review an overview about the different types of excipients and formulations as well as their performance in valid animal models and clinical trials is provided.

Promising Antifungal Potential of Engineered Non-ionic Surfactant-Based Vesicles: In Vitro and In Vivo Studies

Fungal keratitis (FK) is a corneal infection caused by different fungal species. It is treated by the topical application of natamycin (NAT). Nevertheless, this approach faces many limitations like toxic effects, frequent dosing, resistance, and patient discomfort. The present research reports the development of trimethyl chitosan (TMC) coated mucoadhesive cationic niosomes by a modified thin-film hydration method. TMC was synthesized using a one-step carbodiimide method and characterized by ¹H-NMR and degree of quaternization (53.74 ± 1.06%). NAT, cholesterol (CHOL), span 60 (Sp60), and dicetyl phosphate (DCP) were used to prepare niosomes which were incubated with TMC to obtain mucoadhesive cationic NAT loaded niosomes (MCNNs). MCNNs showed a spherical shape with 1031.12 ± 14.18 nm size (PDI below 0.3) and 80.23 ± 5.28% entrapment efficiency. In vitro drug release studies showed gradual drug release from TMC coated niosomes as compared to the uncoated niosomes. MIC assay and disk diffusion assay revealed promising in vitro antifungal potential of MCNNs similar to the marketed formulation. For investigating in vivo performance, ocular retention and pharmacokinetics, ocular irritation, and ulcer healing studies were performed using the rabbit model. Mucoadhesive property and prolonged local drug release improved the safety and efficacy of NAT, suggesting that the developed niosomes could be an emerging system for effective treatment of fungal keratitis.

Current update on nanoplatforms as therapeutic and diagnostic tools: A review for the materials used as nanotheranostics and imaging modalities

In the last decade, the use of nanotheranostics as emerging diagnostic and therapeutic tools for various diseases, especially cancer, is held great attention. Up to date, several approaches have been employed in order to develop smart nanotheranostics, which combine bioactive targeting on specific tissues as well as diagnostic properties. The nanotheranostics can deliver therapeutic agents by concomitantly monitor the therapy response in real-time. Consequently, the possibility of over- or under-dosing is decreased. Various non-invasive imaging techniques have been used to quantitatively monitor the drug delivery processes. Radiolabeling of nanomaterials is widely used as powerful diagnostic approach on nuclear medicine imaging. In fact, various radiolabeled nanomaterials have been designed and developed for imaging tumors and other lesions due to their efficient characteristics. Inorganic nanoparticles as gold, silver, silica based nanomaterials or organic nanoparticles as polymers, carbon based nanomaterials, liposomes have been reported as multifunctional nanotheranostics. In this review, the imaging modalities according to their use in various diseases are summarized, providing special details for radiolabeling. In further, the most current nanotheranostics categorized via the used nanomaterials are also summed up. To conclude, this review can be beneficial for medical and pharmaceutical society as well as material scientists who work in the field of nanotheranostics since they can use this research as guide for producing newer and more efficient nanotheranostics.

Nanotechnological strategies for systemic microbial infections treatment: A review

Systemic infections is one of the major causes of mortality worldwide, and a shortage of drug approaches applied for the rapid and necessary treatment contribute to increase the levels of death in affected patients. Several drug delivery systems based in nanotechnology such as metallic nanoparticles, liposomes, nanoemulsion, microemulsion, polymeric nanoparticles, solid lipid nanoparticles, dendrimers, hydrogels and liquid crystals can contribute in the biological performance of active substances for the treatment of microbial diseases triggered by fungi, bacteria, virus and parasites. In the presentation of these statements, this review article present and demonstrate the effectiveness of these drug delivery systems for the treatment of systemic diseases caused by several microorganisms, through a review of studies on scientific literature worldwide that contributes to better information for the most diverse professionals from the areas of health sciences. The studies demonstrated that the drug delivery systems described can contribute to the therapeutic scenario of these diseases, being classified as safe, active platforms and with therapeutic versatility.

In Situ Gel Incorporating Disulfiram Nanoparticles Rescues the Retinal Dysfunction via ATP Collapse in Otsuka Long-Evans Tokushima Fatty Rats

We attempted to design an ophthalmic in situ gel formulation incorporating disulfiram (DIS) nanoparticles (Dis-NPs/ISG) and demonstrated the therapeutic effect of Dis-NPs/ISG on retinal dysfunction in 15-month-old Otsuka Long–Evans Tokushima Fatty (OLETF) rats, a rat model of diabetes. The DIS particles were crushed using a bead mill to prepare the nanoparticles, and the Dis-NPs/ISG was prepared using a combination of the DIS nanoparticles and an in situ gelling system based on methylcellulose (MC). The particle size of the Dis-NPs/ISG was 80–250 nm, and there was no detectable precipitation or aggregation for 1 month. Moreover, the Dis-NPs/ISG was gelled at 37 °C, and the drug was delivered into the retina by instillation. Only diethyldithiocarbamate (DDC) was detected in the retina (DIS was not detected) when the Dis-NPs/ISG was instilled in the right eye, and the DDC levels in the right retina were significantly higher than those in the left retina. In addition, the retinal residence time of the drug was prolonged by the application of the in situ gelling system, since the DDC levels in the retinas of rats instilled with Dis-NPs/ISG were higher than those in DIS nanoparticles without MC. Furthermore, repetitive instillation of the Dis-NPs/ISG attenuated the deterioration of electroretinograms (ERGs) in 15-month-old OLETF rats by preventing the collapse of ATP production via excessive nitric oxide and recovered the decrease in retinal function. These findings provide important information for the development of novel therapeutic approaches to diabetic retinopathy.

Nanoformulations for Ocular Delivery of Drugs - A Patent Perspective

Efficient delivery of ocular therapeutics with improved efficacy, enhanced bioavailability, and acceptable patient compliance presents unique challenges. This can be attributed to the presence of protective mechanisms, physicobiological barriers, and structural obstacles in the eye. Nanotherapeutic interventions have been explored extensively over the past few years to overcome these limitations. The present review focusses on the nanoformulations developed for the diagnosis and treatment of various ocular diseases besides providing an in-depth insight into the patents reported for the same.

Nanosystems for the Encapsulation of Natural Products: The Case of Chitosan Biopolymer as a Matrix

Chitosan is a cationic natural polysaccharide, which has emerged as an increasingly interesting biomaterialover the past few years. It constitutes a novel perspective in drug delivery systems and nanocarriers' formulations due to its beneficial properties, including biocompatibility, biodegradability and low toxicity. The potentiality of chemical or enzymatic modifications of the biopolymer, as well as its complementary use with other polymers, further attract the scientific community, offering improved and combined properties in the final materials. As a result, chitosan has been extensively used as a matrix for the encapsulation of several valuable compounds. In this review article, the advantageous character of chitosan as a matrix for nanosystemsis presented, focusing on the encapsulation of natural products. A five-year literature review is attempted covering the use of chitosan and modified chitosan as matrices and coatings for the encapsulation of natural extracts, essential oils or pure naturally occurring bioactive compounds are discussed.

Systemic Nanoparticle-Mediated Delivery of Pantetheinase Vanin-1 Regulates Lipolysis and Adiposity in Abdominal White Adipose Tissue

Lipolysis in white adipose tissue (WAT) occurs in response to nutritional signals and helps to regulate lipid turnover/adiposity in animals. However, the causal relationships and the mechanisms controlling WAT morphology are not clear. In this report, Vanin-1, a pantetheinase, is shown to be a novel determinant for lipolysis and adiposity. The expression of Vanin-1 in the abdominal WAT is positively correlated with lipolysis both in mice and in humans. Mice with global Vanin-1 deficiency exhibit adipocyte hypertrophy and impaired lipolysis. Use of a nanosystem comprising P3-peptide, chitosan oligosaccharide lactate, and polyethylene glycol that controls Vanin-1 expression in the abdominal WAT shows that WAT-specific Vanin-1 knockdown blocks fasting-induced lipolysis and prevents WAT loss. However, WAT-specific Vanin-1 mRNA restoration rescues impaired lipolysis and improves glucose/insulin intolerance in diabetic db/db mice. Mechanistically, Vanin-1 induces PPARγ activity and subsequently facilitates its activation on the proximal promoters of lipolytic genes. Thus, an essential role of Vanin-1 in the regulation of lipolysis and adiposity is revealed, and a functional RNA delivering strategy for specific intervention of Vanin-1 expression in WAT is shown. These findings provide a promising approach to treat metabolic diseases caused by dysregulation of Vanin-1 and lipolysis.