Micelle-nanogel platform for ferulic acid ocular delivery

A Nanogel Formulation of Anti-VEGF Peptide for Ocular Neovascularization Treatment

Age-related macular degeneration (AMD) is an eye disorder that can lead to visual impairment in elder patients, and current treatments include repeated injections of monoclonal antibody-based antivascular endothelial growth factor (anti-VEGF) agents. This study investigates the potential of a nanoformulation of a peptide anti-VEGF molecule for neovascular AMD. Anti-VEGF peptide HRHTKQRHTALH (HRH), which has high affinity to VEGF-Fc receptor, was used as the bioactive agent to control neovascularization of the retina. The nanoformulation consisting of hyaluronic acid nanogel was generated by incorporating divinyl sulfone and cholesterol to increase the stability and control the size of the nanodrug. The encapsulation efficacy of nanogel was 65%, and drug release was 34.72% at the end of 192 h. Obtained nanogels were efficiently internalized in 15 min by human umbilical vascular endothelial cells (HUVECs) and ARPE-19 cells, and results indicate that nanoformulation is not toxic to ARPE-19 cells, whereas it inhibits HUVEC proliferation owing to anti-VEGF peptide in the nanogel structure. In the coculture experiment in which retinal penetration was modeled, it was observed that the nanogel reached HUVECs and negatively affected their proliferation without disturbing the monolayer of ARPE-19 cells. In vivo experiments with chick chorioallantoic membrane revealed that nanogel formulation has higher antiangiogenesis activity compared to free HRH. Additionally, in an oxygen-induced retinopathy model, the excessive growth of blood vessels was notably suppressed in mice treated with HRH-loaded nanogel. This research indicates that nanogels formulated in this study are promising candidates as a topical treatment for AMD.

Hydrogel-exosome system in tissue engineering: A promising therapeutic strategy

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

Nanophytomedicine: A promising practical approach in phytotherapy

The long and rich history of herbal therapeutic nutrients is fascinating. It is incredible to think about how ancient civilizations used plants and herbs to treat various ailments and diseases. One group of bioactive phytochemicals that has gained significant attention recently is dietary polyphenols. These compounds are commonly found in a variety of fruits, vegetables, spices, nuts, drinks, legumes, and grains. Despite their incredible therapeutic properties, one challenge with polyphenols is their poor water solubility, stability, and bioavailability. This means that they are not easily absorbed by the body when consumed in essential diets. Because of structural complexity, polyphenols with high molecular weight cannot be absorbed in the small intestine and after arriving in the colon, they are metabolized by gut microbiota. However, researchers are constantly working on finding solutions to enhance the bioavailability and absorption of these compounds. This study aims to address this issue by applying nanotechnology approaches to overcome the challenges of the therapeutic application of dietary polyphenols. This combination of nanotechnology and phytochemicals could cause a completely new field called nanophytomedicine or herbal nanomedicine.

Preparation, Characterization, Antioxidant Activities, and Determination of Anti-Alzheimer Effects of PLGA-Based DDSs Containing Ferulic Acid

Nanoparticle (NP) systems have attracted the attention of researchers in recent years due to their advantages, such as modified release features, increased therapeutic efficacy, and reduced side effects. Ferulic acid (FA) has therapeutic effects such as anti-inflammatory, anti-Alzheimer's, antioxidant, antimicrobial, anticancer, antihyperlipidemic, and antidiabetic. In this study, FA-loaded PLGA-based NPs were prepared by a nanoprecipitation method and the effect of varying concentrations of Poloxamer 188 and Span 60 on NP properties was investigated. FA-loaded A-FA coded formulation was chosen as optimum. High encapsulation efficiency has been achieved due to the low affinity of FA to the water phase and, therefore, its lipophilic nature, which tends to migrate to the organic phase. It was determined that the release of FA from the A-FA was slower than pure FA and prolonged release in 24 h. Antioxidant and anti-Alzheimer's effects of A-FA coded NP formulation were investigated by biological activity studies. A-FA coded NP formulation showed strong DPPH free radical scavenging, ABTS cation decolorizing, and reducing antioxidant activity. Since it has both AChE inhibitor and antioxidant properties according to the results of its anti-Alzheimer activity, it was concluded that the formulation prepared in this study shows promise in the treatment of both oxidative stress-related diseases and Alzheimer's.

Ferulic acid's therapeutic odyssey: nano formulations, pre-clinical investigations, and patent perspective

INTRODUCTION

Ferulic acid (FA) is a phenolic phytochemical that has garnered the attention of the research community due to its abundant availability in nature. It is a compound that has been explored for its multifaceted therapeutic potential and benefits in modern and contemporary healthcare.

AREAS COVERED

This review furnishes a compilation of the molecular mechanisms underlying the anti-diabetic, anticancer, antioxidant, and anti-inflammatory effects of FA. We also aim to excavate an in-depth analysis of the role of nanoformulations to achieve release control, reduce toxicity, and deliver FA at specified target sites. To corroborate the safety and efficacy of FA, a multitude of pre-clinical studies have also been conducted by researchers and have been discussed comprehensively in this review. The various patented innovations and newer paradigms pertaining to FA have also been presented.

EXPERT OPINION

Enormous research has been conducted and should still be continued to find the best possible novel drug delivery system for FA delivery. The utilization of nanocarriers and nanoformulations has intrigued the scientists for delivery of FA, but before that, it is necessary to shed light upon toxicity, safety, and regulatory concerns of FA.

Developments in Emerging Topical Drug Delivery Systems for Ocular Disorders

According to the current information, using nano gels in the eyes have therapeutic benefits. Industry growth in the pharmaceutical and healthcare sectors has been filled by nanotechnology. Traditional ocular preparations have a short retention duration and restricted drug bioavailability because of the eye's architectural and physiological barriers, a big issue for physicians, patients, and chemists. In contrast, nano gels can encapsulate drugs within threedimensional cross-linked polymeric networks. Because of their distinctive structural designs and preparation methods, they can deliver loaded medications in a controlled and sustained manner, enhancing patient compliance and therapeutic efficacy. Due to their excellent drugloading capacity and biocompatibility, nano-gels outperform other nano-carriers. This study focuses on using nano gels to treat eye diseases and provides a brief overview of their creation and response to stimuli. Our understanding of topical drug administration will be advanced using nano gel developments to treat common ocular diseases such as glaucoma, cataracts, dry eye syndrome, bacterial keratitis, and linked medication-loaded contact lenses and natural active ingredients.

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).

NAD+-associated-hyaluronic acid and poly(L-lysine) polyelectrolyte complexes: An evaluation of their potential for ocular drug delivery

This study details the formation and characterisation of a novel nicotinamide adenine dinucleotide (NAD+)-associated polymeric nanoparticle system. The development of a polyelectrolyte complex (PEC) composed of two natural polyelectrolytes, hyaluronic acid and poly(L-lysine), and an evaluation of its suitability for NAD+ ocular delivery, primarily based on its physicochemical properties and in vitro release profile under physiological ocular flow rates, were of key focus. Following optimisation of formulation method conditions such as complexation pH, mode of addition, and charge ratio, the PEC was successfully formulated under mild formulation conditions via polyelectrolyte complexation. With a size of 235.1 ± 19.0 nm, a PDI value of 0.214 ± 0.140, and a zeta potential value of - 38.0 ± 1.1 mV, the chosen PEC, loaded with 430 µg of NAD+ per mg of PEC, exhibited non-Fickian, sustained release at physiological flowrates of 10.9 ± 0.2 mg of NAD+ over 14 h. PECs containing up to 200 µM of NAD+ did not induce any significant cytotoxic effects on an immortalised human corneal epithelial cell line. Using fluorescent labeling, the NAD+-associated PECs demonstrated retention within the corneal epithelium layer of a porcine model up to 6 h post incubation under physiological conditions. A study of the physicochemical behaviour of the PECs, in terms of size, zeta potential and NAD+ complexation in response to environmental stimuli,highlighted the dynamic nature of the PEC matrix and its dependence on both pH and ionic condition. Considering the successful formation of reproducible NAD+-associated PECs with suitable characteristics for ocular drug delivery via an inexpensive formulation method, they provide a promising platform for NAD+ ocular delivery with a strong potential to improve ocular health.

Nanomaterial-based ophthalmic drug delivery

The low bioavailability and side effects of conventional drugs for eye disease necessitate the development of efficient drug delivery systems. Accompanying the developments of nanofabrication techniques, nanomaterials have been recognized as promising tools to overcome these challenges due to their flexible and programmable properties. Given the advances achieved in material science, a broad spectrum of functional nanomaterials capable of overcoming various ocular anterior and posterior segment barriers have been explored to satisfy the demands for ocular drug delivery. In this review, we first highlight the unique functions of nanomaterials suitable for carrying and transporting ocular drugs. Then, various functionalization strategies are emphasized to endow nanomaterials with superior performance in enhanced ophthalmic drug delivery. The rational design of several affecting factors is essential for ideal nanomaterial candidates and is depicted as well. Lastly, we introduce the current applications of nanomaterial-based delivery systems in the therapy of different ocular anterior and posterior segment diseases. The limitations of these delivery systems as well as potential solutions are also discussed. This work will inspire innovative design thinking for the development of nanotechnology-mediated strategies for advanced drug delivery and treatment toward ocular diseases.

Recent development of polymer nanomicelles in the treatment of eye diseases

The eye, being one of the most intricate organs in the human body, hosts numerous anatomical barriers and clearance mechanisms. This highlights the importance of devising a secure and efficacious ocular medication delivery system. Over the past several decades, advancements have been made in the development of a nano-delivery platform based on polymeric micelles. These advancements encompass diverse innovations such as poloxamer, chitosan, hydrogel-encapsulated micelles, and contact lenses embedded with micelles. Such technological evolutions allow for sustained medication retention and facilitate enhanced permeation within the eye, thereby standing as the avant-garde in ocular medication technology. This review provides a comprehensive consolidation of ocular medications predicated on polymer nanomicelles from 2014 to 2023. Additionally, it explores the challenges they pose in clinical applications, a discussion intended to aid the design of future clinical research concerning ocular medication delivery formulations.

Molecular mechanism and research progress on pharmacology of ferulic acid in liver diseases

Ferulic acid (FA) is a natural polyphenol, a derivative of cinnamic acid, widely found in Angelica, Chuanxiong and other fruits, vegetables and traditional Chinese medicine. FA contains methoxy, 4-hydroxy and carboxylic acid functional groups that bind covalently to neighbouring adjacent unsaturated Cationic C and play a key role in many diseases related to oxidative stress. Numerous studies have shown that ferulic acid protects liver cells and inhibits liver injury, liver fibrosis, hepatotoxicity and hepatocyte apoptosis caused by various factors. FA has protective effects on liver injury induced by acetaminophen, methotrexate, antituberculosis drugs, diosbulbin B and tripterygium wilfordii, mainly through the signal pathways related to TLR4/NF-κB and Keap1/Nrf2. FA also has protective effects on carbon tetrachloride, concanavalin A and septic liver injury. FA pretreatment can protect hepatocytes from radiation damage, protects the liver from damage caused by fluoride, cadmium and aflatoxin b1. At the same time, FA can inhibit liver fibrosis, inhibit liver steatosis and reduce lipid toxicity, improve insulin resistance in the liver and exert the effect of anti-liver cancer. In addition, signalling pathways such as Akt/FoxO1, AMPK, PPAR γ, Smad2/3 and Caspase-3 have been shown to be vital molecular targets for FA involvement in improving various liver diseases. Recent advances in the pharmacological effects of ferulic acid and its derivatives on liver diseases were reviewed. The results will provide guidance for the clinical application of ferulic acid and its derivatives in the treatment of liver diseases.

Advances in Nanogels for Topical Drug Delivery in Ocular Diseases

Nanotechnology has accelerated the development of the pharmaceutical and medical technology fields, and nanogels for ocular applications have proven to be a promising therapeutic strategy. Traditional ocular preparations are restricted by the anatomical and physiological barriers of the eye, resulting in a short retention time and low drug bioavailability, which is a significant challenge for physicians, patients, and pharmacists. Nanogels, however, have the ability to encapsulate drugs within three-dimensional crosslinked polymeric networks and, through specific structural designs and distinct methods of preparation, achieve the controlled and sustained delivery of loaded drugs, increasing patient compliance and therapeutic efficiency. In addition, nanogels have higher drug-loading capacity and biocompatibility than other nanocarriers. In this review, the main focus is on the applications of nanogels for ocular diseases, whose preparations and stimuli-responsive behaviors are briefly described. The current comprehension of topical drug delivery will be improved by focusing on the advances of nanogels in typical ocular diseases, including glaucoma, cataracts, dry eye syndrome, and bacterial keratitis, as well as related drug-loaded contact lenses and natural active substances.

Lyophilization for Formulation Optimization of Drug-Loaded Thermoresponsive Polyelectrolyte Complex Nanogels from Functionalized Hyaluronic Acid

The lyophilization of nanogels is practical not only for their long-term conservation but also for adjusting their concentration and dispersant type during reconstitution for different applications. However, lyophilization strategies must be adapted to each kind of nanoformulation in order to minimize aggregation after reconstitution. In this work, the effects of formulation aspects (i.e., charge ratio, polymer concentration, thermoresponsive grafts, polycation type, cryoprotectant type, and concentration) on particle integrity after lyophilization and reconstitution for different types of polyelectrolyte complex nanogels (PEC-NGs) from hyaluronic acid (HA) were investigated. The main objective was to find the best approach for freeze-drying thermoresponsive PEC-NGs from Jeffamine-M-2005-functionalized HA, which has recently been developed as a potential platform for drug delivery. It was found that freeze-drying PEC-NG suspensions prepared at a relatively low polymer concentration of 0.2 g.L−1 with 0.2% (m/v) trehalose as a cryoprotectant allow the homogeneous redispersion of PEC-NGs when concentrated at 1 g.L−1 upon reconstitution in PBS without important aggregation (i.e., average particle size remaining under 350 nm), which could be applied to concentrate curcumin (CUR)-loaded PEC-NGs for optimizing CUR content. The thermoresponsive release of CUR from such concentrated PEC-NGs was also reverified, which showed a minor effect of freeze-drying on the drug release profile.

Nano-based eye drop: Topical and noninvasive therapy for ocular diseases

Eye drops are the most accessible therapy for ocular diseases, while inevitably suffering from their lower bioavailability which highly restricts the treatment efficacy. The introduction of nanotechnology has attracted considerable interest as it has advantages over conventional ones such as prolonged ocular surface retention time and enhanced ocular barrier penetrating properties, and achieving higher bioavailability and improved treatment efficacy. This review describes various ocular diseases treated with eye drops as well as the physiological and anatomical ocular barriers faced with through drug administration. It also summarizes the recent advances regarding the utilization of nanotechnology in developing eye drops, and how to optimize the nanocarrier-based ocular drug delivery systems. The prospective future research directions for nano-based eye drops are also discussed here.

Fucoidan-ferulic acid nanoparticles alleviate cisplatin-induced acute kidney injury by inhibiting the cGAS-STING pathway

Fucoidan (FU) is a natural sulfated polysaccharide with certain biological activity and has been shown to be an excellent nano-delivery material. In this study, ferulic acid (FA)-loaded FU nanoparticles (FA/FU NPs) were prepared and their nephroprotective mechanism was investigated. With a particle size of 158.6 ± 4.5 nm, FA/FU NPs increased the antioxidant activity of FA in vitro, possibly related to the increased dispersity of FA. In vitro results demonstrated that FA/FU NPs significantly protected human renal proximal tubule (HK-2) cells from cisplatin-induced damage, possibly by suppressing cisplatin-induced DNA damage and activating the cGAS-STING pathway. Furthermore, in vivo experiments confirmed that FA/FU NPs protected mice from cisplatin-induced acute kidney injury (AKI). Mechanistic studies confirmed that FA/FU NPs exerted nephroprotective effects by reducing MDA activity and increasing GSH and SOD activity. Our results demonstrated the potential of FU for delivering poorly soluble drug FA and protecting against cisplatin-induced AKI.

Hyaluronic Acid: Its Versatile Use in Ocular Drug Delivery with a Specific Focus on Hyaluronic Acid-Based Polyelectrolyte Complexes

Extensive research is currently being conducted into novel ocular drug delivery systems (ODDS) that are capable of surpassing the limitations associated with conventional intraocular anterior and posterior segment treatments. Nanoformulations, including those synthesised from the natural, hydrophilic glycosaminoglycan, hyaluronic acid (HA), have gained significant traction due to their enhanced intraocular permeation, longer retention times, high physiological stability, inherent biocompatibility, and biodegradability. However, conventional nanoformulation preparation methods often require large volumes of organic solvent, chemical cross-linkers, and surfactants, which can pose significant toxicity risks. We present a comprehensive, critical review of the use of HA in the field of ophthalmology and ocular drug delivery, with a discussion of the physicochemical and biological properties of HA that render it a suitable excipient for drug delivery to both the anterior and posterior segments of the eye. The pivotal focus of this review is a discussion of the formation of HA-based nanoparticles via polyelectrolyte complexation, a mild method of preparation driven primarily by electrostatic interaction between opposing polyelectrolytes. To the best of our knowledge, despite the growing number of publications centred around the development of HA-based polyelectrolyte complexes (HA-PECs) for ocular drug delivery, no review articles have been published in this area. This review aims to bridge the identified gap in the literature by (1) reviewing recent advances in the area of HA-PECs for anterior and posterior ODD, (2) describing the mechanism and thermodynamics of polyelectrolyte complexation, and (3) critically evaluating the intrinsic and extrinsic formulation parameters that must be considered when designing HA-PECs for ocular application.

The Use of Polymer Blends in the Treatment of Ocular Diseases

The eye is an organ with limited drug access due to its anatomical and physiological barriers, and the usual forms of ocular administration are limited in terms of drug penetration, residence time, and bioavailability, as well as low patient compliance. Hence, therapeutic innovations in new drug delivery systems (DDS) have been widely explored since they show numerous advantages over conventional methods, besides delivering the content to the eye without interfering with its normal functioning. Polymers are usually used in DDS and many of them are applicable to ophthalmic use, especially biodegradable ones. Even so, it can be a hard task to find a singular polymer with all the desirable properties to deliver the best performance, and combining two or more polymers in a blend has proven to be more convenient, efficient, and cost-effective. This review was carried out to assess the use of polymer blends as DDS. The search conducted in the databases of Pubmed and Scopus for specific terms revealed that although the physical combination of polymers is largely applied, the term polymer blend still has low compliance.

Considerations for Polymers Used in Ocular Drug Delivery

PURPOSE

Age-related eye diseases are becoming more prevalent. A notable increase has been seen in the most common causes including glaucoma, age-related macular degeneration (AMD), and cataract. Current clinical treatments vary from tissue replacement with polymers to topical eye drops and intravitreal injections. Research and development efforts have increased using polymers for sustained release to the eye to overcome treatment challenges, showing promise in improving drug release and delivery, patient experience, and treatment compliance. Polymers provide unique properties that allow for specific engineered devices to provide improved treatment options. Recent work has shown the utilization of synthetic and biopolymer derived biomaterials in various forms, with this review containing a focus on polymers Food and Drug Administration (FDA) approved for ocular use.

METHODS

This provides an overview of some prevalent synthetic polymers and biopolymers used in ocular delivery and their benefits, brief discussion of the various types and synthesis methods used, and administration techniques. Polymers approved by the FDA for different applications in the eye are listed and compared to new polymers being explored in the literature. This article summarizes research findings using polymers for ocular drug delivery from various stages: laboratory, preclinical studies, clinical trials, and currently approved. This review also focuses on some of the challenges to bringing these new innovations to the clinic, including limited selection of approved polymers.

RESULTS

Polymers help improve drug delivery by increasing solubility, controlling pharmacokinetics, and extending release. Several polymer classes including synthetic, biopolymer, and combinations were discussed along with the benefits and challenges of each class. The ways both polymer synthesis and processing techniques can influence drug release in the eye were discussed.

CONCLUSION

The use of biomaterials, specifically polymers, is a well-studied field for drug delivery, and polymers have been used as implants in the eye for over 75 years. Promising new ocular drug delivery systems are emerging using polymers an innovative option for treating ocular diseases because of their tunable properties. This review touches on important considerations and challenges of using polymers for sustained ocular drug delivery with the goal translating research to the clinic.

Natural Products as Sources of Multitarget Compounds: Advances in the Development of Ferulic Acid as Multitarget Therapeutic

Nature has provided therapeutic substances for millennia, with many valuable medications derived from plant sources. Multitarget drugs become essential in the management of various disorders including hepatic disorders, neurological disorders, diabetes, and carcinomas. Ferulic acid is a significant potential therapeutic agent, which is easily available at low cost, possesses a low toxicity profile, and has minimum side effects. Ferulic acid exhibits various therapeutic actions by modulation of various signal transduction pathways such as Nrf2, p38, and mTOR. The actions exhibited by ferulic acid include anti-apoptosis, antioxidant, anti-inflammatory, antidiabetic, anticarcinogenic, hepatoprotection, cardioprotection, activation of transcriptional factors, expression of genes, regulation of enzyme activity, and neuroprotection, which further help in treating various pathophysiological conditions such as cancer, skin diseases, brain disorders, diabetes, Parkinson's disease, Alzheimer's disease, hypoxia, hepatic disorders, H1N1 flu, and viral infections. The current review focuses on the significance of natural products as sources of multitarget compounds and a primary focus has been made on ferulic acid and its mechanism, role, and protective action in various ailments.

Overview of nanoparticulate strategies for solubility enhancement of poorly soluble drugs

Poor aqueous solubility and poor bioavailability are major issues with many pharmaceutical industries. By some estimation, 70-90% drug candidates in development stage while up-to 40% of the marketed products are poorly soluble which leads to low bioavailability, reduced therapeutic effects and dosage escalation. That's why solubility is an important factor to consider during design and manufacturing of the pharmaceutical products. To-date, various strategies have been explored to tackle the issue of poor solubility. This review article focuses the updated overview of commonly used macro and nano drug delivery systems and techniques such as micronization, solid dispersion (SD), supercritical fluid (SCF), hydrotropy, co-solvency, micellar solubilization, cryogenic technique, inclusion complex formation-based techniques, nanosuspension, solid lipid nanoparticles, and nanogels/nanomatrices explored for solubility enhancement of poorly soluble drugs. Among various techniques, nanomatrices were found a promising and impeccable strategy for solubility enhancement of poorly soluble drugs. This article also describes the mechanism of action of each technique used in solubilization enhancement.

Hyaluronan-Cholesterol Nanogels for the Enhancement of the Ocular Delivery of Therapeutics

The anatomy and physiology of the eye strongly limit the bioavailability of locally administered drugs. The entrapment of therapeutics into nanocarriers represents an effective strategy for the topical treatment of several ocular disorders, as they may protect the embedded molecules, enabling drug residence on the ocular surface and/or its penetration into different ocular compartments. The present work shows the activity of hyaluronan-cholesterol nanogels (NHs) as ocular permeation enhancers. Thanks to their bioadhesive properties, NHs firmly interact with the superficial corneal epithelium, without penetrating the stroma, thus modifying the transcorneal penetration of loaded therapeutics. Ex vivo transcorneal permeation experiments show that the permeation of hydrophilic drugs (i.e., tobramycin and diclofenac sodium salt), loaded in NHs, is significantly enhanced when compared to the free drug solutions. On the other side, the permeation of hydrophobic drugs (i.e., dexamethasone and piroxicam) is strongly dependent on the water solubility of the entrapped molecules. The obtained results suggest that NHs formulations can improve the ocular bioavailability of the instilled drugs by increasing their preocular retention time (hydrophobic drugs) or facilitating their permeation (hydrophilic drugs), thus opening the route for the application of HA-based NHs in the treatment of both anterior and posterior eye segment diseases.

Flexible polymeric nanosized micelles for ophthalmic drug delivery: research progress in the last three years

The eye is a complex structure with a variety of anatomical barriers and clearance mechanisms, so the provision of safe and effective ophthalmic drug delivery technology is a major challenge. In the past few decades, a number of reports have shown that nano-delivery platforms based on polymeric micelles are of great interest, because of their hydrophobic core that encapsulates lipid-soluble drugs and small size with high penetration, allowing long-term drug retention and posterior penetration in the eye. Furthermore, as an ocular delivery platform, polymeric micelles not only cover the single micellar drug delivery system formed by poloxamer, chitosan or other polymers, but also include composite drug delivery systems like micelle-encapsulated hydrogels and micelle-embedded contact lenses. In this review, a number of ophthalmic micelles that have emerged in the last three years will be systematically reviewed, with a summary of and discussion on their unique advantages or unique drug delivery performance. Last but not least, the current challenges of polymeric micelle formulations in potential clinical ophthalmic therapeutic applications will also be proposed, which might be helpful for future design of ocular drug delivery formulations.

Ferulic Acid-Loaded Polymeric Nanoparticles for Potential Ocular Delivery

Ferulic acid (FA) is an antioxidant compound that can prevent ROS-related diseases, but due to its poor solubility, therapeutic efficacy is limited. One strategy to improve the bioavailability is nanomedicine. In the following study, FA delivery through polymeric nanoparticles (NPs) consisting of polylactic acid (NPA) and poly(lactic-co-glycolic acid) (NPB) is proposed. To verify the absence of cytotoxicity of blank carriers, a preliminary in vitro assay was performed on retinal pericytes and endothelial cells. FA-loaded NPs were subjected to purification studies and the physico-hemical properties were analyzed by photon correlation spectroscopy. Encapsulation efficiency and in vitro release studies were assessed through high performance liquid chromatography. To maintain the integrity of the systems, nanoformulations were cryoprotected and freeze-dried. Morphology was evaluated by a scanning electron microscope. Physico-chemical stability of resuspended nanosystems was monitored during 28 days of storage at 5 °C. Thermal analysis and Fourier-transform infrared spectroscopy were performed to characterize drug state in the systems. Results showed homogeneous particle populations, a suitable mean size for ocular delivery, drug loading ranging from 64.86 to 75.16%, and a controlled release profile. The obtained systems could be promising carriers for ocular drug delivery, legitimating further studies on FA-loaded NPs to confirm efficacy and safety in vitro.

Injectable thermosensitive chitosan-based hydrogel containing ferulic acid for treating peripheral arterial disease

Peripheral arterial disease (PAD) affects more than 200 million people worldwide. Recent studies suggest that oxidative stress-related inflammation can lead to the initiation and progression of PAD. Ferulic acid (FA) is a natural phenolic compound and has been proven to have antioxidant and angiogenesis effects. In this study, thermosensitive chitosan-gelatin-based hydrogel was used as a delivery vehicle of FA. The effects of hydrogel encapsulating FA (FA-gel) have been demonstrated in vitro and in vivo. The results revealed that the developed hydrogel with porous structure could provide a sustained release of FA. Post-treatment of FA-gel effectively decreased the oxidative stress-induced damage in human umbilical vein endothelial cells via decreasing endogenous reactive oxygen species production, inflammation-related gene expression and apoptosis level. In the mouse hindlimb ischemia model, the results revealed that FA-gel could improve blood flow, muscle regeneration and decreases inflammation in veins. These results suggested that FA-gel may have a therapeutic potential in PAD.

Poloxamer-407-Co-Poly (2-Acrylamido-2-Methylpropane Sulfonic Acid) Cross-linked Nanogels for Solubility Enhancement of Olanzapine: Synthesis, Characterization, and Toxicity Evaluation

Current study is focused to enhance the solubility of poorly soluble drug olanzapine (OLZ) by nanogels drug delivery system, as improved solubility is one of the most important applications of nanosystems. Poor solubility is a major issue, and 40% of marketed and about 75% of new active pharmaceutical ingredients are poorly water soluble which significantly affect the bioavailability and therapeutic effects of these drugs. In this study, nanogels, a promising system for solubility enhancement, were developed by free-radical polymerization technique. Different formulations were synthesized in which poloxamer-407 was cross-linked with 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with the help of cross-linker methylene bisacrylamide (MBA). The chemically cross-linked nanogels were characterized by Fourier transform infrared spectroscopy (FT-IR), thermos gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta size, swelling, sol-gel analysis, drug loading, solubility, and in vitro drug release studies. In order to determine the biocompatibility and cytotoxicity of nanogels to biological system, toxicity study on rabbits was also carried out. It was confirmed that the developed nanogels was thermally stable, safe, effective, and compatible to biological system, and the solubility of olanzapine (OLZ) was enhanced up to 38 folds as compared with reference product.

Ferulic Acid-NLC with Lavandula Essential Oil: A Possible Strategy for Wound-Healing?

Nowadays, an increasing interest in combinatorial drug delivery systems is emerging, highlighting the possibility of exploiting essential oils (EO) for topical applications. This work aimed at developing nanostructured lipid carriers (NLC) for the combined delivery of ferulic acid and Lavandula EO, whose beneficial effects in wound-healing processes have been widely reported. Homogeneous (polydispersity index, PDI < 0.2) nanoparticles with a small size (<150 nm) and a high encapsulation efficiency (>85%) were obtained. The co-presence of ferulic acid and Lavandula EO, as compared to synthetic isopropyl myristate-based NLC, increased nanoparticles’ stability, due to higher ordering chains, as confirmed by morphological and physicochemical studies. An enhanced cytocompatibility was observed when combining ferulic acid and Lavandula EO, as confirmed by in vitro studies on fibroblasts. Furthermore, the combined delivery of ferulic acid and Lavandula EO significantly promoted cell migration with higher effectiveness in respect to the free drug solution and the carrier without the EO. Taken all together, our results suggest a potential combined effect of the antioxidant ferulic acid and Lavandula EO co-delivered in lipid nanoparticles in promoting cell proliferation and migration, representing a promising strategy in the treatment of wounds.

Micelles: Promising Ocular Drug Carriers for Anterior and Posterior Segment Diseases

Micelles have been studied in the targeting of drug substances to different tissues as a nano-sized delivery system for many years. Sustained drug release, ease of production, increased solubility, and bioavailability of drugs with low water solubility are the most important superiorites of micellar carriers. These advantages paved the way for the use of micelles as a drug delivery system in the ocular tissues. The unique anatomical structure of the eye as well as its natural barriers and physiology affect ocular bioavailability of the drugs negatively. Conventional dosage forms can only reach the anterior segment of the eye and are used for the treatment of diseases of this segment. In the treatment of posterior segment diseases, conventional dosage forms are administered sclerally, via an intravitreal injection, or systemically. However, ocular irritation, low patient compliance, and high side effects are also observed. Micellar ocular drug delivery systems have significant promise for the treatment of ocular diseases. The potential of micellar systems ocular drug delivery has been demonstrated by in vivo animal experiments and clinical studies, and they are continuing extensively. In this review, the recent research studies, in which the positive outcomes of micelles for ocular targeting of drugs for both anterior and posterior segment diseases as well as glaucoma has been demonstrated by in vitro, ex vivo, or in vivo studies, are highlighted.

Crosslinked Hyaluronan Electrospun Nanofibers for Ferulic Acid Ocular Delivery

Electrospun nanofibers are gaining interest as ocular drug delivery platforms that may adapt to the eye surface and provide sustained release. The aim of this work was to design an innovative ophthalmic insert composed of hyaluronan (HA) nanofibers for the dual delivery of an antioxidant (ferulic acid, FA) and an antimicrobial peptide (ε-polylysine, ε-PL). Polyvinylpyrrolidone (PVP) was added to facilitate the electrospinning process. Fibers with diameters of approx. 100 nm were obtained with PVP 5%-HA 0.8% w/v and PVP 10%-HA 0.5% w/v mixtures in ethanol:water 4:6 v/v. An increase in PVP concentration to 20% w/v in both presence and absence of HA rendered fibers of approx. 1 µm. PVP 5%-HA 0.8% w/v fibers were loaded with 83.3 ± 14.0 µg FA per mg. After nanofibers crosslinking with ε-PL, blank and FA-loaded inserts showed a mean thickness of 270 ± 21 µm and 273 ± 41 µm, respectively. Blank and FA-loaded inserts completely released ε-PL within 30 min under sink conditions, whereas FA-loaded inserts released the antioxidant within 20 min. Both blank and FA-loaded inserts were challenged against Pseudomonas aeruginosa and Staphylococcus aureus, demonstrating their efficacy against relevant microbial species.