PLGA nanospheres for the ocular delivery of flurbiprofen: Drug release and interactions

Formulation of Polymeric Nanoparticles Loading Baricitinib as a Topical Approach in Ocular Application

Topical ocular drug delivery faces several challenges due to the eye's unique anatomy and physiology. Physiological barriers, tear turnover, and blinking hinder the penetration of drugs through the ocular mucosa. In this context, nanoparticles offer several advantages over traditional eye drops. Notably, they can improve drug solubility and bioavailability, allow for controlled and sustained drug release, and can be designed to specifically target ocular tissues, thus minimizing systemic exposure. This study successfully designed and optimized PLGA and PCL nanoparticles for delivering baricitinib (BTB) to the eye using a factorial design, specifically a three-factor at five-levels central rotatable composite 23+ star design. The nanoparticles were small in size so that they would not cause discomfort when applied to the eye. They exhibited low polydispersity, had a negative surface charge, and showed high entrapment efficiency in most of the optimized formulations. The Challenge Test assessed the microbiological safety of the nanoparticle formulations. An ex vivo permeation study through porcine cornea demonstrated that the nanoparticles enhanced the permeability coefficient of the drug more than 15-fold compared to a plain solution, resulting in drug retention in the tissue and providing a depot effect. Finally, the in vitro ocular tolerance studies showed no signs of irritancy, which was further confirmed by HET-CAM testing.

Nanosuspensions in ophthalmology: Overcoming challenges and enhancing drug delivery for eye diseases

This review article provides a comprehensive overview of the advancements in using nanosuspensions for controlled drug delivery in ophthalmology. It highlights the significance of ophthalmic drug delivery due to the prevalence of eye diseases and delves into various aspects of this field. The article explores molecular mechanisms, drugs used, and physiological factors affecting drug absorption. It also addresses challenges in treating both anterior and posterior eye segments and investigates the role of mucus in obstructing micro- and nanosuspensions. Nanosuspensions are presented as a promising approach to enhance drug solubility and absorption, covering formulation, stability, properties, and functionalization. The review discusses the pros and cons of using nanosuspensions for ocular drug delivery and covers their structure, preparation, characterization, and applications. Several graphical representations illustrate their role in treating various eye conditions. Specific drug categories like anti-inflammatory drugs, antihistamines, glucocorticoids, and more are discussed in detail, with relevant studies. The article also addresses current challenges and future directions, emphasizing the need for improved nanosuspension stability and exploring potential technologies. Nanosuspensions have shown substantial potential in advancing ophthalmic drug delivery by enhancing solubility and absorption. This article is a valuable resource for researchers, clinicians, and pharmaceutical professionals in this field, offering insights into recent developments, challenges, and future prospects in nanosuspension use for ocular drug delivery.

Central composite design augmented quality-by-design-based systematic formulation of erlotinib hydrochloride-loaded chitosan-poly (lactic-co-glycolic acid) nanoparticles

Aim: This study aimed to formulate erlotinib hydrochloride (ERT-HCL)-loaded chitosan (CS) and poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) using Quality-by-Design (QbD) to optimize critical quality attributes (CQAs). Materials & methods: Quality target product profile (QTPP) and CQAs were initially established. Based on L8-Taguchi screening and risk assessments, central composite design (CCD) design was used to optimize NPs. Results: ERT-HCL-loaded CS-PLGA NPs had a mean particle diameter, zeta potential and entrapment efficiency of 226.50 ± 1.62 d.nm, 27.66 ± 0.64 mV and 78.93 ± 1.94 %w/w, respectively. The NPs exhibited homogenous spherical morphology and sustained release for 72 h. Conclusion: Using systematic QbD approach, ERT-HCL was encapsulated in CS-PLGA NPs, optimizing CQAs. These findings propel future research for improved NSCLC treatment.

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.

d-α-tocopheryl polyethylene glycol 1000 succinate surface scaffold polysarcosine based polymeric nanoparticles of enzalutamide for the treatment of colorectal cancer: In vitro, in vivo characterizations

In this study, Enzalutamide (ENZ) loaded Poly Lactic-co-Glycolic Acid (PLGA) nanoparticles coated with polysarcosine and d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS) were prepared using a three-step modified nanoprecipitation method combined with self-assembly. A three-factor, three-level Box-Behnken design was implemented with Design-Expert® software to evaluate the impact of three independent variables on particle size, zeta potential, and percent entrapment efficiency through a numeric optimization approach. The results were corroborated with ANOVA analysis, regression equations, and response surface plots. Field emission scanning electron microscopy and transmission electron microscope images revealed nanosized, spherical polymeric nanoparticles (NPs) with a size distribution ranging from 178.9 ± 2.3 to 212.8 ± 0.7 nm, a zeta potential of 12.6 ± 0.8 mV, and entrapment efficiency of 71.2 ± 0.7 %. The latter increased with higher polymer concentration. Increased polymer concentration and homogenization speed also enhanced drug entrapment efficiency. In vitro drug release was 85 ± 22.5 %, following the Higuchi model (R2 = 0.98) and Fickian diffusion (n < 0.5). In vitro cytotoxicity assessments, including Mitochondrial Membrane Potential Estimation, Apoptosis analysis, cell cycle analysis, Reactive oxygen species estimation, Wound healing assay, DNA fragmentation assay, and IC50 evaluation with Sulforhodamine B assay, indicated low toxicity and high efficacy of polymeric nanoparticles compared to the drug alone. In vivo studies demonstrated biocompatibility and target specificity. The findings suggest that TPGS surface-scaffolded polysarcosine-based polymer nanoparticles of ENZ could be a promising and safe delivery system with sustained release for colorectal cancer treatment, yielding improved therapeutic outcomes.

Insights on Development Aspects of Polymeric Nanocarriers: The Translation from Bench to Clinic

Scientists are focusing immense attention on polymeric nanocarriers as a prominent delivery vehicle for several biomedical applications including diagnosis of diseases, delivery of therapeutic agents, peptides, proteins, genes, siRNA, and vaccines due to their exciting physicochemical characteristics which circumvent degradation of unstable drugs, reduce toxic side effects through controlled release, and improve bioavailability. Polymers-based nanocarriers offer numerous benefits for in vivo drug delivery such as biocompatibility, biodegradability, non-immunogenicity, active drug targeting via surface modification, and controlled release due to their pH-and thermosensitive characteristics. Despite their potential for medicinal use, regulatory approval has been achieved for just a few. In this review, we discuss the historical development of polymers starting from their initial design to their evolution as nanocarriers for therapeutic delivery of drugs, peptides, and genes. The review article also expresses the applications of polymeric nanocarriers in the pharmaceutical and medical industry with a special emphasis on oral, ocular, parenteral, and topical application of drugs, peptides, and genes over the last two decades. The review further examines the practical, regulatory, and clinical considerations of the polymeric nanocarriers, their safety issues, and directinos for future research.

Preparation of PLGA Nanoparticles by Milling Spongelike PLGA Microspheres

Currently, emulsification-templated nanoencapsulation techniques (e.g., nanoprecipitation) have been most frequently used to prepare poly-d,l-lactide-co-glycolide (PLGA) nanoparticles. This study aimed to explore a new top-down process to produce PLGA nanoparticles. The fundamental strategy was to prepare spongelike PLGA microspheres with a highly porous texture and then crush them into submicron-sized particles via wet milling. Therefore, an ethyl formate-based ammonolysis method was developed to encapsulate progesterone into porous PLGA microspheres. Compared to a conventional solvent evaporation process, the ammonolysis technique helped reduce the tendency of drug crystallization and improved drug encapsulation efficiency accordingly (solvent evaporation, 27.6 ± 4.6%; ammonolysis, 65.1 ± 1.7%). Wet milling was performed on the highly porous microspheres with a D₅₀ of 64.8 μm under various milling conditions. The size of the grinding medium was the most crucial factor for our wet milling. Milling using smaller zirconium oxide beads (0.3~1 mm) was simply ineffective. However, when larger beads with diameters of 3 and 5 mm were used, our porous microspheres were ground into submicron-sized particles. The quality of the resultant PLGA nanoparticles was demonstrated by size distribution measurement and field emission scanning electron microscopy. The present top-down process that contrasts with conventional bottom-up approaches might find application in manufacturing drug-loaded PLGA nanoparticles.

Design, Development, Physicochemical Characterization, and In Vitro Drug Release of Formoterol PEGylated PLGA Polymeric Nanoparticles

Polymeric nanoparticles’ drug delivery systems represent a promising platform for targeted controlled release since they are capable of improving the bioavailability and tissue localization of drugs compared to traditional means of administration. Investigation of key parameters of nanoparticle preparation and their impact on performance, such as size, drug loading, and sustained release, is critical to understanding the synthesis parameters surrounding a given nanoparticle formulation. This comprehensive and systematic study reports for the first time and focuses on the development and characterization of formoterol polymeric nanoparticles that have potential application in a variety of acute and chronic diseases. Nanoparticles were prepared by a variety of solvent emulsion methods with varying modifications to the polymer and emulsion system with the aim of increasing drug loading and tuning particle size for renal localization and drug delivery. Maximal drug loading was achieved by amine modification of polyethylene glycol (PEG) conjugated to the poly(lactic-co-glycolic acid) (PLGA) backbone. The resulting formoterol PEGylated PLGA polymeric nanoparticles were successfully lyophilized without compromising size distribution by using either sucrose or trehalose as cryoprotectants. The physicochemical characteristics of the nanoparticles were examined comprehensively, including surface morphology, solid-state transitions, crystallinity, and residual water content. In vitro formoterol drug release characteristics from the PEGylated PLGA polymeric nanoparticles were also investigated as a function of both polymer and emulsion parameter selection, and release kinetics modeling was successfully applied.

γ-Cyclodextrin-based polypseudorotaxane hydrogels for ophthalmic delivery of flurbiprofen to treat anterior uveitis

Anterior uveitis is a sight-threatening inflammation inside the eyes. Conventional eye drops for anti-inflammatory therapy need to be administered frequently owing to the rapid elimination and corneal barrier. To address these issues, polypseudorotaxane hydrogels were developed by mixing Soluplus micelles (99.4 nm) and cyclodextrins solution. The optimized hydrogels exhibited shear-thinning and sustained release properties. The hydrogels exhibited higher transcorneal permeability coefficient (P_app, 1.84 folds) than that of drug solutions. Moreover, animal study indicated that the hydrogels significantly increased the precorneal retention (AUC, 21.2 folds) and intraocular bioavailability of flurbiprofen (AUC_{Aqueous humor}, 17.8 folds) in comparison with drug solutions. Importantly, the hydrogels obviously boosted anti-inflammatory efficacy in rabbit model of endotoxin-induced uveitis at a reduced administration frequency. Additionally, the safety of hydrogels was confirmed by cytotoxicity and ocular irritation studies. In all, the present study demonstrates a friendly non-invasive strategy based on γ-CD-based polypseudorotaxane hydrogels for ocular drug delivery.

Assessment to the Antifungal Effects in vitro and the Ocular Pharmacokinetics of Solid-Lipid Nanoparticle in Rabbits

Introduction

Fungal keratitis (FK) remains a severe sight-threatening disease, and case management is difficult due to ocular intrinsic barriers and drug shortages. Econazole (ECZ), a broad-spectrum antifungal agent, is limited in ocular applications due to the poor water solubility and strong irritant property.

Methods

We successfully prepared solid-lipid nanoparticle-based ECZ eye drops (E-SLNs) by microemulsion method, and the physicochemical properties of E-SLNs were investigated. Corneal permeability, antifungal ability against Fusarium spp., irritation and bioavailability compared to ECZ Suspension (E-Susp) were evaluated in vitro and in vivo.

Results

E-SLNs were a uniform and stable system which had an average particle size of 19 nm and a spherical morphology. E-SLNs also exhibited controlled release, enhanced antifungal activity without irritation. The pharmacokinetic analysis in vivo confirmed that E-SLNs showed an improved ocular bioavailability and the drug concentration in the cornea were above minimum inhibitory concentration (MIC) for 3 h after single administration.

Conclusion

The E-SLNs colloid system is a promising therapeutic approach for fungal keratitis and could serve as a candidate strategy for other ocular diseases.

Development and Characterization of PLGA Nanoparticle-Laden Hydrogels for Sustained Ocular Delivery of Norfloxacin in the Treatment of Pseudomonas Keratitis: An Experimental Study

Aim

Norfloxacin (NFX) has low ocular bioavailability. The current work aimed to develop NFX-loaded nanoparticle (NP)-laden hydrogels to improve the ocular potential of NFX, minimize the need for frequent instillations and lower undesirable side effects.

Methods

NFX-loaded NPs were developed via the double-emulsion/solvent evaporation technique, according to 2¹.4¹ full factorial design, using two types of polylactic-co-glycolic acid (PLGA) polymer and four (drug: polymer) ratios. NPs were evaluated for particle size (PS), polydispersity index (PDI), zeta potential (ZP), drug entrapment efficiency percentage (EE%), drug percentage released after 30 min (Q_30min) and 12 hours (Q_12h), drug percentage permeated through goat corneas after 30 min (P_30min) and 12 hours (P_12h) and morphology. Two formulae were statistically selected and incorporated into hydroxypropyl methylcellulose (HPMC)-based hydrogels; G1 – G4. The latter systems were evaluated for appearance, clarity, pH, spreadability, rheology, drug percentages released, drug percentages permeated, antimicrobial activity against Pseudomonas aeruginosa, and histopathological changes.

Results

The selected NPs (NP2 and NP6) were spherical in shape and possessed suitable PS (392.02 nm and 190.51 nm) and PDI (0.17 and 0.18), high magnitude of ZP (−30.43 mV and −33.62 mV), high EE% (79.24% and 91.72%), low Q_30min (10.96% and 16.65%) and P_30min (17.39% and 21.05%) and promising Q_12h (58.23% and 71.20%) and P_12h (53.31% and 65.01%), respectively. Clear, spreadable, tolerable, pseudoplastic, and thixotropic HPMC-based hydrogels were developed. They showed more prolonged drug release and drug permeation profiles. NP2- and NP6-laden hydrogels (G3 and G4 systems, respectively) had promising antibacterial activity, and reasonable histopathological safety.

Conclusion

G3 and G4 are potential ocular delivery systems for NFX.

Self-assembled DNA nanoparticles loaded with travoprost for glaucoma-treatment

Lipid DNA nanoparticles (NPs) exhibit an intrinsic affinity to the ocular surface and can be loaded by hybridization with fluorophore-DNA conjugates or with the anti-glaucoma drug travoprost by hybridizing an aptamer that binds the medication. In the travoprost-loaded NPs (Trav-NPs), the drug is bound by specific, non-covalent interactions, not requiring any chemical modification of the active pharmaceutical ingredient. Fluorescently labeled Trav-NPs show a long-lasting adherence to the eye, up to sixty minutes after eye drop instillation. Biosafety of the Trav-NPs was proved and in vivo. Ex vivo and in vivo quantification of travoprost via LC-MS revealed that Trav-NPs deliver at least twice the amount of the drug at every time-point investigated compared to the pristine drug. The data successfully show the applicability of a DNA-based drug delivery system in the field of ophthalmology for the treatment of a major retinal eye disease, i.e. glaucoma.

Recent Advances in the Design of Topical Ophthalmic Delivery Systems in the Treatment of Ocular Surface Inflammation and Their Biopharmaceutical Evaluation

Ocular inflammation is one of the most common symptom of eye disorders and diseases. The therapeutic management of this inflammation must be rapid and effective in order to avoid deleterious effects for the eye and the vision. Steroidal (SAID) and non-steroidal (NSAID) anti-inflammatory drugs and immunosuppressive agents have been shown to be effective in treating inflammation of the ocular surface of the eye by topical administration. However, it is well established that the anatomical and physiological ocular barriers are limiting factors for drug penetration. In addition, such drugs are generally characterized by a very low aqueous solubility, resulting in low bioavailability as only 1% to 5% of the applied drug permeates the cornea. The present review gives an updated insight on the conventional formulations used in the treatment of ocular inflammation, i.e., ointments, eye drops, solutions, suspensions, gels, and emulsions, based on the commercial products available on the US, European, and French markets. Additionally, sophisticated formulations and innovative ocular drug delivery systems will be discussed. Promising results are presented with micro- and nanoparticulated systems, or combined strategies with polymers and colloidal systems, which offer a synergy in bioavailability and sustained release. Finally, different tools allowing the physical characterization of all these delivery systems, as well as in vitro, ex vivo, and in vivo evaluations, will be considered with regards to the safety, the tolerance, and the efficiency of the drug products.

PLA-PCL-PEG-PCL-PLA based micelles for improving the ocular permeability of dexamethasone: development, characterization, and in vitro evaluation

The aim of the present research was to investigate the feasibility of developing polylactide-polycaprolactone-polyethylene glycol-polycaprolactone-polylactide (PLA-PCL-PEG-PCL-PLA) based micelles to improve ocular permeability of dexamethasone (DEX). PLA-PCL-PEG-PCL-PLA copolymers were synthesized by a ring-opening polymerization method. DEX was loaded into the developed copolymers. The DEX-loaded micelles were characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS) methods. Cytotoxicity of the micelles obtained was investigated on L929 cell line. Cellular uptake was followed by fluorescence microscopy and flow cytometry analyses. The release behavior of DEX from the micelles as well as the drug release kinetics was studied. Corneal permeability was also evaluated using an ex vivo bovine model. The pentablock copolymers were successfully synthesized. The TEM results verified the formation of spherical micelles, the sizes of which was approximately 65 nm. The micelles exhibited suitable compatibility on L929 cells. The release profile showed an initial burst release phase followed by a sustained release phase, the kinetic of which was close to the Weibull's distribution model. The micelles showed higher corneal permeability in comparison to a marketed DEX eye drop. Taken together, the results indicated that the PLA-PCL-PEG-PCL-PLA micelles could be appropriate candidates for the ocular delivery of DEX, and probably other hydrophobic drugs.

Diclofenac sodium loaded PLGA nanoparticles for inflammatory diseases with high anti-inflammatory properties at low dose: Formulation, characterization and in vivo HET-CAM analysis

The development of a new drug active substance is not only time-consuming and expensive, but also a chain of operations that often fails. However, increasing the bioavailability, effectiveness, safety, or targeting the drugs used in clinic by various methods, such as nanoparticles (NPs), may be a more effective way of using them in clinic. In addition, NP formulations are becoming increasingly popular in modern medical treatments. Angiogenesis, formation of new capillaries from a pre-existing one, fundamentally occurs in physiological processes such as wound healing, embryogenesis and menstrual cycle, also has a vital role in pathology of cancer, psoriasis, diabetic retinopathy and chronic inflammation. The Hen's Egg Test on the Chorioallantoic Membrane (HET-CAM) assay is a useful, well established and animal alternative in vivo procedure for evaluation of anti-inflammatory potentials and anti-irritant properties of nano drug delivery systems. In this study, diclofenac sodium (DS) loaded PLGA NPs were prepared and characterized. The particle size (PS) of DS-loaded PLGA NPs was between 114.7 and 124.8 nm and all NPs were monodisperse with negative zeta potential values. The encapsulation efficiency was in range of 41.4-77.8%. In vitro dissolution studies of NPs showed up to 24 h of DS release after the first 3 h of burst effect. The 3 h burst effect and 24 h release kinetics studied with DDSolver were found to be predominantly driven not only by one mechanism, by a combined mechanism of Fickian and non-Fickian. Solid state structures of formulations were clarified by DSC and FT-IR analysis. PS, EE% and release rates were found to be affected by the amount of DS added to the formulations. Increasing the amount of DS added to the formulations increased PS, while the EE% decreased. The release rates were affected by PS and the formulation with the lowest PS value showed slower release. The anti-inflammatory activity of optimum formulation (NP-1) was examined using in vivo HET-CAM assay. The anti-inflammatory activity results indicated that NP-1 coded NP formulation showed significantly good anti-inflammatory potential at low dose. As a result, a low dose high anti-inflammatory effect was achieved with the NP structure of DS. To the best of our knowledge this is the first study on in vivo anti-inflammatory activities of DS loaded PLGA NPs by HET-CAM.

Clarithromycin-Loaded Poly (Lactic-co-glycolic Acid) (PLGA) Nanoparticles for Oral Administration: Effect of Polymer Molecular Weight and Surface Modification with Chitosan on Formulation, Nanoparticle Characterization and Antibacterial Effects

Clarithromycin (CLR) is a member of the macrolide antibiotic group. CLR has low systemic oral bioavailability and is a drug of class II of the Biopharmaceutical Classification System. In many studies, using nanoparticles (NPs) as a drug delivery system has been shown to increase the effectiveness and bioavailability of active drug substances. This study describes the development and evaluation of poly (lactic-co-glycolic acid) (PLGA) NPs and chitosan (CS)-coated PLGA NPs for oral delivery of CLR. NPs were obtained by nanoprecipitation technique and characterized in detail, and the effect of three molecular weights (Mw1: 7.000-17.000, Mw2: 38.000-54.000, Mw3: 50.000-190.000) of PLGA and CS coating on particle size (PS), zeta potential (ZP), entrapment efficiency (EE%), and release properties etc. were elucidated. Gastrointestinal stability and cryoprotectant effect tests were performed on the NPs. The PS of the prepared NPs were in the range of 178 to 578 nm and they were affected by the Mw and CS coating. In surface-modified formulations with CS, the ZP of the NPs increased significantly to positive values. EE% varied from 62% to 85%, depending upon the Mw and CS coating. In vitro release studies of CLR-loaded NPs showed an extended release up to 144 h. Peppas-Sahlin and Weibull kinetic model was found to fit best for CLR release from NPs. By the broth microdilution test method, the antibacterial activity of the formulations was determined on Staphylococcus aureus (ATCC 25923), Listeria monocytogenes (ATCC 1911), and Klebsiella pneumoniae (ATCC 700603). The structures of the formulations were clarified by thermal (DSC), FT-IR, and 1H-NMR analysis. The results showed that PS, ZP, EE%, and dissolution rates of NPs were directly related to the Mw of PLGA and CS coating.

PPARγ agonist-loaded PLGA-PEG nanocarriers as a potential treatment for Alzheimer's disease: in vitro and in vivo studies

OBJECTIVE

The first aim of this study was to develop a nanocarrier that could transport the peroxisome proliferator-activated receptor agonist, pioglitazone (PGZ) across brain endothelium and examine the mechanism of nanoparticle transcytosis. The second aim was to determine whether these nanocarriers could successfully treat a mouse model of Alzheimer's disease (AD).

METHODS

PGZ-loaded nanoparticles (PGZ-NPs) were synthesized by the solvent displacement technique, following a factorial design using poly (lactic-co-glycolic acid) polyethylene glycol (PLGA-PEG). The transport of the carriers was assessed in vitro, using a human brain endothelial cell line, cytotoxicity assays, fluorescence-tagged nanocarriers, fluorescence-activated cell sorting, confocal and transmission electron microscopy. The effectiveness of the treatment was assessed in APP/PS1 mice in a behavioral assay and by measuring the cortical deposition of β-amyloid.

RESULTS

Incorporation of PGZ into the carriers promoted a 50x greater uptake into brain endothelium compared with the free drug and the carriers showed a delayed release profile of PGZ in vitro. In the doses used, the nanocarriers were not toxic for the endothelial cells, nor did they alter the permeability of the blood-brain barrier model. Electron microscopy indicated that the nanocarriers were transported from the apical to the basal surface of the endothelium by vesicular transcytosis. An efficacy test carried out in APP/PS1 transgenic mice showed a reduction of memory deficit in mice chronically treated with PGZ-NPs. Deposition of β-amyloid in the cerebral cortex, measured by immunohistochemistry and image analysis, was correspondingly reduced.

CONCLUSION

PLGA-PEG nanocarriers cross brain endothelium by transcytosis and can be loaded with a pharmaceutical agent to effectively treat a mouse model of AD.

Nanoliposome-Encapsulated Brinzolamide-hydropropyl-β-cyclodextrin Inclusion Complex: A Potential Therapeutic Ocular Drug-Delivery System

Novel ocular drug delivery systems (NODDSs) remain to be explored to overcome the anatomical and physiological barriers of the eyes. This study was to encapsulate brinzolamide (BRZ)-hydropropyl-β-cyclodextrin (HP-β-CD) inclusion complex (HP-β-CD/BRZ) into nanoliposomes and investigate its potential as one of NODDS to improve BRZ local glaucomatous therapeutic effect. HP-β-CD/BRZ was firstly prepared to enhance the solubility of poorly water-soluble BRZ. The HP-β-CD/BRZ loaded nanoliposomes (BCL) were subsequently constructed by thin-film dispersion method. After the optimization of the ratio of BRZ to HP-β-CD, the optimal BCL showed an average size of 82.29 ± 6.20 nm, ζ potential of -3.57 ± 0.46 mV and entrapment efficiency (EE) of 92.50 ± 2.10% with nearly spherical in shape. The X-ray diffraction (XRD) confirmed the formation of HP-β-CD/BRZ and BCL. The in vitro release study of BCL was evaluated using the dialysis technique, and BCL showed moderate sustained release. BCL (1 mg/mL BRZ) showed a 9.36-fold increase in the apparent permeability coefficient and had a sustained and enhanced intraocular pressure reduction efficacy when compared with the commercially available formulation (BRZ-Sus) (10 mg/mL BRZ). In conclusion, BCL might have a promising future as a NODDS for glaucoma treatment.

Optimization, Biopharmaceutical Profile and Therapeutic Efficacy of Pioglitazone-loaded PLGA-PEG Nanospheres as a Novel Strategy for Ocular Inflammatory Disorders

PURPOSE

The main goal of this study was to encapsulate Pioglitazone (PGZ), in biodegradable polymeric nanoparticles as a new strategy for the treatment of ocular inflammatory processes.

METHODS

To improve their biopharmaceutical profile for the treatment of ocular inflammatory disorders, nanospheres (NSs) of PGZ were formulated by factorial design with poly (lactic-co-glycolic acid) polyethylene glycol (PLGA-PEG). Interactions drug-polymer have been carried out by spectroscopic (X-ray spectroscopy, FTIR) and thermal methods (DSC). The PGZ-NSs were tested for their in vitro release profile, cytotoxicity, and ocular tolerance (HET-CAM® test); ex vivo corneal permeation, and in vivo inflammatory prevention and bioavailability.

RESULTS

The optimized system showed a negative surface charge of -13.9 mV, an average particle size (Z_av) of around 160 nm, a polydispersity index (PI) below 0.1, and a high encapsulation efficiency (EE) of around 92%. According to the DSC results, the drug was incorporated into the NSs polymeric matrix. The drug release was sustained for up to 14 h. PGZ-NSs up to 10 μg/ml exhibited no retinoblastoma cell toxicity. The ex vivo corneal and scleral permeation profiles of PGZ-NSs showed that retention and permeation through the sclera were higher than through the cornea. Ocular tolerance in vitro and in vivo demonstrated the non-irritant character of the formulation.

CONCLUSION

The in vivo anti-inflammatory efficacy of developed PGZ-NSs indicates this colloidal system could constitute a new approach to prevent ocular inflammation.

Nanomicelle-Assisted Targeted Ocular Delivery with Enhanced Antiinflammatory Efficacy In Vivo

Ocular inflammations are common diseases that may lead to serious vision-threatening obstacles. Eye drops for antiinflammation therapy need to be administered multiple times daily at a high dosage due to the rapid precorneal removal and low bioavailability of drugs. To overcome these problems, a cRGD-functionalized DSPE-PEG2000 nanomicelle (DSPE-PEG2000-cRGD) encapsulated with flurbiprofen is proposed. The tailored nanomicelles trigger specific binding to integrin receptors on the ocular surface, which leads to rapid and robust mucoadhesion, superior ocular surface retention, and transcorneal penetration behaviors of nanomicelles. Due to the enhanced drug delivery on ocular surface and in aqueous humor, the functionalized nanoformulation significantly improves ocular antiinflammation efficacy at a low dosage by blocking the synthesis of inflammatory mediators and cytokines. The present study demonstrates a promising strategy that uses a functional peptide combined with nanomicelles for targeted delivery to the eye in ophthalmologic applications.

Nanoparticles for drug delivery to the anterior segment of the eye

Commercially available ocular drug delivery systems are effective but less efficacious to manage diseases/disorders of the anterior segment of the eye. Recent advances in nanotechnology and molecular biology offer a great opportunity for efficacious ocular drug delivery for the treatments of anterior segment diseases/disorders. Nanoparticles have been designed for preparing eye drops or injectable solutions to surmount ocular obstacles faced after administration. Better drug pharmacokinetics, pharmacodynamics, non-specific toxicity, immunogenicity, and biorecognition can be achieved to improve drug efficacy when drugs are loaded in the nanoparticles. Despite the fact that a number of review articles have been published at various points in the past regarding nanoparticles for drug delivery, there is not a review yet focusing on the development of nanoparticles for ocular drug delivery to the anterior segment of the eye. This review fills in the gap and summarizes the development of nanoparticles as drug carriers for improving the penetration and bioavailability of drugs to the anterior segment of the eye.

Successive Release of Tissue Inhibitors of Metalloproteinase-1 Through Graphene Oxide-Based Delivery System Can Promote Skin Regeneration

The purpose of this study was to testify the hypothesis that graphene oxide (GO) could act as an appropriate vehicle for the release of tissue inhibitors of metalloproteinase-1 (TIMP-1) protein in the context of skin repair. GO characteristics were observed by scanning electron microscopy, atomic force microscopy, and thermal gravimetric analysis. After TIMP-1 absorbing GO, the release profiles of various concentrations of TIMP-1 from GO were compared. GO biocompatibility with fibroblast viability was assessed by measuring cell cycle and apoptosis. In vivo wound healing assays were used to determine the effect of TIMP-1-GO on skin regeneration. The greatest intensity of GO was 1140 nm, and the most intensity volume was 10,674.1 nm (nanometer). TIMP-1 was shown to be continuously released for at least 40 days from GO. The proliferation and viability of rat fibroblasts cultured with TIMP-1-GO were not significantly different as compared with the cells grown in GO or TIMP-1 alone (p > 0.05). Skin defect of rats treated with TIMP-1 and TIMP-1-GO showed significant differences in histological and immunohistochemical scores (p < 0.05). GO can be controlled to release carrier materials. The combination of TIMP-1 and GO promoted the progression of skin tissue regeneration in skin defect.

A potential in situ gel formulation loaded with novel fabricated poly(lactide-co-glycolide) nanoparticles for enhancing and sustaining the ophthalmic delivery of ketoconazole

Oral ketoconazole therapy is commonly associated with serious hepatotoxicity. Improving ocular drug delivery could be sufficient to treat eye fungal infections. The purpose of this study was to develop optimized ketoconazole poly(lactide-co-glycolide) nanoparticles (NPs) with subsequent loading into in situ gel (ISG) formulation for ophthalmic drug delivery. Three formulation factors were optimized for their effect on particle size (Y1) and entrapment efficiency (Y2) utilizing central composite experimental design. Interaction among components was studied using differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. Ketoconazole crystalline state was studied using X-ray powder diffraction. Six different polymeric ISG formulations were prepared and loaded with either optimized NPs or a pure drug. The prepared ISG formulations were characterized for in vitro gelation, drug release and antifungal activity. The permeation through human epithelial cell line was also investigated. The results revealed that all the studied formulation parameters significantly affected Y1 and Y2 of the developed NPs. DSC and FTIR studies illustrated compatibility among NP components, while there was a change from the crystalline state to the amorphous state of the NPs. The in vitro release from the ISG formulations loaded with drug NPs showed sustained and enhanced drug release compared to pure drug formulations. In addition, ISG loaded with NPs showed enhanced anti-fungal activity compared to pure drug formulations. Alginate–chitosan ISG formulation loaded with optimized ketoconazole NPs illustrated higher drug permeation through epithelial cell lines and is considered as an effective ophthalmic drug delivery in the treatment of fungal eye infections.

The dispersion releaser technology is an effective method for testing drug release from nanosized drug carriers

The dispersion releaser (DR) is a dialysis-based setup for the analysis of the drug release from nanosized drug carriers. It is mounted into dissolution apparatus2 of the United States Pharmacopoeia. The present study evaluated the DR technique investigating the drug release of the model compound flurbiprofen from drug solution and from nanoformulations composed of the drug and the polymer materials poly (lactic acid), poly (lactic-co-glycolic acid) or Eudragit®RSPO. The drug loaded nanocarriers ranged in size between 185.9 and 273.6nm and were characterized by a monomodal size distribution (PDI<0.1). The membrane permeability constants of flurbiprofen were calculated and mathematical modeling was applied to obtain the normalized drug release profiles. For comparing the sensitivities of the DR and the dialysis bag technique, the differences in the membrane permeation rates were calculated. Finally, different formulation designs of flurbiprofen were sensitively discriminated using the DR technology. The mechanism of drug release from the nanosized carriers was analyzed by applying two mathematical models described previously, the reciprocal powered time model and the three parameter model.

Lipid nanoparticles (SLN, NLC): Overcoming the anatomical and physiological barriers of the eye - Part I - Barriers and determining factors in ocular delivery

Ocular drug delivery is still a challenge for researchers in the field of pharmaceutical technology due to anatomical and physiological eye characteristics. The tissue barriers (such as cornea, conjunctiva, blood aqueous barrier, and blood-retinal barrier) limit the access of drugs to their targets. Taking into account the short retention time in the precorneal area of classical ocular dosage forms (e.g. solutions, suspensions or ointments) which are rapidly eliminated by tears and eyelid movement, only less than five percent of the administered drug attains intraocular structures. With the aim to overcome ocular barriers, drug delivery systems, able to increase ocular bioavailability reducing side effects, are recognized as promising alternative. In this review, the main barriers and strategies to increase drug transport in ocular delivery are comprehensively discussed, highlighting the factors involved in ocular transport of SLN and NLC.

A novel nanoparticles impregnated ocular insert for enhanced bioavailability to posterior segment of eye: In vitro, in vivo and stability studies

The present investigation was carried out to demonstrate with the help of in vitro and in vivo studies that nanoparticles impregnated ocular inserts effectively delivers significant concentration of drug to the posterior segment of eye after topical administration for treatment of glaucoma. Drug loaded Nanoparticles and their ocular insert have been reported to reduce side effects of orally administered Acetazolamide. Eudragit NPs were prepared by the solvent diffusion nanoprecipitation technique. The prepared NPs were evaluated for various parameters such as particle size, zeta potential, % entrapment efficiency, % drug loading, DSC, FTIR, TEM and stability studies. Ocular inserts of NPs were prepared by solvent casting method. The prepared ocular inserts were evaluated for thickness, content uniformity, folding endurance, disintegration time, morphology and stability study. The NPs and ocular inserts were evaluated for in-vitro drug diffusion study, ex-vivo trans-corneal permeability study, in-vivo ocular tolerability and intra ocular pressure (IOP) reduction study. The optimized batch was stable for a period of 3months in lyophilized form. The optimized formulations had size range of 367nm±8nm, zeta potential around +7mV±1.3mV and 51.61%±3.84% entrapment efficiency with 19%±1.40% drug loading. The ex-vivo trans-corneal study showed higher cumulative corneal permeation, flux across corneal tissue (2.460±0.028μg/ml) and apparent corneal permeability (3.926×10^-6cm²/s & 3.863×10^-6cm²/s) from drug loaded Eudragit NPs and Ocular inserts as compared to drug solution (0.671±0.020μg/ml & 3.166×10^-6cm²/s). In-vivo study showed the Eudragit NPs and ocular insert produced significant (P<0.001) lowering in intra ocular pressure compared with the solution of free drug after 3h of topical ocular administration. Plain Eudragit NPs caused no inflammation and/or discomfort in rabbit eyes and neither affected the intra ocular pressure establishing their safety and non irritancy.

Influence of freeze-drying and γ-irradiation in preclinical studies of flurbiprofen polymeric nanoparticles for ocular delivery using d-(+)-trehalose and polyethylene glycol

This study investigated the suspension of poly(ε-caprolactone) nanoparticles as an ocular delivery system for flurbiprofen (FB-PεCL-NPs) in order to overcome the associated problems, such as stability, sterility, tolerance, and efficacy, with two different FB-PεCL-NP formulations. The formulations were stabilized with poloxamer 188 (1.66% and 3.5%) and submitted individually for freeze-drying and γ-irradiation with polyethylene glycol 3350 (PEG3350) and d-(+)-trehalose (TRE). Both formulations satisfied criteria according to all physicochemical parameters required for ocular pharmaceuticals. The FB-PεCL-NP formulations showed non-Newtonian behavior and sustained drug release. Ex vivo permeation analysis using isolated ocular pig tissues suggested that the presence of PEG3350 results in a reduction of FB transcorneal permeation. Moreover, TRE improved the penetration of FB across the cornea, especially after γ-irradiation. In addition, both formulations did not show a significant affinity in increasing FB transscleral permeation. Both formulations were classified as nonirritating, safe products for ophthalmic administration according to hen’s egg test-chorioallantoic membrane and Draize eye test. Furthermore, an in vivo anti-inflammatory efficacy test showed that irradiated FB-PεCL-NPs prepared with PEG3350 (IR-NPsPEG) have longer anti-inflammatory effects than those presented with irradiated FB-PεCL-NPs prepared with TRE (IR-NPsTRE). IR-NPsPEG showed a suitable physical stability after an aqueous reconstitution over >30 days. This study concludes that both formulations meet the Goldman’s criteria and demonstrate how irradiated nanoparticles, with innovative permeation characteristics, could be used as a feasible alternative to a flurbiprofen solution for ocular application in clinical trials.

In vitro, ex vivo and in vivo characterization of PLGA nanoparticles loading pranoprofen for ocular administration

Pranoprofen (PF) is a NSAID considered as a safe anti-inflammatory treatment for strabismus and/or cataract surgery. The drug has been formulated in poly (lactic/glycolic) acid (PLGA) nanoparticles (PF-F1NPs with cPF 1.5mg/mL, PF-F2NPs with cPF 1mg/mL) produced by solvent displacement technique and tested the in vitro cytotoxicity, ex vivo corneal permeation, in vivo ocular tolerance and in vivo anti-inflammatory efficacy of PF-F1NPs, PF-F2NPs, in comparison to eye drops conventional dosage form (Oftalar(®), PF 1mg/mL) and free drug solution (PF dissolved in PBS, 1.5mg/mL). The mean particle size of both formulations was around 350nm, with polydispersity index below 0.1, and a net negative charge of -7.41mV and -8.5mV for PF-F1NPs and PF-F2NPs, respectively. Y-79 human retinoblastoma cell line was used to evaluate the cytotoxicity of PF-F1NPs and PF-F2NPs, which were compared to blank NPs and free drug solution (PF dissolved in PBS, 1.5mg/mL). Concentrations up to 75μg/mL exhibited no toxicity to Y-79 cells, whereas at 150μg/mL a decrease of about 80% on the cell viability was observed after exposing the cells to PF-F1NPs. When treating the Y-79 cells with concentrations of PF-F2NPs between 1μg/mL to 100μg/mL, the cell viability was similar to control values after 24h and 48h of exposure. An ex vivo corneal permeation study was carried out in New Zealand rabbits. A very similar profile has been observed for the permeation of PF through the cornea when administered as eye drops and as free drug solution, which was kept much lower in comparison to PF-NPs formulations. The permeated amount of PF from the PF-F1NPs was slightly smaller than from PF-F2NPs, attributed to the increase of viscosity of the formulations with the increase of cPVA concentration. New Zealand white rabbits were also used to evaluate the irritancy of PF-F1NPs and PF-F2NPs, which demonstrated to be well-tolerated to the eye (i.e. the mean total score (MTS) was 0). PF-F2NPs exhibited the highest QP (amounts of PF permeated in the cornea) and significantly reduced the ocular edema compared to the tested formulations. The QR (amounts of PF retained in the cornea) of the PF-F1NPs was greater than that obtained for PF-F2NPs.