Nanodelivery of triamcinolone acetonide with PLGA-chitosan nanoparticles for the treatment of ocular inflammation

Absorption enhancement strategies in chitosan-based nanosystems and hydrogels intended for ocular delivery: Latest advances for optimization of drug permeation

Ophthalmic diseases can be presented as acute diseases like allergies, ocular infections, etc., or chronic ones that can be manifested as a result of systemic disorders, like diabetes mellitus, thyroid, rheumatic disorders, and others. Chitosan (CS) and its derivatives have been widely investigated as nanocarriers in the delivery of drugs, genes, and many biological products. The biocompatibility and biodegradability of CS made it a good candidate for ocular delivery of many ingredients, including immunomodulating agents, antibiotics, ocular hypertension medications, etc. CS-based nanosystems have been successfully reported to modulate ocular diseases by penetrating biological ocular barriers and targeting and controlling drug release. This review provides guidance to drug delivery formulators on the most recently published strategies that can enhance drug permeation to the ocular tissues in CS-based nanosystems, thus improving therapeutic effects through enhancing drug bioavailability. This review will highlight the main ocular barriers to drug delivery observed in the nano-delivery system. In addition, the CS physicochemical properties that contribute to formulation aspects are discussed. It also categorized the permeation enhancement strategies that can be optimized in CS-based nanosystems into four aspects: CS-related physicochemical properties, formulation components, fabrication conditions, and adopting a novel delivery system like implants, inserts, etc. as described in the published literature within the last ten years. Finally, challenges encountered in CS-based nanosystems and future perspectives are mentioned.

Injectable nanogels to improve triamcinolone acetonide delivery and toxicity on the treatment of eye diseases

Triamcinolone acetonide (TA) is a corticosteroid, and widely used in the treatment of eye diseases such as macular edema, proliferative vitreoretinopathy, and chronic uveitis. It's also used in diseases such as osteoarthritis and rheumatoid arthritis. Despite the width of its usage, it has toxicity in the eye. Nanogels are advantageous in applying toxic and low bioavailability drugs thanks to their swelling ability and stability. In the presented study, to minimize the disadvantages of TA, and to reach the drug into the back segment of the eye, TA-loaded chitosan (CS) nanogel (CS-TA Nanogel) has been prepared, and in vitro characterized. CS-TA nanogels were prepared by ionic gelation and characterized by SEM, FTIR, and TGA. Drug release profile, and in vitro cytotoxicity was determined to evaluate the efficacy of nanogels for intravitreal eye applications. DNA damage, and oxidative stress caused by nanogels in eye endothelial cells were investigated. CS and CS-TA nanogels were synthesized in the sizes range 200-300 nm with an overall positive charge surface. The loading efficiency of TA on nanogels was determined as 50%. Cells exposed to 250 µg/ml free TA showed 74% viability, while this rate was 90% in cells exposed to CS-TA nanogels. 8-OHdG levels were determined as 54.93 ± 1.118 ng/mL in control cells and 92.47 ± 0.852 ng/mL in cells exposed to 250 µg/ml TA. TA both induces oxidative stress and causes DNA damage in HRMEC cells. However, administration of TA with carrier increased cell viability, total antioxidant capacity, and reduced oxidative DNA damage.

Development of modular polymeric nanoparticles for drug delivery using amine reactive chemistry

Curcumin has been explored for its anti-cancer potential, but is severely limited by its hydrophobicity and sensitivity to light and water. In this study, poly (lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) were synthesized to encapsulate curcumin via single emulsion method to improve curcumin stability and bioavailability. The PLGA NPs were coated with oligomeric chitosan (COS) and RGD peptide (a peptide consisting of Arg-Gly-Asp) using amine-reactive chemistry (NHS and EDC). Both COS and RGD had been previously shown to accumulate and target many different types of cancer cells. NPs were characterised based on size distribution, zeta potential, and binding efficiency of RGD peptide. They were also evaluated on encapsulation efficiency, and stability, of curcumin within the NPs. OVCAR-3 cancer cells were treated with COS and RGD-coated PLGA NPs loaded with Coumarin-6 dye for fluorescent imaging of cell uptake. They were also treated with curcumin-loaded NPs to determine cytotoxicity and effectiveness of delivery. The NPs exhibited size distribution and zeta potential within expected values, though binding efficiency of RGD was low. Curcumin-loaded NPs showed significant increase in cytotoxicity over free (unencapsulated) curcumin, and void (empty) NPs, suggesting successful delivery of curcumin as an anti-cancer agent; the performance of COS and RGD coated NPs over bare PLGA NPs was inconclusive, however, optimization will be required to improve formulation during the coating steps. This method of NP synthesis serves as proof of concept for a modular solution to the development of various coated polymeric NPs for other drugs or applications.

Polymer Nanoparticles with 2-HP-β-Cyclodextrin for Enhanced Retention of Uptake into HCE-T Cells

Triamcinolone acetonide (TA), a medium-potency synthetic glucocorticoid, is primarily employed to treat posterior ocular diseases using vitreous injection. This study aimed to design novel ocular nanoformulation drug delivery systems using PLGA carriers to overcome the ocular drug delivery barrier and facilitate effective delivery into the ocular tissues after topical administration. The surface of the PLGA nanodelivery system was made hydrophilic (2-HP-β-CD) through an emulsified solvent volatilization method, followed by system characterization. The mechanism of cellular uptake across the corneal epithelial cell barrier used rhodamine B (Rh-B) to prepare fluorescent probes for delivery systems. The triamcinolone acetonide (TA)-loaded nanodelivery system was validated by in vitro release behavior, isolated corneal permeability, and in vivo atrial hydrodynamics. The results indicated that the fluorescent probes, viz., the Rh-B-(2-HP-β-CD)/PLGA NPs and the drug-loaded TA-(2-HP-β-CD)/PLGA NPs, were within 200 nm in size. Moreover, the system was homogeneous and stable. The in vitro transport mechanism across the epithelial barrier showed that the uptake of nanoparticles was time-dependent and that NPs were actively transported across the epithelial barrier. The in vitro release behavior of the TA-loaded nanodelivery systems revealed that (2-HP-β-CD)/PLGA nanoparticles could prolong the drug release time to up to three times longer than the suspensions. The isolated corneal permeability demonstrated that TA-(2-HP-β-CD)/PLGA NPs could extend the precorneal retention time and boost corneal permeability. Thus, they increased the cumulative release per unit area 7.99-fold at 8 h compared to the suspension. The pharmacokinetics within the aqueous humor showed that (2-HP-β-CD)/PLGA nanoparticles could elevate the bioavailability of the drug, and its Cmax was 51.91 times higher than that of the triamcinolone acetonide aqueous solution. Therefore, (2-HP-β-CD)/PLGA NPs can potentially elevate transmembrane uptake, promote corneal permeability, and improve the bioavailability of drugs inside the aqueous humor. This study provides a foundation for future research on transocular barrier nanoformulations for non-invasive drug delivery.

Optimization of hyaluronan-enriched cubosomes for bromfenac delivery enhancing corneal permeation: characterization, ex vivo, and in vivo evaluation

To design and evaluate hyaluronan-based cubosomes loaded with bromfenac sodium (BS) for ocular application to enhance the corneal permeation and retention in pterygium and cataract treatment. BS-loaded cubosomes were prepared by the emulsification method, employing 2³ full factorial design using Design-Expert® software. Glycerol monoolein (GMO) and poloxamer 407 (P407) as lipid phase and polyvinyl alcohol (PVA) as stabilizer were the used ingredients. The optimized formulation (OBC; containing GMO (7% w/w), P407 (0.7% w/w) and PVA (2.5% w/w)) was further evaluated. OBC had an entrapment efficiency of 61.66 ± 1.01%, a zeta potential of -30.80 ± 0.61 mV, a mean particle size of 149.30 ± 15.24 nm and a polydispersity index of 0.21 ± 0.02. Transmission electron microscopy confirmed its cubic shape and excellent dispersibility. OBC exhibited high stability and no ocular irritation that was ensured by histopathology. Ex vivo permeation study showed a significant increase in drug deposition and permeability parameters through goat cornea, besides, confocal laser microscopy established the superior permeation capability of OBC, as compared to drug solution. In vivo pharmacokinetics in aqueous humor indicated higher AUC_0-tlast (18.88 µg.h/mL) and mean residence time (3.16 h) of OBC when compared to the marketed eye drops (7.93 µg.h/mL and 1.97 h, respectively). Accordingly, hyaluronan-enriched cubosomes can be regarded as a promising carrier for safe and effective topical ocular delivery.

Subconjunctival therapy by cubic liquid crystalline nanoparticles to deliver Triamcinolone acetonide for the management of diabetic Retinopathy: In vivo evidences

The expression of inflammatory markers and vascular endothelial growth factor (VEGF) was found to be upregulated in various posterior ocular disorders, including diabetic retinopathy (DR). Effective delivery of therapeutic agents to the retina poses a significant challenge in ophthalmic drug delivery due to biological ocular barriers. Triamcinolone acetonide (TA) was selected as the model corticosteroid drug targeting cytokines and VEGF in DR. However, despite TA's low molecular weight and hydrophobicity, which enable it to bypass the conjunctival epithelial barrier, it doesn't efficiently exert its effect at the target site. Nanocarriers have emerged as a solution to enhance drug delivery to the retina and improve bioavailability. This study aimed to compare the effects of Triamcinolone-loaded cubic liquid crystalline nanoparticles (TA-cubic LCNPs) and TA-Suspension in an experimental DR model administered via the subconjunctival (SCJ) route. The results demonstrated that TA-cubic LCNPs enhanced TA periocular delivery efficacy by reducing inflammatory and VEGF markers through the advanced glycation end products (AGE)/protein kinase C pathway. They were identified as promising nano-carriers, exhibiting potential for targeted delivery to the retina.

Polymeric micelles loaded in situ gel with prednisolone acetate for ocular inflammation: development and evaluation

Aim: Our study developed a prednisolone acetate polymeric micelles (PM) system for ocular inflammation related to allergic uveitis. Methods: For PM development, a thin-film hydration procedure was used. Irritation, in vitro, ex vivo transcorneal permeation, micelle size, entrapment efficiency and histology within the eye were all calculated for PM. Results: The optimized in situ gel (A4) showed superior ex vivo transcorneal permeation with zero-order kinetics. Conclusion: The developed formulation could be a promising candidate for treating anterior uveitis via topical application to the anterior segment of the eye.

A New Era in Ocular Therapeutics: Advanced Drug Delivery Systems for Uveitis and Neuro-Ophthalmologic Conditions

The eye's intricate anatomical barriers pose significant challenges to the penetration, residence time, and bioavailability of topically applied medications, particularly in managing uveitis and neuro-ophthalmologic conditions. Addressing this issue, polymeric nano-based drug delivery systems (DDS) have surfaced as a promising solution. These systems enhance drug bioavailability in hard-to-reach target tissues, extend residence time within ocular tissues, and utilize biodegradable and nanosized polymers to reduce undesirable side effects. Thus, they have stimulated substantial interest in crafting innovative treatments for uveitis and neuro-ophthalmologic diseases. This review provides a comprehensive exploration of polymeric nano-based DDS used for managing these conditions. We discuss the present therapeutic hurdles posed by these diseases and explore the potential role of various biopolymers in broadening our treatment repertoire. Our study incorporates a detailed literature review of preclinical and clinical studies from 2017 to 2023. Owing to advancements in polymer science, ocular DDS has made rapid strides, showing tremendous potential to revolutionize the treatment of patients with uveitis and neuro-ophthalmologic disorders.

Use of Poly Lactic-co-glycolic Acid Nano and Micro Particles in the Delivery of Drugs Modulating Different Phases of Inflammation

Chronic inflammation contributes to the pathogenesis of many diseases, including apparently unrelated conditions such as metabolic disorders, cardiovascular diseases, neurodegenerative diseases, osteoporosis, and tumors, but the use of conventional anti-inflammatory drugs to treat these diseases is generally not very effective given their adverse effects. In addition, some alternative anti-inflammatory medications, such as many natural compounds, have scarce solubility and stability, which are associated with low bioavailability. Therefore, encapsulation within nanoparticles (NPs) may represent an effective strategy to enhance the pharmacological properties of these bioactive molecules, and poly lactic-co-glycolic acid (PLGA) NPs have been widely used because of their high biocompatibility and biodegradability and possibility to finely tune erosion time, hydrophilic/hydrophobic nature, and mechanical properties by acting on the polymer's composition and preparation technique. Many studies have been focused on the use of PLGA-NPs to deliver immunosuppressive treatments for autoimmune and allergic diseases or to elicit protective immune responses, such as in vaccination and cancer immunotherapy. By contrast, this review is focused on the use of PLGA NPs in preclinical in vivo models of other diseases in which a key role is played by chronic inflammation or unbalance between the protective and reparative phases of inflammation, with a particular focus on intestinal bowel disease; cardiovascular, neurodegenerative, osteoarticular, and ocular diseases; and wound healing.

Immune modulating nanoparticles for the treatment of ocular diseases

Ocular diseases are increasingly influencing people’s quality of life. Complicated inflammatory mechanisms involved in the pathogenic process of ocular diseases make inflammation-targeting treatment a potential therapeutic approach. The limited efficacy of conventional anti-inflammatory therapeutic strategies, caused by various objective factors, such as complex ocular biological barriers, and subjective factors, such as poor compliance, are promoting the development of new therapeutic methods. With the advantages of considerable tissue permeability, a controllable drug release rate, and selective tissue targeting ability, nanoparticles have successfully captured researchers’ attention and have become a research hotspot in treating ocular diseases. This review will focus on the advantages of nanosystems over traditional therapy, the anti-inflammation mechanisms of nanoparticles, and the anti-inflammatory applications of nanoparticles in different ocular diseases (ocular surface diseases, vitreoretinopathy, uveal diseases, glaucoma, and visual pathway diseases). Furthermore, by analyzing the current situation of nanotherapy and the challenges encountered, we hope to inspire new ideas and incentives for designing nanoparticles more consistent with human physiological characteristics to make progress based on conventional treatments. Overall, some progress has been made in nanoparticles for the treatment of ocular diseases, and nanoparticles have rather broad future clinical translation prospects.

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.

Multiple Roles of Chitosan in Mucosal Drug Delivery: An Updated Review

Chitosan (CS) is a linear polysaccharide obtained by the deacetylation of chitin, which, after cellulose, is the second biopolymer most abundant in nature, being the primary component of the exoskeleton of crustaceans and insects. Since joining the pharmaceutical field, in the early 1990s, CS attracted great interest, which has constantly increased over the years, due to its several beneficial and favorable features, including large availability, biocompatibility, biodegradability, non-toxicity, simplicity of chemical modifications, mucoadhesion and permeation enhancer power, joined to its capability of forming films, hydrogels and micro- and nanoparticles. Moreover, its cationic character, which renders it unique among biodegradable polymers, is responsible for the ability of CS to strongly interact with different types of molecules and for its intrinsic antimicrobial, anti-inflammatory and hemostatic activities. However, its pH-dependent solubility and susceptibility to ions presence may represent serious drawbacks and require suitable strategies to be overcome. Presently, CS and its derivatives are widely investigated for a great variety of pharmaceutical applications, particularly in drug delivery. Among the alternative routes to overcome the problems related to the classic oral drug administration, the mucosal route is becoming the favorite non-invasive delivery pathway. This review aims to provide an updated overview of the applications of CS and its derivatives in novel formulations intended for different methods of mucosal drug delivery.

Chitosan-Coated PLGA Nanoparticles Encapsulating Triamcinolone Acetonide as a Potential Candidate for Sustained Ocular Drug Delivery

The current treatment for the acquired retinal vasculopathies involves lifelong repeated intravitreal injections of either anti-vascular endothelial growth factor (VEGF) therapy or modulation of inflammation with steroids. Consequently, any treatment modification that decreases this treatment burden for patients and doctors alike would be a welcome intervention. To that end, this research aims to develop a topically applied nanoparticulate system encapsulating a corticosteroid for extended drug release. Poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) supports the controlled release of the encapsulated drug, while surface modification of these NPs with chitosan might prolong the mucoadhesion ability leading to improved bioavailability of the drug. Triamcinolone acetonide (TA)-loaded chitosan-coated PLGA NPs were fabricated using the oil-in-water emulsion technique. The optimized surface-modified NPs obtained using Box-Behnken response surface statistical design were reproducible with a particle diameter of 334 ± 67.95 to 386 ± 15.14 nm and PDI between 0.09 and 0.15. These NPs encapsulated 55-57% of TA and displayed a controlled release of the drug reaching a plateau in 27 h. Fourier-transform infrared spectroscopic (FTIR) analysis demonstrated characteristic peaks for chitosan (C-H, CONH2 and C-O at 2935, 1631 and 1087 cm-1, respectively) in chitosan-coated PLGA NPs. This result data, coupled with positive zeta potential values (ranged between +26 and +33 mV), suggests the successful coating of chitosan onto PLGA NPs. Upon coating of the NPs, the thermal stability of the drug, polymer, surfactant and PLGA NPs have been enhanced. The characteristics of the surface-modified NPs supports their use as potential candidates for topical ocular drug delivery for acquired retinal vasculopathies.