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

AS1411 aptamer/RGD dual functionalized theranostic chitosan-PLGA nanoparticles for brain cancer treatment and imaging

Conventional chemotherapy and poor targeted delivery in brain cancer resulting to poor treatment and develop resistance to anticancer drugs. Meanwhile, it is quite challenging to diagnose/detection of brain tumor at early stage of cancer which resulting in severity of the disease. Despite extensive research, effective treatment with real-time imaging still remains completely unavailable, yet. In this study, two brain cancer cell specific moieties i.e., AS1411 aptamer and RGD are decorated on the surface of chitosan-PLGA nanoparticles to improve targeted co-delivery of docetaxel (DTX) and upconversion nanoparticles (UCNP) for effective brain tumor therapy and real-time imaging. The nanoparticles were developed by a slightly modified emulsion/solvent evaporation method. This investigation also translates the successful synthesis of TPGS-chitosan, TPGS-RGD and TPGS-AS1411 aptamer conjugates for making PLGA nanoparticle as a potential tool of the targeted co-delivery of DTX and UCNP to the brain cancer cells. The developed nanoparticles have shown an average particle size <200 nm, spherical in shape, high encapsulation of DTX and UCNP in the core of nanoparticles, and sustained release of DTX up to 72 h in phosphate buffer saline (pH 7.4). AS1411 aptamer and RGD functionalized theranostic chitosan-PLGA nanoparticles containing DTX and UCNP (DUCPN-RGD-AS1411) have achieved greater cellular uptake, 89-fold improved cytotoxicity, enhanced cancer cell arrest even at lower drug conc., improved bioavailability with higher mean residence time of DTX in systemic circulation and brain tissues. Moreover, DUCPN-RGD-AS1411 have greatly facilitated cellular internalization and higher accumulation of UCNP in brain tissues. Additionally, DUCPN-RGD-AS1411 demonstrated a significant suppression in tumor growth in brain-tumor bearing xenograft BALB/c nude mice with no impressive sign of toxicities. DUCPN-RGD-AS1411 has great potential to be utilized as an effective and safe theranostic tool for brain cancer and other life-threatening cancer therapies.

Chitosan-PLGA mucoadhesive nanoparticles for gemcitabine repurposing for glioblastoma therapy

Glioblastoma (GBM) is a highly deadly brain tumor that does not respond satisfactorily to conventional treatment. The non-alkylating agent gemcitabine (GEM) has been proposed for treating GBM. It can overcome MGMT protein-mediated resistance, a major limitation of conventional therapy with the alkylating agent temozolomide (TMZ). However, GEM's high systemic toxicity and poor permeability across the blood-brain barrier (BBB) pose significant challenges for its delivery to the brain. Thus, mucoadhesive poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) coated with chitosan (CH), suitable for intranasal GEM delivery, were proposed in this work. A central composite design (CCD) was implemented for NPs optimization, and NPs with appropriate characteristics for intranasal administration were obtained. in vitro studies revealed that the NPs possess excellent mucoadhesive properties and the ability to selectively release GEM in the simulated tumor tissue environment. In vitro studies using two human GBM cell lines (U215 and T98G) revealed the NPs' ability to promote GEM's antiproliferative activity to sensitize cells to the effect of TMZ. The findings of this work demonstrate that the developed CH-GEM-NPs are suitable delivery systems for GEM, both as a single therapy and as a chemosensitizer to the GBM gold standard therapy.

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.

Comprehensive Ocular and Systemic Safety Evaluation of Polysialic Acid-Decorated Immune Modulating Therapeutic Nanoparticles (PolySia-NPs) to Support Entry into First-in-Human Clinical Trials

An inflammation-resolving polysialic acid-decorated PLGA nanoparticle (PolySia-NP) has been developed to treat geographic atrophy/age-related macular degeneration and other conditions caused by macrophage and complement over-activation. While PolySia-NPs have demonstrated pre-clinical efficacy, this study evaluated its systemic and intraocular safety. PolySia-NPs were evaluated in vitro for mutagenic activity using Salmonella strains and E. coli, with and without metabolic activation; cytotoxicity was evaluated based on its interference with normal mitosis. PolySia-NPs were administered intravenously in CD-1 mice and Sprague Dawley rats and assessed for survival and toxicity. Intravitreal (IVT) administration in Dutch Belted rabbits and non-human primates was assessed for ocular or systemic toxicity. In vitro results indicate that PolySia-NPs did not induce mutagenicity or cytotoxicity. Intravenous administration did not show clastogenic activity, effects on survival, or toxicity. A single intravitreal (IVT) injection and two elevated repeat IVT doses of PolySia-NPs separated by 7 days in rabbits showed no signs of systemic or ocular toxicity. A single IVT inoculation of PolySia-NPs in non-human primates demonstrated no adverse clinical or ophthalmological effects. The demonstration of systemic and ocular safety of PolySia-NPs supports its advancement into human clinical trials as a promising therapeutic approach for systemic and retinal degenerative diseases caused by chronic immune activation.

Polymers and their engineered analogues for ocular drug delivery: Enhancing therapeutic precision

Ocular drug delivery is constrained by anatomical and physiological barriers, necessitating innovative solutions for effective therapy. Natural polymers like hyaluronic acid, chitosan, and gelatin, alongside synthetic counterparts such as PLGA and PEG, have gained prominence for their biocompatibility and controlled release profiles. Recent strides in polymer conjugation strategies have enabled targeted delivery through ligand integration, facilitating tissue specificity and cellular uptake. This versatility accommodates combined drug delivery, addressing diverse anterior (e.g., glaucoma, dry eye) and posterior segment (e.g., macular degeneration, diabetic retinopathy) afflictions. The review encompasses an in-depth exploration of each natural and synthetic polymer, detailing their individual advantages and disadvantages for ocular drug delivery. By transcending ocular barriers and refining therapeutic precision, these innovations promise to reshape the management of anterior and posterior segment eye diseases.

Chitosan surface modification modulates the mucoadhesive, permeation and anti-angiogenic properties of gellan gum/bevacizumab nanoparticles

Bevacizumab (BVZ) was the first monoclonal antibody approved by the FDA and has shown an essential advance in the antitumor therapy of colorectal cancer (CRC), however, the systemic action of BVZ administered intravenously can trigger several adverse effects. The working hypothesis of the study was to promote the modulation of the mucoadhesion properties and permeability of the BVZ through the formation of nanoparticles (NPs) with gellan gum (GG) with subsequent surface modification with chitosan (CS). NPs comprising BVZ and GG were synthesized through polyelectrolyte complexation, yielding spherical nanosized particles with an average diameter of 264.0 ± 2.75 nm and 314.0 ± 0.01 nm, polydispersity index of 0.182 ± 0.01 e 0.288 ± 0.01, and encapsulation efficiency of 29.36 ± 0.67 e 60.35 ± 0.27 mV, for NPs without (NP_BVZ) and with surface modification (NP_BVZ + CS). The results showed a good ability of nanoparticles with surface modification to modulate the NPs biological properties.

Hyaluronic acid-functionalized DDAB/PLGA nanoparticles for improved oral delivery of magnolol in the treatment of ulcerative colitis

Dysfunction of the mucosal barrier as well as local inflammation are major challenges in the treatment of ulcerative colitis (UC). Mag, a natural compound derived from traditional Chinese medicine, has been shown to have anti-inflammatory and mucosal protection properties. However, its poor gastrointestinal stability as well as its insufficient accumulation in inflamed colonic lesions limit its potential use as an alternative therapeutic drug in UC. The present research involved the design and preparation of a hybrid nanoparticle system (LPNs) specifically targeting macrophages at the colonic site. This was achieved by electrostatically adsorbing HA onto positively charged lipid-polymer hybrid nanoparticles (HA-LPNs). The prepared HA-LPNs exhibited a rounded morphology and a narrow size distribution. In vitro, the anti-inflammatory efficacy of Mag-HA-LPNs (which control levels of the pro-inflammatory cytokines NO, IL-6 and TNF-α) was assessed in RAW 264.7 cells. Analysis by flow cytometry and fluorescence microscopy demonstrated increased cellular uptake through HA/CD44 interaction. As expected, Mag-HA-LPNs was found to effectively increased colon length and reduced DAI scores in DSS-treated mice. This effect was achieved by regulating the inflammatory cytokines level and promoting the restoration of the colonic mucosal barrier through increased expression of Claudin-1, ZO-1 and Occludin. In this study, we developed an efficient and user-friendly delivery method for the preparation of HA-functionalized PLGA nanoparticles, which are intended for oral delivery of Mag. The findings suggest that these HA-LPNs possess the potential to serve as a promising approach for direct drug delivery to the colon for effective treatment of UC.

Triamcinolone-loaded self nano-emulsifying drug delivery systems for ocular use: An alternative to invasive ocular surgeries and injections

Inflammation of the posterior segment of the eye is a severe condition and hard to cure as delivery of drugs to the inflammation site is inefficient. Currently, the primary treatment approach is ocular surgery or invasive ocular injections. Herein, we designed and developed a topically self nano-emulsifying drug delivery system (SNEDDs) to deliver triamcinolone acetonide (TCA) to the posterior segment of the eye. A screening based on TCA solubility was conducted on each excipient followed by preparation of various formulations using different ratios of the selected excipients. Vesicles of optimized SNEDDs had less than 100 nm size and spherical morphology. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay showed self-emulsified vesicles have relatively high safety on retinal pigment epithelium (RPE) cell line. Furthermore, efficient cellular uptake of coumarin 6-loaded SNEDDs in RPE using confocal laser scanning microscopy (CLSM) was confirmed. In addition, an in-vivo study using hematoxylin and eosin (H&E) staining revealed that 14 days of topical treatment of albino rabbit eyes with TCA-loaded SNEDDs was safe and no sign of tissue destruction and inflammation was detected in different parts of the eye sections including cornea, sclera, retina, and optic nerve. Also, the CLSM images from topically treated eyes with coumarin 6 (a hydrophobic, fluorescent drug model) loaded SNEDDs, showed that the optimized SNEDDs could properly penetrate toward the posterior segments of the eye especially the retina, posterior parts of the choroid, and sclera. Considering the outstanding results obtained by ocular tissue penetration and low toxicity, prepared SNEDDs, have the potential to be used as a topical administration for treating posterior segment disorders of the eye through an utterly non-invasive route and TCA-loaded SNEDDs could be an alternative for TCA intravitreal and intra conjunctival injections.

Recent advances and prospects for lipid-based nanoparticles as drug carriers in the treatment of human retinal diseases

The delivery of cures for retinal diseases remains problematic. There are four main challenges: passing through multiple barriers of the eye, the delivery to particular retinal cell types, the capability to carry different forms of therapeutic cargo and long-term therapeutic efficacy. Lipid-based nanoparticles (LBNPs) are potent to overcome these challenges due to their unique merits: amphiphilic nanoarchitectures to pass biological barriers, vary modifications with specific affinity to target cell types, flexible capacity for large and mixed types of cargos and slow-release formulations for long-term treatment. We have reviewed the latest research on the applications of LBNPs for treating retinal diseases and categorized them by different payloads. Furthermore, we identified technical barriers and discussed possible future development for LBNPs to expand the therapeutic potential in treating retinal diseases.

Next-Generation Nanomedicine Approaches for the Management of Retinal Diseases

Retinal diseases are one of the leading causes of blindness globally. The mainstay treatments for these blinding diseases are laser photocoagulation, vitrectomy, and repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) or steroids. Unfortunately, these therapies are associated with ocular complications like inflammation, elevated intraocular pressure, retinal detachment, endophthalmitis, and vitreous hemorrhage. Recent advances in nanomedicine seek to curtail these limitations, overcoming ocular barriers by developing non-invasive or minimally invasive delivery modalities. These modalities include delivering therapeutics to specific cellular targets in the retina, providing sustained delivery of drugs to avoid repeated intravitreal injections, and acting as a scaffold for neural tissue regeneration. These next-generation nanomedicine approaches could potentially revolutionize the treatment landscape of retinal diseases. This review describes the availability and limitations of current treatment strategies and highlights insights into the advancement of future approaches using next-generation nanomedicines to manage retinal diseases.

Smart chitosan-PLGA nanocarriers functionalized with surface folic acid ligands against lung cancer cells

Lung cancer is the second most prevalent and first killer cancer worldwide, and conventional approaches do not have enough ability to suppress it. Therefore, a novel targeted chitosan (CS)-poly lactic-co-glycolic acid (PLGA)-folic acid (FA) nanocarrier was developed for delivery of sorafenib (Sor) to lung cancer cells. The nanocarrier (CPSF) had a size of 30-40 nm with globular shapes. Surface charge and drug content of CPSF were ascertained at about 1.1 mV and 15 %, respectively. Controlled (4 % within 2 h) and pH-sensitive (18 % within 2 h at pH = 5.0) Sor release were observed for the nanocarrier. The MTT assay demonstrated a cell viability of 13 % after 24 h treatment with 400 nM CPSF in A549 cancer cells while it was 78 % in MSC normal cells. The qRT-PCR revealed >8 folds and 11 folds increase for Caspase9 and P53 genes after 5 h treatment with 100 nM (IC₅₀) CPSF; but a reduction of 5 folds was observed for the Bcl2 gene. Besides, 57 % and 20 % apoptosis were attained in cell cycle arrest and apoptosis assays for CPSF, respectively. CPF indicated about 88 % internalization in cancer cells. These data prove that CPSF is a promising nanodelivery system for lung cancer suppression.

Modeling of Chitosan modified PLGA atorvastatin-curcumin conjugate (AT-CU) nanoparticles, overcoming the barriers associated with PLGA: an approach for better management of atherosclerosis

Conjugate drugs are evolving into potent techniques in the drug development process for enhancing the biopharmaceutical, physicochemical, and pharmacokinetic properties. Atorvastatin (AT) is the first line of treatment for coronary atherosclerosis; however its therapeutic efficacy is limited because of its poor solubility and fast pass metabolism. Curcumin (CU) is evidenced in several crucial signaling pathways linked to lipid regulation and inflammation. To enhance the therapeutic efficacy and physical properties of AT and CU, a new conjugate derivative (AT-CU) was synthesized and assessed by in silico, in vitro characterizations, and in vivo efficacy through mice model. Although the biocompatibility and biodegradability of Polylactic-co-Glycolic Acid (PLGA) in nanoparticles are well documented, burst release is a common issue with this polymer. Hence the current work used chitosan as a drug release modifier to the PLGA nanoparticles. The chitosan-modified PLGA AT-CU nanoparticles were prepaid by single emulsion and solvent evaporation technique. With raising the concentration of chitosan the particle size grew from 139.2 nm to 197.7 nm, the zeta potential rose from -20.57 mV to 28.32 mV, and the drug encapsulation efficiency improved from 71.81 % to 90.57 %. At 18 hours, the burst release of AT-CU from PLGA nanoparticles was seen, hitting abruptly 70.8%. For chitosan-modified PLGA nanoparticles, the burst release pattern was significantly reduced which could be due to the adsorption of the drug on the surface of chitosan. The efficiency of the ideal formulation i.e F4 (chitosan/PLGA= 0.4) in treating atherosclerosis was further strongly evidenced by in vivo investigation.

Design of Chitosan-Coated, Quercetin-Loaded PLGA Nanoparticles for Enhanced PSMA-Specific Activity on LnCap Prostate Cancer Cells

Nanoparticles are designed to entrap drugs at a high concentration, escape clearance by the immune system, be selectively taken up by cancer cells, and release bioactives in a rate-modulated manner. In this study, quercetin-loaded PLGA nanoparticles were prepared and optimized to determine whether coating with chitosan would increase the cellular uptake of the nanoparticles and if the targeting ability of folic acid as a ligand can provide selective toxicity and enhanced uptake in model LnCap prostate cancer cells, which express high levels of the receptor prostate-specific membrane antigen (PSMA), compared to PC-3 cells, that have relatively low PSMA expression. A design of experiments approach was used to optimize the PLGA nanoparticles to have the maximum quercetin loading, optimal cationic charge, and folic acid coating. We examined the in vitro release of quercetin and comparative cytotoxicity and cellular uptake of the optimized PLGA nanoparticles and revealed that the targeted nano-system provided sustained, pH-dependent quercetin release, and higher cytotoxicity and cellular uptake, compared to the non-targeted nano-system on LnCap cells. There was no significant difference in the cytotoxicity or cellular uptake between the targeted and non-targeted nano-systems on PC-3 cells (featured by low levels of PSMA), pointing to a PSMA-specific mechanism of action of the targeted nano-system. The findings suggest that the nano-system can be used as an efficient nanocarrier for the targeted delivery and release of quercetin (and other similar chemotherapeutics) against prostate cancer cells.

Lysosomal nanotoxicity: Impact of nanomedicines on lysosomal function

Although several nanomedicines got clinical approval over the past two decades, the clinical translation rate is relatively small so far. There are many post-surveillance withdrawals of nanomedicines caused by various safety issues. For successful clinical advancement of nanotechnology, it is of unmet need to realize cellular and molecular foundation of nanotoxicity. Current data suggest that lysosomal dysfunction caused by nanoparticles is emerging as the most common intracellular trigger of nanotoxicity. This review analyzes prospect mechanisms of lysosomal dysfunction-mediated toxicity induced by nanoparticles. We summarized and critically assessed adverse drug reactions of current clinically approved nanomedicines. Importantly, we show that physicochemical properties have great impact on nanoparticles interaction with cells, excretion route and kinetics, and subsequently on toxicity. We analyzed literature on adverse reactions of current nanomedicines and hypothesized that adverse reactions might be linked with lysosomal dysfunction caused by nanomedicines. Finally, from our analysis it becomes clear that it is unjustifiable to generalize safety and toxicity of nanoparticles, since different particles possess distinct toxicological properties. We propose that the biological mechanism of the disease progression and treatment should be central in the optimization of nanoparticle design.

Properties of Poly (Lactic-co-Glycolic Acid) and Progress of Poly (Lactic-co-Glycolic Acid)-Based Biodegradable Materials in Biomedical Research

In recent years, biodegradable polymers have gained the attention of many researchers for their promising applications, especially in drug delivery, due to their good biocompatibility and designable degradation time. Poly (lactic-co-glycolic acid) (PLGA) is a biodegradable functional polymer made from the polymerization of lactic acid (LA) and glycolic acid (GA) and is widely used in pharmaceuticals and medical engineering materials because of its biocompatibility, non-toxicity, and good plasticity. The aim of this review is to illustrate the progress of research on PLGA in biomedical applications, as well as its shortcomings, to provide some assistance for its future research development.

Nanocarriers for the Delivery of Neuroprotective Agents in the Treatment of Ocular Neurodegenerative Diseases

Retinal neurodegeneration is considered an early event in the pathogenesis of several ocular diseases, such as diabetic retinopathy, age-related macular degeneration, and glaucoma. At present, there is no definitive treatment to prevent the progression or reversal of vision loss caused by photoreceptor degeneration and the death of retinal ganglion cells. Neuroprotective approaches are being developed to increase the life expectancy of neurons by maintaining their shape/function and thus prevent the loss of vision and blindness. A successful neuroprotective approach could prolong patients' vision functioning and quality of life. Conventional pharmaceutical technologies have been investigated for delivering ocular medications; however, the distinctive structural characteristics of the eye and the physiological ocular barriers restrict the efficient delivery of drugs. Recent developments in bio-adhesive in situ gelling systems and nanotechnology-based targeted/sustained drug delivery systems are receiving a lot of attention. This review summarizes the putative mechanism, pharmacokinetics, and mode of administration of neuroprotective drugs used to treat ocular disorders. Additionally, this review focuses on cutting-edge nanocarriers that demonstrated promising results in treating ocular neurodegenerative diseases.

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.

Chitosan Surface-Modified PLGA Nanoparticles Loaded with Cranberry Powder Extract as a Potential Oral Delivery Platform for Targeting Colon Cancer Cells

Nutraceutical cranberry powder extract (CBPE) has distinct polyphenols inhibiting colon cancer growth and proliferation. However, its oral therapeutic efficacy is hindered because of its low permeability. This study aims to formulate chitosan surface-modified PLGA nanoparticles (CS-PLGA NPs) for encapsulating CBPE and modulating its release rate, permeation, cell targeting, and, therefore, its cytotoxicity. A full 2³ factorial design is employed to scrutinize the effect of lactide/glycolide ratio, PLGA weight, and stabilizer concentrations on entrapment efficiency percentage (EE%), particle size (PS), polydispersity index (PDI), and zeta potential (ZP). The optimum formula (F4) shows spherical particles with a relatively high EE% (72.30 ± 2.86%), an appropriate size of 370.10 ± 10.31 nm, PDI; 0.398 ± 0.001, and ZP; -5.40 ± 0.21 mV. Alongside the ATR-FTIR outcomes, the chitosan surface-modified formula (CS-F4) demonstrates a significant increase in particle size (417.67 ± 6.77 nm) and a shift from negative to positive zeta potential (+21.63 ± 2.46 mV), confirming the efficiency of surface modification with chitosan. The intestinal permeability of F4 and CS-F4 is significantly increased by 2.19- and 3.10-fold, respectively, compared to the CBPE solution, with the permeability coefficient (P_app) being 2.05 × 10^-4 cm/min and 2.91 × 10^-4 cm/min, for F4 and CS-F4, respectively, compared to the CBPE solution, 9.36 × 10^-5 cm/min. Moreover, CS-F4 evidences significant caspase-3 protein level expression stimulation and significant inhibition of vascular endothelial growth factor (VEGF) and signal transducer and activator of transcription-3 (STAT-3) protein expression levels, confirming the superiority of CS-F4 for targeting HT-29 cells. Briefly, CS-PLGA NPs could be regarded as a prosperous delivery system of CBPE with enhanced permeation, cell targeting, and antitumor efficacy.

Controlled Delivery of Corticosteroids Using Tunable Tough Adhesives

Hydrogel-based drug delivery systems typically aim to release drugs locally to tissue in an extended manner. Tissue adhesive alginate-polyacrylamide tough hydrogels are recently demonstrated to serve as an extended-release system for the corticosteroid triamcinolone acetonide. Here, the stimuli-responsive controlled release of triamcinolone acetonide from the alginate-polyacrylamide tough hydrogel drug delivery systems (TADDS) and evolving new approaches to combine alginate-polyacrylamide tough hydrogel with drug-loaded nano and microparticles, generating composite TADDS is described. Stimulation with ultrasound pulses or temperature changes is demonstrated to control the release of triamcinolone acetonide from the TADDS. The incorporation of laponite nanoparticles or PLGA microparticles into the tough hydrogel is shown to further enhance the versatility to control and modulate the release of triamcinolone acetonide. A first technical exploration of a TADDS shelf-life concept is performed using lyophilization, where lyophilized TADDS are physically stable and the bioactive integrity of released triamcinolone acetonide is demonstrated. Given the tunability of properties, the TADDS are a suggested technology platform for controlled drug delivery.

Sustained therapeutic effect of an anti-inflammatory peptide encapsulated in nanoparticles on ocular vascular leakage in diabetic retinopathy

Pigment epithelium-derived factor (PEDF), an endogenous Wnt signaling inhibitor in the serine proteinase inhibitors (SERPIN) super family, is present in multiple organs, including the vitreous. Significantly low levels of PEDF in the vitreous are found to associate with pathological retinal vascular leakage and inflammation in diabetic retinopathy (DR). Intravitreal delivery of PEDF represents a promising therapeutic approach for DR. However, PEDF has a short half-life after intravitreal injection, which represents a major hurdle for the long-term treatment. Here we report the prolonged therapeutic effects of a 34-mer peptide of the PEDF N-terminus, encapsulated in poly (lactic-co-glycolic acid) (PLGA) nanoparticles (PEDF34-NP), on DR. PEDF34-NP inhibited hypoxia-induced expression of vascular endothelial growth factor and reduced levels of intercellular adhesion molecule 1 (ICAM-1) in cultured retinal cells. In addition, PEDF34-NP significantly ameliorated ischemia-induced retinal neovascularization in the oxygen-induced retinopathy rat model, and significantly reduced retinal vascular leakage and inflammation in streptozotocin-induced diabetic rats up to 4 weeks after intravitreal injection, as compared to PLGA-NP control. Intravitreal injection of PEDF34-NP did not display any detectable toxicities to retinal structure and function. Our findings suggest that PEDF34-NP can confer sustained therapeutic effects on retinal inflammation and vascular leakage, having considerable potential to provide long-term treatment options for DR.

Nanoparticles for the treatment of glaucoma-associated neuroinflammation

Recently, a considerable amount of literature has emerged around the theme of neuroinflammation linked to neurodegeneration. Glaucoma is a neurodegenerative disease characterized by visual impairment. Understanding the complex neuroinflammatory processes underlying retinal ganglion cell loss has the potential to improve conventional therapeutic approaches in glaucoma. Due to the presence of multiple barriers that a systemically administered drug has to cross to reach the intraocular space, ocular drug delivery has always been a challenge. Nowadays, studies are focused on improving the current therapies for glaucoma by utilizing nanoparticles as the modes of drug transport across the ocular anatomical and physiological barriers. This review offers some important insights on the therapeutic advancements made in this direction, focusing on the use of nanoparticles loaded with anti-inflammatory and neuroprotective agents in the treatment of glaucoma. The prospect of these novel therapies is discussed in relation to the current therapies to alleviate inflammation in glaucoma, which are being reviewed as well, along with the detailed molecular and cellular mechanisms governing the onset and the progression of the disease.

3D Printing of Triamcinolone Acetonide in Triblock Copolymers of Styrene–Isobutylene–Styrene as a Slow-Release System

Additive manufacturing has a wide range of applications and has opened up new methods of drug formulation, in turn achieving attention in medicine. We prepared styrene–isobutylene–styrene triblock copolymers (SIBS; Mn = 10 kDa–25 kDa, PDI 1,3–1,6) as a drug carrier for triamcinolone acetonide (TA), further processed by fused deposition modeling to create a solid drug release system displaying improved bioavailability and applicability. Living carbocationic polymerization was used to exert control over block length and polymeric architecture. Thermorheological properties of the SIBS polymer (22.3 kDa, 38 wt % S) were adjusted to the printability of SIBS/TA mixtures (1–5% of TA), generating an effective release system effective for more than 60 days. Continuous drug release and morphological investigations were conducted to probe the influence of the 3D printing process on the drug release, enabling 3D printing as a formulation method for a slow-release system of Triamcinolone.

Formulation and Optimization of Alogliptin-Loaded Polymeric Nanoparticles: In Vitro to In Vivo Assessment

The nano-drug delivery system has gained greater acceptability for poorly soluble drugs. Alogliptin (ALG) is a FDA-approved oral anti-hyperglycemic drug that inhibits dipeptidyl peptidase-4. The present study is designed to prepare polymeric ALG nanoparticles (NPs) for the management of diabetes. ALG-NPs were prepared using the nanoprecipitation method and further optimized by Box−Behnken experimental design (BBD). The formulation was optimized by varying the independent variables Eudragit RSPO (A), Tween 20 (B), and sonication time (C), and the effects on the hydrodynamic diameter (Y1) and entrapment efficiency (Y2) were evaluated. The optimized ALG-NPs were further evaluated for in vitro release, intestinal permeation, and pharmacokinetic and anti-diabetic activity. The prepared ALG-NPs show a hydrodynamic diameter of between 272.34 nm and 482.87 nm, and an entrapment efficiency of between 64.43 and 95.21%. The in vitro release data of ALG-NPs reveals a prolonged release pattern (84.52 ± 4.1%) in 24 h. The permeation study results show a 2.35-fold higher permeation flux than pure ALG. ALG-NPs exhibit a significantly (p < 0.05) higher pharmacokinetic profile than pure ALG. They also significantly (p < 0.05) reduce the blood sugar levels as compared to pure ALG. The findings of the study support the application of ALG-entrapped Eudragit RSPO nanoparticles as an alternative carrier for the improvement of therapeutic activity.

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.

Formulation and Evaluation of Nano Lipid Carrier-Based Ocular Gel System: Optimization to Antibacterial Activity

The present research work was designed to prepare Azithromycin (AM)-loaded nano lipid carriers (NLs) for ocular delivery. NLs were prepared by the emulsification–homogenization method and further optimized by the Box Behnken design. AM-NLs were optimized using the independent constraints of homogenization speed (A), surfactant concentration (B), and lipid concentration (C) to obtain optimal NLs (AM-NLop). The selected AM-NLop was further converted into a sol-gel system using a mucoadhesive polymer blend of sodium alginate and hydroxyl propyl methyl cellulose (AM-NLopIG). The sol-gel system was further characterized for drug release, permeation, hydration, irritation, histopathology, and antibacterial activity. The prepared NLs showed nano-metric size particles (154.7 ± 7.3 to 352.2 ± 15.8 nm) with high encapsulation efficiency (48.8 ± 1.1 to 80.9 ± 2.9%). AM-NLopIG showed a more prolonged drug release (98.6 ± 4.6% in 24 h) than the eye drop (99.4 ± 5.3% in 3 h). The ex vivo permeation result depicted AM-NLopIG, AM-IG, and eye drop. AM-NLopIG exhibited significant higher AM permeation (60.7 ± 4.1%) than AM-IG (33.46 ± 3.04%) and eye drop (23.3 ± 3.7%). The corneal hydration was found to be 76.45%, which is within the standard limit. The histopathology and HET-CAM results revealed that the prepared formulation is safe for ocular use. The antibacterial study revealed enhanced activity from the AM-NLopIG.

Superhydrophilic PLGA-Graft-PVP/PC Nanofiber Membranes for the Prevention of Epidural Adhesion

Background

The frequent occurrence of failed back surgery syndrome (FBSS) seriously affects the quality of life of postoperative lumbar patients. Epidural adhesion is the major factor in FBSS.

Purpose

A safe and effective antiadhesion material is urgently needed.

Methods

A superhydrophilic PLGA-g-PVP/PC nanofiber membrane (NFm) was prepared by electrospinning. FTIR was performed to identify its successful synthesis. Scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and water contact angle measurement were performed. CCK-8 assays were performed in primary rabbit fibroblasts (PRFs) and RAW264.7 cells to explore the cytotoxicity of PLGA-g-PVP/PC NFm. Calcein-AM/PI staining was used to measure the adhesion status in PRFs. ELISA was performed to measure the concentrations of TNF-α and IL-10 in RAW264.7 cells. In addition, the anti-epidural adhesion efficacy of the PLGA-g-PVP/PC NFm was determined in a rabbit model of lumbar laminectomy.

Results

The PLGA-g-PVP/PC NFm exhibited ultrastrong hydrophilicity and an appropriate degradation rate. Based on the results of the CCK-8 assays, PLGA-g-PVP/PC NFm had no cytotoxicity to PRFs and RAW264.7 cells. Calcein-AM/PI staining showed that PLGA-g-PVP/PC NFm could inhibit PRF adhesion. ELISAs showed that PLGA-g-PVP/PC NFm could attenuate lipopolysaccharide-induced macrophage activation. In vivo experiments further confirmed the favorable anti-epidural adhesion effect of PLGA-g-PVP/PC NFm and the lack of a strong inflammatory response.

Conclusion

In this study, PLGA-g-PVP/PC NFm was developed successfully to provide a safe and effective physical barrier for preventing epidural adhesion. PLGA-g-PVP/PC NFm provides a promising strategy for preventing postoperative adhesion and has potential for clinical translation.

Gentiopicroside PLGA Nanospheres: Fabrication, in vitro Characterization, Antimicrobial Action, and in vivo Effect for Enhancing Wound Healing in Diabetic Rats

Purpose

Gentiopicroside (GPS), an adequate bioactive candidate, has a promising approach for enhancing wound healing due to its antioxidant and antimicrobial properties. Its poor aqueous solubility negatively affects oral absorption accompanied by low bioavailability due to intestinal/hepatic first-pass metabolism. Our aim in this study is to fabricate GPS into appropriate nanocarriers (PLGA nanospheres, NSs) to enhance its solubility and hence its oral absorption would be improved.

Methods

Normal and ODS silica gel together with Sephadex LH20 column used for isolation of GPS from Gentiana lutea roots. Crude GPS would be further processed for nanospheres fabrication using a single o/w emulsion solvent evaporation technique followed by in vitro optimization study to examine the effect of two formulation variables: polymer (PLGA) and stabilizer (PVA) concentrations on the physical characterizations of prepared NSs. Possible GPS-PLGA chemical and physical interactions have been analyzed using Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The optimum GPS-PLGA NSs have been chosen for antimicrobial study to investigate its inhibitory action on Staphylococcus aureus compared with unloaded GPS NSs. Also, a well-designed in vivo study on streptozotocin-induced diabetic rats has been performed to examine the wound healing effect of GPS-PLGA NSs followed by histological examination of wound incisions at different day intervals throughout the study.

Results

The optimum GPS PLGA NSs (F5) with well-controlled particle size (250.10±07.86 nm), relative high entrapment efficiency (83.35±5.71), and the highest % cumulative release (85.79±8.74) have increased the antimicrobial activity as it exhibited a higher inhibitory effect on bacterial growth than free GPS. F5 showed a greater enhancing impact on wound healing and a significant stimulating effect on the synthesis of collagen fibers compared with free GPS.

Conclusion

These findings demonstrate that loading GPS into PLGA NSs is considered a promising strategy ensuring optimum GPS delivery for potential management of wounds.

Novel urea derivative-loaded PLGA nanoparticles to inhibit caries-associated Streptococcus mutans

Caries is the most common chronic infectious disease in the human oral cavity and the existing anti-caries agents may lead to drug resistance and microecological imbalance. A novel urea derivative, 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea, has a potentially prominent antibacterial effect on cariogenic bacterial strain Streptococcus mutans UA159. In this study, we encapsulated the water-insoluble urea derivative in poly(lactic-co-glycolic acid) (PLGA) nanoparticles, performed physicochemical characterizations and explored its potential as a caries-preventive agent. The results showed that the drug-loaded PLGA nanoparticles exhibited satisfying surface morphology, particle size, size distribution and stability. With an optimized theoretical drug loading (10%), the drug-loaded PLGA nanoparticles exhibited negligible cytotoxicity against human oral squamous cell carcinoma cells. We noticed a biphasic drug release in vitro and the rate and cumulative release was higher in an acidic environment (pH 4.5) compared to a neutral environment (pH 7.4). The drug-loaded PLGA nanoparticles significantly inhibited the growth and lactic acid production of planktonic S. mutans as well as S. mutans biofilms. Our results indicate that the novel urea derivative-loaded PLGA nanoparticles serve as a promising anti-caries agent with remarkable pharmaceutical characteristics, low cytotoxicity, and satisfying antimicrobial effect.