Vancomycin-loaded N,N-dodecyl,methyl-polyethylenimine nanoparticles coated with hyaluronic acid to treat bacterial endophthalmitis: Development, characterization, and ocular biocompatibility

Recent advances in nanostructured delivery systems for vancomycin

Despite the development of new generations of antibiotics, vancomycin remained as a high-efficacy antibiotic for treating the infections caused by MRSA. Researchers have explored various nanoformulations, aiming to enhance the therapeutic efficacy of vancomycin. Such novel formulations improve the effectiveness of drug cargoes in treating bacterial infections and minimizing the risk of adverse effects. The vast of researches have focuses on enhancing the permeation ability of vancomycin through different biological barriers especially those of gastrointestinal tract. Increasing the drug loading and tuning the drug release from nanocarrier are other important goal for many conducted studies. This study reviews the newest nano-based formulations for vancomycin as a key antibiotic in treating hospitalized bacterial infections.

Miconazole-loaded nanoparticles coated with hyaluronic acid to treat vulvovaginal candidiasis

Miconazole-loaded nanoparticles coated with hyaluronic acid (miconazole-loaded nanoparticles/HA) were developed to overcome the limitations of the conventional therapy of the vulvovaginal candidiasis (VVC). They were synthesized by emulsification and solvent evaporation techniques, characterized by diameter, polydispersity index, zeta potential, encapsulation efficiency, atomic force microscopy (AFM), evaluated in terms of efficacy against C. albicans in vitro, and tested in a murine VVC model. Nanoparticles showed 211nm of diameter with a 0.32 polydispersity index, -53mV of zeta potential, and 90% miconazole encapsulation efficiency. AFM evidenced nanoparticles with a spherical shape. They inhibited the proliferation of C. albicans in vitro and in vivo after a single administration. Nanoparticles released the miconazole directly in the site of action at low therapeutic doses, which was enough to eliminate the fungal burden in the murine VVC model. These systems were rationally designed since the existence of the HA induces their adhesion on the vaginal mucus and their internalization via CD44 receptors, inhibiting the C. albicans. Therefore, miconazole-loaded nanoparticles/HA represent an innovative non-conventional pharmaceutical dosage form to treat the VVC and recurrent VVC.

Recent Advances of Ocular Drug Delivery Systems: Prominence of Ocular Implants for Chronic Eye Diseases

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

OculusGraphy: Signal Analysis of the Electroretinogram in a Rabbit Model of Endophthalmitis Using Discrete and Continuous Wavelet Transforms

BACKGROUND

The electroretinogram is a clinical test used to assess the function of the photoreceptors and retinal circuits of various cells in the eye, with the recorded waveform being the result of the summated response of neural generators across the retina.

METHODS

The present investigation involved an analysis of the electroretinogram waveform in both the time and time-frequency domains through the utilization of the discrete wavelet transform and continuous wavelet transform techniques. The primary aim of this study was to monitor and evaluate the effects of treatment in a New Zealand rabbit model of endophthalmitis via electroretinogram waveform analysis and to compare these with normal human electroretinograms.

RESULTS

The wavelet scalograms were analyzed using various mother wavelets, including the Daubechies, Ricker, Wavelet Biorthogonal 3.1 (bior3.1), Morlet, Haar, and Gaussian wavelets. Distinctive variances were identified in the wavelet scalograms between rabbit and human electroretinograms. The wavelet scalograms in the rabbit model of endophthalmitis showed recovery with treatment in parallel with the time-domain features.

CONCLUSIONS

The study compared adult, child, and rabbit electroretinogram responses using DWT and CWT, finding that adult signals had higher power than child signals, and that rabbit signals showed differences in the a-wave and b-wave depending on the type of response tested, while the Haar wavelet was found to be superior in visualizing frequency components in electrophysiological signals for following the treatment of endophthalmitis and may give additional outcome measures for the management of retinal disease.

Sodium butyrate-loaded nanoparticles coated with chitosan for the treatment of neovascularization in age-related macular degeneration: ocular biocompatibility and antiangiogenic activity

Sodium butyrate-loaded nanoparticles coated chitosan (NaBu-loaded nanoparticles/CS) were developed to treat the choroidal neovascularization in wet age-related macular degeneration (AMD). The nanoparticles were produced by double emulsification and solvent evaporation technique, optimized by experimental statistical design, characterized by analytical methods, investigated in terms of in vitro and in vivo ocular biocompatibility, and evaluated as an antiangiogenic system in vivo. The NaBu-loaded nanoparticles/CS were 311.1 ± 3.1 nm in diameter with a 0.208 ± 0.007 polydispersity index; had a +56.3 ± 2.6 mV zeta potential; showed a 92.3% NaBu encapsulation efficiency; and sustained the drug release over 35 days. The NaBu-loaded nanoparticles/CS showed no toxicity to human retinal pigment epithelium cells (ARPE-19 cells); was not irritant to the chorioallantoic membrane (CAM); did not interfere in the integrity of the retinal layers of rat's eyes, as detected by the Optical Coherence Tomography and histopathology; and inhibited the angiogenesis in CAM assay. The NaBu-loaded nanoparticles/CS could be a therapeutic alternative to limit the neovascularization in AMD.

Nanoantibiotics to fight multidrug resistant infections by Gram-positive bacteria: hope or reality?

The spread of antimicrobial resistance in Gram-positive pathogens represents a threat to human health. To counteract the current lack of novel antibiotics, alternative antibacterial treatments have been increasingly investigated. This review covers the last decade's developments in using nanoparticles as carriers for the two classes of frontline antibiotics active on multidrug-resistant Gram-positive pathogens, i.e., glycopeptide antibiotics and daptomycin. Most of the reviewed papers deal with vancomycin nanoformulations, being teicoplanin- and daptomycin-carrying nanosystems much less investigated. Special attention is addressed to nanoantibiotics used for contrasting biofilm-associated infections. The status of the art related to nanoantibiotic toxicity is critically reviewed.

Biomolecules in Dental Applications: Randomized, Controlled Clinical Trial Evaluating the Influence of Hyaluronic Acid Adjunctive Therapy on Clinical Parameters of Moderate Periodontitis

The biological activity of hyaluronic acid (HA) has been well-researched during the past decades; however, there are few randomized, controlled trials of its clinical effects in periodontal therapy. The purpose of this study was to evaluate the effect of hyaluronic acid on the principal parameters of periodontal healing. A specific, commercially available formulation designed and registered for professional dental application, composed of 16 mg/mL of cross-linked and 2 mg/mL of non-cross-linked HA, was used as an adjunctive to non-surgical periodontal therapy, and clinical parameters were evaluated after 3 months. The addition of HA to periodontal therapy demonstrated more favorable clinical results regarding reduction in inflammation, measured by bleeding on probing (-6% compared to the control group) and gain in periodontal attachment (1 mm more than control group), while it had no effect on probing depth reduction. No side effects were reported. Our study demonstrated that HA is a safe and easy-to-use biological agent; due to its wide array of properties, it may significantly improve the results of periodontal therapy. However, more long-term studies are needed to investigate whether these favorable effects remain over time.

A non-invasive nanoparticle-based sustained dual-drug delivery system as an eyedrop for endophthalmitis

Endophthalmitis is an infectious disease that affects the entire eye spreading to the internal retinal layers and the vitreous and causes severe sight-threatening conditions. Current treatment strategies rely on intraocular injections of antibiotics that are invasive, may lead to procedural complications and, ultimately, blindness. In this study, we developed a non-invasive strategy as an eyedrop containing nanoparticle-based dual-drug delivery system in which the hydrophobic poly-L-lactide core was loaded with azithromycin or triamcinolone acetonide, and the hydrophilic shell was made of chitosan. The developed nanoparticles were ~200-250 nm in size, spherical in shape, moderately hydrophilic, lysozyme tolerant, cytocompatible, and hemocompatible. Application of these chitosan-coated nanoparticles as eye drops to C57BL/6 mice showed higher bioavailability in choroid and retina when compared to the uncoated nanoparticles. The delivery system showed sustained release of drug for 300 h and exhibited antimicrobial effects against Gram-positive and Gram-negative bacteria and anti-inflammatory effects on activated microglial cells. Interestingly, the combination of the nanoparticles loaded with azithromycin and the nanoparticles loaded with triamcinolone acetonide acted synergistically as compared to either of the nanoparticles/drugs alone. Overall, the developed dual-drug delivery system is non-invasive, has antimicrobial and anti-inflammatory effects, and shows potential as an eye drop formulation against endophthalmitis.