Delivering macrolide antibiotics to heal a broken heart - And other inflammatory conditions

In silico screening and synthesis of stable tilmicosin-hydrazone derivatives as potential DNA disruptors towards Staphylococcus aureus

In this study, 30 tilmicosin-hydrazone derivatives were designed using MOE software. Six candidate molecules with strong binding affinity to DNA or DNA-Topo II complexes, as indicated by molecular docking results, were synthesized. These candidates were evaluated for their in vitro antibacterial activities against common Gram-positive and Gram-negative bacteria. Compounds Z-12 and Z-22 demonstrated superior inhibitory effects against most tested strains compared to reference drugs tilmicosin and erythromycin, with minimum inhibitory concentrations (MIC) of 1 μg/mL against S. aureus 25,923 and S. aureus 29,213. HPLC results indicated that Z-12 and Z-22 exhibited improved stability in acidic aqueous solutions compared to tilmicosin. UV-vis, fluorescence spectroscopy, and gel electrophoresis studies confirmed their intercalation into DNA base pairs via a static quenching mechanism. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) revealed irreversible oxidation processes on the glassy carbon electrode, providing insights into their potential metabolic pathways. Finally, a mouse wound infection model demonstrated that Z-12 and Z-22 exhibited good antibacterial efficacy, biocompatibility, and enhanced wound healing effects, surpassing those of tilmicosin. These findings, coupled with their prolonged metabolic half-life, highlight their potential as effective antibacterial agents.

Cardiovascular benefits and safety profile of macrolide maintenance therapy in patients with bronchiectasis

BACKGROUND

Macrolide maintenance therapy (MMT) has demonstrated notable efficacy in reducing exacerbation in patients with bronchiectasis, which is a major risk factor for cardiovascular events. However, a comprehensive assessment of the cardiovascular benefits and safety profile of MMT in this population is lacking.

METHODS

This territory-wide cohort study analysed patients diagnosed with bronchiectasis in Hong Kong between 2001 and 2018. Patients were classified as MMT receivers or macrolide non-receivers based on the administration of MMT. Propensity score (PS) matching was employed for confounding factors adjustment. The primary outcome of interest was major adverse cardiovascular events (MACE), a composite of cardiovascular death, myocardial infarction and stroke. The safety outcome was the occurrence of ventricular arrhythmias or sudden cardiac death. Cox proportional hazard regression analysis was utilised to compare the incidence of outcomes across the two groups.

RESULTS

A total of 22 895 patients with bronchiectasis were identified. Following 1:2 PS matching, the final cohort consisted of 3137 individuals, with 1123 MMT receivers and 2014 macrolide non-receivers. MMT administration was associated with a significantly reduced risk of MACE (16.38 versus 24.11 events per 1000 person-years; hazard ratio (HR) 0.68, 95% CI 0.52-0.90). Importantly, the use of MMT was not associated with elevated risk of ventricular arrhythmias or sudden cardiac death (7.17 versus 7.67 events per 1000 person-years; HR 0.93, 95% CI 0.60-1.44).

CONCLUSIONS

The administration of MMT in patients with bronchiectasis was associated with a significant reduction in the risk of MACE, without any evidence suggesting an increased risk of severe arrhythmia-related adverse events.

Azithromycin-loaded PLGA microspheres coated with silk fibroin ameliorate inflammation and promote periodontal tissue regeneration

Periodontitis, a widespread inflammatory disease, is the major cause of tooth loss in adults. While mechanical periodontal therapy benefits the periodontal disease treatment, adjunctive periodontal therapy is also necessary. Topically applied anti-inflammatory agents have gained considerable attention in periodontitis therapy. Although azithromycin (AZM) possesses excellent anti-inflammatory properties, its bioavailability is limited owing to poor water solubility and the absence of sustained release mechanisms. Herein, we synthesized biodegradable microspheres (AZM@PLGA-SF) for sustained AZM release to locally ameliorate periodontal inflammation and facilitate periodontal tissue regeneration. AZM was encapsulated in poly (lactic-co-glycolic acid) (PLGA) microspheres (AZM@PLGA) using single emulsion-solvent evaporation, followed by surface coating with silk fibroin (SF) via electrostatic adsorption, reducing the initial burst release of AZM. In vivo, local treatment with AZM@PLGA-SF microspheres significantly reduced periodontal inflammation and restored periodontal tissue to healthy levels. Mechanically, the formulated microspheres regulated the periodontal inflammatory microenvironment by reducing the levels of pro-inflammatory cytokines (tumor necrosis factor -α, interleukin [IL]-6, interferon-γ, IL-2, and IL-17A) in gingival crevicular fluid and promoted the expression of anti-inflammatory cytokines (IL-4 and IL-10). AZM@PLGA-SF microspheres demonstrated excellent biological safety. Therefore, we introduce an anti-inflammatory therapy for periodontitis with substantial potential for mitigating periodontal inflammation and encouraging the repair and regeneration of periodontal tissues.

Determination of Macrolides in Water Using Solid-Phase Extraction and Supercritical Fluid Chromatography-Tandem Mass Spectrometry

Macrolides are a group of compounds used to treat bacterial infections in humans and animals. Their widespread use results in the contamination of the water environment, which, on the one hand, has a detrimental effect on aquatic organisms and, on the other hand, can lead to the emergence of resistant strains of microorganisms. All of the above determines the need for monitoring of these compounds in the environment, particularly, in water objects. Usually, the high-performance liquid chromatography combined with tandem mass spectrometry method is used to solve this problem, however, this work shows the possibility of using the supercritical fluid chromatography-tandem mass spectrometry method. An approach for the determination of four common macrolides, namely erythromycin, clarithromycin, midecamycin, and josamycin, was developed. The use of solid-phase extraction allowed to achieve limits of quantification at 0.57-6.8 ng/L. The presented approach was validated and tested on a real object-a sample of municipal wastewater.

Chitosan Nanoparticles Modified by Anredera cordifolia (Ten.) Steenis Leaf Extract for Enhancement of Azithromycin Encapsulation Efficiency and Loading Capacity: In vitro Drug Release Study

The encapsulation efficiency and the loading capacity of azithromycin (AZI) were succesfully enhanced by modifying chitosan nanoparticle (NCh) with Anredera cordifolia leaf extract (ACLE), as demonstrated in this study. The prominent secondary metabolites in ACLE could establish a new chemical bonds with NCh's amino groups and partly improved the hydrophobicity of NCh, which leads to excellent AZI encapsulation efficiency and loading capacity of 95.24 ± 1.30% and 55.74 ± 1.03%, respectively. TEM characterization demonstrated that the AZI-loaded ACLE-NCh nanoparticles were uniformly distributed with a particle size of 24.6 ± 2.9 nm. According to the result of in vitro drug release studies, AZI-loaded ACLE-NCh releases 1.12 ± 0.33% at a pH of 1.6 for 2 h, 82.05 ± 2.26% at a pH of 6.8 for 6 h, and 93.44 ± 1.94% at a pH of 7.4 for 24 h. It is remarkable that the encapsulation activityu of AZI-loaded ACLE-NCh is more effective due to the better interaction between NCh and AZI resulting from the increased hydrophobicity of modified NCh. Moreover, this work provides novel findings on the significant contribution of NCh modified by plant extracts, which has the potential as a carrier for azithromycin.

Dextrin-Based Nanohydrogels for Rokitamycin Prolonged Topical Delivery

Macrolides are widely used antibiotics with a broad spectrum of activity. The development of drug carriers to deliver this type of antibiotics has attracted much research. The present study aims at developing new swellable dextrin-based nanohydrogels for the topical delivery of rokitamycin, as model macrolide. Rokitamycin is a synthetic analogous of macrolides with advantageous characteristics as far as bacterial uptake and post-antibiotic effect are concerned. It is also indicated for the treatment of severe infections caused by Acanthamoeba and for topical infections. The nanohydrogels have been prepared from two types of cross-linked polymers obtained by using β-cyclodextrin or Linecaps^® was provided by the Roquette Italia SPA (Cassano Spinola, Al, Italy) as building blocks. The cross-linked polymers have been then formulated into aqueous nanosuspensions refined and tuned to achieve the incorporation of the drug. Cross-linked β-cyclodextrin (β-CD) and Linecaps^® (LC) polymers formed dextrin-based nanohydrogels with high swelling degree and mucoadhesion capability. Rokitamycin was loaded into the nanohydrogels displaying an average size around 200 nm with negative surface charge. In vitro kinetic profiles of free and loaded drug in nanohydrogels were compared at two pH levels. Interestingly, a sustained and controlled release was obtained at skin pH level due to the high degree of swelling and a pH responsiveness possibly. The results collected suggest that these nanohydrogels are promising for the delivery of rokitamycin and may pave the way for the topical delivery of other macrolide antibiotics.