Formulation and evaluation of azithromycin-loaded silver nanoparticles for the treatment of infected wounds

Abstract

Infected wounds pose a significant challenge in healthcare, requiring innovative therapeutic strategies. Therefore, there is a critical need for innovative pharmaceutical materials to improve wound healing and combat bacterial growth. This study examined the efficacy of azithromycin-loaded silver nanoparticles (AZM-AgNPs) in treating infected wounds. AgNPs synthesized using a green method with Quinoa seed extract were loaded with AZM. Characterization techniques, including X-ray Powder Diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and Uv-Vis analysis were utilized. The agar diffusion assay and determination of the MIC were used to assess the initial antibacterial impact of the formulations on both MRSA and E. coli. In addition, the antimicrobial, wound-healing effects and histological changes following treatment with the AZM-AgNPs were assessed using an infected rat model. The nanoparticles had size of 24.9 ± 15.2 nm for AgNPs and 34.7 ± 9.7 nm for AZM-AgNPs. The Langmuir model accurately characterized the adsorption of AZM onto the AgNP surface, indicating a maximum loading capacity of 162.73 mg/g. AZM-AgNPs exhibited superior antibacterial properties in vivo and in vitro compared to controls. Using the agar diffusion technique, AZM-AgNPs showed enhanced zones of inhibition against E. coli and MRSA, which was coupled with decreased MIC levels. In addition, in vivo studies showed that AZM-AgNP treated rats had the best outcome characterized by improved healing process, lower bacterial counts and superior epithelialization, compared to the control group. In conclusion, AZM-AgNPs can be synthesized using a green method with Quinoa seed with successful loading of azithromycin onto silver nanoparticles. In vitro and in vivo studies suggest the promising use of AZM-AgNPs as an effective therapeutic agent for infected wounds.

Keywords: AZM-AgNPs; Adsorption isotherm; Green biosynthesis; Infected wound.

Graphical abstract

Fig. 1

Ag NPs suggested a formation mechanism via catechin in Quinoa.

Fig. 2

Langmuir's isothermal model of AZM molecules on the surface of Ag NPs.

Fig. 3

Percent of AZM removal by AgNPs at different AZM.

Fig. 4

X-ray diffractogram of the as-biofabricated AgNPs.

Fig. 5

UV–Vis absorption spectrum of the as-prepared AgNPs.

Fig. 6

The as-prepared Ag NPs befor adsorption process a) SEM image, b) TEM image, and c) Particle size distribution, and after adsorption process d) SEM image, e) TEM image, and f) Particle size distribution.

Fig. 7

FTIR spectra of the Quinoa extract, the as-biofabricated Ag NPs, AZM, and AZM-Ag.

Fig. 8

AZM-loaded AgNPs exhibit enhanced antibacterial efficacy. A) depicts the average sizes of inhibition zones caused by AZM, AgNPs, and AZM-AgNPs on agar plates containing MRSA and E. coli cultures, accompanied by a sample image for each treatment. B) presents the MIC for AZM, AgNPs, and AZM-AgNPs directed against MRSA and E. coli. Data are presented as the mean ± standard deviation of at least three experiments. Groups were compared using unpaired t-test. *; denote significance.

Fig. 9

In vivo evaluation of the examined formulations. A) Rats' injuries were exposed to MRSA, followed by treatment with specified formulations. Images were captured on the 7th and 10th days after infection to monitor the healing process. B) On the 10th day following the infection, the bacterial concentration in the damaged skin was analyzed. The outcomes are depicted as average values with standard deviations. CFU stands for colony forming units. Data are presented as the mean ± standard deviation. Groups were compared using unpaired t-test. *; denote significance.

Fig. 10

Histological Sections of Rat Skin Wounds in Various Treatment Groups. (a) Control group showing marked tissue destruction and delayed healing. (b) The Azithromycin (AZM) group demonstrates enhanced epithelialization and increased granulation tissue formation. (c) The AgNPs group shows lower degrees of improvement. (d) The AZM-AgNP combination group exhibits the most favorable outcomes, characterized by superior epithelialization and robust granulation tissue formation, surpassing the individual effects of AZM or AgNPs alone.