Freeze-dried erythromycin nanocrystals: preparation, characterisation, antimicrobial activity, and aerodynamic properties

Background : This study aims to present the development and evaluation of freeze-dried erythromycin nanocrystals to enhance the solubility, dissolution rate, and antibacterial potency of erythromycin. Results : Erythromycin nanocrystals had a particle size of 239.3 ± 24.6 nm with 0.17 ± 0.01 PDI. Erythromycin nanocrystals had significantly higher saturation solubility and a faster dissolution rate compared to coarse erythromycin. Nanocrystals showed a high drug content of 92.69% ± 2.82, while the aerodynamic characteristics demonstrated an emitted dose (ED%) of 83.68% ± 5.32 with a mass median aerodynamic diameter of 2.13 µm. Around half reduction of the minimum inhibitory concentrations were observed against P. aeruginosa and E. coli (125 µg and 62.5 µg, respectively). Conclusion : The nanocrystal formulation of erythromycin presented in this study holds promise as an innovative approach to enhance the solubility, dissolution rate, and antibacterial activity of erythromycin for effective pulmonary administration. Graphical abstract