Stability study of sodium colistimethate-loaded lipid nanoparticles

Abstract

In the last decades, the encapsulation of antibiotics into nanoparticulate carriers has gained increasing attention for the treatment of infectious diseases. Sodium colistimethate-loaded solid lipid nanoparticles (Colist-SLNs) and nanostructured lipid carriers (Colist-NLCs) were designed aiming to treat the pulmonary infection associated to cystic fibrosis patients. The nanoparticles were freeze-dried using trehalose as cryoprotectant. The stability of both nanoparticles was analysed over one year according to the International Conference of Harmonisation (ICH) guidelines by determining the minimum inhibitory concentration (MIC) against clinically isolated Pseudomonas aeruginosa strains and by studying their physico-chemical characteristics. The results showed that Colist-SLNs lost their antimicrobial activity at the third month; on the contrary, the antibacterial activity of Colist-NLCs was maintained throughout the study within an adequate range (MIC ≤16 μg/mL). In addition, Colist-NLCs exhibited suitable physico-chemical properties at 5 °C and 25 °C/60% relative humidity over one year. Altogether, Colist-NLCs proved to have better stability than Colist-SLNs.

Keywords:

• Stability
• solid lipid nanoparticle
• nanocarriers
• sodium colistimethate
• antimicrobial activity

Acknowledgements

Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is gratefully acknowledged. The authors acknowledge the support of the University of the Basque Country UPV/EHU (UFI11/32) and University of Barcelona (UB). Authors also wish to thank the intellectual and technical assistance from the Platform for Drug Formulation (NANBIOSIS) CIBER-BBN.

Disclosure statement

The authors report no declarations of interest.

Funding

This work was carried out by TERFIQEC Project, Comprehensive Research On Effective Therapies For The Treatment of Cystic Fibrosis And Associated Diseases; IPT-2011–1402-900000 funded by the Ministry of Economy and Competitiveness. M. Moreno-Sastre gratefully acknowledges the UPV/EHU for the fellowship grant.