Boosting antibiotics performance by new formulations with deep eutectic solvents

Sónia N. Pedro, Ana T.P.C. Gomes, Párástu Oskoei, Helena Oliveira, Adelaide Almeida, Mara G. Freire*, Armando J.D. Silvestre, Carmen S.R. Freire

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The critical scenario of antimicrobial resistance to antibiotics highlights the need for improved therapeutics and/or formulations. Herein, we demonstrate that deep eutectic solvents (DES) formulations are very promising to remarkably improve the solubility, stability and therapeutic efficacy of antibiotics, such as ciprofloxacin. DES aqueous solutions enhance the solubility of ciprofloxacin up to 430-fold while extending the antibiotic stability. The developed formulations can improve, by 2 to 4-fold, the susceptibility of Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria to the antibiotic. They also improve the therapeutic efficacy at concentrations where bacteria present resistance, without promoting tolerance development to ciprofloxacin. Furthermore, the incorporation of DES decreases the toxicity of ciprofloxacin towards immortalized human epidermal keratinocytes (HaCat cells). The results herein reveal the pioneering use of DES in fluoroquinolone-based formulations and their impact on the antibiotic's characteristics and on its therapeutic action.
Original languageEnglish
Article number121566
JournalInternational Journal of Pharmaceutics
Publication statusPublished - 25 Mar 2022
Externally publishedYes


  • Antibiotics
  • Ciprofloxacin
  • Deep eutectic solvents
  • Solubility
  • Stability
  • Therapeutic efficacy


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