# Levofloxacin-loaded surfactant nanocarriers: a computational study

## TL;DR

This study uses simulations to explore how levofloxacin interacts with different surfactant micelles, finding stronger binding with anionic micelles.

## Contribution

The study provides new insights into the binding and orientation of levofloxacin in anionic and cationic micelles using molecular dynamics simulations.

## Key findings

- Levofloxacin shows significantly higher encapsulation efficiency in anionic (SDS) micelles (∼80%) compared to cationic (CTAB) micelles (∼8%).
- Levofloxacin molecules adopt tilted orientations in both micelle types, with the piperazine group anchoring to anionic headgroups.
- Binding energy calculations and π–π interactions suggest stronger levofloxacin binding to SDS micelles.

## Abstract

We performed extensive all-atom molecular dynamics simulations to investigate the interaction dynamics and orientation of levofloxacin, a newer fluoroquinolone antibiotic, with anionic (SDS) and cationic (CTAB) micelles. The maximum drug/micelle ratio (loading capacity and entrapment efficiency) was estimated for anionic and cationic micelles. High encapsulation efficiencies were observed for SDS (average: ∼80%). In contrast, for CTAB micelles, the efficiency was ∼8%, indicating that the binding of levofloxacin molecules to SDS micelles is significantly higher than that to CTAB micelles. Tilted orientations were observed for levofloxacin in SDS micelles (∼48–51°) and in CTAB micelles (∼40–42°), where the positively charged piperazine group is anchored to anionic headgroups. In contrast, the negatively charged carboxylic group is close to cationic headgroups. Calculating the relative binding energies, we found that levofloxacin binds more strongly to SDS than CTAB. Due to π–π interactions and hydrogen bonding, the formation of concerted columnar stacks of levofloxacin was also recorded for both anionic and cationic micelles.

Molecular dynamics simulations reveal distinct binding modes of levofloxacin in anionic and cationic micelles, highlighting the impact of surfactant type on drug encapsulation and release dynamics.