A simple way for targeted delivery of an antibiotic: In vitro evaluation of a nanoclay-based composite

PLoS One. 2017 Nov 17;12(11):e0187879. doi: 10.1371/journal.pone.0187879. eCollection 2017.

Abstract

The sodium-modified form of fluorohectorite nanoclay (NaFh) is introduced as a potential drug carrier, demonstrating its ability for the controlled release of the broad-spectrum antibiotic Ciprofloxacin through in vitro tests. The new clay-drug composite is designed to target the local infections in the large intestine, where it delivers most of the incorporated drug thanks to its pH-sensitive behavior. The composite has been conceived to avoid the use of coating technology and to decrease the side-effects commonly associated to the burst-release of the ciprofloxacin at the stomach level. NaFh was obtained from lithium-fluorohectorite by ion exchange, and its lack of toxicity was demonstrated by in vivo studies. Ciprofloxacin hydrochloride (Cipro) was encapsulated into the clay at different values of the pH, drug initial concentration, temperature and time. Systematic studies by X-ray diffraction (XRD), infrared and visible spectrophotometry (FT-IR and UV-vis), and thermal analysis (TGA) indicated that the NaFh host exhibits a high encapsulation efficiency for Cipro, which reaches a 90% of the initial Cipro in solution at 65 oC, with initial concentration of drug in solution of 1.36 x 10-2 mol L-1 at acid pH. XRD revealed that a true intercalation of Cipro takes place between clay layers. TG showed an increased thermal stability of the drug when intercalated into the clay, as compared to the "free" Cipro. IR suggested a strong clay-Cipro interaction via ketone group, as well as the establishment of hydrogen bonds between the two materials. In vitro drug release tests revealed that NaFh is a potentially efficient carrier to deliver Cipro in the large intestine, where the release process is mediated by more than just one mechanism.

MeSH terms

  • Adsorption
  • Aluminum Silicates*
  • Anti-Bacterial Agents / administration & dosage*
  • Ciprofloxacin / administration & dosage*
  • Clay
  • Drug Carriers*
  • Drug Delivery Systems*
  • Hydrogen-Ion Concentration
  • In Vitro Techniques
  • Kinetics
  • Nanocomposites*
  • Temperature
  • Thermodynamics

Substances

  • Aluminum Silicates
  • Anti-Bacterial Agents
  • Drug Carriers
  • Ciprofloxacin
  • Clay

Grants and funding

A. Rivera, L. Valdés, I. Pérez and E. Altshuler acknowledge the Ministerio de Educación Superior for partially funding this investigation, through providing salaries, laboratory area with standard working conditions, as well as basic expendables and reagents. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.