A sterilizable platform based on crosslinked xanthan gum for controlled-release of polymeric micelles: Ocular application for the delivery of neuroprotective compounds to the posterior eye segment

Int J Pharm. 2024 May 25:657:124141. doi: 10.1016/j.ijpharm.2024.124141. Epub 2024 Apr 26.


TPGS (D-α-tocopheryl polyethylene glycol 1000 succinate) polymeric micelles show interesting properties for ocular administration thanks to their solubilization capability, nanometric size and tissue penetration ability. However, micelles formulations are generally characterized by low viscosity, poor adhesion and very short retention time at the administration site. Therefore, the idea behind this work is the preparation and characterization of a crosslinked film based on xanthan gum that contains TPGS micelles and is capable of controlling their release. The system was loaded with melatonin and cyclosporin A, neuroprotective compounds to be delivered to the posterior eye segment. Citric acid and heating at different times and temperatures were exploited as crosslinking approach, giving the possibility to tune swelling, micelles release and drug release. The biocompatibility of the platform was confirmed by HET-CAM assay. Ex vivo studies on isolated porcine ocular tissues, conducted using Franz cells and two-photon microscopy, demonstrated the potential of the xanthan gum-based platform and enlightened micelles penetration mechanism. Finally, the sterilization step was approached, and a process to simultaneously crosslink and sterilize the platform was developed.

Keywords: Crosslinking; Ocular drug delivery; Polymeric film; Sterilization; TPGS micelles; Xanthan gum.

MeSH terms

  • Administration, Ophthalmic*
  • Animals
  • Cross-Linking Reagents / chemistry
  • Cyclosporine / administration & dosage
  • Cyclosporine / chemistry
  • Delayed-Action Preparations* / chemistry
  • Drug Carriers / chemistry
  • Drug Delivery Systems / methods
  • Drug Liberation*
  • Eye / drug effects
  • Eye / metabolism
  • Melatonin / administration & dosage
  • Melatonin / chemistry
  • Melatonin / pharmacokinetics
  • Melatonin / pharmacology
  • Micelles*
  • Neuroprotective Agents* / administration & dosage
  • Neuroprotective Agents* / chemistry
  • Neuroprotective Agents* / pharmacokinetics
  • Polysaccharides, Bacterial* / chemistry
  • Sterilization
  • Swine
  • Vitamin E* / administration & dosage
  • Vitamin E* / chemistry


  • xanthan gum
  • Polysaccharides, Bacterial
  • Micelles
  • Neuroprotective Agents
  • Vitamin E
  • Delayed-Action Preparations
  • Cyclosporine
  • Melatonin
  • tocophersolan
  • Cross-Linking Reagents
  • Drug Carriers