Micelle directed chemical polymerization of polypyrrole particles for the electrically triggered release of dexamethasone base and dexamethasone phosphate

Int J Pharm. 2018 May 30;543(1-2):38-45. doi: 10.1016/j.ijpharm.2018.03.039. Epub 2018 Mar 23.

Abstract

Conducting polymers such as polypyrrole (PPy) can be used as electrically responsive drug delivery systems typically prepared by electrochemical polymerisation, however, the amount of drug that can be delivered is typically low. To increase drug delivery capacity and prepare larger amounts of polymer, PPy nanoparticles were produced by chemical polymerisation over drug-loaded micelles. Two forms of dexamethasone were included to increase total drug loading and to explore the mechanisms of loading and release. The particles produced were approximately 50 nm in size and their conductivity and reversible redox activity were demonstrated. Loading of the hydrophobic dexamethasone base was more efficient than for the more hydrophilic phosphate salt. After pressing the particles into the desired form, electrically-responsive drug release was achieved with a pulsed potential signal being the most effective way to trigger release. Notably, the anionic phosphate salt of the drug was more sensitive to electrically stimulated release than the uncharged base of dexamethasone, highlighting the role of electrostatic forces in driving drug release. This system has potential to be loaded with different drugs widening the scope of application of these smart particles to treat a range of disease states.

Keywords: Controlled release; Drug delivery; Drug release mechanism; Electrically responsive; Tunable release.

MeSH terms

  • Benzenesulfonates / chemistry
  • Cell Line
  • Cell Survival / drug effects
  • Dexamethasone / administration & dosage
  • Dexamethasone / analogs & derivatives*
  • Dexamethasone / chemistry
  • Drug Carriers / chemistry*
  • Drug Liberation
  • Electrochemical Techniques
  • Electrochemistry
  • Glucocorticoids / administration & dosage
  • Glucocorticoids / chemistry*
  • Humans
  • Micelles*
  • Polymerization
  • Polymers / administration & dosage
  • Polymers / chemistry*
  • Pyrroles / administration & dosage
  • Pyrroles / chemistry*
  • Retinal Pigment Epithelium / cytology
  • Surface-Active Agents / chemistry

Substances

  • Benzenesulfonates
  • Drug Carriers
  • Glucocorticoids
  • Micelles
  • Polymers
  • Pyrroles
  • Surface-Active Agents
  • dexamethasone 21-phosphate
  • polypyrrole
  • dodecylbenzenesulfonic acid
  • Dexamethasone