Preformed microcapsules for loading and sustained release of ciprofloxacin hydrochloride.

A novel pathway for ciprofloxacin hydrochloride delivery system based on spontaneous deposition mechanism was introduced with respect to encapsulation, quantitative drug loading and sustained release. Layer-by-layer assembly of oppositely charged polyelectrolytes onto melamine formaldehyde (MF) colloidal particles, followed by removal of the cores at low pH has yielded hollow microcapsules having a unique property to induce spontaneous deposition of various water-soluble substances. Observations under scanning electron microscopy, atomic force microscopy and transmission electron microscopy provided direct proofs of the spontaneous deposition. The quantitative drug loading and sustained release properties were elucidated. Results show that the loaded drug is proportional to drug feeding concentrations, temperature and salt concentrations, demonstrating tailorable deposition behavior that is crucial for the drug carrier. The deposited ciprofloxacin hydrochloride could be again released in a sustained manner and exhibited a significant antiseptic activity with high biocompatibility.