Chitosan nanoparticles for loading of toothpaste actives and adhesion on tooth analogs

Abstract

AbstractDelivery and sustained release of toothpaste actives is an important but unexplored area. In this work, chitosan nanoparticles were prepared by a water‐in‐oil emulsion/glutaraldehyde crosslinking method. The typical number average diameter of chitosan and toothpaste active (cetylpyridiniumchloride and NaF) nanoparticles was within the range of 100–500 nm. The particles increased their size at higher pH value. The morphology, adherence, and stability of these nanoparticles were investigated by scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectroscopy. The size of the chitosan/NaF nanoparticles was doubled after they were stored at 4°C for 20 days, and then kept constant till 251 days, the examined time so far. These particles showed good stability in toothpaste lixivium after incubated at 60°C for 30 days too. By contrast, the chitosan/cetylpyridiniumchloride nanoparticles were easy to form floccules in the toothpaste lixivium. The loaded toothpaste actives showed a sustained released behavior for at least 10 h. All the particles could adhere onto the tooth analogs such as hydroxyapatite discs and glass slides in a simulated brushing and rinsing process. In vitro cell culture did not find any cytotoxicity of the as‐prepared chitosan nanoparticles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007