Sustained release of amoxicillin from ethyl cellulose-coated amoxicillin/chitosan-cyclodextrin-based tablets

Sustained release mucoadhesive amoxicillin tablets with tolerance to acid degradation in the stomach were studied. The sustained-release tablets of amoxicillin were prepared from amoxicillin coated with ethyl cellulose (EC) and then formulated into tablets using chitosan (CS) or a mixture of CS and beta-cyclodextrin (CD) as the retard polymer. The effects of various (w/w) ratios of EC/amoxicillin, the particle sized of EC coated amoxicillin and the different (w/w) ratios of CS/CD for the retard polymer, on the amoxicillin release profile were investigated. The physicochemical properties of the EC coated amoxicillin particles and tablets were determined by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. The result showed that the release profiles of amoxicillin were greatly improved upon coating with EC, while the inclusion of CD to the CS retardant additionally prolonged the release of the drug slightly. Overall, a sustained release of amoxicillin was achieved using amoxicillin coated with EC at a (w/w) ratio of 1:1 and a particle size of 75-100 μm. Therefore, the tablet formulation of amoxicillin may be an advantageous alternative as an orally administered sustained-release formulation for the treatment of peptic ulcers.