Abstract
An application of curdlan, a natural β-1, 3-glucan, to controlled drug delivery was investigated in a form of oral dosage form. Theophylline was chosen as a model drug to be incorporated with curdlan in a tablet. It was found that the drug release rate from the tablets prepared from spray-dried particles of curdlan/theophylline was constant up to 8 hr in vitro studies. Since theophylline release was not influenced by pH or various ions, curdlan tablets could control the drug release in physiological fluids after oral administration. Drug release was estimated to be diffusion controlled by applying the release data to Higuchi's equation. The theophylline release profile from the curdlan tablets was compared with those from 5 kinds of commercially obtained sustained release tablets in pH 1.2 medium for 2 hrs followed by in pH 6.8 medium for 6 hrs at 37°C. In addition to theophylline, release profiles of acetaminophen, propranolol hydrochloride and salbutamol sulfate were also obtained from their curdlan tablets. Although the release rates were influenced by their solubilities, each drug release was sustained greatly compared with corresponding drug powder. Adjustment of drug content in the tablets and of tablet surface area allows formulation of the desired preparation.
