Diltiazem release from Eudragit NE40 coated Pellets and effects of Thermal Treatment

A film coat for diltiazem pellets was applied with aqueous dispersion of Eudragit NE40 using bottom spray Fluidized-bed coater. The effects of thermal treatment, dissolution media and ionic strength of media on drug release from the pellets were evaluated. Coated pellets were treated at 37C, 40C, 50c and 60C for 24 hours. Thermally treated pellets showed slight reduction in the release rates at 50C and 60c compared to initial release profile at 37c. Curing or thermal treatment of the coat at an appropriate temperature and the length of the time was found essential to achieve complete coalescence of the polymer particles such the arte of drug release was stable during prolonged storage. Diltiazem release was fairly independent of pH and the ionic strength of dissolution media. However, the release rates were slightly decreased with increasing molar concentrations of sodium chloride in the buffer media. (author)