Development and evaluation of press-coated salbutamol sulfate tablet for delayed-release dosage forms

The purpose of this work was to develop optimized press-coated tablets of salbutamol sulfate using polyethylene glycol 6000 (PEG 6000)-Eudragit S100 dispersion blends in the outer shell. To facilitate the direct application of the Eudragit S100 and PEG 6000 onto the inner core, solid Eudragit S100 powder was mixed with PEG 6000 by fusion method. The optimized, pulverized dispersions of polymer blends were evaluated by various methods of characterization, including differential scanning calorimetry, X-ray diffraction and spectroscopy. The press-coated tablets containing salbutamol sulfate in the inner core were prepared by compression-coating with (PEG 6000)-Eudragit S100 dispersion blends as the outer layer in different ratios. The amount of outer layer on the delayed drug release was investigated. The press-coated tablets release were evaluated in 0.1 M HCl for the first 2 h and then in pH 6.8 phosphate buffer for 7 h. The mechanism of delayed drug release is based on erosion of the out layer blends. The results showed the 0.15 g of PEG 6000/ Eudragit S100 (2:1) in the outer shell achieving delayed release of drug in vitro as well as in the plasma of beagle dogs.