Abstract: 
The objectives of present investigation were to design and evaluate stable, delayed Controlled release formulation of zileuton, which may provide peak plasma concentration early morning and compare with marketed formulation available in USA under the brand name of “Zyflo® CR”. The matrix coated and bialyer tablets, were prepared by wet granulation technology and some critical processing parameters were studied like in granulation time and extent of granulation. Loss on drying of the granules, coating pan speed, inlet temperature, bed temperature, Distance between spray gun and product bed. The prepared tablets were evaluated for official evaluation parameters and effect of speed of agitation and Ph of dissolution media were studied. ZIB/03 showed the same dissolution profile that of the innovator at pH 6.8 and 7.2 tris buffer but, compare to innovator at pH 1.2 and 4.5 acetate buffer it showed dissolution dissimilarity. One month accelerated stability study of the batch no. ZIB/03 showed a slightly faster release than the initial. Developing delayed and controlled release formulation of zileuton might provide peak plasma concentration in the early morning. So it could be said that a superior formulation than currently marketed formulation (Zyflo CR) was achieved.

Keywords: Delayed Release, Controlled Release, Chronopharmaceutics, Zileuton, Bilayer Tablet.