time controlled drug delivery

Aim of the present work was to formulate and evaluate an oral, time controlled drug delivery system to achieve timed release of Montelukast sodium, for the treatment of nocturnal asthma. An asthmatic attack mainly takes place early in the morning. Time controlled delivery system is capable of delivering drug when and where it is required most. Time-delayed tablets, designed to release drug after a predictable lag time, are intended for oral chronotherapy. A time dependant pulsed release system consisting of a core surrounded by coat layer of different ratios of swellable erodible hydrophilic layer HPMC K100M and rupturable hydrophobic layer Eudragit L 100 and Eudragit S 100 were prepared. These pulsatile tablets were evaluated for the drug content, thickness and in-vitro release profile, etc. and  two optimized formulation were selected and subjected to further studies. .