The development of controlled release formulations continues to be a big success for pharmaceutical industry due to its ease of manufacturing process and reproducibility of desirable pharmaceutical properties. Controlled drug delivery systems are receiving more and more attention as they control the rate of drug release and sustain the duration of therapy. Oral controlled drug delivery systems release the drug with constant or variable release rates.A delivery system with a release profile that is characterized by a time period of no release (lag time) followed by a rapid and complete drug release (pulse release) can be called as an ideal pulsatile drug delivery system. In other words, it is required that a drug should not be released at all during the initial phase of dosage form administration. A timed, pulsatile delivery system provides one or more rapid release pulses at predetermined lag times or at specific sites resulting in better absorption of the drug, and thereby providing more effective plasma concentration time profile. Pulsatile drug delivery systems are generally classified into time-controlled pulsatile release and site specific delivery systems.