This study aims to investigate whether a self-made novel pulsatile drug delivery system--razine phosphate pulsincap capsule-will achieve a pulsatile drug release in vivo and to study the drug release sites. A gamma scintigraphic study was conducted to assess the in vivo transit and release behavior of the pulsincap capsule with a drug tablet containing 99mTc-labeled diethylenetriamine pentaacetic acid (DTPA) in the gastrointestinal (GI) tract of dog. The results revealed that after a time interval (lag time), the drug tablet began to disintegrate and then released at the pylorus of stomach or in the small intestine of dogs with a relatively rapid release rate, which was consistent with the expected pulsed release pattern. The in vivo lag time of the pulsincap capsule in dog was shortened with the decrease of erodible plugs(EP) weight. Thus we can achieve a desirable lag time to meet the chronotherapeutic requirements by adjusting the weight of EP.