Pulsatile delivery systems: An approach for chronotherapeutic diseases

Delivery systems with a pulsatile release pattern are receiving a sprouting attraction for the development of drugs for which conventional controlled-release systems with a continuous release are not ideal. Most physiological, biochemical, and molecular processes in healthy organisms display robust, predictable changes on a 24-h schedule. Chronotherapeutic products can synchronize drug delivery with circadian rhythms in order to optimize efficacy and/or minimize side effects. These products follow a sigmoidal release profile characterized by a time period of no release (lag time) followed by a rapid and complete drug release. Various capsular, osmotic, single and multiple unit systems are based on the use of soluble/erodible polymer coatings, rupturable membranes, and membrane permeabilities. Marketed technologies such as PULSYS(TM), CODAS® , TIMERx® , and DIFFUCAPS® follow one of the above mechanisms to render a sigmoidal drug release profile. So these systems are tuned according to body's circadian clock having a potential to improve quality of patients life undergoing conventional drug therapy. [PUBLICATION ABSTRACT]