ABSTRACT:
Certain diseases have predictable cyclic rhythms and that the timing of medication regimens can improve outcome in selected chronic conditions. These condition demand for release of drug after lag time i.e. chronopharmacotherapy of disease which shows circadian rhythm in their pathophysiology. Pulsatile system is amongst one of them and gaining a lot of interest as it is increasing patient compliance by means of providing time and site-specific drug delivery system, thus providing special and temporal delivery. Pulsed or pulsatile drug release is defined as the rapid and transient release of a certain amount of drug molecules within a short time-period immediately after a predetermined off-release period. PDDS can be classified into time controlled systems wherein the drug release is controlled primarily by the delivery system; stimuli induced PDDS in which release is controlled by the stimuli like the temperature, pH or enzymes present in the intestinal tract or enzymes present in the drug delivery system and externally regulated system where release is programmed by external stimuli like magnetism, ultrasound, electrical effect and irradiation. The current article focuses on the diseases requiring PDDS, marketed technologies, method of formulation of existing systems, recent advances, advantages and limitation of PDDS. Pulsatile drug delivery is one such systems that by delivering drug at the right time, right place and in right amounts, holds good promises of benefit to the patients suffering from chronic problems like arthritis, myocardial infarction, angina pectoris, asthma, hypertension etc.