PULSATILE DRUG DELIVERY SYSTEM: AN OVERVIEW

INTRODUCTION: The newer technologies are developing in pharmaceutical field. The most efficacious dosage forms are generated on already existing molecules because many hurdles occur during discovery of the new molecules . Pulsatile drug delivery system is gaining a lot of interest and attention now a day. Though most delivery system is designed for constant drug release over a prolonged period of time, PDDS are characterized by a programmed drug release, as constant blood level may not always be desirable. These systems have a typical mechanism of delivering the drug rapidly and completely after a lag time . In traditional days, drug delivery has meant for getting a simple chemical absorbed predictably from the gut or from the site of injection. A second generation drug delivery goal has been the perfection of continuous, constant rate delivery of bioactive agents. However, living organisms are not ‘‘zero-order’’ in their requirement or response to drugs. They are predictable resonating dynamic systems, which require different amounts of drug at predictably different times within the circadian cycle which will maximize desired and minimize undesired drug effects . Modified release dosage forms have a great importance in this regard. Such systems control the release pattern of drug, either with constant or variable rates drug is released with predetermined release rates. However, there are certain conditions for which such a release pattern is not suitable. These conditions demand release of drug after a lag time. This condition can be achieved by Pulsatile drug delivery system which is defined as the rapid and transient release of certain amount of molecules within a short time period immediately after a predetermined offrelease period i.e. lag time. A pulse has to be generated in such a way that a complete and rapid drug release is achieved after the lag time so as to match body’s circadian rhythms with the release of drugs .