REVIEW ON RECENT TRENDS AND APPROACH FOR PULSATILE DRUG DELIVERY SYSTEMS
M. Ramakrishna* and A. Prameela Rani
ABSTRACT
Pulsatile drug delivery aims to release drugs on a programmed pattern i.e.: at appropriate time and/or at appropriate
site of action. Currently, it is gaining increasing attention as it offers a more sophisticated approach to the traditional
sustained drug delivery i.e: a constant amount of drug released per unit time or constant blood levels. Technically,
pulsatile drug delivery systems administered via the oral route could be divided into two distinct types, the time
controlled delivery systems and the site-specific delivery systems. The simplest pulsatile formulation is a two layer
press coated tablet consisted of polymers with different dissolution rates. Homogenicity of the coated barrier is
mandatory in order to assure the predictability of the lag time. The disadvantage of such formulation is that the
rupture time cannot be always adequately manipulated as it is strongly correlated with the physicochemical
properties of the polymer. Gastric retentive systems, systems where the drug is released following a programmed lag
phase, chronopharmaceutical drug delivery systems matching human circadian rhythms, multiunit or multilayer
systems with various combinations of immediate and sustained-release preparation, are all classified under pulsatile
drug delivery systems. On the other hand, site-controlled release is usually controlled by factors such as the pH of
the target site, the enzymes present in the intestinal tract and the transit time/pressure of various parts of the
intestine. In this review, recent patents on pulsatile drug delivery of oral dosage forms are summarized and
discussed.
Keywords: Pulsatile release, chronotherapeutics, time controlled systems, pH target release.
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