Chronomodulated pulsatile drug delivery systems (PDDSs) are beneficial for treating diseases exhibiting chronopharmacological behavior in their disease pattern and in the expression of symptoms. These formulations release the drug in coordination with the circadian and biological rhythm of the disease. The difference from other formulations like conventional and oral controlled release systems includes that in these pulsatile dosage forms drug release is observed at a right time point when the incidence of disease is high with immense symptoms. The drug will be discharged completely and quickly at an accurate site at an exact time after the initial predetermined lag time (the time period during which no drug will be released). This type of drug release pattern is suitable for disease conditions like asthma, peptic ulcers, arthritis, hypercholesterolemia, cerebrovascular accidents, cardiovascular disorders, epilepsy, cancer, etc. They are beneficial for patients suffering from the above diseased conditions where the drug is available at the site of activity as the drug is released as a pulse only after a lag time according to the biological rhythm of the disease-producing required therapeutic efficacy. PDDS increase patient compliance by reducing the dosing frequency of the medication, as a reason they are attaining a lot of attention in the market. This article focuses on an introduction to chronotherapy, necessities for pulsatile drug delivery, conditions that require pulsatile delivery, classification of PDDS, and methodologies for pulsatile drug delivery formulations including the technologies like capsular system, osmotic system, single and multiple unit systems by utilizing various polymers. They offer assuring advantages to patients through continuous uninterrupted research development.
Key words: Chronotherapy, Arthritis, lag time, Circadian rhythm and Bronchial Asthma.
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