In last several decades, conventional dosage forms are replaced by oral controlled release preparations due to poor drug efficacy, side effects and frequency of administration due to maximum concentration of drug (Cmax) normally reduced within 1-2 h which may not match with the maximum intensity of disease state.
Oral controlled drug delivery system release the drug with constant rate to maintain drug concentration in the human body, regardless of the patient physiological conditions .These dosage forms offer many advantages like nearly constant drug levels at the site of action, prevention of peak valley fluctuation, reduction in dose of drug, reduced dosage frequency, promoting drug efficacy, improved patient compliance [1, 2, 3]. However, long term constant drug concentrations in the human body can cause problems like resistance, tolerability and drug side effects [4] and activation of physiological …show more content…
However there are certain diseases which vary in the pathophysiology of disease which may worsen the disease condition due to circadian rhythms. Diseases like allergic rhinitis [5], cardiovascular diseases [6&7], asthma, cancer [8], peptic ulcers, rheumatoid arthritis, osteoarthritis, etc. shows circadian rhythms in their pathophysiology. Hence Chronomodulated systems are gaining a lot of interest and attention these days as these systems deliver the drugs at specified time as per the pathophysiological need of the disease resulting in improved patient therapeutic efficacy and compliance [9&10]. Chronomodulated system is also known as pulsatile system or sigmoidal system. Pulsatile drug delivery system is a system that releases the drug at fast or controlled rate with a programmable lag time or phase after administration. These systems are useful for the drugs having