With increasing poorly water soluble drugs in pharmaceutical industry, nanosized formulations is a growing strategy in increasing the solubility of poorly water soluble drugs. Nanosized formulations are prepared by bottom up, top down, top down and bottom up, and spray drying. The advantages of using nanoparticles as a drug delivery system include increased dissolution rate, increased rate of absorption, increased oral bioavailability, rapid effect, improved dose proportionality, reduction in required dose.

Chronotherapy refers to the use of circadian, ultradian, infradian & seasonal or other rhythmic cycles in the application of therapy. There are number of conditions which show a circadian pattern and advantage could be taken by timing and adjusting the administration of drugs according to the circadian rhythm of the disease. Some of the conditions, which may be significantly benefited, are hypertension, myocardial infarction, bronchial asthma, peptic ulcer, arthritis, duodenal ulcer, diabetes, neurological disorder, cancer and hypercholesterolemia. Chronotherapy 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, such as the 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.