absorption

In order to design proper protocol for drug administration is consideration of circadian rhythm in drug pharmacokinetics. Several studies have concluded that all organisms including humans are highly organized by circadian rhythms. These changes in cycles will influence on physiological function thus, can influence on pharmacokinetics phases. Drug pharmacokinetic parameters can be changed according to the time of administration. The main objective of the chronopharmacokinetic study is to control the time of administration which among others can be responsible for variations of drug kinetics but also chronopharmacological effects observed with certain drugs. This article gives brief information regarding the changes of pharmacokinetics of the drug due to circadian rhythms.

Phytosomes are recently introduced herbal formulations that are better absorbed, and as a result produce better bioavailability and actions than the conventional phytomolecules or botanical extracts. This is an advanced form of herbal formulations which contains the bioactive phytoconstituents of herbal extract bounded in a lipophilic carrier. Phytosome technology has been effectively used to enhance the bioavailability of many popular herbal extracts and phytoconstituents including Ginkgo biloba, milk thistle, grape seed, green tea, hawthorn, ginseng etc and can be developed for various therapeutic uses or dietary supplements.

  Many therapeutic drugs are difficult to reach the central nervous system (CNS) from the systemic blood circulation because the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) form a very effective barrier which prevents most molecules from passing through. BBB allows a selective entry of nutrients and minerals across it and limits the entry of foreign substances like drugs as well as neuropharmaceutical agents. To bypass BBB, drugs can be delivered through olfactory region for nose-to-brain targeting. . Intranasal administration of therapeutic agents (i.e., drug delivery via the nose) offers several advantages over oral, intravenous, and other routes of administration. Drugs can be rapidly absorbed through the large surface area of the nasal mucosa. Intranasal delivery is also non-invasive and essentially painless.  This review provides an overview of strategies to improve the drug delivery to the brain via the nasal mucosa and recent advances in the field.