A Review on Chronobiology & Chronopharmacokinetics and Their Applications

E-mail: [email protected] Chrono-pharmacokinetics investigates the variation in drug plasma levels as a function of time of day and the mechanisms responsible for time dependent variations. Chrono-pharmacokinetics may also be due to variations in levels of various metabolic enzymes such as Cyt. P450 (Cyp 3A). Similarly, patients of essential hypertension can be given a programmed delivery system to check early morning rise in blood pressure. The phenomenon of chronopharmacokinetics can not only be exploited to prevent rhythmic attacks as in angina but also can be used to prevent toxicity as in case of gentamicin induced nephrotoxicity. Another application of chrono-pharmacokinetics is its importance in the design and evaluation of transdermal drug delivery systems. Recently chrono-pharmacokinetics of Tacrolimus in kidney patients and metronidazole in healthy volunteers has been studied. Propanolol is absorbed more rapidly after morning dosing than after night time dosing in younger hypertensive subjects. Investigators have often stated that in most situations alcohol produces “rebound” hyperthermia, a response by the body to counter the hypothermia initially produced by alcohol.