ABSTRACT:
The goal in drug delivery research is to develop formulations to meet therapeutic needs relating to particular pathological conditions. Variation of physiological and pathophysiological functions in time has brought a new approach to the development of drug delivery systems. Research in chronopharmacological field has demonstrated the importance of biological rhythms in drug therapy. Optimal clinical outcome can not be achieved if drug plasma concentrations are constant. If symptoms of a disease display circadian variation drug release should also vary over time. Utilisation of different technologies in development of time-controlled, pulsed, triggered and programmed drug delivery devices has been undergoing recent years. Formulations should be justified by biopharmaceutical and pharmacokinetic study in order to choose the best hour for administration. Another point raised by circadian variation of physiological function is that drug pharmacokinetics can also be time-dependent (i.e. chronopharmacokinetics). Both variations in a disease state and in drug plasma concentration need to be taken into consideration in developing of drug delivery systems intended for treatment of disease with adequate dose at appropriate time.