Affiliation: Faculdade de Ciencias da Saude da Universidade Fernando Pessoa, Rua Carlos da Maia, 296, 4200-150 Porto, Portugal.
The human body follows 24 hours cycles called the circadian rhythm that affect many physiological and physiopathological processes. Chronotherapeutic diseases include asthma, cardiovascular diseases, cancer, rheumatoid arthritis and other algesia processes. Drugs behaviours in the human body are also strongly affected by circadian changes, especially in what concerns absorption and elimination. Anti-inflammatory drugs are excellent candidates to chronotherapeutical delivery. Chronotherapeutic products are able to synchronize drug delivery with circadian rhythms in order to enhance efficacy and reduce side effects. These products mainly offer pulsatile release that follow a sigmoid release profile with a combination of periods of lag time and periods of fast drug release. Many technologies, either single units or multiparticulate systems, have been suggested and some have been successfully marketed improving patients adherence and quality of life. This review aims to describe the circadian rhythms and their influences in therapeutics as well as the technologies that have been proposed to develop chronopharmaceutical dosage forms.