In vitro and in vivo evaluation of oral systems for time and site specific delivery of drugs (Chronotopic technology)

This paper reports the in vivo and in vitro evaluation of an oral system for time and/or site specific drug delivery prepared according to Chronotopic technology. The proposed device consists of a drug containing core coated by a hydrophilic polymeric layer, which determines the delay in release onset. By applying an outer gastroresistant film, and by properly modulating the delay duration, a colon-specific release can be achieved. The obtained results show that the proposed delivery system is capable of releasing drug after a programmed time (time-specific release) and of targeting the colon (site-specific release) when an external gastroresistant film is applied on units coated with an appropriate amount of a hydrophilic retarding polymer.