ABSTRACT
Two types of modified (or controlled) drug delivery systems can be distinguished: (i) devices that decrease the release rate of the drug compared to conventional dosage forms, often during prolonged periods of time (e.g., several hours, days, or months) (1-3), and (ii) systems that increase the release rate compared to conventional dosage forms (e.g., in the case of poorly water-soluble drugs) (4,5). Both types of systems can be very helpful to improve the therapeutic efficacy of many pharmaco-treatments.
