Microparticles used as drug delivery systems
Microparticles offer var- ious significant advantages as drug delivery systems, including: (i) an ef- fective protection of the encapsulated active agent against (e.g. enzymatic) degradation, (ii) the possibility to accurately control the release rate of the incorporated drug over periods of hours to months, and (iii) an easy administration (compared to alter- native parenteral controlled release dosage forms, such as macro-sized implants). Desired, pre-programmed drug release profiles can be provided which match the therapeutic needs of the patient. This article gives an overview on the most important past, current and future strategies using drug-loaded microparticles to improve the efficiency of various medical treatments. Special em- phasis is laid on the different types of preparation techniques that are commonly used, the physicochemical properties of the devices and practical examples illustrating the considerable benefits of this type of advanced drug delivery systems. But also the major challenges and obstacles to be over- come during the development and production of these pharmaceutical dosage forms are pointed out.