Microparticles, Microspheres, and Microcapsules for Advanced Drug Delivery
Department of Pharmaceutics, Semmelweis University, Hőgyes E. str 7, 1092 Budapest, Hungary
Pázmány Péter Catholic University, Faculty of Information Technology and Bionics, Práter str 50/A, 1083 Budapest, Hungary
Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó str. 37-47, 1094 Budapest, Hungary
Author to whom correspondence should be addressed.
Sci. Pharm. 2019, 87(3), 20; https://doi.org/10.3390/scipharm87030020
Received: 11 July 2019 / Revised: 31 July 2019 / Accepted: 1 August 2019 / Published: 9 August 2019
(This article belongs to the Special Issue New Insights into Drug Delivery and Absorption)
Microparticles, microspheres, and microcapsules are widely used constituents of multiparticulate drug delivery systems, offering both therapeutic and technological advantages. Microparticles are generally in the 1–1000 µm size range, serve as multiunit drug delivery systems with well-defined physiological and pharmacokinetic benefits in order to improve the effectiveness, tolerability, and patient compliance. This paper reviews their evolution, significance, and formulation factors (excipients and procedures), as well as their most important practical applications (inhaled insulin, liposomal preparations). The article presents the most important structures of microparticles (microspheres, microcapsules, coated pellets, etc.), interpreted with microscopic images too. The most significant production processes (spray drying, extrusion, coacervation, freeze-drying, microfluidics), the drug release mechanisms, and the commonly used excipients, the characterization, and the novel drug delivery systems (microbubbles, microsponges), as well as the preparations used in therapy are discussed in detail.