Controlled drug delivery systems, which release drug/s in a predetermined
manner, offer numerous advantages over conventional drug delivery systems. These
advantages include improved bioavailability, reduced dose frequency, minimized
fluctuations in plasma drug concentration, and sustained drug release. The major
drawback of the unit dosage form is dose dumping, which can be effectively overcome
by multiple unit dosage forms like microcapsules. The microencapsulation technique
involves enclosing drug/s by a thin coating shell, and the resultant product is referred to
as microcapsules. This technique has potential applications, especially in delivering
enclosed drug/s in a controlled manner, protecting them from harsh environments,
masking unpleasant tastes, and many more. Several techniques, such as mechanical
processes, chemical processes, and physicochemical processes, are used to encapsulate
drug/s. Drug release from microcapsules is predominantly facilitated by diffusion,
whereas swelling and dissolution, erosion and degradation, and osmosis are minor
mechanisms. The polymers, which can be natural or synthetic, play a stellar role in the
controlled release of drug/s from microcapsules. Prepared microcapsules are
characterized and evaluated by various techniques for shape, size, surface
characteristics, drug release and release kinetics, rheological behavior, etc. Despite the
significant promise, various constraints and restrictions hinder the use of
microencapsulation technology, creating a gap between real-life clinical practice and its
therapeutic applications. The current chapter provides a comprehensive analysis of the
most recent techniques, characterization and evaluation techniques, challenges, and
commercially available microencapsulated pharmaceutical products.
Keywords: Air suspension, Coacervation phase separation, Interfacial polymerization, Ionotropic gelation, Microencapsulation, Microcapsules, Vibrational jet extrusion.