Microencapsulated Beadlets: A Comprehensive Review

Microencapsulated beadlets are versatile multiparticulate drug delivery systems designed to incorporate active pharmaceutical ingredients within polymeric matrices, core–shell structures, or functional coatings to achieve improved stability and controlled drug release. These systems combine the advantages of microencapsulation with the flexibility of multiparticulate dosage forms and can be formulated to provide immediate, sustained, delayed, pulsatile, biphasic, or site-specific drug delivery. The present review provides a comprehensive overview of the formulation strategies, preparation techniques, characterization, evaluation, and pharmaceutical applications of microencapsulated beadlets. Various manufacturing methods, including solvent evaporation, coacervation-phase separation, fluid-bed coating, extrusion–spheronization, ionotropic gelation, spray drying, spray congealing, melt-based processes, microfluidics, and electrohydrodynamic atomization, are discussed. Particular emphasis is given to the selection and role of natural, semi-synthetic, synthetic, and biodegradable polymers in controlling drug loading, encapsulation efficiency, particle morphology, mechanical strength, and release behavior. Critical quality attributes, including particle size, size distribution, sphericity, surface morphology, density, porosity, drug content, encapsulation efficiency, swelling behavior, drug–polymer compatibility, solid-state properties, and in vitro drug release, are reviewed. Drug release mechanisms involving diffusion, swelling, erosion, dissolution, pore-mediated transport, and polymer degradation are also examined. Microencapsulated beadlets offer significant advantages, including improved patient compliance, flexible dosing, reduced dosing frequency, enhanced stability, taste masking, and the ability to combine different release profiles within a single dosage form. Despite challenges related to manufacturing reproducibility, scale-up, coating uniformity, and process control, emerging technologies such as quality-by-design, continuous manufacturing, advanced polymeric materials, and microfluidics are expected to further enhance their pharmaceutical applications. Keywords: Microencapsulation; beadlets; microbeads; microspheres; multiparticulate drug delivery; controlled release.