Synthesis and drug loading improvements on mesoporous SBA-15 by spray drying

SBA-15 mesoporous silica is a material used as drug carrier material due to its structural characteristics and biocompatibility. The large surface area of this material improves drug loading and drug release. Typically, SBA-15 is produced by a cooperative self-assembly process under acidic conditions using the triblock copolymers as template and tetraethoxysilane (TEOS) as the silica sources under conventional and batched process. In the last years, spray drying has been proposed to reduce the time to obtain SBA-15 (dry and not calcined) to just seconds, whereas with conventional techniques, this process can take from 6 to 48 h. Additionally, the loading, dissolution, and stability of drugs are improved using co-spray drying (SBA-15 and drugs) due to the pore spatial confinement and avoiding the re-crystallization process of drugs. Furthermore, drug-loaded SBA-15 particles obtained by spray drying have a defined size, high sphericity, and easy handling these characteristics are relevant to its incorporation in dosage forms. Several factors influence the final characteristics of SBA-15 drug-loaded particles, for mention a few: precursors, solvents, time of aging, the temperature of drying, pressure, etc. In this review, the key parameters for the synthesis and loading of drugs on SBA-15 using the spray drying technique are explored and analyzed giving information about how these parameters impact the loading, dissolution, and stability of drugs.