A novel strategy to produce spherical SBA-15 by polymeric macrospheres as a template for drug delivery

Abstract

Mesoporous silica SBA-15 has been a material widely studied for drug delivery due to its high biocompatibility and chemical stability, its ordered mesoporous cavities allow drug loading. However, it has a non-spherical particle shape, making it difficult to use in solid dosage forms, where spherical particles are preferred for better flow and distribution. In this regard, this study presented a novel strategy to produce spheric SBA-15 using polymeric macrospheres of a pharmaceutical grade acidic-resistant copolymer (Eudragit^®S) stabilized with Pluronic^® 123, as a template. The macrospheres of Eudragit^®S were fabricated using the double emulsion (W1/O/W2) solvent-diffusion technique and then were used as a template to synthesize macrospheres of SBA-15 following acidic hydrolysis. The physicochemical analysis revealed that the SBA-15 has a spherical morphology (SEM) with pores arranged in a hexagonal lattice (TEM). The XRD showed signals at 0.71, 0.88 y 2.03 °2θ, that were indexed at the Miller indices (100), (110), (200). Nitrogen adsorption-desorption isotherms (type IV, H3) demonstrated mesoporous characteristics with a pore size of 9.3 nm, a wall thickness of 3 nm, a pore volume of 0.7538 cm³g⁻¹, and a surface area of 640 m²g⁻¹. These SBA-15 macrospheres also showed a zero-order release of ibuprofen. The SBA-15 formation using Eudragit^®S macrospheres suggests that P123 on the macrosphere acts as a spherical core, as shown by FT-IR analysis. The acid-resistant copolymer maintained macrosphere integrity, enabling the assembly of the SBA-15 mesostructure in a 24-hour manufacturing time under acidic conditions.