Synthesis and characterization of porous and spherical silica nano-shells for controlled release of doxorubicin

The present doctoral research focuses on the development, characterisation, and potential applications of porous and spherical silica nano-shells (PSNS) in drug delivery systems. The study specifically aims to optimise the release profiles of the anticancer agent Doxorubicin (DOX) and to design controlled drug delivery systems. Seven different PSNS formulations were synthesised using sol-gel and template-based methods, employing industrially precipitated calcium carbonate (PCC) as the template. The PCC template was then removed using diluted HCl, resulting in hollow and porous structures. The synthesized nano-shells were characterized using various techniques, including BET analysis, TEM, XRD, FTIR, and Zeta potential measurements. The surface areas of the S-4 and S-7 formulations were found to be 702.2 m²/g and 452.2 m²/g, respectively, with pore sizes ranging between 7.3 nm and 10.6 nm. Six different DOX formulations were prepared to evaluate the drug-loading capacities and in vitro release profiles of these materials. The results of the drug release studies demonstrated that certain PSNS formulations were capable of achieving sustained DOX release for approximately 10 hours. Kinetic analysis of the in vitro release data indicated that the release profiles were consistent with the Higuchi and Korsmeyer-Peppas models. It was observed that pore size and surface properties significantly influenced drug-loading capacity and release kinetics. Furthermore, the use of industrial PCC as a cost-effective and environmentally friendly alternative was highlighted. In conclusion, the study demonstrates the significant potential of porous and spherical silica nano-shells as a platform for drug delivery systems, and the synthesis methods employed in this study were found to be both economical and scalable. This work provides a valuable contribution to the fields of nanotechnology-based drug delivery systems.