Study of hydroxyapatite-coated calcium carbonate microparticles in a controlled drug delivery system
Date of Issue2010
School of Mechanical and Aerospace Engineering
Controlled drug delivery systems can now be developed in the scale of the nano/ micron sizes due to the rapid advancement in the development of nanotechnology. Nano/ micron sized templates are synthesized and used as carriers (liposomes, microspheres or microparticles) to deliver drugs to targeted areas in the body. These carriers are capable of releasing drugs at a controlled rate such that the drugs can be administered proficiently over a period of time. An example of such carriers is the Calcium Carbonate (CaCO3) microparticles. These CaCO3 microparticles are synthesized using carboxymethycellulose (CMC) as a cross-linker which helps in the formation of a spherical or colloidal particle. Hydroxyapatite (HA), Ca10(PO4)6(OH)2, which is highly similar to the human bone structure is coated onto theses carriers due to its excellent biocompatibility and its ability to increase the bioactivity of the template. After which, protein drugs such as the Bovine Serum Albumin (BSA) are coated onto the surface or encapsulated in the carriers. Spherical CaCO3 microparticle is synthesized by mixing NaHCO3 solution and CaCl2 solutions of various concentrations with 2% wt CMC with the aim of synthesizing particles of about 1 micron (µm). It is found that by using 0.05M concentration of the NaHCO3 solution and CaCl2 solutions respectively, microparticles of 1 µm is obtained. These CaCO3 microparticles obtained are then immersed into HA solution for HA to coat onto its surface before using the new HA-coated template to adsorb BSA proteins onto its surface. HA-coated CaCO3 microparticles size measured after 6h of reaction time is found to be about 3300 ± 300 nm and FTIR analysis have shown the presence of School of Mechanical and Aerospace Engineering Final Year Project Report 2009/10 (B454: Study of HA-Coated CaCO3 Microparticles in Controlled Drug Delivery System) ii BSA on the surface of the HA-coated CaCO3 microparticles. The adsorption rate of the BSA protein onto the surface is also found to be relatively constant after 6 h. The CaCO3 microparticles was also immersed into HA/ BSA for simultaneous precipitation onto the surface of the CaCO3 microparticles. The particle sizes measured after 6 h is found to be smaller than the HA-coated samples. When the concentration of BSA protein solution used is increase, the HA/BSA CaCO3 microparticles were found to have a tendency to conglomerate which is undesired. These findings now gave a better understanding of the coating of HA and loading of drugs onto CaCO3 microparticles which can be used in a controlled drug delivery system.
Final Year Project (FYP)
Nanyang Technological University