Microencapsulation of Gadolinium Citrate using Silica for Contrast Agent Development

Abstract

Gadolinium is a potential T1 contrast agent because it provides a better image for magnetic resonance imaging (MRI). However, as toxic gadolinium ions can be released from the coordination compounds, it is often encapsulated using silica. Silica-encapsulated gadolinium citrate is a colloid, therefore, encapsulation efficiency should be determined by the standard addition method, not the external standard, to minimize errors in the matrix. Silica-encapsulated gadolinium citrate (Gd-C6H5O7@SiO2) was prepared via the Stöber sol-gel method by mixing gadolinium citrate, ethanol, aqua proinjection, tetraethylorthosilicate (TEOS) and ammonia, then the encapsulation efficiency was determined using the standard addition method. Particle size analysis revealed that the average size of Gd-C6H5O7@SiO2 particles was 1.53 μm having a encapsulation efficiency of 90.44%.