Preparation and Applicationof Immobilized Valproic Acid Xerogel as Delivery System

The objective of this study is to conduct the preparation and characterization of a xerogel through the co-gelation process involving tetraethyl orthosilicate (TEOS) and 2-propylpentanoic acid (Valproic acid, VA). The characterization of the resulting xerogel utilized techniques such as infrared spectroscopy (FT-IR), X-ray diffraction (XRD), as well as scanning and transmitting electron microscopes (SEM and TEM). Furthermore, the in vitro release of VA and the kinetics ofits release were investigatedemploying various mathematical models (zero-order, first-order, and Higuchi) in a phosphate buffer solution at pH 7.4 and 37°C utilizing HPLC. The findings from the FTIR and XRD analyses provided evidence supporting the successful synthesis of the xerogel with an amorphous configuration. Nevertheless, observations from TEM images exhibited a spherical-like morphology with an average dimension of approximately 1910 d.nm, contrasting with the pure TEOS measuring 924 d.nm. Moreover, the research illustrated aregulated release of VA after 4 h, indicating that the TEOS-based xerogel presents a promising approach for VA delivery characterized by sustained release following the Higuchi kinetic over a 24-h period. Subsequent to these outcomes, the xerogel with an amorphous configuration was successful synthesized for VA regulated release.