Structural, optical and vibrational properties of sol-gel titania valproic acid reservoirs

Organically modified sol-gel derived titania xerogels were prepared by co-gellation of titanium n-butoxide and 2-propylpentanoic acid (valproic acid) at room temperature. Materials with different content of valproic acid were obtained varying the concentration of the drug, during the mixing stage of the sol-gel processing with two concentrations 400 and 800 mg/g of titania. Resulting xerogels were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and electron microscopy techniques. Analysis of infrared spectra provides information on the interaction between titania and the adsorbed valproic acid. XRD show an amorphous structure at room temperature. SEM micrographs revealed that the nanoparticles of the xerogels form heterogeneous plates, meanwhile a homogeneous nanostructure was observed by TEM. This study shows the optical and structural properties of the materials and the chemical stability of the encapsulated drug, and suggests that these sol-gel titania are promising carriers for controlled drug release.