Mesoporous Silica-Based Strategy for Enhancing Indomethacin Dissolution: Syloid® XDP 3050 for Oral Equine Delivery

Abstract

Mesoporous silica excipient Syloid® XDP 3050 was formulated with 
indomethacin, a model drug characterised by poor aqueous solubility, to 
enhance its dissolution rate and extent. While various mesoporous silicas have 
been previously studied, the specific interaction and performance of Syloid® 
XDP 3050 with indomethacin had not been reported.  Formulations at drug-to
silica ratios of 1:1, 2:1, and 1:3 (w/w) were prepared using the microwave 
method and characterised by DSC, XRD, FTIR, and SEM. In vitro dissolution 
was assessed in phosphate buffer (pH 7.0) at 37 °C for 45 min using the USP 
type II paddle method. This study demonstrates a significant improvement in 
both the dissolution rate and extent of drug release at drug-to-silica ratios of 1:1, 
2:1, and 1:3 over 45 minutes. DSC and XRD confirmed the conversion of 
indomethacin from crystalline to amorphous form in all microwave-processed 
formulations. FTIR revealed no evidence of strong chemical interactions, while 
SEM images showed the drug uniformly dispersed within the silica matrix. The 
observed enhancement is attributed to the conversion of indomethacin from its 
crystalline to amorphous form, as well as the silica’s superior drug-loading 
capacity within its porous structure. Variations in release profiles among the 
different ratios were linked to the physicochemical properties of the 
formulations. Overall, the findings confirm that Syloid® XDP 3050 can 
effectively enhance the dissolution and potentially the bioavailability of poorly 
water-soluble drugs like indomethacin. Moreover, drug release profiles can be 
modulated by selecting appropriate silica types and drug-to-carrier ratios, 
offering a promising approach to tailor oral drug delivery systems.