Mesoporous spheres of Calciutri silicate hydrate (MS-CSH) have been prepared by an ulttasonie method. Following an earlier work in which we have revealed the interactions between ibuprofen (IBU) :and CSH carriers with different morphologies by X-ray absorption neat edge structures (XANES) analysis. In the present investigation, two new drug Molecules, alendronate sodium (ALN) and gentamicin Sulfate (GS), were incorporated into MS-CSH, and their drug loading capacities (DLCs) weremeasured using thermogravimetric analysis to establish the relatiOnshiP between drug-carrier interactions' and PLCs. The XANES spectra clearly indicate that acidic functional groups of the drug molecules linked to the active sites (Ca-OH and Si-OH groups) of MS-CSH on the surface by electrostatic interactions. In addition, it is found that the stoichioinetric ratio of Ca2+ ions of CSH carriers and the functional groups of drug molecules may significantly influence the DLCs.