Interactions between sulfa drug sulfadiazine and hydrophobic talc surfaces

Interactions between sulfadiazine (SDZ), a sulfa drug antibiotic, and talc, a low charge 2:1 phyllosilicate, were investigated under batch experimental conditions. The SDZ adsorption on talc was instantaneous, with a very large rate constant and a fast rate, although with a low amount. SDZ adsorption followed a linear sorption isotherm, suggesting that the hydrophobic interact instead of cation exchange was more like responsible for the uptake of SDZ. Solution pH had a unique influence on SDZ adsorption. The solute distribution coefficient was low in pH 3–7 range and increase at even lower and higher pH conditions. Molecular simulation suggested that the interactions between the benzene ring as well as the O of SDZ and the Mg in the octahedral site of talc was partially responsible for SDZ uptake. In addition, the hydrogen bonding between the N in the amine as well as in the hetero ring and the broken bond of O on the 010 plane of talc also contributed to SDZ uptake by talc.