IN-VITRO STUDY ON THE ADSORPTION OF RIFAMPICIN FROM AQUEOUS SOLUTION

Document Type : Original Article

Authors

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, Egypt

Abstract

The adsorption of rifampicin has been investigated onto kaolin, talc, magnesium trisilicate, magnesium oxide and avicel pH 101. Adsorption of rifampicin was markedly dependent on the nature of the adsorbent used. The amount of rifampicin adsorbed was found to be in obedience with both Langmuir and Freundlich equations. The extent of the amount adsorbed was correlated with the adsorbent structure. The decreasing order for the affinity of rifampicin to the selected adsorbents was as follows: kaolin > talc > magnesium trisilicate > avicel pH 101 > magnesium oxide.
The effect of different concentrations of polysorbate 80 on the amount of rifampicin adsorbed onto activated charcoal surface has revealed that as the surfactant concentration was increased the amount of the drug adsorbed was correspondingly decreased. The mechanism through which the decrease in the extent of adsorption, in the presence of the surfactant, has been discussed.