In vitro interaction between artemether and some antacids and edible clay
In vitro interaction between artemether and some antacids and edible clay was investigated. Adsorption studies using three antacids namely, magnesium trisilicate, aluminium hydroxide, magnesium hydroxide as well as edible clay were carried out to determine extent of adsorption of artemether onto the adsorptive materials. A commercial artemether tablet brand was evaluated for some tablet properties and used to determine the effects of the adsorptive materials on tablet disintegration time and dissolution. Adsorption of artemether by the adsorbents followed the rank order; magnesium trisilicate (79.98%) > magnesium hydroxide (74.21%) > aluminium hydroxide (70.90%) > edible clay (37.10%). The adsorption of the drug onto the adsorptive materials was proportional to the drug concentration. The tablet parameters (weight, hardness, friability and content of active) of the commercial tablets met official BP specifications. There was significant increase (p = 0.0012) in the disintegration times of the tablets in the presence of the antacids, edible clay and a commercial antacid suspension Emtrisil®, however there was retardation of dissolution in the presence of the adsorptive materials. The percentage amount of artemether dissolved in 60 min and the order of dissolution retardation was as follows: Emtrisil® (49.58%) > magnesium trisilicate (52.20%) > magnesium hydroxide (58.92%) > aluminium hydroxide (62.67%) > edible clay (67.42%) as against 88.86% in 0.1 N HCl solution. Co-administration of artemether with adsorptive antacid formulations and concomitant consumption of edible clay with artemether should be strongly discouraged.
Keywords: artemether, adsorption, antacids, edible clay, dissolution