In Vitro Interaction Between Zidovudine and Some Adsorptive Antacids

Abstract

The in vitro interaction between zidovudine and three antacids and a commercial product was
investigated. The extent of adsorption of zidovudine by the antacids, and the effects of the antacids on the
disintegration time and dissolution of the drug from tablets were studied. Adsorption of the drug by the antacids
followed the order; magnesium trisilicate > aluminium hydroxide > magnesium hydroxide. Retardation of dissolution
amongst the antacids and commercial product was of the order; Jawasil® > magnesium trisilicate > aluminium
hydroxide > magnesium hydroxide. Also, the degree of retardation of dissolution from the tablets increased as the
amount of adsorbent increased. Co-administration of zidovudine and adsorptive antacid formulations should be
avoided in clinical practice since it can lead to a decrease in the bioavailability of zidovudine, ultimately leading to
therapeutic failure.