Cocaine adsorption to activated charcoal in vitro.

Although activated charcoal (AC) is commonly used after ingestions of cocaine, the ability of AC to bind with this drug is unknown. We studied binding of cocaine to AC in vitro. Cocaine adsorption to charcoal for AC:drug ratios of 1:1, 2.5:1, and 5:1 at pH 1.2 was 40%, 92%, and 99%, respectively; at pH 8.0, it was 78%, 98%, and 99%, respectively. All means were significantly different (P less than 0.05) versus the control (no AC) at each pH. At the AC:drug ratio of 1:1, there was also significantly greater adsorption of cocaine at pH 8.0 than at pH 1.2. This study shows that AC strongly adsorbs cocaine under both acidic and alkaline conditions.