Comparison of adsorptive capacity for different types of activated charcoal for common veterinary toxicants

Activated charcoal (AC) is a convenient, effective method for gastrointestinal decontamination, typically supplied as either activated charcoal powder (pAC) or proprietary mixtures in granules or suspension (e.g., Toxiban^®, Tox). We compared the adsorptive capacity for common veterinary toxicants of a new resin-bound activated charcoal product (Ready Rescue™; RR) to PAC and Tox. We hypothesized that RR is equivalent to Tox and PAC in binding of these toxicants. Solutions of simulated low pH (pH = 1.5) and neutral (pH 6-7) environments were incubated at 38 °C with continuous agitation. Commercial products containing the following toxicants (final concentration) were evaluated: Naproxen (8.8 mg/mL), ivermectin (1.1 mg/mL), bromethalin (0.028 mg/mL), xylitol (17.9 mg/mL), ethylene glycol (400 mg/mL), Delta-9 THC (1.5 mg/mL), baker's chocolate (567 mg/mL), roquefortine (500 mg/mL of cheese), tartaric acid (133 mg/mL). Toxicants were incubated in separate reaction mixtures for 30 min before the equivalent of 15 g of charcoal product (RR, PAC, or Tox) was added. The reaction mixtures were sampled prior to charcoal addition, and at 30, 60, and 240 min after, and assayed for toxicant concentration. The different AC formulations decreased concentrations of the assayed toxicant in most tested conditions, in both acidic and neutral pH environments. Exceptions included tartaric acid, bromethalin, ethylene glycol, and xylitol, which showed variable changes in concentration. In general, the rate of decrease was similar between AC products with the exception of Delta-9 THC in the neutral environment, where Tox showed a more rapid rate of decrease than RR. In this in vitro system, the three tested AC products effectively decreased concentration of most toxicants over a 4 h period, with pAC and Tox showing a more rapid rate of decline for some toxicants compared to RR.