Easily swallowed formulations of antidote charcoals

Assessment of the palatability of vehicles for activated charcoal in pediatric volunteers

OBJECTIVE

To evaluate the palatability of 4 common flavoring vehicles (water, chocolate milk [CM], orange juice [OJ], and cola) combined with activated charcoal (AC) in pediatric volunteers.

DESIGN

A single-blind taste test of 4 different vehicles (water, OJ, a cola drink, and CM) was conducted in healthy volunteer children. Each child tasted 1.25 mL of Charcodote (0.2g/mL) mixed with 1.25 mL of each vehicle.

SETTING

Palatability testing was conducted at the office of 1 of the authors.

PARTICIPANTS

Thirty children (16 male, 14 female), aged 6.5 +/- 1.4 years (range 5-9 years).

OUTCOME MEASURES

After each test dose, each child rated its taste on a modified 10 cm visual analog scale incorporating a facial-hedonic scale. Each child was also asked for his/her overall preference.

RESULTS

Taste scores (cm) were as follows: water 5.6 +/- 1.8, OJ 5.4 +/- 1.0, cola 7.6 +/- 0.7, and CM 5.6 +/- 0.8. There was a significant difference in the taste scores between the cola drink (P = 0.01) and the other 3 vehicles. The cola drink was also selected as the most preferred vehicle by 50% of the children as compared with 19.2% for CM and 15.4% for OJ. In contrast, water was selected as the least preferred vehicle by 36.4% of children versus 31.8% for CM and 27.3% for OJ. Only 4 children (15.4%) stated that water was their preferred vehicle, and only 1 child (4.5%) stated that cola drink was the least preferred drink.

CONCLUSIONS

Children rate the palatability higher and prefer charcoal given with a cola drink rather than with water. OJ and CM do not seem to improve the acceptability of charcoal.

Formulation of activated charcoal for per os administration to addicted subjects

The objective of this work was to develop a galenic form of activated charcoal appropriate for the needs of clinical toxicology. To preserve the adsorption capacity of charcoal, we developed an extemporaneous preparation of activated charcoal intended for clinical toxicology. To improve the wettability of activated charcoal, we used densification by wet granulation. The presence of a viscosity agent is necessary to ensure the homogeneity of the suspension and its adhesiveness on gastric mucous membrane. Five formulations with different viscosity agents were prepared, and their adsorption capacity, wettability, viscosity, and adhesiveness were studied.

The adsorption of salicylates by a milk chocolate-charcoal mixture

STUDY OBJECTIVE

To evaluate the adsorptive capacity of a milk chocolate-charcoal mixture to aspirin, compared with superactivated charcoal and conventional activated charcoal.

DESIGN

A prospective, randomized, crossover study.

SETTING

The Massachusetts Poison Control Center office in The Children's Hospital, Boston.

TYPE OF PARTICIPANTS

Six healthy adult volunteers with no known allergies to aspirin or chocolate, bleeding disorders, or peptic ulcer disease.

INTERVENTIONS

Each participant ingested 975 mg of crushed aspirin on separate days, followed by either water; 10 g milk chocolate-charcoal mixture; 10 g SuperChar Liquid; or 10 g Actidose Aqua activated charcoal. Total serum salicylate concentrations were determined by high-performance liquid chromatography at zero, one, two, four, eight, and 24 hours after ingestion.

MEASUREMENTS AND MAIN RESULTS

Neuman-Keuls analysis was used to measure time-to-peak concentration, which was reduced by SuperChar Liquid, 67%; milk chocolate-charcoal mixture, 106%; and activated charcoal, 56%. Aspirin absorption was calculated using Neuman-Keuls analysis to measure area under the concentration-time curve. Total aspirin absorption was reduced by SuperChar, 67%; milk chocolate-charcoal mixture, 50%; and activated charcoal, 2%. There was no difference in serum salicylate concentrations between SuperChar and milk chocolate-charcoal mixture at all time intervals. Also, all serum salicylate concentrations with milk chocolate-charcoal mixture were consistently lower than with activated charcoal.

CONCLUSION

Although the formulation of milk chocolate with activated charcoal reduces its adsorptive capacity compared with superactivated charcoal, it is still able to bind aspirin effectively and is superior to conventional activated charcoal. Further research may improve the binding and palatability of milk chocolate-charcoal mixture, especially for home use.

A ready-to-use activated charcoal mixture. Adsorption studies in vitro and in dogs: its influence on the intestinal secretion of theophylline in a rat model

A practical, ready-to-use preparation of activated charcoal (AZU mixture) for application in toxicology has been formulated. To establish its efficacy, the formulation was tested in vitro and in dogs. The in vitro adsorption capacity was compared to that of freshly prepared charcoal suspension in water (CW) and to Carbomix. Langmuir adsorption coefficients demonstrated small but clinically insignificant differences in adsorption capacity between the preparations. The laxative sodium sulfate did not reduce the adsorption capacity of charcoal in vitro. Dogs were given 60 mg of paracetamol per kg as an oral solution followed by 5 g of activated charcoal preparation. The area under the plasma concentration versus time curve (control 2955 +/- 353 mg.min-1.l-1) was significantly reduced following CW (921 +/- 453) and AZU (786 +/- 270). The premixed AZU charcoal formulation is efficacious, inexpensive and overcomes the problems of bed-side preparation. An isolated vascularly perfused rat small intestine can be used to describe the effect of activated charcoal on the intestinal secretion of theophylline.

Freundlich and Langmuir isotherms as models for the adsorption of toxicants on activated charcoal

The Langmuir isotherm has been widely used to characterize the adsorption of solutes from aqueous solutions. Activated charcoal adsorption data obtained experimentally, using a wide range of adsorbate concentrations, fit the Langmuir isotherm poorly but evidence a good fit to the Freundlich isotherm. Statistical analysis reveals this to be also true of published data that was previously considered to adhere to the Langmuir isotherm. Over the range of possible adsorbate concentrations, the two isotherms predict rather different adsorption behavior. Of the two, the Freundlich isotherm is able to more fully account for observed antidotal effectiveness of activated charcoal in vivo. A method of graphical analysis is advanced that more readily distinguishes the relative goodness-of-fit of the two isotherms. This and the statistical paradigm employed to decide between the two competing hypotheses should allow the adsorption phenomena involving other adsorbents to be re-examined.

The new black magic: activated charcoal and new therapeutic uses

Activated charcoal has been used for centuries as antidotal therapy for poisonings. New variations of charcoal therapy have developed over the last two decades. These modifications include multiple-dose activated charcoal (MDAC) therapy, charcoal hemoperfusion, and a new "superactive" charcoal (SAC). Recent literature suggests using initial charcoal therapy instead of ipecac as a first-line antidotal agent for many acute poisonings. The palatability of charcoal slurries has been enhanced by the addition of carboxymethylcellulose, sucrose, saccharin, chocolate syrup, or sorbitol. The new SAC has shown to adsorb 1.7 to 4 times the amount of substance tested compared with other activated charcoal preparations. Multiple-dose activated charcoal therapy has been shown effective in treating phenobarbital, digoxin, digitoxin, theophylline, and dapsone intoxications, among others. The problems associated with charcoal hemoperfusion therapy have been partially alleviated, and it is now alternative therapy for the seriously intoxicated patient.

Evaluation of activated charcoal-sorbitol suspension as an antidote

Studies in rats were performed to evaluate the effect of sorbitol on the antidotal efficacy of activated charcoal against four test drugs and to investigate the influence of storage upon the antidotal effect of activated charcoal-sorbitol suspension. The antidotal potency of activated charcoal was not diminished by sorbitol solution 70% w/v. In fact, it was enhanced by the sorbitol solution, as indicated by greater decrease in peak tissue drug concentration, compared to the effect produced by activated charcoal in aqueous suspension. Furthermore, storage of activated charcoal in sorbitol for as long as 1 year did not reduce the antidotal-efficiency of the absorbent.

Effect of type and amount of carboxymethylcellulose on in vitro salicylate adsorption by activated charcoal

The effect of the type of carboxymethylcellulose (CMC) and amount of CMC used in preparing antidotal charcoal formulations on the in vitro kinetics of sodium salicylate adsorption from simulated gastric fluid was assessed in agitated vessels of two designs. Mixtures made with low, medium, and high viscosity CMC were tested. Additionally, the effects of the charcoal and water contents of these mixtures on adsorption kinetics were considered. The results suggest that charcoal mixtures which are fluid enough to be pourable (hence, drinkable) are strongly to be preferred from the standpoint of rate of adsorption. More particularly, gel-like formulations should be avoided because they disperse poorly and result in rather slow rates of drug uptake.

In-vivo comparison of the adsorption capacity of "superactive charcoal" and fructose with activated charcoal and fructose

This study was undertaken to assess the in-vivo capacity of two activated charcoal products to adsorb aspirin after its ingestion by seven healthy volunteers. The two products, Norit-A and Super-Sorb, were combined with fructose solution and administered after the subjects ingested 975 mg of aspirin. Urinary excretion of salicylates was measured during both charcoal administration phases and after ingestion of aspirin alone in all subjects. Results showed statistically significant differences in salicylate excretion between all phases. Super-Sorb ("superactive charcoal") adsorbed almost twice (1.7) as much as aspirin as the regular activated charcoal, Norit-A. Super-Sorb therefore has a greater in-vivo adsorption capacity for aspirin and should be a more effective antidote in poisonings with this drug.

Effect of magnesium citrate on the in vitro adsorption of aspirin by activated charcoal

The objective of this study was to determine if magnesium citrate solution given concurrently with activated charcoal would affect charcoal's in vitro ability to bind aspirin. Aspirin and charcoal were mixed in simulated gastric fluid and simulated intestinal fluid, and then magnesium citrate solution was added in proportions simulating those encountered clinically. Results indicate that no clinically significant interaction occurs between magnesium citrate and activated charcoal in either fluid, and that these two agents can be given simultaneously without decreasing the binding capacity for aspirin.

Enhanced adsorptive capacity of activated charcoal in the presence of magnesium citrate, N.F

In a series of experiments to determine the effect of magnesium citrate solution, NF, on the adsorption of sodium salicylate onto charcoal, salicylate adsorption was shown to be enhanced in the presence of citrate ion and, to a lesser extent, magnesium ion. Additional in vitro and in vivo studies with sodium salicylate, as well as other drugs, will be necessary to fully assess the potential clinical implications of these findings.

NAGD regimen for the coma of drug-related overdose

A specific arousal therapy with NAGD (Naloxone, Activated Charcoal, Glucagon, Doxapram) is outlined for victims of drug overdose in comatose and semi-comatose states. Several direct benefits accrue if early awakening or lightening of such patients is safely accomplished. There are: 1) elimination of need for prolonged intubation or tracheostomy; 2) patient's ability to tell which drug(s) were taken; 3) excessively frantic and vigorous supportive treatment is obviated; and 4) the overall hospital stay is shortened. The NAGD regimen has been found to effectively, safely, and predictably reverse coma. Therapy consists of: naloxone 0.8 mg to 1.6 mg intravenously; large-bore orogastric tube instillation of 100 gm to 120 gm activated charcoal slurry; glucagon 1 mg to 2 mg intravenously; and, in selected cases, doxapram 1 mg/kg to 2 mg/kg intravenously.

Omission of pepsin from simulated gastric fluid in evaluating activated charcoals as antidotes

Although simulated gastric fluid USP calls for 3.2 g of pepsin/liter, most researchers omit pepsin when evaluating adsorbents. The present results show that, although pepsin adsorbs strongly to activated charcoal, it does not interfere significantly with the adsorption of a typical drug like sodium salicylate. Therefore, its omission is justified. Gastric mucin also had almost no effect on salicylate adsorption.

Interference by tannic acid with the effectiveness of activated charcoal in "universal antidote"

Evidence is presented to show that tannic acid is responsible for the reduced effectiveness of "universal antidote" as compared with activated charcoal alone. Adsorption isotherm data indicate that tannic acid binds strongly to charcoal and hence uses up part of the adsorption capacity that would otherwise be available for binding of a drug or poison. Data on sodium salicylate adsorption from simulated gastric fluid, both with and without the presence of tannic acid, are presented that illustrate clearly that tannic acid interferes significantly with the adsorption of salicylate. Magnesium oxide, another component of "universal antidote," was found to offer no interference to salicylate adsorption, presumably because it does not adsorb to charcoal to any significant extent.

Evaluation of a charcoal-sorbitol mixture as an antidote for oral aspirin overdose

The preparation of charcoal in a 70% sorbitol solution results in a suspension that is more palatable and less gritty than an aqueous slurry of charcoal. Although the charcoal-sorbitol mixture may be slightly less effective in reducing the extent of aspirin absorption compared with a charcoal slurry, it may prove to be of particular value in those cases where acceptance of a charcoal slurry presents a problem.

A "superactive" charcoal for antidotal use in poisonings

Amoco Grade PX-21 powdered activated charcoal was found to adsorb nearly three times as much sodium salicylate from simulated gastric fluid than did another charcoal (Norit A), which is representative of the best of all other charcoals heretofore available. This indicates the potential superior effectiveness of the Amoco charcoal as an oral antidote in poisonings.

Influence of "thickening" agents on the antidotal efficacy of activated charcoal

The addition of "thickening" agents such as bentonite and carboxymethylcellulose to activated charcoal slurries considerably improves the palatability of this antidote yet does not reduce the efficacy of the activated charcoal in reducing the gastrointestinal absorption of aspirin. Flavoring of such preparations may further enhance this palatability.