Parameters for the adsorption of thallium ions by activated charcoal and Prussian blue

Activated charcoal and Prussian blue are effective antidotes in acute thallium (T1+) intoxication in rats. They act by trapping any metal present in or secreted into the gut by the gastro-intestinal epithelium. It was therefore of interest to determine the parameters of the Langmuir adsorption isotherms of T1+ ions for these two adsorbents. The data from equilibration experiments were analyzed by direct least-squares fitting to a hyperbola and with Langmuir's equation to give the following results: Activated charcoal: K1(-1) = 192 micrograms ml-1, K2 = 124 mg g-1 Prussian Blue: K1(-1) = 130 micrograms ml-1, K2 = 72 mg g-1. These high values provide in vitro confirmation of their in vivo antidotal efficacy and show that activated charcoal can replace Prussian blue when this latter drug is unobtainable.     

Amitriptyline,clomipramine, and doxepin adsorption onto sodium polystyrene sulfonate

Purpose of the study

Comparative in vitro studies were carried out to determine the adsorption characteristics of 3 drugs on activated charcoal (AC) and sodium polystyrene sulfonate (SPS). Activated charcoal (AC) has been long used as gastric decontamination agent for tricyclic antidepressants (TCA).

Methods

Solutions containing drugs (amitriptyline, clomipramine, or doxepin) and variable amount of AC or SPS were incubated for 30 minutes.

Results

At pH 1.2 the adsorbent: drug mass ratio varied from 2 : 1 to 40 : 1 for AC, and from 0.4 : 1 to 8 : 1 for SPS. UV–VIS spectrophotometer was used for the determination of free drug concentrations. The qmax of amitriptyline was 0.055 mg/mg AC and 0.574 mg/mg SPS, qmax of clomipramine was 0.053 mg/mg AC and 0.572 mg/mg SPS, and qmax of doxepin was 0.045 mg/mg AC and 0.556 mg/mg SPS. The results of adsorption experiments with SPS revealed higher values for the qmax parameters in comparison with AC.

Conclusion

In vitro gastric decontamination experiments for antidepressant amitriptyline, clomipramine, and doxepin showed that SPS has higher qmax values than the corresponding experiments with AC. Therefore, we suggest SPS is a better gastric decontaminating agent for the management of acute TCA intoxication.     

In vitro binding characteristics for cesium of two qualities of prussian blue, activated charcoal and Resonium-A.

The in vitro binding characteristics of radioactive 137Cs to two forms of Prussian blue [colloidally (soluble) K3Fe[Fe(CN)6] and insoluble Fe4[Fe(CN)6]3] and to activated charcoal and sodium polystyrene sulfonate (Resonium-A) were investigated by constructing Langmuir isotherms at pH = 1.0, 6.5 and 7.5 at 37 degrees C. At the three pHs investigated, 137Cs binding to activated charcoal and sodium polystyrene sulfonate was negligible. Binding of 137Cs to insoluble Prussian blue exceeded that for the soluble form and was pH dependent for both formulations. Maximum binding capacities were 87 mg/g (pH = 1.0), 194 mg/g (pH = 6.5) and 238 mg/g (pH = 7.5) for the insoluble form and 48 (pH = 1.0), 73 (pH = 6.5) and 78 (pH = 7.5) for the soluble form. As activated charcoal did not bind 137Cs, charcoal hemoperfusion is of no value. This has been confirmed by an in vitro experiment, using a Gambro Adsorbs 300 C cartridge.     

Ferrous sulfate adsorption by activated charcoal

Although activated charcoal is thought to not appreciably adsorb iron salts, previous in vitro work indicates some adsorption of iron. This study characterized the adsorptive capacity of activated charcoal for ferrous sulfate at 3 pH environments. Langmuir adsorption isotherms were determined with a fixed amount of iron in the reaction vessels. Activated charcoal USP (20, 40, 60, 80, 100, or 120 mg) was placed in plastic tubes to which were added 1 of 3 different simulated gastrointestinal fluids (pH = 1.5, 4.5, or 7.5) and 1.49% ferrous sulfate in water. The reaction vessels were agitated and immersed in a water bath at 37 C for 30 min. Each series was performed in triplicate. Following temperature eQuilibration filtration yielded an aliquot that was assayed for iron by atomic absorption spectrophotometry. Adsorptive capacities (mean +/- SD) of activated charcoal for ferrous sulfate (mg elemental iron/g charcoal) at pH 4.5 (102.96+/-4.49) and pH 7.5 (100.94+/-19.02) were higher (P<0.01) than at pH 1.5 (-0.01+/-0.26). At pH 1.5 iron was not appreciably adsorbed by activated charcoal. Activated charcoal adsorbed ferrous sulfate to a greater extent at pH environments where iron is typically absorbed from the gastrointestinal tract. These results indicate that activated charcoal may prove an effective therapy for acute iron poisoning and further investigation is warranted.     

Administration of activated charcoal or sodium polystyrene sulfonate (Kayexalate) as gastric decontamination for lithium intoxication: an animal model

To determine whether sodium polystyrene sulfonate (SPS; Kayexalate) is effective in decreasing the absorption of lithium (Li) and to test the assumption that Li is poorly adsorbed by activated charcoal, 130 mice were administered an orogastric dose of LiCl (250 mg/kg) followed immediately by orogastric SPS (10 g/kg, SPS Group), activated charcoal (6.7 g/kg, AC Group), or water in an equivalent volume (Control Group). Subgroups of each of the 3 groups were sacrificed at 1, 2, 4 and 8 hr after treatment and serum analyzed for Li concentration. Statistical analyses revealed no overall difference between the AC Group and the Control Group. However, the SPS Group differed from both the Control and the AC Group at each time interval, with Li concentrations significantly lower in the SPS Group. These results demonstrate that: 1) SPS, in this study, effectively reduced serum Li concentrations in an in vivo model, and 2) activated charcoal did not.     

D-penicillamine and prussian blue as antidotes against thallium intoxication in rats.

D-penicillamine (DP) and prussian blue (PB), given alone and in combination, were evaluated in rats as treatments against acute thallotoxicosis. Animals were poisoned by intraperitoneal (i.p.) injection of thallium(I) acetate at different doses (16, 30, 40, 50 and 70 mg/kg). Later (24 h), treatments were administered until day 5, as follows: D-penicillamine (DP), 25 mg/kg, i.p. route, twice daily; prussian blue (PB), 50 mg/kg, oral route, twice daily. LD50 values were estimated for each treatment with the following results: control, 32 mg/kg; DP, 27 mg/kg; PB, 42 mg/kg; PB + DP, 64 mg/kg. Thallium content was analyzed in six body organs and eight brain regions after treatments. PB administration induced significant elimination of thallium from all tissues. DP treatment diminished thallium content in body organs, but increased it in brain regions, indicating a redistributive effect of DP. DP + PB treatment decreased thallium content in all body organs and brain regions. Renal thallium content in the DP + PB group was significantly lower than that of PB alone group, suggesting accelerated urinary excretion of thallium as a result of DP action. Results indicate that DP administered alone may be dangerous because of its redistributive effect, but given in combination with PB may be useful as treatment against thallium poisoning.     

Comparative antidotal efficacy of activated charcoal tablets,capsules and suspension in healthy volunteers

Summary The efficacy of several formulations of activated charcoal (AC) was compared by measuring the intestinal absorption of a solution of 1 g paracetamol administered 2 min before administration of 5 g AC as suspension (200 ml), tablets (40 of 125 mg) or capsules (25 of 200 mg). The suspension medium without AC was used as the control treatment. Based on the results of a pilot experiment, an 8 subject panel was used in a two 4×4 Latin square design.All treatments with AC resulted in a statistically significant decrease in paracetamol absorption compared to the control treatment. The suspension was considerably and significantly more effective than the tablets or capsules. Treatment with tablets was slightly but significantly more effective than capsules. The intake of large numbers of tablets and capsules was difficult.In the hospital AC suspensions are available. For first aid elsewhere, at home, at the working place or in the general practitioner's surgery a preservable and easily redispersible AC formulation would be preferable to the present solid forms.The study was carried out at the request of the Dutch Committee for Evaluation of Medicines, Rijswijk, the Netherlands.     

The adsorption of isopropanol and acetone by activated charcoal.

This study was performed to determine the adsorption of isopropanol and acetone by activated charcoal over a range of charcoal:solvent ratios. The charcoal binding of isopropanol was studied in both hydrochloric acid and water solutions, while acetone was analyzed in water. Gram ratios of charcoal to solvent ranged from 1:1 to 20:1. After the addition of charcoal the solution was agitated and centrifuged. The supernatant was then analyzed by gas chromatography. Each increment in charcoal dose increased the percent adsorption of both isopropanol and acetone. At the 20:1 ratio 87-92% of the solvent was bound by activated charcoal. In vivo study is needed to determine if activated charcoal therapy can shorten the half-life of isopropanol and acetone and decrease the duration of supportive care needed following ingestions of these solvents.     

In vitro adsorption of tilidine HCl by activated charcoal

In vitro studies were carried out in order to determine the adsorption of tilidine HCl, a narcotic analgesic, by activated charcoal (max. adsorption capacity 185.5 mg/g of charcoal). The path of the adsorption isotherms at pH 1.2 and 7.5 suggests that the in vivo adsorption of tilidine HCl may be increased when the drug passes from the stomach to the intestine, unless the intestinal content exerts a displacing effect. Nevertheless, the adsorption was dependent on the quantity of activated charcoal used, becoming more complete when the quantity of activated charcoal was increased. The effects of additives on the adsorption capacity of activated charcoal were also investigated in vitro. Ethanol, sorbitol and sucrose significantly reduced drug adsorption, while cacao powder, milk and starch had no effect on tilidine adsorption. At an acid pH, Federa Activated Charcoal significantly adsorbed more drug than either Norit A or Activated Charcoal Merck.     

聚苯乙烯磺酸钠理化性质的考察

目的:考察新型药用辅料-聚苯乙烯磺酸钠的基本理化性质.方法:测定聚苯乙烯磺酸钠不同粒径下含水量,湿真密度,交换容量,溶胀率等基本理化性质.结果:聚苯乙烯磺酸钠粒径减小,含水量增大,湿真密度减小,交换容量增大,溶胀率增大.结论:聚苯乙烯磺酸钠的基本理化性质均受粒径影响.     

In vitro study of lithium carbonate adsorption by activated charcoal

The purpose of this study was to determine whether lithium carbonate (Li2CO3) is effectively adsorbed by activated charcoal (AC). Either 0 (control), 1.5, 3.0 or 9.0 grams of AC were added to Li2CO3 (300 mg) in distilled deionized water or simulated gastric fluid USP, filtered and and the filtrate analyzed for lithium by flame photometry. Adsorption of lithium was dependent on AC concentration and pH. In water, lithium was 14.7%, 26.5% and 40.4% adsorbed at AC:Li2CO3 ratios of 5:1, 10:1 and 30:1, respectively (p less than 0.05). In simulated gastric fluid, there was no significant adsorption at any of the AC concentrations studied. Since simulated gastric fluid more closely resembles in vivo conditions, the efficacy of AC in lithium carbonate overdoses is questionable but in vivo studies are needed to confirm these findings.     

Absorption of sodium pentobarbital by three types of activated charcoal

The in vitro adsorption of sodium pentobarbital by activated charcoal (USP), Darco G-60 and SuperChar was studied. Various solutions of sodium pentobarbital, ranging in concentration from 2.5 to 10 mg/ml (pH = 9), were prepared in distilled water. Radiolabeled (14C) sodium pentobarbital was added to serve as a concentration marker. Two millimeters of each solution was added to from 5 to 350 mg of each charcoal in a test tube. The resulting charcoal-drug slurries were mixed thoroughly and incubated at 37 C for 10 min. Analysis of supernatant allowed calculation of percentage of drug bound. Plots of percentage of drug bound vs log quantity of charcoal necessary to bind 50% of the drug (B-50) were constructed. B-50 was lowest for SuperChar (indicating highest binding capacity), followed by USP and Darco G-60 activated charcoals. In a second series of experiments, drug adsorption was determined at various pH's, or when sodium pentobarbital was dissolved in various volumes of distilled water. Adsorption of the drug from solutions buffered at pH 8.1, 9, 9.7, 11 and 12 did not differ from adsorption in aqueous solution. Adsorption of sodium pentobarbital by 50 or 100 mg of each charcoal did not change when 5 mg of the drug was dissolved in 1, 2, 4, 6, 8 or 10 ml of water. The results suggest that sodium pentobarbital is most readily adsorbed by SuperChar under all conditions studied, followed by USP and Darco G-60 activated charcoals. Changes in pH, or in the initial mixture volume, did not influence the degree of drug adsorption to activated charcoal.     

Factors influencing the clinical efficacy of activated charcoal

The use of activated charcoal as part of the treatment of intoxicated patients has increased dramatically over the last ten years. Activated charcoal is currently suggested as therapy to prevent the absorption of orally ingested compounds, and is gaining popularity as a method of increasing systemic drug clearance. This review presents variables that should be considered when activated charcoal is used in the treatment of intoxicated patients. Variables that may alter the efficacy of charcoal therapy include the preparation and dose of charcoal used, the intoxicants involved, stomach contents, the gastrointestinal pH, concurrently administered materials, and time from toxin ingestion to charcoal administration. As a general guideline, a single, large dose should be administered with a cathartic as soon as possible after oral ingestion to prevent drug absorption. When charcoal is used to enhance systemic drug clearance, the dosage regimen should be individualized, based on the drugs involved and the patient's gastrointestinal tract function, fluid and electrolyte status, and the severity of intoxication.     

普鲁士蓝联合血液净化救治急性铊中毒2例

2例患者（男性36岁,女性68岁）因四肢麻木刺痛入院。病例1和2的血铊浓度分别为1 642和158μg/L,诊断为铊中毒。患者给予口服普鲁士蓝250 mg/（kg.d）和血液净化等治疗。之后,病例1和2的血铊浓度分别逐步降至5和4μg/L,临床症状明显缓解。     

Inhibition by ice cream of the antidotal efficacy of activated charcoal.

A study was conducted to determine if ice cream and sherbet interfered with the adsorption of aspirin onto activated charcoal both in vivo and in vitro. An aqueous suspension of 20 g activated charcoal decreased the absorption of 1 g aspirin by 65%; the same dose of activated charcoal with 50 g of ice cream reduced aspirin absorption by only 42% under otherwise identical conditions. In vitro tests showed that different ice creams and sherbet decrease the adsoprtion of aspirin onto activated charcoal. Thus, although ice cream is useful for preparing palatable suspensions of activated charcoal, it decreases appreciably the antidotal efficacy of the adsorbent.     

Efficacy of the cation exchange resin, sodium polystyrene sulfonate, to decrease iron absorption

BACKGROUND: Iron is not bound by charcoal; therefore, a method of binding iron in the gastrointestinal tract to prevent absorption in iron overdose is needed. This study investigated the efficacy and safety of sodium polystyrene sulfonate to prevent absorption of iron in human volunteers. METHODS: Six adult volunteers completed this prospective crossover trial. Following an oral dose of elemental iron 10 mg/kg, each subject received sodium polystyrene sulfonate 30 g or water as control. Baseline and serial serum iron samples were drawn to determine pharmacokinetic parameters. RESULTS: A trend toward increased time to peak following sodium polystyrene sulfonate compared to the control arm (5.7 vs 3.6 hours) was observed but was not statistically significant (p = 0.517). A trend toward smaller area-under-the-curve for the sodium polystyrene sulfonate was evident but was not statistically significant (p = 0.77). Iron concentration increased on average 298 mcg/dL and 370 mcg/dL above baseline in the treatment and control arms (p = 0.44). Sodium polystyrene sulfonate is not an effective method of decontamination for iron overdose.     

Determination of the adsorption of tramadol hydrochloride by activated charcoal in vitro and in vivo

Although tramadol is one of the most widely used centrally acting analgesics worldwide, no literature is available regarding adsorption of tramadol HCl powder or tablets (Ultram; 50 mg tramadol HCl per tablet) by activated charcoal (AC) for use as potential adjunct treatment of overdose. The present study incorporated a novel combination of in vitro and in vivo methods to investigate this question. Based on a binding curve of tramadol UV absorbance (UV(a); 225 nm) plotted against the amount of AC, the ratio of amount of tramadol completely adsorbed by AC was 0.05 mg/mg. Also based on UV(a), no tramadol was detected in filtrate of slurries in which up to 62 tablets of Ultram were mixed with 50 g AC; 4.6% of unbound tramadol was detected when 100 tablets of Ultram were mixed with AC. The ratio of amount of tramadol completely adsorbed by AC in this test was 0.10. In vivo, co-administration of 0.1 g/ml of AC produced a 13- to 14-fold rightward shift in tramadol's antinociceptive dose-response curve and a 1.6-fold rightward shift in tramadol's lethality dose-response curve.