Biochemical reagent

Tris(hydroxymethyl)aminomethane hydrochloride is a biochemical reagent that can be utilized in research pertaining to life sciences as an organic compound or biological material.
THAM (trometamol; tris-hydroxymethyl aminomethane) is a biologically inert amino alcohol of low toxicity, which buffers carbon dioxide and acids in vitro and in vivo. At 37 degrees C, the pK (the pH at which the weak conjugate acid or base in the solution is 50% ionised) of THAM is 7.8, making it a more effective buffer than bicarbonate in the physiological range of blood pH. THAM is a proton acceptor with a stoichiometric equivalence of titrating 1 proton per molecule.[1]

In vivo, THAM supplements the buffering capacity of the blood bicarbonate system, accepting a proton, generating bicarbonate and decreasing the partial pressure of carbon dioxide in arterial blood (paCO2). It rapidly distributes through the extracellular space and slowly penetrates the intracellular space, except for erythrocytes and hepatocytes, and it is excreted by the kidney in its protonated form at a rate that slightly exceeds creatinine clearance. Unlike bicarbonate, which requires an open system for carbon dioxide elimination in order to exert its buffering effect, THAM is effective in a closed or semiclosed system, and maintains its buffering power in the presence of hypothermia. THAM rapidly restores pH and acid-base regulation in acidaemia caused by carbon dioxide retention or metabolic acid accumulation, which have the potential to impair organ function. Tissue irritation and venous thrombosis at the site of administration occurs with THAM base (pH 10.4) administered through a peripheral or umbilical vein: THAM acetate 0.3 mol/L (pH 8.6) is well tolerated, does not cause tissue or venous irritation and is the only formulation available in the US. In large doses, THAM may induce respiratory depression and hypoglycaemia, which will require ventilatory assistance and glucose administration. The initial loading dose of THAM acetate 0.3 mol/L in the treatment of acidaemia may be estimated as follows: THAM (ml of 0.3 mol/L solution) = lean body-weight (kg) x base deficit (mmol/L). The maximum daily dose is 15 mmol/kg for an adult (3.5L of a 0.3 mol/L solution in a 70kg patient). When disturbances result in severe hypercapnic or metabolic acidaemia, which overwhelms the capacity of normal pH homeostatic mechanisms (pH < or = 7.20), the use of THAM within a 'therapeutic window' is an effective therapy. It may restore the pH of the internal milieu, thus permitting the homeostatic mechanisms of acid-base regulation to assume their normal function. In the treatment of respiratory failure, THAM has been used in conjunction with hypothermia and controlled hypercapnia. Other indications are diabetic or renal acidosis, salicylate or barbiturate intoxication, and increased intracranial pressure associated with cerebral trauma. THAM is also used in cardioplegic solutions, during liver transplantation and for chemolysis of renal calculi. THAM administration must follow established guidelines, along with concurrent monitoring of acid-base status (blood gas analysis), ventilation, and plasma electrolytes and glucose.[1]

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In the controls, the decrease in VT from 6 to 3 ml/kg increased PaCO2 from 6.0±0.5 to 13.8±1.5 kPa and lowered pH from 7.40±0.01 to 7.12±0.06, whereas base excess (BE) remained stable at 2.7±2.3 mEq/L to 3.4±3.2 mEq/L. In the THAM groups, PaCO2 decreased and pH increased above 7.4 during the infusions. After discontinuing the infusions, PaCO2 increased above the corresponding level of the controls (15.2±1.7 kPa and 22.6±3.3 kPa for 1-h and 3-h THAM infusions, respectively). Despite a marked increase in BE (13.8±3.5 and 31.2±2.2 for 1-h and 3-h THAM infusions, respectively), pH became similar to the corresponding levels of the controls. PVR was lower in the THAM groups (at 6 h, 329±77 dyn∙s/m(5) and 255±43 dyn∙s/m(5) in the 1-h and 3-h groups, respectively, compared with 450±141 dyn∙s/m(5) in the controls), as were pulmonary arterial pressures.
Conclusions: The pH in the THAM groups was similar to pH in the controls at 6 h, despite a marked increase in BE. This was due to an increase in PaCO2 after stopping the THAM infusion, possibly by intracellular release of CO2. Pulmonary arterial pressure and PVR were lower in the THAM-treated animals, indicating that THAM may be an option to reduce PVR in acute hypercapnia.[2]

A one-hit injury ARDS model was established by repeated lung lavages in 18 piglets. After ventilation with VT of 6 ml/kg to maintain normocapnia, VT was reduced to 3 ml/kg to induce hypercapnia. Six animals received THAM for 1 h, six for 3 h, and six serving as controls received no THAM. In all, the experiment continued for 6 h. The THAM dosage was calculated to normalize pH and exhibit a lasting effect. Gas exchange, pulmonary, and systemic hemodynamics were tracked. Inflammatory markers were obtained at the end of the experiment.[2]

Absorption, Distribution, and Excretion
Trebutaline is primarily excreted via the kidneys. …Ionized tromethamine (mainly in bicarbonate form) is rapidly and preferentially excreted in the urine, with the excretion rate depending on the infusion rate. The manufacturer states that urinary excretion can continue for up to 3 days; after 8 hours, 75% or more of the drug is present in the urine. Some studies suggest that 50-75% of the intravenously administered dose is recovered from the urine within 24 hours, but another study reported recovery rates of 64% and 77% after 2 and 3 days, respectively, in healthy adults.
It is currently unclear whether tromethamine is distributed into human breast milk.
Ionized tromethamine is excreted via the kidneys, therefore its function is to remove hydrogen ions. The drug is completely eliminated from the body via renal excretion. Tromethamine excretion is accompanied by osmotic diuresis, as clinical doses of tromethamine significantly increase the osmotic pressure of the glomerular filtrate.
This study investigated the renal excretion of tris(hydroxymethyl)aminomethane (THAM) in rats of different ages (5 to 240 days old). Results showed that THAM excretion was slower in 5-day-old and 240-day-old rats than in other age groups. Intraperitoneal injection of mannitol, thiazide diuretics, or oral rehydration to stimulate diuresis increased THAM excretion in both 5-day-old and 240-day-old rats. Repeated administration of THAM to all age groups, except newborn rats, also increased THAM excretion. The possible mechanism of action is discussed. PMID:240333
Under a constant plasma pH of 7.4, the distribution of THAM labeled with 14C in the intracellular and extracellular spaces of nephrectomized Sprague-Dawley rats over time was measured. Results showed that the equilibrium between the extracellular and intracellular spaces of THAM was not reached within 6–12 hours after administration. This indicates that THAM infiltrates the intracellular interstitial space very slowly, contrary to the common belief that THAM rapidly diffuses into the intercellular space to restore intracellular acidosis. The disappearance of THAM from the extracellular space exhibits a multi-exponential decay, suggesting significant differences in the rate at which it reaches equilibrium with different tissues. The equilibrium achieved between the two fluid compartments 6–12 hours after THAM administration does not conform to expectations considering only the transport of non-ionized substances. At a plasma pH of 7.4 and a mean systemic pH of 6.88, the distribution ratio of THAM was 4 (ICS/ECS), far exceeding the expected value of 11 for non-ionized diffusion. Therefore, THAM also crosses the cell membrane in an ionized form. These results suggest that the rate of THAM influx into cells is too slow (compared to renal clearance kinetics) to significantly affect intracellular pH through direct buffering. Furthermore, only a portion of THAM enters the cells in a non-ionized form, thus (to a greater extent) reducing the direct impact of THAM on intracellular acid-base balance. PMID:6711774

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Metabolism/Metabolites
The metabolism of tromethamine is not obvious.

Human Toxicity Excerpt
/Human Exposure Studies/ In studies of tromethamine administration to healthy individuals, respiratory rate remained constant, but decreased tidal volume led to a decrease in minute ventilation and carbon dioxide output; arterial oxygen saturation decreased by an average of approximately 5%.
/Signs and Symptoms/ Rapid and/or excessive administration of tromethamine may lead to alkalosis, hypoglycemia, hyperhydration, or solute overload.

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Non-Human Toxicity Excerpt
/Laboratory Animals: Acute Exposure/ Even after neutralization, oral administration of high doses of tromethamine to laboratory animals resulted in weakness, syncope, and coma (without seizures). Injection of high doses of tromethamine to animals caused hypoglycemia, but simultaneous glucose supplementation did not prevent death.

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Non-human toxicity values
Rat intravenous LD50: 2300 mg/kg
Rat oral LD50: 5900 mg/kg
Mouse intravenous LD50: 3500 mg/kg
Environmental fate/exposure overview
Grammatical alcohol is used as an emulsifier in the synthesis of surfactants and vulcanization accelerators. Its production and use may result in the release of tromethamine into the environment through various waste streams. If released into the air, the estimated vapor pressure at 25°C is 2.2 × 10⁻⁵ mmHg, indicating that tromethamine is expected to exist in the atmosphere in both gaseous and particulate phases. Gaseous tromethamine degrades in the atmosphere by reacting with photochemically generated hydroxyl radicals; the half-life of this reaction in the air is estimated to be 11 hours. Particulate tromethamine is removed from the atmosphere by dry and wet deposition. Tromethamine does not contain chromophores with absorption wavelengths greater than 290 nm, therefore it is not expected to be subject to direct photolysis by sunlight. If released into soil, its Koc value is estimated to be 1, indicating high mobility of tromethamine in soil. Tromethamine has a pKa value of 8.07. Therefore, this compound exists in the environment partially in cationic form, and cations are generally more readily adsorbed onto organic carbon and clay than neutral molecules. Thus, the adsorption of tromethamine may be higher than indicated by its Koc value, while its mobility may be lower than estimated. Since the cationic form is non-volatile, and the Henry's Law constant for the neutral form (free base) of tromethamine is estimated at 8.7 × 10⁻¹³ atm·m³/mol, tromethamine is not expected to volatilize from moist soil. Based on its estimated vapor pressure, tromethamine is also not expected to volatilize from dry soil surfaces. No oxygen uptake was observed when tromethamine was co-cultured with pure cultures of different strains, suggesting that its biodegradation in the environment may be relatively slow. Based on the estimated Koc value, tromethamine is not expected to adsorb onto suspended matter and sediment after release into water. However, based on its pKa value of 8.07, it should exist partially in cationic form under ambient conditions (pH 5–9). Therefore, the adsorption capacity of tromethamine on suspended matter and sediment is likely higher than its estimated Koc value. Since the cationic form is non-volatile, and considering the Henry's Law constant for neutral substances, volatilization from the water surface is not a significant fate process. The estimated BCF value of 3 indicates a low likelihood of bioaccumulation in aquatic organisms. Hydrolysis is also not expected to be a significant environmental fate process due to the lack of functional groups that allow hydrolysis under ambient conditions. Occupational exposure to tromethamine may occur through inhalation and skin contact in workplaces where it is produced or used. (SRC)

[1]. Guidelines for the treatment of acidaemia with THAM. Drugs. 1998 Feb;55(2):191-224.

[2]. THAM reduces CO2-associated increase in pulmonary vascular resistance - an experimental study in lung-injured piglets. Crit Care. 2015 Sep 17;19(1):331.

For patients with acute respiratory distress syndrome (ARDS), low tidal volume (VT) ventilation is recommended. This may increase arterial partial pressure of carbon dioxide (PaCO2), decrease pH, and increase pulmonary vascular resistance (PVR). We hypothesize that pure proton acceptor tris(hydroxymethyl)aminomethane (THAM) can mitigate these effects, thereby preventing an increase in PVR. [2]

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Mechanism of Action
Trebutadiene is an alkalizing agent that acts as a proton (hydrogen ion) acceptor. Trobutadiene is a weak base; after intravenous injection, it attracts and binds to hydrogen ions and their associated anions, and the resulting salts are excreted in the urine. Trobutadiene can bind to lactate, pyruvate, and other metabolic acids, as well as carbonic acid. …At pH 7.4, about 70% of trobutadiene in plasma is in an ionized (protonated) form; if the pH decreases from 7.4, the ionized portion of the drug increases. Unlike the ionized portion of tromethamine (which reacts only with acids in the extracellular fluid after administration), the unionized portion of the dose, which remains unionized at physiological pH, is thought to be able to penetrate cell membranes and bind to intracellular acids. Because tromethamine administration lowers hydrogen ion concentration, proton donor concentrations in the body's buffer solution decrease, while proton acceptor concentrations increase. In bicarbonate-carbonate buffers, dissolved carbon dioxide concentrations decrease (at least before regulatory mechanisms compensate), while bicarbonate concentrations increase. This decrease in carbon dioxide tension eliminates the potent stimulus to respiration and may lead to hypoventilation and hypoxia. McEvoy, GK (ed.). American Hospital Formulary Service. AHFS Drug Information. American Society of Health-System Pharmacists, Bethesda, MD. 2007., p. 2647 Hazardous Substances Database (HSDB) Tromethamine…is a weakly osmotic diuretic that increases the flow rate of alkaline urine containing large amounts of electrolytes. McEvoy, GK (ed.). American Hospital Formulary Service. AHFS Drug Information. American Society of Health-System Pharmacists, Bethesda, Maryland. 2007, p. 2647. Hazardous Substances Database (HSDB) The ionization of carbonic acid is altered by removing protons from hydrated hydrogen ions, thereby lowering pCO2 and increasing bicarbonate. Excess bicarbonate is then gradually excreted in the kidneys. Tromethamine is a particularly effective treatment for high pCO2 in respiratory acidosis…

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Drug Indications
For the prevention and correction of metabolic acidosis.

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Therapeutic Use
Buffer; Excipient
Tremate is indicated for the prevention and correction of metabolic acidosis. /US Product Label Includes/
Metabolic acidosis associated with coronary artery bypass surgery. Tromethamine solution is primarily used to correct metabolic acidosis occurring during or immediately after coronary artery bypass surgery. /US Product Label Includes/
Correction of ACD blood acidity during coronary artery bypass surgery. ACD blood is known to be acidic, and this acidity increases further upon storage. Tromethamine effectively corrects this acidity. Tromethamine solution can be added directly to the blood used for pre-filling pump oxygenators. Patients can avoid initial acid load when the pH of the ACD blood returns to the normal range. Additional tromethamine may be required if metabolic acidosis occurs during coronary artery bypass surgery. /US product label contains/

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Drug Warnings: Local reactions may include irritation and tissue inflammation or infection at the injection site, febrile reaction, chemical phlebitis, venous spasm, hypervolemia, and venous thrombosis. Administration should be done using a large-bore needle or indwelling catheter to minimize irritation to veins from the highly alkaline tromethamine solution. Extravasation may cause inflammation, necrosis, and shedding of the covering skin. If perivascular infiltration occurs, tromethamine use should be discontinued immediately. Infiltrating the affected area with a 1% procaine hydrochloride solution containing hyaluronidase can usually relieve venous spasm and dilute residual tromethamine in the local tissue. It is recommended to locally infiltrate the vasospastic area with an alpha-adrenergic blocker (e.g., phentolamine mesylate). If necessary, nerve blocks can be applied to the autonomic nerve fibers in the affected area. A transient decrease in blood glucose levels may occur during tromethamine administration. If the recommended dose is exceeded or administered too quickly, hypoglycemia may persist for several hours after discontinuation. Tromethamine should be administered slowly, with the dose only sufficient to correct existing acidosis to avoid overdose and alkalosis. Blood glucose levels should be monitored frequently during and after treatment. High doses of tromethamine may cause respiratory depression due to increased blood pH and decreased carbon dioxide levels; respiratory depression may also occur in patients with chronic hypoventilation or those taking other respiratory depressant medications. The dose must be carefully adjusted to prevent blood pH from rising above normal, and mechanical ventilation should be readily available during tromethamine use. If both respiratory and metabolic acidosis are present, tromethamine may be used in combination with mechanical ventilation support.

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Reported lethal dose
3.3 = Moderate toxicity: Possible oral lethal dose (human) 0.5-5 g/kg, equivalent to 1 ounce to 1 pint for a 70 kg (150 lb) person.

C4H12CLNO3

157.60

157.05

1185-53-1

77-86-1; 6850-28-8 (acetate)

93573

Typically exists as White to off-white solid at room temperature

1.05 g/mL at 20 °C

357ºC at 760 mmHg

150-152 °C

169.7ºC

5

4

3

9

54

0

Cl[H].O([H])C([H])([H])C(C([H])([H])O[H])(C([H])([H])O[H])N([H])[H]

QKNYBSVHEMOAJP-UHFFFAOYSA-N

InChI=1S/C4H11NO3.ClH/c5-4(1-6,2-7)3-8;/h6-8H,1-3,5H2;1H

2-amino-2-(hydroxymethyl)propane-1,3-diol;hydrochloride

1185-53-1; Tris hydrochloride; Tris(hydroxymethyl)aminomethane hydrochloride; 2-Amino-2-(hydroxymethyl)propane-1,3-diol hydrochloride; Tromethamine hydrochloride; TRIS HCl; Tris-HCl; Trometamol hydrochloride;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO: 250 mg/mL (1586.29 mM)
H2O: 50 mg/mL (317.26 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (13.20 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (13.20 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (13.20 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)