Potassium (S)-lactate

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics, other

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Data source

Reference

Reference Type:

review article or handbook

Title:

Potassium chloride - SIDS Initial Assessment Report for 13th SIAM

Author:

OECD SIDS

Year:

2001

Bibliographic source:

OECD SIDS. Potassium chloride, UNEP Publication: SIDS Initial Assessment Report 13th SIAM. Bern, 6-9 November 2001

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Potassium chloride

EC Number:

231-211-8

EC Name:

Potassium chloride

Cas Number:

7447-40-7

Molecular formula:

ClK

IUPAC Name:

potassium chloride

Applicant's summary and conclusion

Conclusions:

Potassium and chloride are essential constituents and two of the most abundant ions in all animal species. In adult humans, the total body potassium is approx. 3.5 mol (135 g). 98% of this is located intracellularly (150 mmol/L), the extracellular potassium concentration is approx. 4 mmol/L. Overall, potassium concentrations is body fluids are actively regulated by the mammalian body.

Executive summary:

In the published review document OECD SIDS (2001), the following information is provided on toxicokinetics, metabolism, mechanisms of action of potassium chloride:

Potassium and chloride are essential constituents and two of the most abundant ions in all animal species. In adult humans, the total body potassium is approximately 3.5 mol (135 g). 98 % of this amount is located intracellularly (150 mmol/L), the extracellular potassium concentration is approximately 4 mmol/L. Total body chloride in adult humans is approximately 2.1 mol (75 g). 80 % of this is located extracellularly (120 mmol/L), and the the intracellular concentration of chloride is approximately 3-4 mmol/L.

Metabolism, biotransformation and kinetics

About 90 % of the ingested dose of potassium is absorbed by passive diffusion in the membrane of the upper intestine. Potassium is distributed to all tissues where it is the principal intracellular cation. Insulin, acid-base status, aldosterone, and adrenergic activity regulate cellular uptake of potassium. The majority of ingested potassium is excreted in the urine via glomerular filtration. The distal tubules are able to secrete as well as reabsorb potassium, so they are able to produce a net secretion of potassium to achieve homoeostasis in the face of a potassium load due to abnormally high levels of ingested potassium. About 15 % of the total amount of potassium excreted is found in faeces. Chloride leaves the tubular lumen by secondary active transport of sodium, and also passive diffusion. Excretion and retention of potassium is mainly regulated by the main adrenal cortical hormones. Normal homoeostatic mechanisms controlling the serum potassium levels allow a wide range of dietary intake. The renal excretory mechanism is designed for efficient removal of excess potassium, rather for its conservation during deficiency. Even with no intake of potassium, humans lose a minimum of 585–1170 mg K per day. However, the distribution of potassium between the intracellular and the extracellular fluids can markedly affect the serum potassium level without a change in total body potassium.

Mechanisms of action

K+ is the principal cation mediating the osmotic balance of body fluids. In animals, the maintenance of normal cell volume and pressure depends on Na+ and K+ pumping. The K+/Na+ separation has allowed for evolution of reversible transmembrane electrical potentials essential for nerve and muscle action in animals, and both potassium and chloride are important in transmission of nerve impulses to the muscle fibers.

Potassium transport through the hydrophobic interior of a membrane can be facilitated by a number of natural compounds that form lipid-soluble alkali metal cation complexes. Potassium fulfils a critical role as counterion for various carboxylates, phosphates and sulphates, and stabilises macromolecular structures. Potassium and chloride is also important in the regulation of the acid-base balance of the body.