Boron

Scientific Name(s):Boron, boric acid, sodium borate

Common Name(s): Boron

Uses of Boron

Boric acid is a topical astringent, mild disinfectant and eye wash. Sprinkled in crevices and corners, boric acid powder controls rodents and insects. Sodium borate is used in cold creams, eye washes and mouth rinses. Boron compounds are used to enhance the cell selectivity of radiation therapy.

Boron Dosing

Boron has been studied in several clinical studies at a wide range of doses. Daily dosage of 2.5 to 6 mg as boron has been administered for osteoarthritis and strength conditioning. Intravaginal boric acid (600 mg daily) was administered for vulvovaginal candidiasis. A single dose of 102.6 mg sodium tetraborate was studied for its effects on factor VIIa.

Contraindications

Contraindications have not yet been identified.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Boron Interactions

None well documented.

Boron Adverse Reactions

There is little or no clinical data about the adverse effects of boron; boron compounds can be toxic to humans.

Toxicology

While boric acid, borates, and other compounds containing boron are used medicinally, they are potentially toxic if ingested or absorbed through nonintact skin.

The element boron (B, atomic number 5) is found in deposits in the earth's crust at a concentration of about 0.001%. It is obtained in the form of its compounds and never in its elemental state. 1 Environmental boron is taken up by plants in trace amounts, thereby contributing to dietary boron intake. Boron was originally obtained in 1895 from the reduction of boric anhydride; today this remains a commercially important way to produce impure boron. Pure boron takes the form of clear red or black crystals, depending upon its crystalline shape. 1 The crystals can be as hard as diamonds. The chemistry of boron is extremely complex, with entire texts devoted solely to this topic.

History

Boron has been used in nuclear chemistry as a neutron absorber. It has also been added to other metals to form harder alloys. In medicine, boron is most commonly found in the form of boric acid, which is used as a topical astringent and anti-infective, as well as an ophthalmologic irrigant. Sodium borate is bacteriostatic and is commonly added to cold creams, eye washes and mouth rinses.

Boron Uses and Pharmacology

Radiation therapy aid

Because of boron's ability to absorb electromagnetic radiation, boron-based compounds are used in conjunction with radiation therapy to enhance the selective killing of neoplastic cells, particularly those of resistant neoplasia such as glioblastoma. 2

Eye wash and disinfectant

Boric acid solutions for topical use are generally used in diluted concentrations. A 2.2% solution of boric acid is isotonic with lacrimal fluid. Because boric acid has weak antifungal and antibacterial activity, it is employed as a mild disinfectant in concentrations ranging from 2% to 10%. 3

Rodent and insect repellent

Boric acid powder has been used as an insect and rodent repellent, being sprinkled in corners and along floor boards. This use, however, should be avoided because of the serious toxicity that can occur if ingested orally by small children or pets.

Other uses

Over-the-counter supplements containing boron compounds are purported to enhance mental power, sometimes citing poorly substantiated studies that found alterations in the electroencephalogram in the presence of a low-boron diet. These studies also reported a correlation between a low-boron diet and a decrease in mental alertness. There is no evidence, however, that diet supplementations of boron compounds, above the levels derived from a normal balanced diet, can enhance mental acuity or improve alertness.

Dosage

Boron has been studied in several clinical studies at a wide range of doses. Daily dosage of 2.5 to 6 mg as boron has been administered for osteoarthritis and strength conditioning. Intravaginal boric acid (600 mg daily) was administered for vulvovaginal candidiasis. A single dose of 102.6 mg sodium tetraborate was studied for its effects on factor VIIa. 4 , 5 , 6 , 7 , 8

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

There is little or no clinical data about the adverse effects of boron. While compounds containing boron are used medicinally, they are potentially toxic if ingested or absorbed through nonintact skin.

Toxicology

Boric acid and borates are toxic when ingested or absorbed through broken skin. An oral dose of 0.3 g/kg can be fatal, and serious toxicity can occur following the ingestion of as little as 5 g in infants and 15 to 20 g in adults. 9 Boric acid solutions should be labeled not to be used on broken skin or on severely irritated or inflamed mucous membranes in order to prevent toxicity as a result of its topical absorption.

Fatalities have been reported because of confusion between boric acid and similar-looking powders (ie, baking soda, dextrose). Stringent controls should be maintained in hospitals, nursing homes and other public facilities to prevent possible intoxications due to boron-containing products.

There is no effective antidote to boron poisoning, and treatment is symptomatic and supportive. Symptoms of toxicity include irritation and sloughing of skin, gastrointestinal irritation, restlessness, weakness, kidney and liver damage, convulsions, coma or death.

Bibliography

1. Windholz M, ed. The Merck Index, ed. 10 . Rahway, NJ: Merck & Co., 1983.
2. Haselsberger K, et al. Subcellular boron-10 localization in glioblastoma for boron neutron capture therapy with Na2B12H11SH. J Neurosurg . 1994;81:741.
3. Olin BR, Hebel SK, eds. Drug Facts and Comparisons . St. Louis: Facts and Comparisons, July 1992.
4. Wallace JM, Hannon-Fletcher MP, Robson PJ, Gilmore WS, Hubbard SA, Strain JJ. Boron supplementation and activated factor VII in healthy men. Eur J Clin Nutr . 2002 Nov;56(11):1102-1107.
5. Newnham RE. Essentiality of boron for healthy bones and joints. Environ Health Perspect . 1994;102 Suppl 7:83-85.
6. Green NR, Ferrando AA. Plasma boron and the effects of boron supplementation in males. Environ Health Perspect . 1994;102 Suppl 7:73-77.
7. Ferrando AA, Green NR. The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders. Int J Sport Nutr . 1993 Jun;3(2):140-149.
8. Van Slyke KK, Michel VP, Rein MF. Treatment of vulvovaginal candidiasis with boric acid powder. Am J Obstet Gynecol . 1981 Sep 15;141(2):145-148.
9. Haddad LM, Winchester JF. Clinical Management of Poisoning and Drug Overdose . ed. 2. Philadelphia: Saunders, 1990:1447.

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