Pyridoxine[1]
IUPAC name	4,5-Bis(hydroxymethyl)- 2-methylpyridin- 3-ol
Identifiers
CAS number	65-23-6 Y, 58-56-0 (hydrochloride)
PubChem	1054
SMILES	CC1=NC=C(C(=C1O)CO)CO
Properties
Molecular formula	C8H11NO3
Molar mass	169.18 g/mol
Melting point	159-162 °C
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Pyridoxine is one of the compounds that can be called vitamin B6, along with pyridoxal and pyridoxamine. It differs from pyridoxamine by the substituent at the '4' position. It is often used as 'pyridoxine hydrochloride'.

[edit] Chemistry

It is based on a pyridine ring, with hydroxyl, methyl, and hydroxymethyl substituents. It is converted to the biologically active form pyridoxal 5-phosphate.

[edit] Function in the body

Pyridoxine assists in the balancing of sodium and potassium as well as promoting red blood cell production. It is linked to cardiovascular health by decreasing the formation of homocysteine. It has been suggested that Pyridoxine might help children with learning difficulties, and may also prevent dandruff, eczema, and psoriasis.^{[citation needed]} In addition, pyridoxine can help balance hormonal changes in women and aid in immune system. Lack of pyridoxine may cause anemia, nerve damage, seizures, skin problems, and sores in the mouth^[2].

It is required for the production of the monoamine neurotransmitters serotonin, dopamine, norepinephrine and epinephrine, as it is the precursor to pyridoxal phosphate: cofactor for the enzyme aromatic amino acid decarboxylase. This enzyme is responsible for converting the precursors 5-hydroxytryptophan (5-HTP) into serotonin and levodopa (L-DOPA) into dopamine, noradrenaline and adrenaline. As such it has been implicated in the treatment of depression and anxiety.^{[citation needed]}

A very good source of pyridoxine is dragon fruit from South East Asia^[3]. Pyridoxine is not normally found in plants and plants are not the principal source of this vitamin. This vitamin is made by certain bacteria. Some vegetarians may get adequate pyridoxine simply from eating plants that have traces of soil (like potato skins). Most people get their supply of this vitamin from either milk or meat products.

[edit] Medicinal uses

It is given to patients taking isoniazid to combat the toxic side effects of the drug. Pyridoxine is given 10-50 mg/day to patients on INH (Isoniazid) to prevent peripheral neuropathy and CNS effects that are associated with the use of isoniazid.

It is also essential for the patients with the extremely rare pyridoxine-dependent epilepsy, thought to be caused by mutations in the ALDH7A1 gene.

Vitamin B₆ can be compounded into a variety of different dosage forms. It can be used orally as a tablet, capsule, or solution. It can also be used as a nasal spray or for injection when in its solution form. The following is a procedure for producing a diluting solution of vitamin B6, taken from the USP/NF.

"Diluting Solution: Dissolve 25g of edentate disodium in 1000mL of water and mix. Dissolve an accurately weighed quantity of USP Pyridoxine Hydrochloride RS in Diluting Solution, and dilute quantitatively, and stepwise if necessary, with Diluting Solution to obtain a Solution having a known concentration of about 0.024mg/mL."^[4]

Vitamin B6 is usually safe, at intakes up to 200 mg per day in adults. However, vitamin B6 can cause neurological disorders, such as loss of sensation in legs and imbalance, when taken in high doses (200 mg or more per day - 10,000% of US RDA) over a long period of time. Vitamin B6 toxicity can damage sensory nerves, leading to numbness in the hands and feet as well as difficulty walking. Symptoms of a pyridoxine overdose may include poor coordination, staggering, numbness, decreased sensation to touch, temperature, and vibration, and tiredness for up to six months.^[5]

A contradictory publication on pyridoxine toxicity (K Dalton & MJT Dalton, Characteristics of pyridoxine overdose neuropathy syndrome, Acta Neurol Scand 76:8-11, 1987) reported that over a 6 month period or longer, 21% of women taking doses of less than 50 mg daily experienced neurological toxicity. The doses below 50 mg were not reported.

Based on the contradictory results of the two references cited above, the reader may wish to use extreme caution when taking this vitamin at high doses (say, for example, greater than 5 mg daily). Consultation with a physician is advised.

[edit] References

1. ^ Pyridoxine at Sigma-Aldrich
2. ^ www.HowStuffWorks.com - vitamin-b1
3. ^ Proximate analysis of dragon fruit http://findarticles.com/p/articles/mi_7109/is_7_6/ai_n38016782/
4. ^ Council of Experts. USP/NF. 2006 Ed. Rockville, MD: The United States Pharmacopeial Convention; 2005.
5. ^ Vitamin B6 (pyridoxine) - sources, benefits, dosage, deficiency, overdose, toxicity