Insights on Localized and Systemic Delivery of Redox-Based Therapeutics

Table 5

Preclinical and clinical studies using vitamin B₁₂.

Vitamin B12 (cobalamin)
Route	Results	Reference
Preclinical studies
In vitro	Pulse radiolysis determined that the rate constant between Cob(II)alamin and superoxide (O2^•−) is 6.8 × 10^8 M^−1 s^−1, which is within an order of magnitude of cytosolic and mitochondrial superoxide dismutase (SOD)	[79]
In vitro	Cob(II)alamin reacts with O2^•− at a rate similar to that of the SOD	[80]
In vitro	Cyanocobalamin treatment inhibited O2^•−-induced damage in human aortic endothelial cells by scavenging intracellular O2^•−	[83]
Clinical studies
0.5 mg; Oral	Daily supplementation with folic acid, vitamin B6, and vitamin B12 for one year significantly reduced the carotid intima-media thickness, a marker of atherosclerosis, in at-risk patients	[86]
0.4 mg; Oral	Six months of daily folic acid and vitamin B12 supplementation improved coronary endothelial function in patients at risk for coronary artery disease	[87]
0.4 mg; Oral	Two years of daily supplementation with folic acid and vitamin B12 significantly increased coronary blood flow in patients with stable coronary artery disease	[88]
25 or 0.5 mg; I.M.	Daily ultrahigh-dose injections (25 mg) of methylcobalamin improved the compound muscle action potentials of patients with amyotrophic lateral sclerosis	[89]
Eyedrops	Eyedrops containing 0.15% hyaluronic acid and vitamin B12 reduced oxidative stress markers in the conjunctiva (mucous membrane covering eye) and improved the overall symptoms of patients with chronic dry eye	[90]

I.M.: intramuscular.