Stability of methylnicotinate in aqueous solution as utilized in the 'niacin patch test'

Abstract

BackgroundThe topical application of methylnicotinate results in a localized vasodilatatory response which has been found to differ from that observed to occur in healthy controls in a variety of medical conditions. The stability of the drug in aqueous solution is unclear while difficulties can be encountered when preparing methylnicotinate solutions for this purpose. To aid in the determination of how long solutions of the drug should be stored before discarding we have used a collection of aged batches of methylnicotinate to determine the stability of the drug in aqueous solution.FindingsThe degradation of methylnicotinate was determined in batches which had been stored at 4°C for between 5 and 1062 days prior to analysis by High Performance Liquid Chromatography. The major degradation product of methylnicotinate was nicotinic acid which formed at an approximate rate of 0.5% of the starting methylnicotinate concentration per annum. Furthermore, the ability of methylnicotinate solutions of different ages to induce vasodilatation was assessed in healthy volunteers. No significant difference in vasodilatatory response was apparent between batches which had been stored for between zero and 1057 days.ConclusionMethylnicotinate exhibits excellent chemical and biological stability in solution facilitating its use in clinical applications.

A review of the possible role of the essential fatty acids and fish oils in the aetiology, prevention or pharmacotherapy of schizophrenia

“…Omega‐3 PUFA play an important role in the developing and perinatal brain by its incorporation into the neuronal membrane imparting fluidity necessary for proper growth and development 1. Omega‐3 PUFA must play a similar role on the neurophysiology and neurosignalling of the mature brain, but direct demonstration is less clear 24. Current findings suggest involvement of omega‐3 PUFA in modulation of Na + , K + and Ca 2+ channels and phospholipase C and D activity, the protein kinase C signalling system, regulation of neurotransmitter receptor and transporter levels, and expression of a variety of genes 24.…”

“…24 Current findings suggest involvement of omega-3 PUFA in modulation of Na + , K + and Ca 2+ channels and phospholipase C and D activity, the protein kinase C signalling system, regulation of neurotransmitter receptor and transporter levels, and expression of a variety of genes. 24 Omega-3 PUFA may also exert neurotrophic effects contributing to cell membrane integrity 1 and increased levels of brain-derived neurotrophic factor, neuroprotectins and resolvins. 24 The emerging fields of metabolomics and lipidomics should yield more insight on the specific roles of omega-3 PUFA in the CNS, particularly in the ageing brain.…”

“…Omega‐3 PUFA must play a similar role on the neurophysiology and neurosignalling of the mature brain, but direct demonstration is less clear 24. Current findings suggest involvement of omega‐3 PUFA in modulation of Na + , K + and Ca 2+ channels and phospholipase C and D activity, the protein kinase C signalling system, regulation of neurotransmitter receptor and transporter levels, and expression of a variety of genes 24. Omega‐3 PUFA may also exert neurotrophic effects contributing to cell membrane integrity1 and increased levels of brain‐derived neurotrophic factor, neuroprotectins and resolvins 24.…”

“…24 The emerging fields of metabolomics and lipidomics should yield more insight on the specific roles of omega-3 PUFA in the CNS, particularly in the ageing brain. 24 In schizophrenia brain…”

“…Omega‐3 PUFA may also exert neurotrophic effects contributing to cell membrane integrity1 and increased levels of brain‐derived neurotrophic factor, neuroprotectins and resolvins 24. The emerging fields of metabolomics and lipidomics should yield more insight on the specific roles of omega‐3 PUFA in the CNS, particularly in the ageing brain 24…”