title: Thin-layer chromatography-densitometric measurements for determination of N-(hydroxymethyl)nicotinamide in tablets and stability evaluation in solutions.
abstract: A thin-layer chromatography (TLC)-densitometric method was developed to determine N-(hydroxymethyl)nicotinamide in tablets and basic solutions along with nicotinic acid. Analysis was performed on silica gel F254 plates using chloroform-ethanol (2 + 3, v/v) mobile phase. The densitometric observations were made at 260 nm. The results showed good precision and accuracy; relative standard deviation was 2.37%, and recovery ranged from 97.60 to 100.82%. The limit of detection was 0.1 microg/spot, while the linearity range was from 0.2 to 1.75 microg/spot. Applicability of the newly developed method was tested for determination of N-(hydroxymethyl)nicotinamide in the preparation Cholamid. Densitometric measurements were used to evaluate stability of N-(hydroxymethyl)nicotinamide in basic solutions. It was found that decomposition corresponded to first-order reaction kinetics. The computed kinetic and thermodynamic parameters at 30 degrees C were as follows: k = 0.00675/min, t0,5 = 1.71 h, t0,1 = 0.26 h, and Ea = 44.75 kJ/mol.
authors.affiliation: Collegium Medicum of Jagiellonian University, Department of Inorganic and Analytical Chemistry, Kraków, Poland.
authors.forename: Urszula
authors.initials: U
authors.lastname: Hubicka
authors.forename: Jan
authors.initials: J
authors.lastname: Krzek
authors.forename: Justyna
authors.initials: J
authors.lastname: Luka
mesh_terms: D000465:Algorithms; D002855:Chromatography, Thin Layer; D003720:Densitometry; D004355:Drug Stability; D007202:Indicators and Reagents; D007700:Kinetics; D009525:Niacin / Q000032:analysis; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000032:analysis; D019999:Pharmaceutical Solutions; D011199:Potentiometry; D012015:Reference Standards; D015203:Reproducibility of Results; D012997:Solvents; D013607:Tablets; D013816:Thermodynamics
chemical_list: D007202:Indicators and Reagents; D019999:Pharmaceutical Solutions; D012997:Solvents; D013607:Tablets; C004962:N-(hydroxymethyl)nicotinamide; D009536:Niacinamide; D009525:Niacin