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Amobarbital interactions with 25-hydroxycholecalciferol: effects on the extraction, quantification, and competitive protein binding in vitro.

S H Majors·J C Howe·G R Beecher
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Abstract

Amobarbital has been found to coelute with 25-hydroxycholecalciferol (25OHD3) on a normal phase high performance liquid chromatographic system and cause subsequent interference in the UV detection and plasma transport competitive protein binding assay for this vitamin D metabolite. Concentrations of 25OHD3 were overestimated by 95% in the presence of 0.4 mg amobarbital in the competitive protein binding assay; as little as 0.1 mg amobarbital caused a 22% overestimation in the concentration of 25OHD3 in the assay. Separation of 25OHD3 from amobarbital on a reverse phase high performance liquid chromatographic system allowed for proper quantification without interference. Because of the similarity of chemical structures, other barbital-based compounds may cause similar interactions with 25OHD3 or other vitamin D metabolites as well.

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AmobarbitalAnimalsBinding, CompetitiveCalcifediolChromatography, High Pressure LiquidIn Vitro TechniquesProtein BindingRatsRats, Inbred StrainsJournal Article

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S H Majors, J C Howe, G R Beecher. 1985. Amobarbital interactions with 25-hydroxycholecalciferol: effects on the extraction, quantification, and competitive protein binding in vitro.. https://doi.org/10.1210/jcem-60-4-706

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