Influence of structural differences of dextromethorphan and its three metabolites on their simultaneous separation using various silica columns with a simple aqueous mobile phase

Chien Ho Chen, Ming Chun Huang, Hsiu O. Ho, Hsueh Hui Chen, Ming Thau Sheu

Research output: Contribution to journalArticle

Abstract

The retention behaviors and efficiencies of the chromatographic separation of dextromethorphan (DM) and its metabolites (dextrorphan (DX), 3-methoxymorphinan (MM), and 3-hydroxymorphinan (HM)), on three different silica columns (Inertsil, μ-Porasil, and Lichrospher), were compared using a simple aqueous mobile phase consisting of an organic solvent (methanol or acetonitrile) and water at different volume ratios (1:9 to 9:1) containing triethylamine (TEA) and acetic acid (ACH). Results demonstrated that the retention capacities for basic compounds with the same ionization conditions of the silanol group were the largest for the Lichrospher column, followed by the μ-Porasil one, with the Inertsil column exhibiting the lowest level. Based on their physical characteristics, the larger retention capacities for DM and its three metabolites in the LiChrospher column compared to those of the Inertsil and μ-Porasil columns may have been because the LiChrospher column has the largest surface area for interaction. However, since the surface areas of the Inertsil and μ-Porasil columns are similar, the greater retention capacities for DM and its three metabolites in the μ-Porasil column can probably be attributed to the existence of a greater number of silanol groups than in the Inersil column. This also demonstrates that the interaction of tertiary amines with ionized silanol groups is greater than that of secondary amines resulting in the elution order being MM>DM and HM>DX. However, O-demethylation to expose metabolites with a phenolic hydroxy group seemed to decrease the retention capacity, thus yielding the elution order of DX>DM (tertiary amine) and HM>MM (secondary amine). This might be attributable to the negative charge repulsion between phenoxyl groups (PhO-) and ionized silanol groups (SiO-) decreasing the affinity of basic compounds.

Original languageEnglish
Pages (from-to)97-106
Number of pages10
JournalJournal of Liquid Chromatography and Related Technologies
Volume31
Issue number1
DOIs
Publication statusPublished - Jan 2008

Fingerprint

Dextromethorphan
Metabolites
Silicon Dioxide
Dextrorphan
Amines
Acetic Acid
Organic solvents
Ionization
Methanol
silanol
Water
3-methoxymorphinan
norlevorphanol

Keywords

  • Acetic acid
  • Aqueous eluents
  • Dextromethorphan
  • Silica column
  • Triethylamine

ASJC Scopus subject areas

  • Analytical Chemistry
  • Clinical Biochemistry

Cite this

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title = "Influence of structural differences of dextromethorphan and its three metabolites on their simultaneous separation using various silica columns with a simple aqueous mobile phase",
abstract = "The retention behaviors and efficiencies of the chromatographic separation of dextromethorphan (DM) and its metabolites (dextrorphan (DX), 3-methoxymorphinan (MM), and 3-hydroxymorphinan (HM)), on three different silica columns (Inertsil, μ-Porasil, and Lichrospher), were compared using a simple aqueous mobile phase consisting of an organic solvent (methanol or acetonitrile) and water at different volume ratios (1:9 to 9:1) containing triethylamine (TEA) and acetic acid (ACH). Results demonstrated that the retention capacities for basic compounds with the same ionization conditions of the silanol group were the largest for the Lichrospher column, followed by the μ-Porasil one, with the Inertsil column exhibiting the lowest level. Based on their physical characteristics, the larger retention capacities for DM and its three metabolites in the LiChrospher column compared to those of the Inertsil and μ-Porasil columns may have been because the LiChrospher column has the largest surface area for interaction. However, since the surface areas of the Inertsil and μ-Porasil columns are similar, the greater retention capacities for DM and its three metabolites in the μ-Porasil column can probably be attributed to the existence of a greater number of silanol groups than in the Inersil column. This also demonstrates that the interaction of tertiary amines with ionized silanol groups is greater than that of secondary amines resulting in the elution order being MM>DM and HM>DX. However, O-demethylation to expose metabolites with a phenolic hydroxy group seemed to decrease the retention capacity, thus yielding the elution order of DX>DM (tertiary amine) and HM>MM (secondary amine). This might be attributable to the negative charge repulsion between phenoxyl groups (PhO-) and ionized silanol groups (SiO-) decreasing the affinity of basic compounds.",
keywords = "Acetic acid, Aqueous eluents, Dextromethorphan, Silica column, Triethylamine",
author = "Chen, {Chien Ho} and Huang, {Ming Chun} and Ho, {Hsiu O.} and Chen, {Hsueh Hui} and Sheu, {Ming Thau}",
year = "2008",
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TY - JOUR

T1 - Influence of structural differences of dextromethorphan and its three metabolites on their simultaneous separation using various silica columns with a simple aqueous mobile phase

AU - Chen, Chien Ho

AU - Huang, Ming Chun

AU - Ho, Hsiu O.

AU - Chen, Hsueh Hui

AU - Sheu, Ming Thau

PY - 2008/1

Y1 - 2008/1

N2 - The retention behaviors and efficiencies of the chromatographic separation of dextromethorphan (DM) and its metabolites (dextrorphan (DX), 3-methoxymorphinan (MM), and 3-hydroxymorphinan (HM)), on three different silica columns (Inertsil, μ-Porasil, and Lichrospher), were compared using a simple aqueous mobile phase consisting of an organic solvent (methanol or acetonitrile) and water at different volume ratios (1:9 to 9:1) containing triethylamine (TEA) and acetic acid (ACH). Results demonstrated that the retention capacities for basic compounds with the same ionization conditions of the silanol group were the largest for the Lichrospher column, followed by the μ-Porasil one, with the Inertsil column exhibiting the lowest level. Based on their physical characteristics, the larger retention capacities for DM and its three metabolites in the LiChrospher column compared to those of the Inertsil and μ-Porasil columns may have been because the LiChrospher column has the largest surface area for interaction. However, since the surface areas of the Inertsil and μ-Porasil columns are similar, the greater retention capacities for DM and its three metabolites in the μ-Porasil column can probably be attributed to the existence of a greater number of silanol groups than in the Inersil column. This also demonstrates that the interaction of tertiary amines with ionized silanol groups is greater than that of secondary amines resulting in the elution order being MM>DM and HM>DX. However, O-demethylation to expose metabolites with a phenolic hydroxy group seemed to decrease the retention capacity, thus yielding the elution order of DX>DM (tertiary amine) and HM>MM (secondary amine). This might be attributable to the negative charge repulsion between phenoxyl groups (PhO-) and ionized silanol groups (SiO-) decreasing the affinity of basic compounds.

AB - The retention behaviors and efficiencies of the chromatographic separation of dextromethorphan (DM) and its metabolites (dextrorphan (DX), 3-methoxymorphinan (MM), and 3-hydroxymorphinan (HM)), on three different silica columns (Inertsil, μ-Porasil, and Lichrospher), were compared using a simple aqueous mobile phase consisting of an organic solvent (methanol or acetonitrile) and water at different volume ratios (1:9 to 9:1) containing triethylamine (TEA) and acetic acid (ACH). Results demonstrated that the retention capacities for basic compounds with the same ionization conditions of the silanol group were the largest for the Lichrospher column, followed by the μ-Porasil one, with the Inertsil column exhibiting the lowest level. Based on their physical characteristics, the larger retention capacities for DM and its three metabolites in the LiChrospher column compared to those of the Inertsil and μ-Porasil columns may have been because the LiChrospher column has the largest surface area for interaction. However, since the surface areas of the Inertsil and μ-Porasil columns are similar, the greater retention capacities for DM and its three metabolites in the μ-Porasil column can probably be attributed to the existence of a greater number of silanol groups than in the Inersil column. This also demonstrates that the interaction of tertiary amines with ionized silanol groups is greater than that of secondary amines resulting in the elution order being MM>DM and HM>DX. However, O-demethylation to expose metabolites with a phenolic hydroxy group seemed to decrease the retention capacity, thus yielding the elution order of DX>DM (tertiary amine) and HM>MM (secondary amine). This might be attributable to the negative charge repulsion between phenoxyl groups (PhO-) and ionized silanol groups (SiO-) decreasing the affinity of basic compounds.

KW - Acetic acid

KW - Aqueous eluents

KW - Dextromethorphan

KW - Silica column

KW - Triethylamine

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