title: Analysis of magnesium from magnesium stearate in pharmaceutical tablet formulations using hydrophilic interaction liquid chromatography with nano quantity analyte detection.
abstract: This study demonstrates the use of hydrophilic interaction liquid chromatography with a nano quantity analyte detector for the retention, separation and detection of magnesium from magnesium stearate in tablet formulations for a drug product formulation blend containing a hydrochloride salt of a weakly basic compound as the active ingredient. The nano quantity analyte detector can provide direct detection of inactive excipients and inorganic salts lacking ultraviolet chromophores, as well as, all non-volatile compounds. The separation was accomplished using a SeQuant ZIC-HILIC column and mobile phase consisting of 32.5:32.5:35 of acetone/methanol/ammonium formate buffer (150 mM, pH 4.5). Common validation parameters were evaluated to assess the method's quantitative potential for magnesium (from magnesium stearate) including: linearity, accuracy, specificity, solution stability, repeatability, and intermediate precision. Overall, the method described in this report proved to be very robust and represents a novel technique to conveniently separate and detect magnesium from magnesium stearate in pharmaceutical preparations both quickly and accurately.
authors.affiliation: Eli Lilly and Company, Pharmaceutical Sciences Research and Development, Lilly Research Laboratories, Indianapolis, IN, USA. risley@lilly.com
authors.forename: Donald S
authors.initials: DS
authors.lastname: Risley
authors.forename: Lars-Erik
authors.initials: LE
authors.lastname: Magnusson
authors.forename: Paul R
authors.initials: PR
authors.lastname: Morow
authors.forename: Aktham
authors.initials: A
authors.lastname: Aburub
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D057230:Limit of Detection; D008274:Magnesium / Q000032:analysis*; D004364:Pharmaceutical Preparations; D015203:Reproducibility of Results; D013229:Stearic Acids / Q000737:chemistry*; D013607:Tablets
chemical_list: D004364:Pharmaceutical Preparations; D013229:Stearic Acids; D013607:Tablets; C031183:stearic acid; D008274:Magnesium