DETERMINATION OF THE IMPURITY PROFILE OF GAMMA-CYCLODEXTRIN BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

High-performance liquid chromatography (HPLC) was used to determine the impurity profile of gamma-cyclodextrin (gamma-CD), a compound used as a stabilizer in pharmaceutical formulations. An HPLC assay was developed which separated gamma-CD from potential impurities which included 7 linear (glucose to maltoheptaose) and 2 unbranched cyclic (alpha- and beta-CD) glucose polymers. The method employed a mobile phase consisting of acetonitrile-water (73:27), a Whatman 5-mum Partisil PAC column (250 x 4.6 mm I.D.), refractive index detection, and achieved a resolution (R(s)) greater-than-or-equal-to 1.5 for all impurities in the presence of gamma-CD.The method presented provided improvements over existing methods by achieving a rapid separation (< 25 min) of compounds not previously reported using moderate temperature control and quantitated impurities at the 0.1-1.2% (w/w) level of sensitivity.