HPLC/DAD ASSAY OF CYCLOHEXANAMINE AS RELATED IMPURITY IN GLIPIZIDE THROUGH DERIVATIZATION WITH O-PHTALDIALDEHYDE

Assay of cyclohexanamine as related impurity in glipizide (as active ingredient or in its pharmaceutical formulations) has been achieved through pre-column derivatization with o-phtaldialdehyde (OPA) followed by the HPLC/DAD assay. Derivatization reaction was found to be fast, quantitative, and produces required sensitivity under UV detection at 245 nm. The absolute limit of quantitation is placed around 0.05 mu g/mL, meaning less than 0.001% with respect to the amount of glipizide used in the test solution and 1/10 from the maximum threshold imposed for cyclohexanamine in glipizide through the European Pharmacopoeia compendial monograph. No interferences from the derivatization reagent or its related by-products and from the other impurities of glipizide were observed. The assay was validated according to guidances in force. The precision of the method is placed within the 10% interval (expressed as relative standard deviation) while accuracy is placed in the +/- 10% range (expressed as % bias). This method can successfully replace the gas chromatographic/flame ionization detection (GC-FID) method recommended by the compendial European Pharmacopoeia monograph.