Development and validation of a liquid chromatographic method for the determination of the related substances of ramipril in Altace capsules.

The development and validation of a reversed-phase liquid chromatographic method for the determination of the related substances of 2-[N-[(S)-1-Ethoxycarbonyl-3-phenylpropyl]-L-alanyl]-(1S, 3S, 5S)-2-azabicyclo[3.3.0]octane-3-carboxylic acid (ramipril) in Altace capsules is described. The method utilizes an ion-pairing agent and a simple two-step gradient for the separation of ramipril and ten related substances from each other in a 40-min run time. Four of the related substances are ramipril diastereomers. To the best of our knowledge, no method described previously in the literature has demonstrated resolution of ramipril from this set of related substances. No method for the determination of the related substances of ramipril is currently described in the United States Pharmacopoeia or the European Pharmacopoeia. The proposed method was validated with respect to accuracy, precision, linearity, and specificity. Also, the method was determined to be robust with regards to the following parameters: mobile phase apparent pH: mobile phase organic content: mobile phase perchlorate concentration; detection wavelength and time dependence of sample and standard stability.