Development and validation of a stability indicating HPLC method for determination of lisinopril, lisinopril degradation product and parabens in the lisinopril extemporaneous formulation

The purpose of the research described herein was to develop and validate a stability-indicating HPLC method for lisinopril, lisinopril degradation product (DKP), methyl paraben and propyl paraben in a lisinopril extemporaneous formulation. The method developed in this report is selective for the components listed above, in the presence of the complex and chromatographically rich matrix presented by the Bicitra® and Ora-Sweet SF™ formulation diluents. The method was also shown to have adequate sensitivity with a detection limit of 0.0075 μg/mL (0.03% of lisinopril method concentration). The validation elements investigated showed that the method has acceptable specificity, recovery, linearity, solution stability, and method precision. Acceptable robustness indicates that the assay method remains unaffected by small but deliberate variations, which are described in ICH Q2A and Q2B guidelines.