RP-HPLC method validation for fast extraction and quantification of Levonorgestrel drug from silicone based intrauterine device intended for in-process and finished formulation

Background To develop and validate a simple and consistent reversed phase high performance liquid chromatography (RP-HPLC) method for the estimation of Levonorgestrel (LNG) drug from silicone based intrauterine device. Methods Sample solution was prepared using tetrahydrofuran (THF) as solvent for the drug extraction, and RP-HPLC analysis was performed using Luna C18 analytical column (150 × 4.6 mm, 5 μm, 100 Å – Phenomenex), with a mobile phase consisting of a mixture of acetonitrile and water (50:50, v /v) at a flow rate of 1.0 ml/min and injection volume of 20 μl. Detection was carried out at 241 nm in PDA detector, with a total run time of 15 min. The method was validated in accordance with ICH guidelines. Method applicability was tested for optimizing formulation using quality-by-design approach, to check the stability and content uniformity of levonorgestrel-silicone mixture (core blend), and quantifying the amount of LNG from commercially available silicone based formulation. Results The retention time for LNG drug was obtained at 8.5 min (± 0.3 min). A linear relationship was observed over the concentration range of 2.6–15.6 μg/ml with the correlation coefficient (r) value 0.9999. The method was found to be precise within the acceptable limit (RSD