Development and Validation of a UPLC Method for Determination of Content Uniformity in Low-Dose Solid Drug Products Using the Design Space Approach

A UPLC method was developed and validated for analyzing finasteride in low-dose drug products, focusing on robustness and reliability. The study used response surface methodology and a central composite design to optimize the method, identifying methanol content and flow rate as key factors. The method's robustness was evaluated by defining a Design Space (DS) and using Monte Carlo simulations to verify results. The study concluded that variability must be calculated for each case, ensuring the % label claim response lies within specified limits (98.5–101.5%). If not, the method should be re-developed.