Compounded medicinal products containing bupropion hydrochloride (BUP·HCl) and naltrexone hydrochloride (NTX·HCl) are available as adjunct therapy for the management of weight in obese/overweight adults. The present work describes the development and validation of a novel RP-HPLC method for a simultaneous quantitation during the dissolution of both drugs from compounded bilayer composition tablets. The method involves a Nucleosil 100-3 C-18 column (4.6 × 150 mm) and a mobile phase of a 70%/30% v/v ACN/KH2PO4·H2O aqueous solution of a 5 mM concentration. The flow rate was set at 1.35 mL/min and the detection was conducted using UV spectrophotometry (λmax 214 nm). The method was validated according to the ICH guidelines and fulfilled the specifications for the specificity, linearity, accuracy, precision and stability for both the sample and standard solutions. Furthermore, the robustness of the method was evaluated by applying a fractional factorial experimental design and by utilizing both graphical and statistical approaches to identify the HPLC factors that should be strictly controlled during the analysis. The method proved to be suitable for the analysis of the dissolution samples and, consequently, the release of BUP·HCl and NTX·HCl from the formulations.
Keywords: HPLC method; bilayer tablets; bupropion; dissolution; experimental design; naltrexone.