Challenges in sample preparation for swellable core technology tablets: Approaches for the removal of polyethylene oxide and optimization of API recovery.

Swellable Core Technology (SCT) tablets, a solid oral dosage formulation designed for the controlled release of Active Pharmaceutical Ingredient (API), are made up of two distinct layers; an active layer containing the active ingredient (10-30%wt) and up to 90%wt polyethylene oxide (PEO); and a sweller layer which contains up to 65%wt PEO. The objective of this study was to develop a process to remove PEO from analytical test solutions and optimize API recovery using physicochemical properties of the API. Quantitation of PEO was performed by liquid chromatography (LC) using an evaporative light scattering detector (ELSD). This was used to build an understanding of removal of PEO using solid-phase extraction and liquid-liquid extraction techniques. A workflow was proposed to allow efficient development of analytical methods for SCT tablets with optimized sample clean-up.