Non-Systemic Oral Cellulose-Based Superabsorbent Hydrogels for Weight Management: Potential Drug-Device Interactions Estimated by a Simplified In Vitro Assay

Background/Objectives: A technological platform of non-systemic oral cellulose-based superabsorbent hydrogels (CB-SAHs) has been recently developed as novel therapeutics for treating obesity. Further clinical advancement of CB-SAH candidates from this platform requires evaluating their potential impact on the absorption of co-administered drugs. Methods: In this work, we developed a simplified in vitro assay to assess whether and to what extent given CB-SAHs may interact with co-administered drugs. We selected two different CB-SAHs and tested them in contact with various solubilized drug substances under simulated gastrointestinal conditions. A total of 23 drugs were chosen among those that could be used to treat frequent conditions associated with excess weight (e.g., type 2 diabetes) or to deal with common therapeutic needs (e.g., pain relief). Final drug recovery (FDR) in the simulated intestinal medium was quantified using UV-Vis spectroscopy to assess drug–hydrogel interactions. Results: While most drugs achieved an average FDR exceeding 80% with both hydrogels, six compounds exhibited lower FDR values (~68–78%) with at least one CB-SAH, indicating stronger, specific drug–hydrogel interactions. Notably, the FDR measured for metformin with both CB-SAHs (~94%) was consistent with previous clinical findings demonstrating negligible metformin–CB-SAH interaction. Conclusions: Although simplified, the in vitro assay shows promise as an exploratory screening tool to identify specific drug–CB-SAH interactions that warrant subsequent clinical evaluation.