In-Vitro Drug Release from Abuse-Deterrent Therapeutic Polymers

Nova Southeastern University, Davie, Florida, USA

Objective: The objective was to evaluate the release of Dextromethorphan HBr (DEX) from its starch-based and cellulose-based therapeutic polymers in simulated gastric and intestinal media. Background: We have previously prepared DEX-loaded therapeutic polymers of crosslinked carboxymethyl derivative of cellulose (CMC) and starch (CMS), and evaluated their intravenous abuse-deterrence in different extracting solvents. Further studies were needed to confirm that such therapeutic polymers could maintain their therapeutic effectiveness under legitimate use. Methods: DEX-CMS/CMC complexes were mixed with binder and compressed into tablets. Using USP Apparatus II @ 50 rpm, dissolution studies were performed in two stages: Stage I (900mL 0.1N HCl), followed by Stage II (900mL water or pH 7.5 phosphate buffer). Samples of 5mL were withdrawn at predetermined time points with immediate media replacement. UV spectrophotometer was used to determine % drug release in two stages. Results: Immediate and complete drug release was achieved for all complexes in 0.1 N HCl (>95% after 15 minutes). Stage 2 in water and phosphate buffer showed >90% drug release after 24 hours, complying with the USP limit. Conclusion: Drug-loaded therapeutic polymers were found to be a successful approach in deterring intravenous drug abuse, while at the same time delivering the intended drug amounts under therapeutic use. Full protonation of the polymer in gastric medium and lack of (or very slow) drug rebinding with the protonated polymer in simulated intestinal fluid makes this approach feasible in formulating both immediate and sustained release abuse deterrent opioid formulations. Grants: This study was supported by NSU Grant 335081.