An aptamer-based depot system for sustained release of small molecule therapeutics

Delivery of hydrophilic small molecule therapeutics by traditional systems is challenging. The authors use the specific interaction between DNA aptamers and drugs to create simple, effective depot systems. Phosphorothioate-modified aptamers form non-covalent aptamer/drug complexes enabling sustained release. Using tetrodotoxin (TTX) and saxitoxin (STX) as models, the aptamer-based system greatly prolonged local anesthesia and reduced systemic toxicity. Benefits were restricted to compounds for which the aptamers were specific. These studies establish aptamers as highly specific, modifiable drug delivery systems with potential for postoperative pain management.