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

Controlled delivery of small molecule therapeutics is challenging. Here the authors report a simple and effective aptamer-based depot system where the formation of aptamer/drug complexes leads to sustained release, and using this approach demonstrate improved in vivo delivery of channel blockers. Delivery of hydrophilic small molecule therapeutics by traditional drug delivery systems is challenging. Herein, we have used the specific interaction between DNA aptamers and drugs to create simple and effective drug depot systems. The specific binding of a phosphorothioate-modified aptamer to drugs formed non-covalent aptamer/drug complexes, which created a sustained release system. We demonstrated the effectiveness of this system with small hydrophilic molecules, the site 1 sodium channel blockers tetrodotoxin and saxitoxin. The aptamer-based delivery system greatly prolonged the duration of local anesthesia and reduced systemic toxicity. The beneficial effects of the aptamers were restricted to the compounds they were specific to. These studies establish aptamers as a class of highly specific, modifiable drug delivery systems, and demonstrate potential usefulness in the management of postoperative pain.

Automated summary

The authors present a simple and effective aptamer-based depot system for controlled release of small molecule therapeutics. The system forms aptamer/drug complexes that sustain the release of drugs, leading to improved in vivo delivery of channel blockers. This approach greatly prolongs local anesthesia and reduces systemic toxicity, demonstrating the potential usefulness of aptamers as specific drug delivery systems.