Pain - particularly chronic pain - is a major cause of morbidity, especially in patients with cancer or neuropathic pain. These conditions are often refractory to treatment. The purpose of this research is to develop particulate prolonged duration local anesthetics (PDLA) employing site 1 sodium channel blockers such as saxitoxin (STX). To date, this line of inquiry has been very productive;since the current R01 began 3.5 years ago, we have produced 31 papers, and met or exceeded the goals of our Specific Aims. The underlying hypothesis - which was validated in the preceding research - is that STX, encapsulated in combination with compounds such as conventional local anesthetics and steroids, can produce extremely long nerve blocks. As envisioned here, PDLA could last weeks to months for chronic pain, or could be tailored to shorter durations for other (e.g. perioperative) applications. Our research could potentially be applicable to any excitable tissue, and in fact to any environment where controlled release could be useful.
One specific aim of this research is to resolve difficult formulation problems such as burst release, which arise in encapsulating potentially toxic hydrophilic molecules. Our base formulation is a liposome containing saxitoxin and other drugs, where we have shown we can obtain nerve blocks lasting a week with minimal systemic and local toxicity. We propose a spectrum of potential modifications to produce yet longer blocks while maintaining safety. These include producing single-agent microparticles, constructing secondary polymeric shells, use of hydrogels inside or outside of the particles, and devising macroscopic devices. An equally important aim will be the in vivo assessment of the efficacy and toxicity of these new formulations by neurobehavioral tests in rats and rabbits, and by following serum drug levels. Another crucial aspect of the research, which has not received sufficient attention, will be to study the development of inflammation, myotoxicity, and neurotoxicity with these formulations, and means of preventing them.

Public Health Relevance

Prolonged pain after surgery and chronic pain afflict millions of people in the U.S. and across the globe. The purpose of this application is to develop means of treating such localized pain with a single injection that would last for days to weeks without patients having to take pain medications that would cloud their minds.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Cole, Alison E
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Children's Hospital Boston
United States
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Rwei, Alina Y; Sherburne, Robert T; Zurakowski, David et al. (2018) Prolonged Duration Local Anesthesia Using Liposomal Bupivacaine Combined With Liposomal Dexamethasone and Dexmedetomidine. Anesth Analg 126:1170-1175
Santamaria, Claudia M; Woodruff, Alan; Yang, Rong et al. (2017) Drug delivery systems for prolonged duration local anesthesia. Mater Today (Kidlington) 20:22-31
Rwei, Alina Y; Paris, Juan L; Wang, Bruce et al. (2017) Ultrasound-triggered local anaesthesia. Nat Biomed Eng 1:644-653
Santamaria, Claudia M; Zhan, Changyou; McAlvin, J Brian et al. (2017) Tetrodotoxin, Epinephrine, and Chemical Permeation Enhancer Combinations in Peripheral Nerve Blockade. Anesth Analg 124:1804-1812
Li, Mengyuan; Li, Lele; Zhan, Changyou et al. (2016) Core-Shell Nanostars for Multimodal Therapy and Imaging. Theranostics 6:2306-2313
Salvador-Culla, Borja; Jeong, Kyung Jae; Kolovou, Paraskevi Evi et al. (2016) Titanium Coating of the Boston Keratoprosthesis. Transl Vis Sci Technol 5:17
Li, Lele; Tong, Rong; Li, Mengyuan et al. (2016) Self-assembled gemcitabine-gadolinium nanoparticles for magnetic resonance imaging and cancer therapy. Acta Biomater 33:34-9
Zhan, Changyou; Wang, Weiping; McAlvin, James B et al. (2016) Phototriggered Local Anesthesia. Nano Lett 16:177-81
Lim, Dong-Kwon; Wylie, Ryan G; Langer, Robert et al. (2016) Selective binding of C-6 OH sulfated hyaluronic acid to the angiogenic isoform of VEGF(165). Biomaterials 77:130-138
Rwei, Alina Y; Lee, Jung-Jae; Zhan, Changyou et al. (2015) Repeatable and adjustable on-demand sciatic nerve block with phototriggerable liposomes. Proc Natl Acad Sci U S A 112:15719-24

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