Comparative Med
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Opioids have been shown to relieve thermal hyperalgesia associated with neuropathic pain. We used a novel technique to produce liposome-encapsulated hydromorphone (LEH), which we then tested in a chronic constriction injury (CCI) thermal hyperalgesia model of neuropathic pain. Rats were divided into sham-operated and CCI groups. ⋯ Preemptive injection of LEH prevented hyperalgesia in this model for as long as 5 d. In addition, hyperalgesia was alleviated for at least 2 d after injection of a single dose of LEH. These results suggest that liposome-encapsulation of hydromorphone offers a convenient and effective means to provide relief from neuropathic pain in this rodent model.