Chronically, medically resistant pain is one of the most significant health problems in our country and affects more than 50 million Americans. Neuropathic pain syndromes are for the most part resistant to traditional analgesic treatments with NSAIDs, acetaminophen, or opiate medications (eg, morphine, codeine). Furthermore, most therapeutics currently used to treat neuropathic pain, including some antidepressants (eg, amitriptyline) and anticonvulsants (eg, gabapentin), were not specifically developed for that purpose, and show efficacy in only a fraction of the patients. We have been exploring a series of new and proprietary acetaminophen analogs, in which the lead compound (SCP-1) and it's active metabolite (SCP-123) show a favorable safety profile and are active in rodent models of neuropathic pain. In the first year under this Phase II SBIR translational research project, we will evaluate both an oral solid and an intravenous (iv) solution of SCP-123 in three models of neuropathic pain and compare them to gabapentin. We will also evaluate the safety and pharmacokinetic profile of these two formulations. When these evaluations are complete, we will analyze the data and choose one of the formulations as a clinical candidate. In the second and third year of this grant we will conduct the preclinical studies (on the chosen formulation) that are necessary for an Investigative New Drug (IND) application to the FDA. At the end of the third year of this grant project, we will write and assemble the IND package and submit it to the FDA. If the FDA accepts the IND application, we will shortly thereafter begin the Phase I human clinical of SCP-123 Chronically, medically resistant pain is one of the most significant health problems in our country and affects more than 50 million Americans. Patients with neuropathic pain are often treated with medications from different drug classes including tricyclic antidepressants, anticonvulsants, topical agents, and opioids, but the use of these pharmacological agents is limited both because of lack of efficacy and/or the occurrence of undesirable side-effects. St Charles Pharmaceuticals is proposing to develop a new class of compounds that have activity in neuropathic pain models and hold the promise of addressing the shortcomings of current treatments.