Presented at the 2013 AAPM Annual Meeting « Back

Gallium Maltolate: A New Topical Analgesic Agent

Lawrence R. Bernstein, PhD, lawrencerbernstein@gmail.com¹, (1) Gallixa LLC, Menlo Park, California

Introduction: Preclinical and clinical studies have shown that gallium can exert antiproliferative and anti-inflammatory activity. Gallium's anti-inflammatory activity is due, in part, to its ability to inhibit the activation and proliferation of T-helper-type-1 cells and the secretion of inflammatory cytokines by activated macrophages. Gallium's analgesic properties likely relate to its anti-inflammatory activities as well as to its actions on certain metalloproteinases and neuropeptides. Methods: A formulation consisting of 0.5 wt% gallium maltolate (GaM) in an emulsion of water and hydrophilic petrolatum was applied to the skin at sites of neuropathic pain in five subjects: three with refractory postherpetic neuralgia, one with neuropathic pain following nerve damage to the hand, and one with CRPS. In addition, an aqueous solution of 1 wt% GaM was used to rinse the mouth of a patient who had oral squamous cell carcinoma accompanied by severe tongue and mouth pain. For the subjects using the topical cream, pain was recorded over periods of weeks to years; for the subject using the mouth rinse, pain was recorded for seven days. Results: All six patients experienced significant and rapid pain relief. One subject, who had endured severe refractory postherpetic neuralgia for four years, experienced almost complete pain relief within 10 minutes of applying the GaM topical cream, and used the formulation daily for more than five years. Conclusions: Controlled, systematic research is warranted to further investigate the analgesic properties of GaM and to investigate GaM’s mechanisms of action. References: 1) Bernstein LR (2012) Successful treatment of refractory postherpetic neuralgia with topical gallium maltolate: Case study. Pain Medicine 13:915-918. 2) Bernstein LR (1998) Mechanisms of therapeutic activity for gallium. Pharmacological Reviews 50:665-682. 3) Bernstein LR, Tanner T, Godfrey C, Noll B (2000) Chemistry and pharmacokinetics of gallium maltolate, a compound with high oral gallium bioavailability. Metal Based Drugs 7:33-48. 4) Schwendner SW, Allamneni KP, Bendele A, et al. (2005) Efficacy of oral gallium maltolate in acute and chronic models of rheumatoid arthritis (abs.). FASEB Journal 19 (4, Suppl. S, Part 1):A926. 5) Ji RR, Xu ZZ, Wang X, Lo EH (2009) Matrix metalloprotease regulation of neuropathic pain. Trends in Pharmacological Sciences 30:336-340. 6) Tang HB, Miyano K, Nakata Y (2009) Modulation of the substance P release from cultured rat primary afferent neurons by zinc ions. Journal of Pharmacological Sciences 110:397-400.

Funding: None