{'fraction_non_alphanumeric': 0.01909307875894988, 'fraction_numerical': 0.001431980906921241, 'mean_word_length': 5.275449101796407, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 1, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A Comparative Study of Two Analgesic Compounds, Fenobam Sulfate and Fenobam Free Base, Using a Model of Inflammatory Nociception

A diverse array of chronic pain conditions exist, each with varying causative mechanisms and multiple hypothesized receptor targets for treatment. One potentially effective target for analgesia is the metabotropic glutamate receptor subtype 5 (mGluR5). A selective antagonist of mGluR5, fenobam free base, has been shown to provide pain relief in preclinical models. Due, in part, to fenobam free base's poor solubility and short half‐life, however, it carries limitations for efficacy in human conditions. A new salt formulation of the compound, fenobam sulfate, has improved solubility and a longer half‐life, which may contribute to extended analgesic effects. A comparative study of fenobam sulfate and fenobam free base was performed in male and female mice using the spontaneous formalin pain model. The main objective was to determine if fenobam sulfate shares similar analgesic properties with its free base counterpart. The two compounds were each dissolved in two separate vehicles, DMSO and BCD. Fenobam sulfate produced analgesic effects similar to those of free base when dissolved in either vehicle. Both compounds dissolved in DMSO, however, produced greater analgesic effects compared to BCD. The duration of time in which fenobam sulfate had an effect was also characterized through mechanical hypersensitivity tests two and three hours following formalin injection. Fenobam sulfate in BCD induced analgesia in female mice for at least two hours, but not in male mice. As fenobam free base has been shown to increase locomotion, the impact of fenobam sulfate on locomotion was investigated using an open field assay. Both compounds were found to induce similar increases in locomotive activity. Overall, these results suggest that fenobam sulfate may be a more effective analgesic compound than fenobam free base. In the future, it would be valuable to analyze sex differences that may contribute to the observed prolonged analgesia in female mice.