Methylnaltrexone Bromide

Methylnaltrexone Bromide (CAS No.: 73232-52-7) is a synthetic small molecule and quaternary ammonium derivative in the opioid receptor ligand class that is broadly categorized as a peripherally acting mu opioid receptor antagonist for pharmacology and translational biology research, with established utility as a mechanistic probe to investigate opioid receptor dependent signaling outside the central nervous system and to dissect receptor selective effects in complex tissue systems. In biochemical and cellular contexts, it is primarily associated with antagonism of mu opioid receptor mediated pathways, and published experimental observations also indicate modulation of Src linked signaling with consequent reduction of viability in selected lung cancer cell models, supporting its use in studies of receptor crosstalk, growth regulatory networks, and microenvironment responsive signaling rather than any direct therapeutic interpretation. Reported activity in research settings is generally described within nanomolar to micromolar concentration ranges depending on assay platform, receptor expression, and endpoint selection, while precise potency metrics can vary across model systems and should be established under laboratory specific conditions. The compound is commonly applied in cell based assays, receptor pharmacology panels, and preclinical animal experiments to evaluate peripheral opioid biology, on target versus off target pathway contributions, and combination strategy hypotheses in discovery workflows, and the concentrations or doses used in experiments typically depend on specific experimental designs and research objectives.