Chemically, potassium bromide is quite simple. Composed of only one potassium ion and one bromide ion, potassium bromide nevertheless is extremely versatile. This white, odorless, crystalline compound with an extremely high melting point of 1346 degrees F plays roles in theoretical science investigations, in practical photography solutions and in animal and human medicine.
Potassium bromide treats seizures in dogs. Seizure activities initiate with high levels of electrical activity in brain tissues. High levels of chloride encourage this electrical activity. The bromide ions from potassium bromide compete with chloride in brain tissues, decreasing chloride levels and inhibiting the initiation of seizures. Potassium bromide is not a first-line drug to treat seizures as there are significant side effects compared to the more popular phenobarbital and because it may take as long as four months to reach a therapeutic steady-state concentration of bromide in the brain.
Seizures in cats and horses can also be treated and controlled with potassium bromide, but because of the incidence of side effects, particularly in cats, it is rarely used.
In 1857, Sir Charles Locock discovered the anti-convulsant and sedative activity of potassium bromide in humans. As a result, potassium bromide was used to treat epileptic and seizure disorders until the discovery of phenobarbital in 1927. While no longer a licensed medication in the United States, special approval from the FDA can be granted for use, but the manufacture of bromides is now primarily relegated to chemical companies only.
Potassium bromide helps characterize liquid compounds using infrared spectroscopy. Infrared spectroscopy, like all types of spectroscopy, is a technique used to identify compounds and investigate sample compositions. Every molecule has a unique absorbance profile determined by passing a beam of infrared light through the sample. To prepare liquid and gas samples for infrared spectroscopy, the sample is sandwiched between two plates of a salt, such as potassium bromide. The plates are transparent to the infrared light and do not introduce any lines onto the spectra. Potassium bromide salt plates are used because they have the desired feature of being soft and hygroscopic--able to attract water molecules.
Potassium bromide is a salt used to make photographic papers and plates and for process engraving. Found in general purpose and print developing solutions, potassium bromide is a highly soluble alkaline accelerator in solutions for X-ray films, continuous tone films requiring higher than normal contrast, intensifier solutions recommended for increasing the printing density of thin negatives, cold and warm tone developer solutions and universal developers for projection and contact papers.
Potassium bromide is often used in scientific research projects, including the isolation of plant plasma membrane proteins, insect lipoproteins, and apoflavoproteins. Capillary electrophoresis, the separation of double stranded DNA, uses potassium buffer solutions. Potassium bromide also provides the chemical intermediates for the manufacture of various industrial and research chemicals.