Penicillamine

Penicillamine is the characteristic degradation product of penicillin-type antibiotics. It is used medically as a treatment for medical problems such as Wilson's disease (too much copper in the body), rheumatoid arthritis, cystinuria, and lead poisoning. Penicillamine is a fine white or practically white crystalline powder having a slight characteristic odor and a slightly bitter taste. This chapter discusses the physical properties of d-penicillamine including crystal properties, infrared spectrum, Raman spectrum, nuclear magnetic resonance (NMR), mass spectra, optical rotation, melting range, solubility, and acid–base properties. Penicillamine is prepared by acid hydrolysis of penicillin followed by precipitation from the hydrolysis mixture as the mercuric salt, which is then collected, suspended in water, and treated with hydrogen sulfide to liberate the free acid. Purification involves only recrystallization from water. Penicillamine is relatively stable in both light and air. Aqueous solutions of d-penicillamine are comparatively stable at pH 2–4. In aqueous solution, penicillamine degrades slowly by first order or pseudo–first order kinetics.