On the preparation of beta-haematin

Synthetic beta-haematin is considered to be identical, or at least very similar to, purified malaria pigment. Methods for its preparation use ferriprotoporphyrin IX at acid pH in the presence of acetic acid at different concentrations and degrees of ionization, elevated temperatures and long reaction times. Here we show that certain widely used reaction conditions, involving very high concentrations of acetic acid/acetate mixtures, do not produce substantial amounts of polymeric beta-haematin on immediate isolation of the reaction products, but only during prolonged drying of the products at 37 degrees C after washing with water. Alternative, more convenient methods of preparation of pure beta-haematin are suggested.