The decomposition of phenylmercuric nitrate in sulphacetamide drops during heat sterilization

Analytical methods have been developed which enable phenylmercuric nitrate, mercuric ion and diphenylmercury to be measured in sulphacetamide drops. Application of these methods demonstrate that during heat sterilization of both 10 and 30% sulphacetamide drops containing phenylmercuric nitrate, together with disodium edetate and sodium metabisulphite, there is a 20-30% overall loss of phenylmercuric nitrate. This loss occurs mainly due to the phenylmercuric ion establishing an equilibrium with equimolar amounts of mercuric ion and diphenylmercury.