[On the stability of phenylmercury salts. Part 50: Contributions to problems concerning the use of plastic receptacles for liquid pharmaceuticals (author's transl)].

The authors describe a dithizone method for the determination of phenylmercury salts that yields easily reproducible results on examining the stability of these preserving agents. Aqueous solutions of phenylmercury salts are instable already in glass bottles, but they are instable to a much greater extent in low-density polyethylene bottles. Their degradation is accelerated in the presence of chloride ions. When stored under nitrogen, the phenylmercury salt solutions show lower losses of preserving agents than when stored under normal air. The ultra-violet extinction of phenylmercury salt solutions increases during storage in glass bottles, and decreases during storage in plastic bottles. In plastic bottles, the degradation is associated with sorption.