1988 Volume 14 Issue 3 Pages 161-166
The stability of halothane stored in five different vaporizers for a week was studied by gas chromatography (G.C.). An impure material of low boiling points was detected in halothane whichwas kept only in a particular vaporizer. The impure material increased to be detectable within 30 minutes after halothane was transferred into thevaporizer. After 3 months, the level of the impure material exceeded 0.005% which was the maximum allowable amount for volatile impurities regulated by Pharmacopoeia of Japan. Thenature of the impure material was not known.
On the other hand, the impure materials of high boiling points were detected in all vapori zers. GC-MS analysis indicated that these materials were brominated thymoles, suggesting that halothane was dissociated and the released bromide reacted with thymole, a disinfectant. Amounts of the materials of high boiling points increased by irradiation with white light and the halothane colored yellow.
The halothane manufactured 30 years ago and kept in a sealed brown bottle was also tested for its stability. In this halothane, although it was so old, noimpure materials of high boiling points or yellow color was observed. These results suggested that halothane was unstable in a vaporizer especially when exposed to light. Therefore, the remained halothane should not be left in the vaporizer.
