Pharmacy World and Science

, Volume 16, Issue 1, pp 18–21 | Cite as

The preservation of some oral liquid preparations

The replacement of chloroform by other preservatives
  • H. van Doorne
  • J. B. Leijen
Practice/Case Reports


Chloroform should be considered as an obsolete preservative for pharmaceutical preparations, because of its toxicological implications and its physical instability. The effectiveness of possible alternatives for chloroform in three oral liquid pharmaceutical preparations was investigated, using a microbiological challenge test. Magnesium trisilicate mixture (British Pharmacopoeia) can be adequately preserved with methylparaben (2 g/l). Only insignificant amounts of methylparaben were absorbed by the solids present in the magnesium trisilicate mixture. Ferrous sulfate mixture (British Pharmacopoeia) can be preserved with a mixture of methylparaben (1.8 g/l) and propylparaben (0.2 g/l). Sorbic acid (1 g/l) is a suitable preservative for promethazine hydrochloride syrup.


Chloroform Drug stability Ferrous sulfate Magnesium trisilicate Parabens Promethazine Sorbic acid 


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Copyright information

© Royal Dutch Association for Advancement of Pharmacy 1994

Authors and Affiliations

  • H. van Doorne
    • 1
  • J. B. Leijen
    • 1
  1. 1.Department of Pharmaceutical Technology and BiopharmacyUniversity of GroningenAV Groningenthe Netherlands

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