Oxytocin and desamino-oxytocin tablets are not stable under simulated tropical conditions

J Clin Pharm Ther. 1995 Apr;20(2):115-9. doi: 10.1111/j.1365-2710.1995.tb00638.x.


Objectives: This study is part of a programme on reduction of postpartum haemorrhage. Buccal oxytocin and desamino-oxytocin administration with a favourable effect on both blood loss and maternal morbidity and mortality were regarded as possible treatments for use in tropical countries. The stability of buccal oxytocin and desamino-oxytocin under tropical conditions was unknown and therefore tested in this study.

Study methods: The 'experimental shelf lives' of buccal oxytocin and desamino-oxytocin were examined by exposing the tablets to seven artificially controlled conditions. Samples were analysed by high performance liquid chromatography to determine the content of oxytocin and desamino-oxytocin at nine different times during the period of 1 year.

Results: Oxytocin and desamino-oxytocin are fairly stable under refrigeration. Instability for both drugs was detectable after 20 weeks' storage under humid conditions, independent of temperature. Desamino-oxytocin is more sensitive to light exposure; its concentration declines to 55.6% of the stated amount after 1 year of exposure to light compared to 85% in the case of oxytocin. Oxytocin packaged as supplied by the manufacturer were stable for 21 weeks when exposed to simulated humid (75% relative humidity) conditions. At 40 degrees C and 25% relative humidity there is no difference in stability between tablets in sealed aluminium packs as supplied by the manufacturer and unpackaged tablets.

Conclusions: Tropical conditions make oxytocin and desamino-oxytocin tablets unstable, with humidity as the most adverse factor. The oxytocin tablets were partially protected from the harmful effect of humidity by sealed aluminium package.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Drug Packaging
  • Drug Stability
  • Humidity
  • Oxytocics / metabolism*
  • Oxytocin / analogs & derivatives*
  • Oxytocin / metabolism*
  • Refrigeration
  • Tablets
  • Temperature
  • Tropical Climate*


  • Oxytocics
  • Tablets
  • deaminooxytocin
  • Oxytocin