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


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.
de Groot
A N
AN
Department of Gynaecology & Obstetrics, University Hospital Nijmegen, The Netherlands.
Hekster
Y A
YA
Vree
T B
TB
van Dongen
P W
PW
D004349:Drug Packaging; D004355:Drug Stability; D006813:Humidity; D010120:Oxytocics / Q000378:metabolism*; D010121:Oxytocin / Q000031:analogs & derivatives* / Q000378:metabolism*; D012034:Refrigeration; D013607:Tablets; D013696:Temperature; D014329:Tropical Climate
D010120:Oxytocics; D013607:Tablets; C004748:deaminooxytocin; D010121:Oxytocin