ERGOMETRINE AND METHYLERGOMETRINE TABLETS ARE NOT STABLE UNDER SIMULATED TROPICAL CONDITIONS

Objectives. This study is part of a programme on reduction of postpart um haemorrhage (PPH). Ergometrine and methylergometrine have favourabl e effect on both blood loss and maternal morbidity and mortality and o ral preparations were regarded as a possible treatment for use in trop ical countries. The stability of oral preparations of the two ergometr ine compounds under tropical conditions was unknown and was therefore examined in this study. Study methods. The 'experimental shelf lives' of ergometrine and methylergometrine tablets were examined by exposing the tablets to seven artificially controlled conditions. Samples were analysed by high performance liquid chromatography at nine different sampling times over a period of 1 year to determine the content of erg ometrine and methylergometrine. Results. Under refrigeration (test I), less than 90% of the stated amount of active ingredient was found in the tablets after 14 weeks in the case of ergometrine and 21 weeks in the ease of methylergometrine. When stored in the dark at 40 degrees C and 75% relative humidity (test VI), the tablets fall outside accepte d specification (=90-110% of state amount of active ingredient) within 3 weeks in the ease of ergometrine and 21 weeks in the case of coated methylergometrine tablets. The stability of uncoated ergometrine tabl ets was far less than that of coated methylergometrine tablets. Instab ility worsened under extreme humid conditions (test IV and VI), and ho t conditions (test V), for both ergometrine and methylergometrine. Fro m week 31 onwards the coating did not seem to protect the compound any more, irrespective of the condition of exposure. Conclusions. Tropical conditions make the tablets unstable with humidity as the main advers e factor, The sugar-coated methylergometrine tablets are more stable u nder humid/hot conditions than the non-coated ergometrine tablets. Und er all simulated conditions both oral ergometrine and methylergometrin e tablets are unstable.