Determination of compatibility and stability of drugs used in palliative care

Background: Drugs for symptom control in the terminal phase of palliative p atients may be used in pump systems. Objective: To investigate the compatibility and stability of solutions of m orphine hydrochloride, haloperidol, metoclopramide hydrochloride, atropine sulphate, butylhyoscine bromide and ranitidine hydrochloride, which may be used together under such circumstances. Method: Solutions of the drugs were exposed to ambient light at a temperatu re of 20 +/-5 degrees C and +/-31 degrees C for 24h and 7 days and the solu tions studied by ultraviolet spectrophotometry. Results: The combination of haloperidol or metoclopramide hydrochloride wit h different concentrations of morphine hydrochloride seemed to be compatibl e and stable. The concentration of atropine sulphate or butylhyoscine bromi de could not be determined by the study method, but morphine hydrochloride seemed to be stable. The combination of ranitidine hydrochloride and morphi ne hydrochloride showed a change in colour after 7 days. Conclusion: The results suggest that the combination of different concentra tions of morphine hydrochloride with haloperidol, metoclopramide hydrochlor ide, atropine sulphate, butylhyoscine bromide or ranitidine hydrochloride d o not affect their stability when stored for 7 days up to 30 degrees C unde r the influence of ambient light. However, more robust stability-indicating methods are required to confirm these results. The proposed method is more useful for identifying combinations that are clearly incompatible than to identify those that are compatible.