Morphine is used routinely in clinical practice to manage moderate to severe pain, whereas levomepromazine is commonly used at low doses to manage intractable nausea and vomiting. While it has been reported that an injection combination of morphine sulphate (0.5 mg/mL) and levomepromazine (0.1 mg/mL) was physically compatible, data on the chemical stability of combinations of these drugs has not been reported. Thus, a method was required for the assessment of the stability of morphine sulphate/levomepromazine hydrochloride combinations. A high-performance liquid chromatography (HPLC) method was developed to assess the stability of the combinations. The injections were stored at 4 degrees C in the dark at room temperature under natural light and at 37 degrees C under artificial lighting. Morphine sulphate was stable under all storage conditions, but the degree of degradation of levomepromazine hydrochloride increased as the storage temperature increased. The disappearance of levomepromazine hydrochloride was correlated with the appearance of a sulphoxide degradant. The injection combinations of morphine sulphate and levomepromazine hydrochloride were shown in the current study to have a limited storage life with respect to their levomepromazine hydrochloride content.
- morphine sulphate
- levomepromazine hydrochloride
- palliative care