Stability of extemporaneously compounded domperidone 5 mg/mL suspension in oral mix in plastic and glass bottles and plastic syringes

Abstract

Background: Domperidone liquid for oral administration is not commercially available in Canada, but is needed for patients who cannot swallow intact tablets. Objective: To evaluate the stability of domperidone 5 mg/mL suspensions prepared in Oral Mix vehicle and stored, for up to 91 days, in amber polyvinylchloride (PVC) bottles, amber glass bottles, or amber polyethylene terephthalate (PET) bottles at 4°C or 25°C or in polypropylene oral syringes at 25°C. Methods: Three separate 300-mL batches of domperidone suspension 5 mg/mL were prepared with Oral Mix vehicle. Fifty-millilitre aliquots of the suspension were stored in 100-mL bottles (amber PVC, amber glass, or amber PET). Half of the bottles of each type were stored at 25°C and half at 4°C. On study days 0, 1, 2, 4, 7, 10, 14, 21, 28, 35, 42, 49, 63, 77, and 91, domperidone concentration was determined, with a validated reverse-phase, stability-indicating liquid chromatographic method, in samples drawn from each type of container stored at each temperature. In addition, 1.5-mL aliquots of a fourth 100-mL batch of suspension were stored in 3-mL oral syringes at 25°C and were tested on the same study days. Results: The concentration of domperidone in all study samples remained above 93% of initial concentration after storage for 91 days. The percent remaining on day 91, based on fastest degradation rate (as represented by the lower limit of the 95% confidence interval [CI]), was at least 92.3% for suspensions stored at 4°C in PVC, glass, and PET bottles. With storage at 25°C, suspensions in PVC and glass bottles retained more than 90% of initial concentration, whereas suspensions in PET bottles and plastic syringes retained 88.9% and 88.0% of initial concentration, respectively. Conclusions: Because suspensions of domperidone in PET bottles and oral syringes retained less than 90% of their initial concentration on day 91 (based on the 95% CI), it is suggested that such suspensions be stored at 4°C or 25°C in any bottle type or syringe with an assigned beyond-use date not exceeding 75 days.