The present disclosure includes a method of making an improved carbetocin drug product. The disclosed method for making an improved carbetocin drug product comprises agitating a carbetocin preparation containing an aqueous solution of carbetocin and one or more excipients for a period of time to initiate the formation of aggregate-forming solids and filtering off the aggregates that form before further processing the remaining carbetocin into a final drug product. The present disclosure also relates to an improved carbetocin drug product, wherein the drug product is substantially free of aggregate-forming solids. The disclosed carbetocin drug product can be used for the treatment of a neurodevelopmental disorder, such as Präder-Willi syndrome. Additionally, the disclosed carbetocin drug product shows content uniformity of carbetocin over long periods of time before and after one or more freeze/thaw cycles, provides enhanced convenience and patient compliance, and/or are highly concentrated.