Seven products, currently on the market as acetaminophen suppository 100 mg, are commonly used for pyrexia in children, and yet there have been no reports on their solubility and divisibility. We examined the hourly solubility rate of each suppository using a dissolution tester for suppositories. In addition, we conducted a hardness test using the EZ-test, a questionnaire-based investigation on the accuracy and divisibility when the suppositories were divided. There was a significant difference between each suppository (P < 0.01). While 4 types dissolved completely within 60 minutes, one type took 120 minutes to dissolve completely. Another two had only 51 and 67%, respectively, at 180 minutes. The bases are hard fat in all suppositories. The types and additives of hard fat may have had an influence on solubility. The hardest suppository was assessed as showing marked differences in the weight ratio and solubility between the distal and tail portions when divided in half, due to which division was considered inappropriate, and there were differences in accuracy and divisibility among suppositories.
From the above, it was suggested that the acetaminophen suppository 100 mg products may show differences in the solubility, time to action onset, and duration of the action. In addition, we should instruct physicians on important points of caution regarding the characteristics of each preparation when dividing the suppositories so that they can be given safely to infants.
