A preliminary examination was undertaken to diazepam stability in parenteral and tablets dosage forms. Newton method for diazepam assay was employed to correct the potential error of official USP method in aged products. Approximately 11.6% and 3.7% loss of , diazepam in parenteral solution and in tablets were found during n three months storage at room temperature. the instability of diazepam in dosage form might be one of factors which responsible for poor clinical claim. 有關Di azepam在製劑中之穩定度，一向受忽視，而被錯認為頗安定之製劑，但在臨床上，常經驗其注射液之低效應。經貯藏一段時間之Diazepam製劑，如以USP法定方法定量時，常獲得反較共初濃度為高之定量值，造成品管上之困擾。本篇利用Newton氏定量法分離在USP定量法中造成干擾之主要水解生成物之定量值，闡明Diazepam在注射液中及在錠劑中之不穩定性。結果顯示在常溫保存三個月，Di az epam在注射液中之分解量達11.6%，在錠劑中之分解率為3.7%，此種不穩定性，擬為臨床上低效應之原因之一。
