PROBLEM TO BE SOLVED: To provide a technique with which long-term storage stability in the market is guaranteed, in a stain formation inhibiting liquid composition for oral cavity including a predetermined amino acid-based surfactant, wherein the composition is excellent not only in storage stability at about 0 to 40°C, but also in storage stability even when exposed to a severe environment, for example exposed to an extremely low temperature such as -5°C, and preferably even when exposed to an extremely high temperature of about 55°C.SOLUTION: A composition is a stain formation inhibiting liquid composition for oral cavity, which contains 0.01 to 0.5 mass% of at least one amino acid-based surfactant selected from among 8-18C saturated or unsaturated acyl group-containing amino acids and salts thereof, and has a pH value of 6.4 to 10.5 at 25°C.COPYRIGHT: (C)2014,JPO&INPIT【課題】特定のアミノ酸系界面活性剤を含むステイン形成阻害用液体口腔用組成物において、約0℃~40℃での保存安定に優れることは勿論のこと、例えば、-5℃のような極低温下、好ましくは、約55℃程度の非常に高温下の過酷な環境下に曝されても保存安定性に優れ、市場における長期保存安定性を保証可能な技術を提供する。【解決手段】本発明の組成物は、炭素数8~18の飽和または不飽和のアシル基を有するアミノ酸およびその塩から選択される少なくとも1種以上のアミノ酸系界面活性剤を0.01~0.5質量%含有するステイン形成阻害用液体口腔用組成物であって、25℃でのpHが6.4以上、10.5以下である。【選択図】なし
