Shin-Etsu AQOAT^® (hypromellose acetate succinate) is our second enteric coating material, and it was developed for aqueous coating. Shin-Etsu AQOAT^® was approved as a pharmaceutical excipient in Japan in 1987, and then in the United States and several European countries in 2001. In an aqueous system, a suspension containing Shin-Etsu AQOAT^® (fine powder), triethyl citrate as a plasticizer, talc as an anti-tacking agent, and sodium lauryl sulfate as a wetting agent is typically used. Shin-Etsu AQOAT^® also shows excellent performance when it is used as a carrier for solid dispersions in order to enhance solubility of poorly soluble drugs.