On the list of recognized raw materials I find 3 types of colloidal SiO2. Which of these can be used as excipients in the preparation of capsules with dry extracts to absorb moisture?

Collo ï DAL silicon oxide hydrogen (AEROSIL 200) is the silicon dioxide that is usually used for moisture absorption. It also serves as a lubricant. The hydrophobic vari ë ility (Aerosil R972) is mainly used to improve the flow properties of a powder mixture. By its hydrophoid character it will of course also reduce the ad and absorption of moisture. So that one can eventually ask the question whether a bit of the first together with bit of the second would not be the ideal combination? Given the Collo ï Dale Vari ë ties are difficult to mix homogeneously due to the occurrence of agglomerates (due to the very high degree of finality), which are difficult to break down, one prefers in the preparation of capsules, where a problem of Moisture absorption does not suggest, utilizing the silicon dioxide heavily.