BRIEFING

 〈561〉 Articles of Botanical Origin. This proposal is based on the version of the chapter official as of November 1, 2021, as well as an upcoming revision approved for publication in USP–NF 2026 Issue 6, which was proposed in PF 51(4). In this chapter, Water Content includes only one method, as directed in Water Determination 〈921〉, Method III, which is based on Loss on Drying 〈731〉 and suitable for plants that do not contain volatile components. The azeotropic–toluene distillation (ATD) method (〈921〉, Method II) is often used in pharmacopeial monographs to determine the water content of plant materials containing volatile components. ATD is an environmentally hazardous method as it uses relatively large amounts of toluene with distillation at high temperature. To seek a greener approach for water determination in plant materials, 〈921〉, Method I, is recommended due to its efficiency, specificity, and accuracy. However, it is difficult to determine water content of plant materials by titrating the plant material directly because water is tightly trapped in plant cells. An alternative method is titration of a water extract. In this revision, the following three methods are being added:

• Method I—Direct Titration with Solvent Extraction: This method includes water extraction with formamide followed by titration using 〈921〉, Method I, Method Ia.

• Method II—Loss on Drying: This is the current method with changes and suitable for plant materials that do not contain volatile components.

• Method III—Azeotropic–Toluene Distillation: This uses 〈921〉, Method II and is suitable for plant materials containing volatile components. This method is environmentally hazardous.

 Additionally, minor editorial changes have been made to update the chapter to current USP style.

 (BDSHM: C. Ma)

 Case ID—SUB-3021