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General Chapter <711> Dissolution

Type of Posting: Notice of Intent to Revise

Posting Date: 11–Mar–2008

The USP Biopharmaceutics Expert Committee has received comments on the mesh size used in the construction of the baskets for Apparatus 1 (basket) and described in General Chapter <711> Dissolution. The comments indicate that the harmonized mesh size official in <711> does not reflect the material that is used in the U.S.

The current standard, which resulted from harmonization of the General Chapter through the Pharmacopoeial Discussion Group (PDG) process, allows wire diameters to range from 0.25 mm to 0.31 mm. The standard contained in the version of <711> effective prior to the harmonization effort allowed a nominal diameter (0.25 mm) with no range. USP's understanding is that the wire used in manufacturing Apparatus 1 baskets has not changed significantly over the years, and has a manufacturing tolerance from 0.21- 0.32. Thus, it appears this situation existed under the USP standard even before harmonization of the chapter, but has only now come to the attention of industry and USP.

USP is posting this Notice of Intent to Revise pursuant to the Rules and Procedures of the 2005-2010 Council of Experts (Section 9.05c) to make both industry and regulators aware that USP is working to resolve the issue and revise the chapter to accommodate the wire dimension historically used in construction of the baskets. Since the text in question is harmonized, any change, barring those made for public health reasons (see Section 9.04 of the Rules and Procedures), must be made in accordance with Pharmacopoeial Discussion Group processes.

Should you have any questions, please contact William E. Brown, Senior Scientist and Liaison to the Biopharmaceutics Expert Committee (301-816-8380) or