US Food and Drug Administration (FDA) has issued norms on the Q4B evaluation and recommendation of pharmacopoeial texts for use in the ICH regions specifically with reference to Bulk Density and Tapped Density of Powders.

The Indian active pharmaceutical ingredient (API) industry has stated that this guidance from the US FDA provides the clarity during exports of bulk drugs. The implementation of the Q4B annexes is intended to avoid redundant testing by industry, stated the regulatory authority.

The ICH Steering Committee, based on the evaluation by the Q4B Expert Working Group (EWG), recommends the analytical procedures described in the official pharmacopoeial texts for the bulk density and tapped density of powders, determination of bulk and tapped densities, and USP General Chapter on bulk density and tapped density of powders which can be used as interchangeable in the ICH regions of EU, UK,  US and Japan.

When manufacturers change their existing methods to the implemented Q4B evaluated pharmacopoeial texts that are referenced in section II.A (2.1) of this annex, any change notification, variation, or prior approval procedures should be handled in accordance with established regional regulatory mechanisms pertaining to compendial changes, according to the regulator.

Based on the recommendation, the pharmacopoeial texts referenced in section II.A (2.1) can be considered interchangeable. However, FDA might request that a company demonstrate that the chosen method is acceptable and suitable for a specific material or product, irrespective of the origin of the method.

When this annex is implemented in a region, it can be used in that region. Timing might differ for each region. For instance in the European Union, regulatory authorities can accept the reference in a marketing authorization application, renewal or variation application citing the use of the corresponding text from another pharmacopoeia as referenced in section II.A (2.1), in accordance with the conditions set out in the annex, as fulfilling the requirements for compliance with the Ph. Eur. Chapter 2.9.34. on the basis of the declaration of interchangeability made above.

In Japan, the pharmacopoeial texts referenced in section II.A (2.1) of this annex can be used as interchangeable in accordance with the conditions set out in this annex. Details of implementation requirements will be provided in the notification by Ministry of Health, Labour and Welfare (MHLW) when implemented.

In Canada any of the pharmacopoeial texts cited in section II.A (2.1) can be considered interchangeable, stated the guidance.