301-How To Measure Tapped Density

How To Measure Tapped Density.

Tapped density is an increased bulk density attained after mechanically tapping a container containing the powder sample.Tapped density is obtained by mechanically tapping a graduated measuring cylinder or vessel containing a powder sample.After observing the initial powder volume or weight, the measuring cylinder or vessel is mechanically tapped,and volume or weight readings are observed. The mechanical tapping is achieved by raising the cylinder or vessel and allowing it to drop under its own weight a specified distance by either of three methods as described in USP Chapter 616. Devices that rotate the cylinder or vessel during tapping may be preferred to mimimize any possible separation of the mass during tapping down.


How to Measure Tapped Density LABULK 0335

How to Measure Tapped Density LABULK 0335


<616> Bulk Density and Tapped Density of Powders

Coordinating Pharmacopoeia: European Pharmacopoeia

A revision to the harmonized standard for Bulk Density and Tapped Density of Powders has been approved by the Pharmacopeial Discussion Group (PDG) as described in its PDG Rev. 3 sign-off cover sheet. Having reached Stage 6 of the PDG process, the general chapter of Bulk Density and Tapped Density of Powders has been formally approved by the USP General Chapters—Physical Analysis Expert Committee in accordance with the Rules and Procedures of the 2010–2015 Council of Experts.

Changes from the existing USP–NF General Chapter include:

Bulk Density

Method II: Measurement in a Volumeter

  • In the footnote for apparatus, changed from “ASTM 329 90” to “ASTM B 329-06(2012)”
  • To be consistent with significant figures, changed from “The cup may be … cubical
    (16.39 ± 0.2 mL)” to “The cup may be … cubical (16.39 ± 0.20 mL)”

Tapped Density

Method I

  • Added “If the difference between V500 and V1250 is less than or equal to 1 mL, V1250 is the tapped volume. If the difference between V500 and V1250 exceeds 1 mL, repeat in increments such as 1250 taps, until the difference between succeeding measurements is less than or equal to 1 mL.” before the last sentence.

General Chapter <616>  Bulk Density and Tapped Density of Powders will be incorporated into and become official with the First Supplement to USP 38–NF 33.

Should you have any questions, please contact Kevin Moore (301-816-8369 or For any questions about the PDG and its processes, please see Pharmacopeial Harmonization Group or contact Richard Lew at (240-221-2060 or

Revision History

  • Previous Stage 6 (posted 23–Nov–2011; official Date: 01–Dec–2012)
  • Previous Stage 6 posted in PF 36(5), 2010
  • Previous Stage 6 posted in PF 35(3), 2009