Particle Size and Content Uniformity

Samuel H. Yalkowsky, Sanford Bolton

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


The requirements of the USP Content Uniformity test are translated into physical and mathematical parameters. Assuming spherical particle sizes with a log normal distribution, the mean particle size and particle size distribution required to insure a high probability of passing the content uniformity test are calculated. On the basis of these calculations it is shown that satisfactory tablets of low doses cannot be manufactured from a drug that does not meet certain particle size distribution specifications. It is recommended that particle size specifications for low dose drugs include a requirement for a limit to size distribution.

Original languageEnglish (US)
Pages (from-to)962-966
Number of pages5
JournalPharmaceutical Research: An Official Journal of the American Association of Pharmaceutical Scientists
Issue number9
StatePublished - Sep 1990


  • content uniformity
  • distribution
  • particle size
  • probability
  • tablets
  • uniformity

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry
  • Pharmacology (medical)


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