The influence of liquid spray rate and atomizing pressure on the size of spray droplets and spheroids

Lucy S.C. Wan, Paul W.S. Heng, Celine V. Liew

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The effects of liquid spray rate and atomizing pressure on the size of spray droplets and spheroids were investigated in this study. The range of droplet sizes tended to narrow and relatively smaller droplets were formed at higher atomizing pressures. When liquid spray rate was increased, the droplets were larger and had a wider size range. Although alterations in liquid spray rate could affect spray droplet size, greater changes in droplet size were achieved by varying atomizing pressure. In these investigations, changes in spray droplet size and atomizing pressure did not appear to greatly affect mean spheroid size. However, the presence of an atomizing pressure was necessary for the even distribution of the moistening liquid to reduce localized overwetting during spheronization by rotary processing. The amount of oversized particles may thus be decreased and a more uniformly sized yield may be achieved with the use of relatively higher atomizing pressures. With a fixed volume of moistening liquid sufficient for spheronization, larger spheroids were produced with increasing liquid spray rates. The increased wetting per unit time resulted in the formation of larger nuclei and enhanced the growth rate of spheroids.

Original languageEnglish
Pages (from-to)213-219
Number of pages7
JournalInternational Journal of Pharmaceutics
Issue number2
Publication statusPublished - 16 May 1995
Externally publishedYes


  • Atomizing pressure
  • Liquid spray rate
  • Spheroid
  • Spheroid size
  • Spray droplet size

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