Document D1 related to the provision of surface-modified drug particles with improved inhalation properties. The claimed subject-matter differed from the teaching in document D1 by the choice of magnesium stearate as the surface modifying additive material. The objective technical problem was the provision of an alternative method for making composite active particles for inhalation. Document D1 described calcium stearate as part of an extensive list of surface modifiers, but failed to provide any general teaching suggesting magnesium stearate as a suitable alternative surface modifier. Moreover, document D1 referred to document D15, a handbook on pharmaceutical excipients, which explicitly warned against the harmful inhalation of magnesium stearate.




Handbook Of Pharmaceutical Excipients 2nd Edition 1994