Appeal No. 1999-2230
Application 08/465,236
the spray-drying process, they are able to produce microcapsules having a unique
combination of size, pressure resistance, and size distribution. This unique combination of
characteristics results in mircocapsules said to be outstanding deposit echocontrast
agents.
As can be seen from a review of representative claims 22, 23, 24, and 28, the
claims before us recite microcapsules where “at least 30%” or “more than 30%” of the
microcapsules have a diameter within a 2 :m range, and at least 90% have a diameter of
12.0-25.0 :m; or “the interquartile range of diameters is 2 :m or less and the median
diameter is between 12.0 :m and 25.0 :m inclusive.” Having carefully reviewed the
content of Sands, Erbel, and Mathiowitz, we find that the combined disclosures of cited
references are insufficient to support a conclusion of obviousness of claims containing
those numerical limitations.
Sands discloses hollow microspheres, prepared by spray-drying, having a particle
size of about 1 to 500 microns (column 2, lines 27 through 30; column 3, lines 51 through
53). The Sands process is said to produce microspheres having particle diameters in the
range of “about 1 to 500 microns,” suggesting that size distribution of this product is poorly
controlled (Osborne Declaration, page 2, paragraph 5). In contrast, the numerical
limitations in the claims before us reflect that applicants’ hollow microcapsules have a
tightly controlled size distribution.
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