Appeal No. 95-1820
Application 08/115,836
than 150 microns average and a length to width aspect ratio of
from about 4 to 1 to about 5 to 1 comprising
(a) forming a saturated solution of ibuprofen in a
liquid hydrocarbon solvent at a temperature from about 20EC to
about 60EC;
(b) seeding said saturated solution with solid
ibuprofen;
(c) cooling said saturated solution to a temperature of
about 0EC to about -20EC at a rate to retard primary nucleation
and promote secondary nucleation to obtain a slurry; and
(d) separating the crystalline ibuprofen from the liquid
phase of the slurry.
15. Crystalline ibuprofen having a crystal habit
characterized by having a particle length larger than 150 microns
average and a length-to-width aspect ratio of from about 4.1 to 1
to about 5 to 1.
The examiner relies upon the following reference as evidence
of obviousness:
Gordon et al. (Gordon) 4,476,248 Oct. 9, 1984
Appellants' claimed invention is directed to crystalline
ibuprofen having a specific crystal habit, and a process for
preparing the crystalline ibuprofen. The crystalline ibuprofen
of the present invention has an average particle length greater
than 150 microns and a length to width aspect ratio of from about
4 to 1 to about 5 to 1. The process entails seeding a saturated
solution of ibuprofen in a liquid hydrocarbon solvent followed by
cooling the saturated solution at a rate which retards primary
nucleation and promotes secondary nucleation. According to the
-2-
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