Appeal No. 95-4433
Application No. 07/994,040
of water as required by appealed claim 2. This is because
Desposato, although disclosing the existence of erythromycin
dihydrate (see line 6 in column 3), contains no disclosure
regarding the crystalline form of this compound much less
crystalline azithromycin dihydrate. Similarly, although
patentee discloses crystallizing erythromycin ethyl succinate
from an aqueous mixture containing tetrahydrofuran as solvent
or ethyl acetate as solvent combined with hexane (e.g., see
lines 37 through 56 in column 1), Desposato contains no
disclosure of using a mixture of tetrahydrofuran and a C -C
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aliphatic hydrocarbon in the presence of at least two molar
equivalents of water in order to prepare crystalline
azithromycin dihydrate.
As rebuttal evidence, the appellants have advanced a
number of declarations. These declarations include the
Forcier Declaration signed March 19, 1992 and the Hangac
Declaration signed February 16, 1994 which compare
respectively the hygroscopicity and stability characteristics
of crystalline azithromycin dihydrate and azithromycin
monohydrate. Notwithstanding the examiner’s criticisms
thereof, these declarations quite plainly show that the
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