Appeal 2007-0711
Reexamination 90/006,706
ibuprofen’s enantiomeric mixture by SMBC using an achiral liquid mobile
phase composition having a retention capacity (k’) for a chiral isomer of
ibuprofen to be separated such that 0.1<k’<1.0. While Appellants and the
Examiner appear to agree that Pirkle does not describe the separation of at
least one chiral isomer from ibuprofen by the SMBC process, we find that
Pirkle compares the chiral isomer retention capacity (k’) and the resultant
degree of chromatographic chiral isomer separation (α) for several different
achiral liquid mobile phase compositions in a process for separating chiral
isomers from an enantiomeric mixture of ibuprofen (Pirkle, Tables 9, 16, 17,
18). Pirkle’s Tables 9, 16, 17, and 18 show that, for ibuprofen, achiral liquid
mobile phase compositions having k’<1 are most effective for separating its
chiral isomers. Thus, a person having ordinary skill in the art at the time,
considering the data in Pirkle’s tables, reasonably would have expected to
effectively separate the chiral isomers of ibuprofen using an achiral liquid
mobile phase composition having a chiral isomer retention capacity (k’)
value of less than one. As stated, however, neither the Examiner nor
Appellants found that Pirkle disclose a process for separating chiral isomers
from enantiomeric mixtures using a simulated moving bed chromatography
(SMBC) process.
The achiral liquid mobile phase composition employed in Pirkle’s
separation process employing an achiral mobile phase composition includes
a “chiral selector useful in separating underderivatized enantiomers of
nonsterodial anti-inflammatory agents” (Pirkle, Abstract). Pirkle’s chiral
selector “is also useful in achieving the enantiomeric separation of amines,
alcohol derivatives, epoxides and sulfoxides” (Pirkle, Abstract).
Nevertheless, we find that Pirkle would have taught a person having
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