Appeal No. 2006-0762 Page 5
Application No. 09/982,113
As to claims 139 and 140, appellants assert that “[t]he examiner has not
even attempted to make a prima facie rejection of the subject matter of these
claims.” Id. at 7.
Appellants’ arguments are not found to be convincing. Mehta teaches that
the liposomes used to encapsulate the retinoid may be made by methods that
are well known in the field, see Col. 6, lines 24-35, and also teach that the
liposomes used in the invention include multilamellar liposomes, see Col. 3, lines
26-27. As defined in the instant specification on page 32, “[a] multilamellar
liposome has multiple lipid layers separated by aqueous medium,” and that
“[t]hey form spontaneously when lipids comprising phospholipids are suspended
in an excess of aqueous solution.” Thus, Mehta does teach liposomes in which a
retinoid is encapsulated by a combination of lipid material and water.
In Example I found at Column 7, Mehta exemplifies the preparation of
liposomal-all trans-retinoic acid, in which a solution of retinoic acid was added to
a dry lipid film containing DMPC, and then lyophilized to a powder, which Mehta
characterizes at column 7, line 18, as a preliposomal powder. Thus the
lyophilized powder made using the t-butanol alone does not, as argued by
appellants, contain already formed liposomes. Mehta teaches in Example I that
the powder was mixed with normal saline “to form multilamellar liposomes
containing trans-retinoic acid.” Mehta therefore teaches a liposomal retinoid in
which the lipid material comprises DMPC and water, and Ulukaya is not needed
to teach the use of water in the lipid material.
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