Appeal No. 2006-2213 Page 7
Application No. 09/771,151
precipitated compound, and selecting a liposome size that corresponds to liposomes
having no precipitated compound.3
Regarding the claimed step of preparing liposomes at selected sizes, page 12 of
Abra (cited in the examiner’s rejection) states at lines 13-14, that “[t]he liposomes,
following diafiltration and dialysis, were extruded through 0.2 μm and 0.1 μm
polycarbonate filters to size the liposomes to between about 100-120 nm.” (Emphasis
added.) In our view, this disclosure meets the limitation in claims 1 and 16 requiring
the preparation of liposomes of selected sizes.
Regarding the claimed step of analyzing the liposomes for the presence or
absence of precipitated compound, Abra performed a number of analyses on the
liposomes described on page 12. Specifically, Abra determined (page 12, lines 17-18)
the concentration of cisplatin within the internal phase of the liposomes. (“The final
liposomes contained an internal phase of cisplatin encapsulated at a concentration of
8.5 mg/ml in 0.9% sodium chloride . . . .”). Abra also evaluated the stability of the
liposomes (page 12, line 23, through page 14, line 8). The stability analysis required
“determining the percent of encapsulated platinum” (page 12, lines 25-26), as well as
verifying that the encapsulated platinum was “in the form of cisplatin” (page 13, lines 32-
33).
3 Regarding Appellants’ statement that “Abra et al. fail to teach each of steps (ii), (iii) and (iv) as set forth
in independent claims 1 and 16” (Brief, page 8), we note that the second, third, and fourth steps of claim 1
actually correspond, albeit not identically, to the third, fourth and fifth steps of claim 16. Despite
Appellants’ numbering scheme, however, it is clear from their argument that Appellants assert that Abra
does not disclose the claimed steps of preparing liposomes at selected size intervals, analyzing the
liposomes for the presence or absence of precipitated compound, and based on the analyzing, selecting
a liposome size that corresponds to liposomes having no precipitated compound.
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