Appeal No. 2006-2213 Page 8
Application No. 09/771,151
In view of Abra’s extensive analysis of the liposomes (pages 12-16), it is
reasonable to expect that precipitated cisplatin would have been detected if it had been
present. Abra’s liposome analysis therefore reasonably appears to be a step of
“analyzing . . . liposomes for the presence or absence of precipitated compound,” as
recited in claim 1.
As pointed out by Appellants, Abra states on page 4, lines 34-35, that “[t]he drug
is entrapped in the inner aqueous compartment [26] in dissolved form or in precipitated
form.” At no point, however, does Abra describe the cisplatin in the liposomes as
precipitated. In fact, Abra expressly states that the cisplatin that was entrapped in the
liposomes was in dissolved form, not solid (precipitated). See page 12, lines 7-12: “An
aqueous solution of cisplatin (8.5 mg/ml cisplatin in 0.9% sodium chloride) was
warmed. . . . The cisplatin solution and the lipid solution were added together to form
liposomes” (emphases added). Abra states that the liposomes were cooled and the
“final liposomes contained an internal phase of cisplatin encapsulated at a concentration
of 8.5 mg/ml in 0.9% sodium chloride.” Page 12, lines 17-18. That is, the internal
phase of the liposomes was the “aqueous solution of cisplatin” that was used to form
the liposomes.
Abra also describes the claimed step requiring selection of a liposome size that
corresponds to liposomes having no precipitated compound. As noted above, Abra
selected liposomes with a particle size of 100-120 nm (page 12, lines 13-14). (“The
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.) Liposomes within the range of 100-120 nm are disclosed in Appellants’
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