Appeal No. 2005-0590
Application 09/854,435
We further find that Heller would have disclosed polyorthoester polymers which are
prepared from a diketene acetal and a mixture of diols to form a random polymer (e.g., col. 2, ll.
11-22, col. 5, l. 18, to col. 7, l. 63, and col. 8, l. 52, to col. 9, l. 26). One of ordinary skill in this
art routinely following the teachings of Heller would have arrived at polyorthoesters which
contain units that correspond to “A units” “R1,” “R2” and “R3” to provide units of the structure
shown in of structural formula (I) of appealed claim 1, wherein the former unit is derived from
an α-hydroxyacid containing diol and the latter two units are hard or rigid units and flexible
or soft units, respectively, and (e.g., col. 5, l. 58, to col. 6, l. 32, col. 6, l. 33 and 45-65, and col.
4, ll. 1 and 11-27). The amounts of and arrangement of the respective units in the
polyorthoesters are disclosed to be based in the properties desired for bioerodibility and in the
fabrication of medical devices such as implants, and controlled release drug delivery forms,
wherein the polymer can be cross-linked (e.g., col. 1, ll. 16-22, col. 2, ll. 12-18, col. 5, ll. 31-32,
col. 7, ll. 55-67, and col. 10, ll. 15-54). Thus, because the units is derived from α-hydroxyacid
containing diols can be present at least in some amount, the polyorthoesters of Heller differ from
the claimed polyorthoesters encompassed by claim 1 in the absence of unit(s) corresponding to
“A unit” “R4,” that is, hydrogen bonding unit(s) containing at least one amide, imide, urea and
urethane group.
The examiner finds that, prima facie, one of ordinary skill in the art would have modified
the polyorthoester polymers of Heller by using the hydrogen bonding unit(s) containing at least
one amide, imide, urea and urethane group as taught by Sparer in the expectation of obtaining
bioerodible polyorthoester polymers, pointing out that the polyorthoesters of each reference are
prepared in the same manner from diketene acetals and diols (Office action, mailed September
27, 2002; pages 2-3; see also answer, pages 3-4).
We find in the combined teachings of Heller and Sparer substantial evidence supporting
the examiner’s position with respect to appealed claim 1 as we have interpreted this claim above.
We determine that in view of the common polyorthoester chemical structure, the common
bioerodible-based utility, the common method of preparation as random polymers, and the
common direction in these references to use the same type of groups that provide bioerodibility
to the polyorthoesters for purposes of the common utility, there is in the combined teachings of
Heller and Sparer ample direction to one of ordinary skill in this art to use the hydrogen bonding
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