Appeal No. 1996-3973
Application No. 08/048,657
Phillips both describe determining glucose in human sera/blood using a coupled glucose oxidase
- peroxidase enzyme system and an oxygen acceptor, e.g., 3-methyl-2-benzothiazolione
hydrazone (MBTH) (see page 392-384 in Ngo and col. 6, lines 45-65 in Phillips). Both Ngo and
Phillips additionally couple MBTH to 3-(dimethylamino)benzoic acid (DMAB). According to
Ngo use of the MBTH-DMAB couple increases the sensitivity and versatility of the glucose
assay and is safer because MBTH-DMAB are not carcinogenic like other reagents, e.g., o-
diansidine, widely used as chromogens for peroxidase-catalyzed reactions (abstract; page 394).
According to Phillips, use of the MBTH-DMAB couple allows for correction of hematocrit and
degree of oxygenation of blood (col. 10, lines 57-59). Therefore, it would have been obvious to
one of ordinary skill in the art to modify the generic test slide described by Tietz or Eggert to
assay for a clinically significant analyte, i.e., glucose, using a conventional glucose oxidase-
peroxidase-MBTH reagent system as described by Evans, Ngo and Phillips, and to further use an
MBTH-DMAB couple as suggested by Ngo and Phillips to improve the sensitivity, versatility,
safety and specificity of the assay, wherein the enzyme and chromogen reactions are separated
into an enzyme and a dye-couple layers, respectively, as suggested by Eggert, and because
Przybylowicz suggests that separation of reaction steps into separate, discrete layers can enhance
the overall assay reaction.
Claims 1, 2 and 14-19 are rejected under 35 U.S.C. § 103 as being unpatentable over
Przybylowicz, Phillips, Eggert and Tietz. Przybylowicz, Phillips, Eggert and Tietz have been
discussed above. Przybylowicz also describes conventional processes for preparing multilayered
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