toothpaste-3067570_1280.jpg
Blog

What Does “Stable” Mean in a Composition Claim? – Clearly Defining Claimed Parameters

August 3, 2021by Jacob Doughty

Ex parte Ratcliff, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing whether the requirement that a component of a claimed composition “remains stable in the composition” was indefinite.

In Ex parte Ratcliff, the claim at issue was directed to an oral rinse composition. The relevant claim recited:

An oral rinse composition for enhancing tooth remineralization, comprising:

stabilized chlorine dioxide that remains stable in the composition, the stabilized chlorine dioxide capable of reacting with acidic elements of oral biofilms to produce chlorine dioxide gas;

sodium fluoride; and

a pharmaceutically acceptable buffer effective at establishing an effective pH range of the composition from about 6.0 to about 7.4 for maintaining the stability of the chlorine dioxide in the composition;

wherein the stabilized chlorine dioxide and the sodium fluoride in combination are more effective at enhancing tooth remineralization and reducing tooth demineralization than either of the stabilized chlorine dioxide or the sodium fluoride alone.

In this case, the examiner took issue with the above-emphasized phrase “stabilized chlorine dioxide that remains stable in the composition.” Particularly, the examiner asserted that “… the claim does not provide a discernable boundary on what provides the functional characteristic to the stabilized chlorine dioxide (SCD),” wondering whether stabilized chlorine dioxide is stable in the composition:

… due to the addition of some other structure (such as pH modifiers, stabilizers, etc.), absence of destabilizing agents (such as stannous chloride), other features of the composition (such as specific pH ranges)… due to a sequence of steps by which it is made or by some other means, or a certain combination of these.

Applicant argued that “stability” was adequately defined in the specification as the “ability to maintain levels of the… chlorine dioxide source… within the levels specified by the present invention when the final composition is placed under…” specified storage conditions. However, the PTAB noted that the “levels specified by the present invention” were not defined in the claim or specification (or identified by applicant in its appeal briefing).

The PTAB searched the specification for further guidance and found a general disclosure of amounts of the chlorine dioxide source (0.005% w/w to 0.800% w/w) and disclosure that a reduction in the amount of stabilized chlorine dioxide after storage (0.125% w/w >> 0.04% w/w) indicated that stability was achievable. However, the PTAB found that there was insufficient guidance in the specification regarding “how much stabilized chlorine dioxide must remain in the composition after being stored under the specified conditions, in order to be stable according to the definition of stability provided in [the specification].” Thus, the PTAB affirmed the examiner, finding the claim so ambiguous that it failed to inform a skilled artisan about the scope of the claimed invention with reasonable certainty.

The PTAB reversed the only other rejection on appeal – an obviousness rejection. However, this was a pyrrhic victory. The PTAB stated that “the scope of the claimed subject matter is so uncertain that we cannot meaningfully perform the required comparison between the composition recited in [the claim] and the compositions of the cited prior art.”

Takeaway: It was apparent in this case that the PTAB was looking for a number – how much stabilized chlorine dioxide would need to remain in the composition after storing under specified conditions for the stabilized chlorine dioxide to be deemed “stable in the composition”? For claims as in this case, it can be helpful to consider how the difference between “stable” and “not stable” will be explained to a lay jury. If it will be hard to show a lay jury the line between infringing and not infringing, it may be preferable to claim the composition differently (maybe product-by-process).

In this case, both the examiner and the PTAB relied on their own judgment of how a skilled artisan would have viewed the meaning of stability. While applicant provided experimental evidence to show that certain prior art compositions did not include stabilized chlorine dioxide that remains stable, a succinct statement from a skilled artisan regarding how to determine whether stabilized chlorine dioxide “remains stable in the composition” may have framed the issue of indefiniteness in a more favorable manner.

Judges: Adams, Prats, Townsend

CONTINUE READING
pexels-nikolaj-jepsen-4370289.jpg
Blog

PTAB Reverses Examiner’s Inherency Rejection

August 28, 2020by Matthew Barnet

Patent claims often recite structural limitations in combination with one or more properties. For example, a product claim might recite a composition comprising three components, where one of the components is specified as having certain physical properties. In such cases, U.S. patent examiners often reject the claims as either anticipated or obvious based on prior art describing the structural limitations but not describing the properties.

CONTINUE READING
foliage-5009109_1280.jpg
Blog

Revisiting “Informative” Board Decisions: Indefiniteness and Parameter Patents

July 13, 2020by Jacob Doughty

Ex parte Bobrowski is a 2008 decision of the Board of Patent Appeals and Interferences (BPAI) that is listed among the Patent Trial and Appeal Board’s (PTAB) informative decisions. Ex parte Bobrowski is indicated by the PTAB to be informative as to “35 U.S.C. § 112 – indefiniteness – In re Steele.”

The BPAI considered whether claims reciting particular parameters were indefinite and, thus, unpatentable under pre-AIA 35 USC § 112, second paragraph (which, like AIA 35 USC § 112(b), requires one or more claims “particularly pointing out and distinctly claiming the subject matter [regarded as the] invention”).

While the decision focused entirely on indefiniteness, the appeal was, in fact, an appeal of prior art rejections. However, the BPAI found the claims to be insufficiently clear and definite – even after consulting the specification – to allow comparison with the prior art. In framing its analysis, the BPAI cited In re Steele, 305 F.2d 859 (CCPA 1962), for the proposition that it is erroneous to analyze claims based on “speculation as to the meaning of the terms employed and assumptions” as to their scope (In re Steele is also cited for this proposition in MPEP 2143.03 and 2173.06).

A representative claim, as separated into its constituent parts by the BPAI, recited:

An extract of plant material from family Euphorbaciae and species Croton

(1) that reduces at least one opioid-induced complication selected from the group consisting of[:] nausea, emesis, retching and itch,

(2) the extract at a concentration of 1mg/mL of 50% (v/v) ethanol/water having reduced UV absorbency of about at least 4.3 between the range of 390 nm and 430 nm relative to the absorbency within the same range for unextracted plant material.

The BPAI first construed the terms “extract” and “plant material” in the preamble of the claim. Consulting the specification, the BPAI found that it was clear that the application dealt with a solvent extraction process, so the term “extract” was construed to mean a solvent extracted portion of plant material from Croton. The BPAI construed “plant material” to mean any part of a plant. The BPAI then addressed “ambiguities” in feature (2).

During examination, the examiner found that feature (2) should be given no patentable weight, because it did not make clear the amount of Croton relative to the claimed composition. The BPAI disagreed, noting that feature (2) – though ambiguous – was intended to characterize UV absorbency (a parameter), which could properly define the recited extract.

The BPAI looked to the specification in its consideration of how a skilled artisan would interpret and apply feature (2). The specification described an extraction process in which latex or sap from Croton was mixed with an organic solvent in a 1:1 proportion and, separately, the specification described a relative absorbency of a “concentration of 1 mg of extracted latex to 1 mL of water.”  The specification further described the comparative UV absorbency of proanthocyanidin between the “parent latex” and the extract, noting that “the reduced proanthocyanidin content is quantifiable spectrophotometrically.”

The BPAI noted that, even with the benefit of such description, the claim did not tell a skilled artisan what the baseline should be for comparison of the extract’s UV absorbency. While the specification discussed comparison with a “latex,” the claim referred without antecedent basis to “unextracted plant material,” which could be any plant material. The BPAI noted that applicant presumably intended something broader than “latex,” when it selected the term “unextracted plant material” for its claim and, thus, refused to import a limitation from the specification. In the absence of specificity as to the baseline for comparison, the BPAI concluded that it was not possible to compare the claimed invention with the prior art.

While the ambiguity as to baseline was fatal, the BPAI also noted that, even if the baseline was limited to a “latex,” neither the claim nor the specification described the amount, concentration, or method of preparation of the “unextracted plant material.”

Further, the BPAI stated that the “reduced UV absorbency of about at least 4.3… relative to the absorbency… for unextracted plant material,” was unclear because no units for “4.3” were provided. The BPAI noted that, while the specification described a 4.3 “fold” reduction in absorbance, absorbency was also described in in terms of “absorbance units” or “AU” in the art.

Thus, the BPAI concluded that the claim was so unclear that it could not be interpreted to resolve issues raised on appeal with respect to the examiner’s prior art rejections.

 Takeaway: Claims reciting new or unconventional parameters can be useful tools for protecting new discoveries and improvements in existing technologies. Also, it can be difficult for competitors to quickly confirm freedom-to-operate/practice when confronted with claims reciting new or unconventional parameters. However, clarity in defining how new or unconventional parameters are measured is essential – both in the specification and the claims themselves. Extra, pre-filing review of parameter claim language is recommended, particularly when a US application is a translation of a prior application in a language other than English.

Judges: Torczon, Lane, Moore

CONTINUE READING