CAFC Voids Certificate of Correction

Central Admixture Pharmacy v. Advanced Cardiac Solutions (Fed. Cir 2007).

Central Admixture (CAPS) owns a patent covering a glucose-protein solution used to help overcome ischemia during heart surgery. During prosecution, CAPS made a Freshman-Chem error — claiming the fluid concentration range in units of osmolarity (solute per liter of total solution) instead of osmolality (solute per kilogram of solvent). In this case, for instance, the unit change moves the claimed range by only a few percent. However, the defendant’s concentration was on the border-line — making the issue critical.

CAPS applied for and received a certificate of correction.  The certificate, however, was not issued until after the litigation had already begun.

Certificate of Correction: A certificate of correction can be used to correct a minor mistake such as a “clerical or typographical” error or other minor error. In Superior Fireplace, the court held that a certificate of correction that broadens the claim is only permissible when it is clear from the specification and prosecution history how to correct the error.

Broadening: Here, the CAFC found that the correction broadened the claims because they now cover “less-concentrated solutions which would not be covered under the original claims.” [DDC: Of course, a range should not be considered broadened if you are merely shifting the range].

Clear Error Correction: CAPS error is not plain to a reader since solutions have both an osmolality and and osmolarity.  The error can be seen when examining the units used in the specification (mOsmol/L, rather than mOsmol/kg), but the CAFC saw the difference between these units as “very slight.” (noting that the difference between miles and meters is much different).

Since the error corrected here was not clearly evident to one of skill in the art and the result of its correction was to broaden the claims, ACS should be granted summary judgment that the certificate of correction is not valid.

The relief for an improper certificate of correction is simply to cancel the certificate.  Thus, in this case the patent “continues to read as it did prior to the issuance of the certificate.”

Voidable Title: The research that led to the patent was funded by an NIH grant. The NIH indicated that it would waive its rights to obtain patent protection, but the inventor (Dr. Buckberg of UCLA) failed to properly perfect the waiver.  In Campbell Plastics, the CAFC held that a similar error would allow the Government to obtain title to the patent. However, in this case, the inventor retains title until the day that the NIH goes after it.


  • The certificate of correction was issued in 2001. The CAFC did not mention that a reexamination certificate was issued in 2005 that made no-change to the corrected patent. 
  • Factually, is an osmolarity of 400-500 mOsmol broader than an osmolality of 400-500 mOsmol?
  • Footnote 5: ‘The result might be different if the patentee’s choice of unit resulted in a clearly incorrect claim—“fifty miles” instead of “fifty meters,” for instance. Here, though, the difference between an osmolarity of 400 mOsmol/L and an osmolality of 400 mOsmol/kg is very slight.’

12 thoughts on “CAFC Voids Certificate of Correction

  1. 12

    RE: [DDC: Of course, a range should not be considered broadened if you are merely shifting the range].

    DDC, in the past 10 years I have gained 5 inches around my waist, lost 3 around my chest, and 1 inch around each bicep. It is a great personal relief to me that I should not consider myself broadened, merely “shifted.”

  2. 11

    Notes from a PhD Chemist and law student:

    “Now you may argue that 1 liter of water has a mass of 1 kilogram, so there is no difference.”

    In addition to the difference John Spevack highlighted (which doesn’t account for much difference between molar and molal), if the fluid is not water or something else that has a density near 1.0 kg/L, the molarity and molality of the same solutions can be quite different.

    For instance, organic solvents often have densities over 1.5 (e.g. carbon tetrachloride = 1.584 kg/L). Thus, a solution of 400 mol of solute in 1 L of carbon tetrachloride would have a molarity of 400.0 mol/L but would have a molality of 252.5 mol/kg, a 37% change.

    Changing a 400.0 – 500.0 molar carbon tetrachloride solution to molal would give a range of 252.5 – 315.7 mol/kg.

    This chemistry problem likely has little real-world significance because we’re talking often talking about pharmaceutical solutions which are in water or buffers that have a density very close to 1.0 kg/L.

    Why do I hear a mixture of snores and crickets?

  3. 10

    Good comments from everyone. My two cents: Comments from John Spevack highlight the benefit (need?) to have technically adept patent prosecutors. I’d probably have to hit the books pretty hard to understand the chemistry. Kudos to John for making it seem like basic college level info.

  4. 9

    (thoughts from a Ph.D. chemical engineer):

    To make a MOLAR solution, you add the correct amounts (masses) of salts, sugars,… to a special flask marked known as a volumetric flask. You then add some water, (shake to dissolve the salts) and then add more water until the water is level with the etched mark on the neck of the flask, typically 1 liter. To make a MOLAL solution, you just add the correct masses of salt and water (typically 1 kilogram) in whatever container you want and shake/stir well.

    Now you may argue that 1 liter of water has a mass of 1 kilogram, so there is no difference. That is not correct. In the MOLAR case, the salts take up some space, so if you were to add 1 liter of water to the volumetric flask, you would end up adding too much water and going past the mark on the neck.

    The examples in the patent may look like MOLAL solutions since the recipe calls for 1000 ml of water, BUT there is a (qs) after that, indicating that only a “Quantity Sufficient” to make a full liter of solution is needed. The text also indicates this clearly for all the examples.

    All of this can be calculated/predicted using whopping dose of thermodynamics combined with relevent data for the partial molr volume changes, ionic interaction characteristics… (Gee, I just 100 lawyers’ eyes glazing over. Usually it’s the other way around!)

  5. 8

    Assuming this to be the case, then certainly the use of a Certificate of Correction was not the proper avenue to pursue.

    Not if your planning to get all aggro and start sueing people for infringement.

    They did get their certificate, after all, and they were probably offered some money to license it. It’s a relatively cheap band-aid and band-aids serve a useful purpose. You probably shouldn’t go swimming nematode-infested water, however.

  6. 7

    Please correct me if I am wrong, but are not the terms “osmolarity” and “osmolatity” different in meaning for reasons other that just using different units? In other words, it is not the equivalent of expressing kilometers per hour as miles per hour. The transposition from osmolarity to osmolality is not a linear function.

    Assuming this to be the case, then certainly the use of a Certificate of Correction was not the proper avenue to pursue.

  7. 6

    RE broadening – technically, any change to a claim that results in that claim encompassing anything that it didn’t encompass before the amendment is “broadening.” Therefore, even changing the range from 400-500 to 399.999-400.001 is “broadening” (assuming no DOE expansion of 400-500). Same goes for changing it to 200-200.00001.

  8. 5

    crs asked “If the correct units were consistently indicated (thus supported) in the specification, what was the fuss about?”

    Taking an admittedly quick look at the patent, I can see only refrences to molarity, osmolarity, and liters. Indeed, there is absolutely nothing in there to give me any inkling that molality should be taken into consideration at all, so I don’t see how the patentee could have hoped that their argument that correction was available would fly. In other words, the patent is consistent – for using osmolarity and not the osmolality that they wanted it corrected to.

    Given the two are so similar, there appears to simply be no way of knowing, by say looking at the concentrations expressed in the examples etc, that there is any error, let alone one that should be corrected in a particular way.

    (I guess if one looked at say the example where they give a calculated osmolarity of 380 mOsmol, one could theoretically say that the figure if calculated in terms of molality, it should be some figure slightly different – but given this is for a solution not all of whose components are clearly pelt out, I am not sure if this could be done in actuality)

    As for Dennis’ concern that shifting a merely range shouldn’t be sematically be “broadening” it, the CAFC make it clear in their judgment that by “broadening” a claim, they merely mean encompasses any ground that wasn’t previously encompassed – whether the sum total of all ground now encompassed is more/greater/broader than before is irrelevant. Possibly confusing to those not in the know, yes, but that’s hardly unusual for a legal term of art, is it? Anyway, what term would you use if not “broadening”? “Shifting” or something similar won’t do, because a narrowing amendment shifts the scope as well, albeit not in one concerted direction.

    Regards, Luke

  9. 4

    If the correct units were consistently indicated (thus supported) in the specification, what was the fuss about?

  10. 3

    Since osmolarity and osmolality are not strictly linear functions of molarity and molality, it is likely that the breadth of the range was changed, not just shifted. As an example in the same vein, a pH range that is shifted from “between 6.1 and 7.1” to “between 6.0 and 7.0” has been broadened in some sense, as it now covers a greater range of H+ concentrations.

  11. 2

    Here’s the claim at issue (before correction):

    In an amino acid enriched cardioplegic solution for use in treating human hearts to prevent or reverse heart muscle damage due to ischemia, said cardioplegic solution having a calcium ion concentration, a metabolizable substrate concentration and an osmolarity, wherein the improvement comprises:

    maintaining said calcium ion concentration of said cardioplegic solution at a lowered level of between about 50-300 umol;

    maintaining said concentration of metabolizable substrate in said cardioplegic solution between about 400-1000 mg % wherein said metabolizable substrate is selected from the group consisting of glucose, fructose, a salt of malic acid, a salt of succinic acid and a salt of pyruvic acid;

    maintaining said **osmolarity** of said cardioplegic solution at an increased level of between about 400-500 mOsmol.


    Even if the correction issue wasn’t raised, everyone knows now that this “comprising” claim is not enabled anyway because its scope includes non-enabled embodiments.

    /snark off

  12. 1

    ‘The result might be different if the patentee’s choice of unit resulted in a clearly incorrect claim—“fifty miles” instead of “fifty meters,” for instance.

    Oh no, you didn’t!!!! Chef America is rolling in its grave.

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