There is no universally accepted or standard level of imprecision afforded to numerical values in claims. Any desired flexibility in numerical values should be expressly recited (e.g., using the term “about”) and supported in the description. Ultimately, “[t]he construction that stays true to the claim language and most naturally aligns with the patent’s description of the invention will be, in the end, the correct construction.”
Background / Facts: The patents being asserted here are directed to the formulation for the brand-name drug Prevacid® SoluTab™, which contains the active ingredient lansoprazole, a proton pump inhibitor used to treat acid reflux, and is the only proton pump inhibitor available as an orally disintegrable tablet. In this regard, the claims recite “fine granules having an average particle diameter of 400 μm or less.”
Issue(s): Whether the claimed particle size should be afforded a ±10% deviation rather than requiring an average particle diameter of precisely the recited “400 μm or less.”
Holding(s): No. “Beginning with the claim language itself – as we must – there is no indication in the claim that 400 μm was intended to mean anything other than exactly 400 μm. To the contrary, the phrase ‘400 μm or less’ is not qualified by the word ‘about’ or any other indicator of imprecision. Moreover, the specification confirms that the inventors did not intend to deviate from that clear and unambiguous plain meaning” by “contrast[ing] the ‘fine granules’ of the claimed invention with larger ‘conventional’ granules, which it defines as ‘400 μm or more of average particle diameter.’” “That clear dividing line between the ‘fine’ granules of 400 μm or less (which avoid a feeling of roughness in the mouth) and ‘conventional’ granules of 400 μm or more (which do not) disappears if the ‘fine granules’ are construed as incorporating a 10% deviation. Thus, there can be little doubt that the narrower construction ‘most naturally aligns with the patent’s description of the invention.’” Secondarily, the court also went on to note mathematical inconsistencies that would arise under the broader interpretation as well as statements in the prosecution history that discussed a dividing line at precisely the 400 μm threshold.