PTAB

PGR2026-00021

Sun Pharmaceutical Industries Inc v. Biofrontera Bioscience GmbH

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Topical Nanoemulsion Formulation
  • Brief Description: The ’146 patent discloses a topical oil-in-water nanoemulsion formulation for delivering the active ingredient 5-aminolevulinic acid (ALA). The formulation is characterized by the explicit exclusion of propylene glycol and sorbitol, which are described as causing degradation of ALA.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1, 4-7, and 14-17 over Uhlmann (Example 5)

  • Prior Art Relied Upon: Uhlmann (Patent 5,520,905).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Example 5 of Uhlmann, which discloses a “Day-car[e] skin cream O/W” formulation, teaches every limitation of the challenged claims. Independent claim 1 requires a nanoemulsion comprising an aqueous component, a carrier component (with a lipophilic component, surfactant, and alcohol), and ALA, while being essentially free of propylene glycol and sorbitol. Petitioner asserted that Uhlmann’s Example 5 is an oil-in-water emulsion containing water (aqueous component), caprylic/capric triglyceride (lipophilic component), PEG-5 glyceryl stearate (surfactant), cetyl alcohol/ethanol/glycerine (alcohols), and δ-aminolevulinic acid (identical to ALA). The petition contended that the complete ingredient list in Example 5, which sums to 100% with water, inherently discloses the absence of propylene glycol and sorbitol, thus anticipating the negative limitations of claim 1. Petitioner further mapped specific components and concentrations from Example 5 to show anticipation of dependent claims 4-7 and 14-17, such as the 3-carbon alcohol (glycerine), the aqueous component amount (calculated to be within 70-95%), and the lipophilic component type (triglyceride).

Ground 2: Anticipation of Claims 1, 4-7, and 14-17 over Uhlmann (Example 3)

  • Prior Art Relied Upon: Uhlmann (Patent 5,520,905).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner presented a parallel anticipation argument based on Uhlmann's Example 3, a "Sun Milk O/W" formulation. It was argued that this example also explicitly discloses all elements required by claim 1. The formulation is an oil-in-water emulsion containing water (aqueous component), caprylic/capric triglyceride (lipophilic component), multiple surfactants (PEG-40 castor oil, sodium cetearyl sulphate), multiple alcohols (cetearyl alcohol, glycerine, ethanol), and δ-aminolevulinic acid (ALA). Similar to the argument for Example 5, Petitioner contended that the complete formulation disclosed in Example 3 does not include propylene glycol or sorbitol and therefore anticipates the negative limitations. Petitioner asserted that this formulation also meets the limitations of the challenged dependent claims, citing the presence of glycerine (a 3-carbon alcohol), the calculated water content (within 50-99%), the use of caprylic/capric triglyceride, and the presence of a polyoxyethylene-type surfactant (PEG-40 castor oil).

Ground 3: Obviousness of Claims 2, 3, and 8-13 over Uhlmann (Modified Example 5)

  • Prior Art Relied Upon: Uhlmann (Patent 5,520,905).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that the challenged dependent claims, which require specific low amounts of or the absence of a "non-cyclic polyol having 2 to 12 carbon atoms," would have been obvious over Uhlmann's Example 5. The petition identified glycerine as the only component in Example 5 that meets the definition of a non-cyclic polyol within the claimed carbon range. The core of the argument was that a person of ordinary skill in the art (POSITA) would have been motivated to modify the Example 5 formulation by replacing glycerine with a simple alcohol like isopropanol, which is not a polyol.
    • Motivation to Combine: The motivation was twofold. First, Uhlmann explicitly taught that alcohols (like isopropanol) and polyols (like glycerine) are suitable and interchangeable components for its emulsions. Second, Petitioner argued it was well-known in the art that glycerine (also called glycerol) caused the degradation of ALA. A POSITA would therefore have been motivated to remove the known destabilizing agent (glycerine) and substitute it with a known, suitable alternative (isopropanol) to create a more stable ALA formulation.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because this modification involved the simple substitution of one known, preferred excipient for another to achieve the predictable result of improved stability. The resulting formulation, lacking any non-cyclic polyol, would render claims 2, 3, and 8-13 obvious.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on modifying Uhlmann’s Example 3 in a similar manner and combining Uhlmann with Palazzolo (Application # 2003/0198654) to teach specific amounts of preservatives or perfumes.

4. Key Claim Construction Positions

  • "nanoemulsion": Petitioner argued this term should be construed as "a dispersion of oil in water." This construction was based on the patent’s specification, where the patent owner acted as a lexicographer by stating: "[a]s used herein, a ... 'nanoemulsion' is a dispersion of oil in water (oil-in-water dispersion, oil-in-water emulsion, O/W emulsion)." This construction is central to the anticipation arguments, as it allows prior art oil-in-water (O/W) emulsions to meet the "nanoemulsion" limitation.

5. Relief Requested

  • Petitioner requests the institution of a Post-Grant Review and cancellation of claims 1-17 of the ’146 patent as unpatentable under 35 U.S.C. §§ 102 and 103.