PTAB

PGR2026-00021

Sun Pharmaceutical Industries Inc v. Biofrontera Bioscience GmbH

Key Events

Petition

Title: Topical Nanoemulsion Formulation
Brief Description: The ’146 patent describes a topical oil-in-water nanoemulsion formulation for delivering the active ingredient 5-aminolevulinic acid (ALA). A key feature of the invention is that the formulation comprises "essentially no propylene glycol and essentially no sorbitol" to prevent degradation of the ALA.

Prior Art Relied Upon: Uhlmann (5,520,905).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Example 5 of Uhlmann, which describes a "Day-car[e] skin cream O/W," discloses every limitation of independent claim 1. Uhlmann's formulation is an oil-in-water emulsion containing ALA, which meets the ’146 patent’s definition of a "nanoemulsion." The formulation explicitly includes an aqueous component (water), a lipophilic component (caprylic/capric triglyceride), surfactants (PEG-5 glyceryl stearate, glyceryl stearate), and alcohols (cetyl alcohol, ethanol, glycerine). Crucially, the complete list of ingredients in Example 5 does not include propylene glycol or sorbitol, thereby meeting the negative limitation of "essentially no" of these components. Petitioner asserted that Uhlmann also anticipates the dependent claims by disclosing specific concentration ranges for the aqueous and lipophilic components and the use of a 3-carbon alcohol (glycerine).

Prior Art Relied Upon: Uhlmann (Patent 5,520,905).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner contended that these dependent claims, which require the formulation to have less than 1% (or essentially none) of a non-cyclic polyol with 2-12 carbons, would have been obvious based on Uhlmann's Example 5. The only component in Example 5 meeting the definition of a non-cyclic polyol is glycerine (4% w/w).
- Motivation to Combine (for §103 grounds): A POSITA would have been motivated to remove or replace the glycerine in Uhlmann’s Example 5. First, Uhlmann itself teaches that alcohols (like isopropanol, which is not a polyol) and polyols (like glycerine) are interchangeable and preferred components for its emulsions. Second, a POSITA would have known that glycerine (also called glycerol) causes degradation of ALA, the active ingredient. Removing a known destabilizing agent to achieve a more stable formulation was argued to be an obvious modification.
- Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success in replacing glycerine with another suitable alcohol like isopropanol, as this was a simple substitution of one known, interchangeable excipient for another to achieve the predictable result of improved stability.

Prior Art Relied Upon: Uhlmann (Patent 5,520,905).
Core Argument for this Ground:
- Prior Art Mapping: In parallel to the arguments based on Example 5, Petitioner argued that Uhlmann’s Example 3, a "Sun Milk O/W" formulation, also anticipates the same set of claims. This oil-in-water emulsion contains all the required components of claim 1: an aqueous component (water), a lipophilic component (caprylic/capric triglyceride), surfactants (PEG-40 castor oil, sodium cetearyl sulphate), alcohols (cetearyl alcohol, glycerine, ethanol), and the active ingredient ALA. Like Example 5, the formulation disclosed in Example 3 is a complete formulation that does not contain propylene glycol or sorbitol, thus satisfying the negative limitation.
Additional Grounds: Petitioner asserted additional obviousness challenges based on modifying Uhlmann's Example 3 (Ground IIB) and combining Uhlmann's examples with Palazzolo (2003/0198654) to establish conventional concentration ranges for excipients (Grounds IC and IIC).

"nanoemulsion": Petitioner argued this term should be construed as "a dispersion of oil in water" based on the patent owner’s explicit lexicography in the ’146 patent specification. This construction is central to the argument, as it allows Uhlmann’s "oil-in-water emulsion" and "O/W emulsion" formulations to directly meet this claim limitation.

Petitioner requests institution of post-grant review and cancellation of claims 1-17 of the ’146 patent as unpatentable.