The U.S. Court of Appeals for the Federal Circuit recently highlighted an important rule of patent claim construction: that claim limitations should be construed in a way that avoids rendering claim terms meaningless or superfluous.

Claim terms are presumed to have their ordinary and accustomed meaning based on the plain language of the claim. However, claim interpretation can be more complicated when a claim limitation has more than one possible construction.

On March 4, in Olaplex Inc. v. L’Oreal USA Inc., the Federal Circuit supported its holding by pointing to its previous decision in 2017 in Wasica Financial GmbH v. Continental Automotive Systems Inc.,[1] in which it held that “[i]t is highly disfavored to construe terms in a way that renders them void, meaningless, or superfluous.”

In Olaplex v. L’Oreal, the Federal Circuit vacated the U.S. District Court for the District of Delaware’s summary judgment finding that L’Oreal infringed claims of Olaplex’s U.S. Patent No. 9,668,954, directed to methods for bleaching hair. However, the Federal Circuit at the same time affirmed the lower court’s claim construction of the ‘954 patent claims in favor of Olaplex.

The claim construction issue in Olaplex v. L’Oreal involves a particular problem that can arise when claiming pharmaceutical and consumer product formulations: A chemical compound may be converted to different forms, e.g., salts, once added to a formulation. Claim limitations that aim to specify the amounts or concentrations of such compounds can be problematic when it is unclear how they are to be calculated.


L’Oreal markets products to protect hair that has been colored or bleached. Olaplex alleged in district court that L’Oreal infringed claims of its ‘954 patent through three of L’Oreal’s maleic acid-containing hair treatment systems. Each system consists of three iterative treatments – referred to by the court collectively as the Step 1, Step 2 and Step 3 products – that are applied to the hair during or after the bleaching process.

The claims at issue in this case were the so-called breakage Claims 14-16, 18 and 24-28 of the ‘954 patent. Claim 14, for example, is directed to a method for bleaching hair comprising a first step of adding maleic acid to a bleaching formulation, “wherein the [maleic acid] in the mixture is at a concentration ranging from about 0.1% by weight to about 50% by weight.” Claim 14 further requires that “breakage of the hair is decreased by at least 5% compared to hair bleached … in the absence of [maleic acid].”

The relevant claims require a specified concentration of maleic acid to be present in the mixture. However, both Olaplex and L’Oreal agreed that maleic acid is fully neutralized and converted to maleate, a salt, upon addition to the bleaching formulation. The mixture does not actually contain maleic acid, as recited in the claim, because it is converted to maleate in the basic environment of the bleaching formulation. This fact complicates the meaning of the recited maleic acid concentration.

Claim Construction

L’Oreal argued that the claim should be construed as requiring maleic acid to be present in the mixture at the recited concentration, based on the plain language of the claim.

By contrast, Olaplex argued that the claim should be construed as being based on the weight of maleic acid added into the active agent formulation, relative to the final weight of the mixture comprising the bleaching formulation. The district court agreed with Olaplex, and the Federal Circuit affirmed the construction.

The Federal Circuit acknowledged that under L’Oreal’s proposed claim construction, the claim term “maleic acid” would be rendered meaningless and unsatisfied since, as agreed to by both parties, “there would be no maleic acid in the final bleaching solution.” The court reiterated that a claim construction should be avoided if it renders a claim term void or meaningless.

Olaplex’s claim construction was also supported by an example in the ‘954 patent specification, which describes the amount of maleic acid as by weight prior to mixing with the bleaching formulation.

In addition, the court credited testimony of Olaplex’s expert who explained that a person of ordinary skill in the art would understand that the recited maleic acid concentration refers to the amount of maleic acid in the active agent formulation before it is mixed with the bleaching formulation.

As maleic acid is totally neutralized and transformed into maleate, a salt, upon addition to a bleaching solution, a requirement that the resulting mixture include maleic acid at “a concentration ranging from about 0.1% by weight to about 50% by weight” could never be satisfied. Because L’Oreal’s proposed construction based on the plain language of the claim would render this claim limitation meaningless, it was strongly disfavored.

Infringement and Summary Judgment

With respect to infringement, Olaplex’s expert was able to show by nuclear magnetic resonance that L’Oreal’s Step 1 products contain added maleic acid between 10.2% and 10.6% by weight, well within the claimed range.

In accord with the affirmed claim construction, the Federal Circuit acknowledged that maleic acid salts – maleate, hydrogen maleate – detected in the mixture can serve as a proxy for determining the concentration of maleic acid. Accordingly, the Federal Circuit held that there was no question of material fact as to whether L’Oreal’s Step 1 products contain the claimed amount of maleic acid.

However, the Federal Circuit agreed with L’Oreal that questions of material fact existed as to whether its products met other ‘954 patent claim limitations, including whether use of its Step 1 and Step 2 products would have decreased breakage of hair by at least 5% as required by Claim 14.

The Federal Circuit also agreed with L’Oreal that its Step 3 products did not infringe because they were at-home products outside of the scope of the claimed hair bleaching methods.

The Federal Circuit therefore vacated the district court’s summary judgment finding of infringement. The Federal Circuit also vacated the lower court’s permanent injunction that blocked L’Oreal from making and/or selling its Step 1, 2 and 3 hair products. The matter was remanded to district court for further proceedings.

Important Considerations After Olaplex

For patent prosecutors drafting formulation claims, it is important to consider what the actual components of your formulation are, keeping in mind that chemical compounds can undergo changes – e.g., acid-base reactions, racemization, hydrolysis, tautomerization – under certain conditions. What is added to a mixture of chemicals may not represent the actual components of the final mixture.

Although the Federal Circuit’s flexible claim construction in Olaplex v. L’Oreal was a victory for the patent holder, more thoughtful and precise claim drafting could have avoided this issue altogether.

There are several complementary claim approaches that could avoid issues raised in this case.

One approach is to draft claims that strive to capture the actual components of the final formulation you are claiming. In this case, for example, reciting that “the mixture comprises maleate at a concentration ranging from about 0.1% by weight to about 50% by weight” would have accurately captured the final mixture. Simply reciting “maleic acid or a salt thereof” in the claim may have sufficed.

Another approach to avoid issues raised in Olaplex is to draft claims that focus on the process by which the formulation is prepared. For example, consider claiming “a formulation prepared by adding” specified amounts the components, relative to the final weight or volume of the formulation. These claims could be presented instead of, or in addition to, claims that rely on reciting the concentration of compounds present in a mixture.

Yet another way to strengthen a formulation claim is to explain, at least in the specification, how the concentration of a component should be calculated. Is a recited concentration based on the amount present in the formulation, or based on the amount added?

In this case, Olaplex’s proposed claim construction was supported by an example in the ‘954 patent specification that describes the weight of maleic acid prior to addition to the bleaching solution. Although there is no explicit discussion in the specification regarding how the concentration of maleic acid should be calculated, the court noted that the ‘954 patent tended to focus on premixing weights of maleic acid.

Further disclosure in the ‘954 patent specification to the effect of, “the concentration of maleic acid in the mixture is based on the weight of maleic acid added to the bleaching solution, relative to the total weight of the resulting mixture” would have added a bit more color to the claims.

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