Abstract
In Azurity Pharms., Inc. v. Alkem Lab’ys Ltd., 655 F. Supp. 3d 270 (D. Del. 2023), U.S. Patent Nos. 10,786,482 and 10,918,621 covering Epaned® liquid were invalidated on the ground of obviousness. The claimed invention was an oral liquid formulation of enalapril consisting of enalapril, a buffer, sweetener, a preservative, and water. The district court there found that before the claimed invention, a person of ordinary skill in the art would have combined those ingredients recited in the disputed claims. The appellate court then upheld the district court’s obviousness determination because there was substantial evidence supporting the factual findings. This article is intended to analyze the district court to figure out what constitutes substantial evidence of obviousness. Azurity Pharms., Inc. may block the patenting of “ready-to-use” oral liquid formulations that consist of known excipients. Four aspects can be drawn: (1) it may be obvious to combine ingredient limitations and stability limitations; (2) a buffer limitation with a range of pH values would have been obvious; (3) common excipient limitations would have been obvious; (4) a buffer limitation with a concentration value or range would have been obvious because adjusting the concentration of a chosen buffer to meet the target pH is routine.
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