Novel 4-phenyl-4-substituted-5-oxo-7-aryl-heptanoic acids are prefaced by either of two synthetic processes. The first method involves the reaction of a 4-phenyl-4-substituted-5-oxo-hexanoic acid with an arylcarboxyaldehyde. The second method involves reaction of an arylcarboxaldehyde with an appropriate ketone, treatment of the product with an acrylic acid ester, followed by hydrolysis of the resulting ester. The compounds of the invention are prostaglandin antagonists and are particularly useful as topical anti-inflammatory agents.