The city was even dubbed Chissos "castle town," in reference to the capital cities of feudal lords who ruled Japan during the Edo period.The Chisso factory first started acetaldehyde production in 1932, with 210 tons that year. In 1951, production had jumped to 6,000 tons and eventually peaked at 45,245 tons in 1960. The factorys output historically amounted to between a quarter and a third of Japans total acetaldehyde production. The chemical reaction used to produce the acetaldehyde employed mercury sulfate as a catalyst. Starting in August 1951, the co-catalyst was changed from manganese dioxide to ferric sulfide. A side reaction of this catalytic cycle led to the production of a small amount (about 5% of the outflow) of the organic mercury compound methylmercury. As a result of the catalyst change, this highly toxic compound was released into Minamata Bay regularly between 1951 and 1968, when this production method was finally discontinued. 1956–1959
On 21 April 1956, a five-year-old girl was examined at Chissos factory hospital in Minamata. The physicians were puzzled by her symptoms: difficulty walking, difficulty speaking, and convulsions. Two days later, her younger sister also began to exhibit the same symptoms and she, too, was hospitalised. The girls mother informed doctors that her neighbours daughter was also experiencing similar problems. After a house-to-house investigation, eight further patients were discovered and hospitalised.
Difluprednate is a corticosteroid, It is chemically a butyrate ester of 6(alpha),9(alpha)-difluoro prednisolone acetate. Accordingly, difluprednate is sometimes abbreviated DFBA, for difluoroprednisolone butyrate acetate. Approval
On June 24, 2008, the US Food and Drug Administration (FDA) approved difluprednate for the treatment of post-operative ocular inflammation and pain. It is marketed by Alcon under the tradename Durezol. Clinical trials
Difluprednate ophthalmic emulsion 0.05% is also being studied in other ocular inflammatory diseases, including a phase 3 study evaluating difluprednate for the treatment of anterior uveitis


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