Abstract: Provided is a pharmaceutical composition for use in treating postsurgical pain. The pharmaceutical composition comprises a lipid-based complex. The lipid-based complex comprises an amide-type anesthetic and at least one lipid, wherein a molar ratio of the amide-type anesthetic to the at least one lipid of the lipid-based complex is at least 0.5:1. The total amount of the amide-type anesthetic is at least 1.5 to 5 times of a standard therapeutic dose for treating postsurgical pain with the amide-type anesthetic to achieve an improved pain control with desired prolonged analgesic effect.

Abstract: The present invention relates to a process for producing carboxylic acid anhydrides by the carbonylation reaction of a carboxylic acid ester, derived from an alcohol and a carboxylic acid, with carbon monoxide containing a small amount of hydrogen in a liquid reaction medium in the presence of a Group VIII B catalyst to produce a carboxylic acid anhydride. The liquid reaction medium comprises the Group VIII B catalyst, an organic halide, the carboxylic acid ester, an alkali metal salt, the carboxylic acid anhydride, the carboxylic acid, N-acetylimidazole as a protecting agent, and ethylidene diacetate (EDA) as an organic promoter. By making use of the protecting agent of N-acetylimidazole, metal ions in the reactor can be prevented from reacting with EDA so as to reduce the formation of hardly-soluble tars during the reaction. Also, the EDA organic promoter is kept at a certain content in the system to promote the overall carbonylation reaction rate.

Abstract: The present invention relates to a process for producing carboxylic acid anhydrides by the carbonylation reaction of a carboxylic acid ester, derived from an alcohol and a carboxylic acid, with carbon monoxide containing a small amount of hydrogen in a liquid reaction medium in the presence of a Group VIII B catalyst to produce a carboxylic acid anhydride. The liquid reaction medium comprises the Group VIII B catalyst, an organic halide, the carboxylic acid ester, an alkali metal salt, the carboxylic acid anhydride, the carboxylic acid, N-acetylimidazole as a protecting agent, and ethylidene diacetate (EDA) as an organic promoter. By making use of the protecting agent of N-acetylimidazole, metal ions in the reactor can be prevented from reacting with EDA so as to reduce the formation of hardly-soluble tars during the reaction. Also, the EDA organic promoter is kept at a certain content in the system to promote the overall carbonylation reaction rate.