An American woman serving a life sentence for killing her husband in Hong Kong lost an appeal of her murder conviction Monday.

Nancy Kissel, 44, from Minnesota was found guilty of the 2003 slaying for giving her husband a milkshake laced with sedatives and then bashing his head with a metal ornament while he lay in bed.

Kissel and her husband Robert, an investment banker with Merrill Lynch & Co., were married in the U.S. in 1989 and later moved to Hong Kong.

Prosecutors said she killed him for his $18-million US estate, consisting of stocks, life insurance, cash and real estate.

Kissel admitted killing her husband, but claimed he was abusive and that she was defending herself. Prosecutors portrayed her as a cold-blooded wife who planned the attack

A defence lawyer and Kissel's mother, Jean McGlothlin, said they plan to take the case to Hong Kong's Court of Final Appeal.

With files from the Associated Press