ethyl (2S)-3-(3,4-dihydroxyphenyl)-2-hydrazinyl-2-methylpropanoate; Ethyl (2S)-3-(3,4-dihydroxyphenyl)-2-hydrazino-2-methylpropanoate; (αS)-α-Hydrazinyl-3,4-dihydroxy-α-methylbenzenepropanoic Acid Ethyl Ester; (S)-Ethyl 3-(3,4-dihydroxyphenyl)-2-hydrazinyl-2-methylpropanoate; Carbidopa ethyl ester; Ethyl (S)-3-(3,4-dihydroxyphenyl)-2-hydrazineyl-2-methylpropanoate (As per USP Commenting Opening 51(2))