Ampicillin EP Impurity I 

Chemical Name: (2S,5R,6R)-6-[[(2R)-2-[[(2R)-2-amino-2-phenylacetyl]amino]-2-phenylacetyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (as per EP); (2S,5R,6R)-6-{(R)-2-[(R)-2-Amino-2-phenylacetamido]-2-phenylacetamido}-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (as per USP)

Synonym: Lamotrigine USP Related Compound C