Loratadine Impurity: 4[8-?chloro-?5,?6-?dihydro- ?4-?(hydroxymethyl)?-?11H-?benzo[5,?6]?cyclohepta[1,?2-?b] ?pyridin-?11-?ylidene]?-1-?Piperidinecarboxylic acid ethyl ester(4-Hydroxymethyl loratadine).