<p>The present invention relates to a process for the preparation of irbesartan or its pharmaceutically acceptable salts comprising a synthesis of trityl irbesartan by a reaction of 5-(4-(bromomethyl)biphenyl-2-yl)-1-(triphenylmethyl)tetrazole and 2-n-butyl-4-cyclopentane-2-imidazolin-5-one or a salt therof in an organic solvent in the presence of a phase transfer catalyst and a base, a removal of the protecting group and an isolation of irbesartan or its pharmaceutically acceptable salt.</p>
