Technetium-99m labeled p-aminohippuric acid analogues: renal function agents.

A number of p-aminohippuric acid analogues were synthesized in order to develop clinically useful 99mTc-labeled radiopharmaceuticals for evaluation of renal function measurements. Stable 99mTc-labeled complexes were formed at pH 5.7 using a Sn(II) reduction method with all derivatives. The newly synthesized complexes were screened utilizing biodistribution studies in small animals. All complexes were excreted via the GU tract within 60 min post iv administration, with no significant activity in GI tract and liver. The [99mTc]methyl-PAHIDA complex showed optimal biodistribution among these analogues. Further investigation is needed to determine if these derivatives may be used to replace [131I]o-iodohippuric acid for the evaluation of renal function.