Calculation of pharmacokinetic and dosimetric characteristics of Lu-177-EDTMP – a potential drug for radionuclide therapy of bone metastases

Phosphonic acids labeled with beta-emitting radionuclides are promising radiopharmaceutical drugs for palliative therapy of bone metastases. Currently, the possibility using a new osteotropic compound N,N,N’,N’-ethylenediaminetetrakis (methylene phosphonic acid) lutetium-177 (177Lu-EDTMP) is being studied. The aim work to develop compartment mathematical model kinetics 177Lu in body laboratory animals and calculate their pharmacokinetic dosimetric characteristics based on it. To assess stability 177Lu-EDTMP vivo, distribution free lutetium form 177LuCl3 were also identify parameters drugs, quantitative data bio-distribution intact Wistar rats used. A has been developed two approaches identification its transport constants have proposed – through residual functional approximation by monoexponential functions. According modeling, it was found that deposited tissues (up 55% administered dose). calculated value apparent volume approximately 200 times greater than blood plasma, values biological half-lives from 10-20 higher internal organs. excretion occurs mainly renal clearance. Comparative modeling revealed high resistance vivo. highest absorbed doses formed skeleton kidneys minimal radiation load other organs blood. results obtained indicate prospects further studies clinical application treatment skeletal