Effects of human serun albumin in some biological properties of rhodium(II) complexes

The affinities for human albumin (HSA) of five rhodium(II) complexes of gen eral formula [Rh-2(bridge)(4)] (bridge = acetate, propionate, butyrate, tri fluoroacetate and trifluoroacetamidate) were determined by spectrophotometr y. In the case of the alkylcarboxylates, an inverse correlation of affinity with their liposolubilities was observed. Diffusion of the free or protein -bound complexes into Ehrlich cells in vitro seems to be primarily governed by the hydrophobic character of the complex. The complex [Rh-2(tfc)(4)] ex hibited affinity towards the protein (K = 214.1) as well as cell partition both in the absence (32.1%) and presence (48.6%) of HSA. The compound HSA: [Rh-2(tfc)(4)] has had its antitumoral action in tumor-bearing Balb-c mice investigated, showing that HSA can be a drug reservoir for the rhodium comp lex.