Reactivity of Cu2(lonazolac)4, a lipophilic copper acetate derivative

In vitro and in vivo stability investigations of Cu(ii), Zn(ii), Ca(ii) and Gd(iii) complexes with N,N′-bis(2-hydroxyiminopropionyl) propane-1,3-diamine

Formation constants of copper(II), zinc(II), calcium(II) and gadolinium(III) with N,N'-bis(2-hydroxyiminopropionyl) propane-1,3-diamine (L2) have been studied at 25 degrees C and an ionic strength of 0.15 mol dm(-3). The reasonably high formation constants of the copper with this ligand are due to the ease with which the metal ion deprotonates the amide moieties. The square-planar coordination of L2 towards copper as predicted from UV-visible data may also account for the high selectivity of L2 towards the metal ion. Octanol/water partition coefficients of Cu(II)-L2 complexes indicate that although these complexes are largely hydrophilic, approximately 1.86% of the [CuL2H(-1)] species goes into the octanol layer and hence may promote dermal absorption of copper with a calculated penetration rate of 1.24 x 10(-5) cm h(-1). The [CuL2H(-1)] complex which predominates at pH 7.4 is a poor mimic of native copper-zinc superoxide dismutase. Blood-plasma simulation studies predict that, despite the high concentration of zinc and calcium in vivo, L2 is able to increase the low-molecular-mass fraction of copper. Biodistribution experiments using 64Cu-labelled [CuL2H(-1)] indicate an initial high uptake of this species in the liver, but it is predominantly excreted through the renal system.

Gastrointestinal toxicity, antiinflammatory activity, and superoxide dismutase activity of copper and zinc complexes of the antiinflammatory drug indomethacin

Gastrointestinal (GI) toxicity is one of the major problems associated with antiinflammatory drugs. The complexation of the powerful antiinflammatory drug (IndoH) by metal ions, as a means of reducing GI toxicity, has been studied. The in vitro superoxide dismutase (SOD) activity, in vivo antiinflammatory activity, and gastrointestinal ulcerogenic properties of IndoH, [Cu2(Indo)4(DMF)2], and [Zn2(Indo)4(DMA)2] are reported. No SOD activity was observed for IndoH or [Zn2(Indo)4(DMA)2], but [Cu2(Indo)4(DMF)2] inhibited the reduction of nitroblue tetrazolium (NBT) at an IC50 value of 0.23 microM. All three compounds exhibited antiinflammatory activity in male Sprague-Dawley rats at an equivalent Indo dose of 10 mg/kg following oral administration of the drugs in 2% CMC solution. The severity of the toxicity (macroscopic ulcerations) in the stomach following oral dosing with [Zn2(Indo)4(DMF)2] was not significantly lower than that induced by IndoH (P = 0.78). Gastric ulcerations induced by [Cu2(Indo)4(DMF)2] were significantly lower than those induced by IndoH or [Zn2(Indo)4(DMA)2] (P = 0.0012 and P = 0.0175, respectively) but significantly greater than the control (P = 0.0013). The intestinal ulcerations induced by [Cu2(Indo)4(DMF)2] or [Zn2(Indo)4(DMA)2] were approximately 15 times lower than those of IndoH. A further indicator of gastrointestinal toxicity, caecal haemoglobin, increased in the following order: control < [Cu2(Indo)4(DMF)2] < [Zn2(Indo)4(DMA)2] < IndoH.[Cu2(Indo)4(DMF)2] exhibited the most promising results of the Indo complexes assayed, in that it exhibited SOD activity and the lowest gastrointestinal damage while also exhibiting antiinflammatory activity that was comparable to that for IndoH. Low-temperature EPR analyses also showed that the formulation used for [Cu2(Indo)4(DMF)2] administration was crucial to the integrity of the complex.

Stable superoxide dismutase (SOD)-mimetic ternary human serum albumin-Cu(II)(3,5-diisopropylsalicylate)2/Cu(II)2(3,5-diisopropylsalicylate)4 complexes in tissue distribution of the binary complex

Copper(II)2(3,5-diisopropylsalicylate)4 [Cu(II)2(3,5-DIPS)4] has been found to have antiinflammatory, antiulcer, anticancer, anticonvulsant, antimutagenic, antidiabetic, analgesic, and radiation protection and recovery activities. It has also been found to reduce ischemia-reperfusion injury. Because of these activities it was of interest to understand how this compound is transported in the body to affected tissues. Evidence supporting the suggested formation of ternary human serum albumin (HSA)-Cu(II)(3,5-DIPS)2 or Cu(II)2(3,5-DIPS)4 complexes was obtained using ultraviolet spectrophotometry, dialysis, and atomic absorption spectrophotometry or atomic emission spectroscopy. Superoxide dismutase (SOD)-mimetic activity was also determined using the xanthine/xanthine oxidase/cytochrome c system. Ultraviolet spectra of aqueous solution mixtures of Cu(II)2(3,5-DIPS)4 in equilibrium with 2Cu(II)(3,5-DIPS)2 and HSA as well as aqueous solutions of solid Cu(II)2(3,5-DIPS)4 obtained by stirring the solid with an aqueous solution of HSA showed no obvious change in absorbance to indicate ternary complex formation. However, comparison of ultraviolet spectra taken before and after dialysis supports the suggested bonding of Cu(II)(3,5-DIPS)2 or Cu(II)2(3,5-DIPS)4 to HSA. Comparison of copper concentrations before and after dialysis also supports the suggested bonding of Cu(II)(3,5-DIPS)2 or Cu(II)2(3,5-DIPS)4 to HSA. Based upon these data it is plausible that Cu(II)(3,5-DIPS)2 or Cu(II)2(3,5-DIPS)4 form stable ternary complexes with HSA. These stable ternary complexes were also found to have SOD-mimetic activity.