Determination of titanocene, a new drug with anticancer potential, and its metabolism in solution by capillary electrophoresis.

Titanocene dichloride is one of the most promising cancerostatica of the future: nevertheless, its high activity against several tumor cells was discovered 20 years ago. Detailed knowledge of the mechanism of hydrolysis of titanocene dichloride and its stability in the infusion liquid is a prerequisite for clinical tests and for a successful application for permission as medication. Capillary electrophoresis (CE) was used to observe the hydrolysis behavior of titanocene dichloride in aqueous solutions. The hydrolysis products were separated in a 20 mM phosphate buffer, pH 6, and in a 20 mM malic acid buffer, pH 3. Up to five hydrolysis products were obtained. A significant influence of the sample preparation (pH, isoionic additives) on the hydrolysis rate was observed. The hydrolysis products were characterized by the UV scan and the element-selective particle-induced X-ray emission (PIXE) detection technique. The results obtained correspond with the hydrolysis mechanism described in the literature. The determination of free titanocene dichloride in human plasma failed due to the high affinity of the plasma proteins for this compound.

In vivo changes of heterogeneity of mouse peritoneal macrophages induced by cis-diamminedichloroplatinum (II) (cis-DDP) and related platinum compounds.

The s.c. injection of cis-DDP into ABD2F1 mice (8 mg/kg b.m.) resulted in alterations of size and surface structure of peritoneal macrophages (PM) and in a reduction of the mean number of Concanavalin A (ConA) binding sites of PM. The PM population of control mice which received physiological saline only consisted of 2 subgroups with a higher and a lower mean ConA binding site number per cell. Contrarily, PM of cis-DDP-treated mice failed the subpopulation with higher ConA binding site number. A loss of this subpopulation was also found in mice treated with platinum salt K2PtCl4 or K2PtCl6. X-ray microanalytically determined elemental contents of PM of control and treated mice showed a correlation between ConA binding site number and cellular concentration of phosphorus or sulphur with the exception of a small group of PM which was characterized by a high content of sulphur and a low number of ConA binding site. This correlation was not found in normal mice.

Is the proliferation inhibition of K562 cells by cisplatin also a membrane effect?

Using K562 tumour cells as model, the effect of cisplatin on cellular morphology and electrolyte balance was examined by scanning electron microscopy and energy-dispersive X-ray microanalysis. The data imply that the membrane surface alterations are a secondary effect following cross-linking reaction of this drug with DNA.

[Acute and subacute toxicity of antineoplastic Pt(II) and Pt(IV) coordination compounds in laboratory rodents]. / Akute und subakute Toxizität antineoplastisch wirksamer Pt(II)- und Pt(IV)-Koordinationsverbindungen bei Labornagern.

After single i.v. administration of cis-diammine-platinum(II)-lactate cis-diammine-platinum(II)-lactate, L cis-diammine-platinum(II)-dilactate trans-dihydroxy-cis-dichlorodiammine-platinum(IV), the LD50 values have been calculated to range between 80 and 130 mg/kg in mice, and between 22 and 45 mg/kg in rats. The LD50 of cis-DDP amounted to 17 mg/kg and 6.6 mg/kg, respectively. Likewise, the compounds have been found to be about 3 to 5 times less toxic than the standard cis-DDP when administered daily for 5 consecutive days. Since the kidneys, the bone marrow, the lymphatic tissue and the intestinal tract have been proved to be the main target organs, the profile of the toxic action of the Pt(II)-complexes seems to be similar to that of cis-DDP. Additionally, the Pt(IV) compound has been found to be toxic to the pancreas, the liver and the salivary glands. With regard to the antineoplastic activity the more soluble lactates of cis-DDP showed a smaller therapeutic index compared to cis-DDP.

[Structure-activity relations of antineoplastic platinum II and platinum IV coordination compounds]. / Struktur-Wirkungsbeziehungen antineoplastisch wirksamer Koordinationsverbindungen des II- und IV-wertigen Platins.

Five diammine-Pt(II) or Pt(IV) coordination compounds, namely cis-diammine-dichloro-platinum (II) "cis-DDP", transdihydroxy-cis-diammine-dichloro-platinum (IV) "trans-ODDP", and derived substitution products of lactic acid (racemates or L-forms) with diminished toxicity in comparison to cis-DDP have been tested against mouse leukemia P388, and partly on melanoma B16 for antineoplastic activity. The results have been compared with those obtained with the clinical approved cis-DDP. They were not in every way equal to the antitumor efficiency of cis-DDP. Improved physicochemical properties as well as favorable differences of side effects in contrast to cis-DDP, could be decisive for the potential value of these substances.

[Nephrotoxicity and myelotoxicity of antineoplastic Pt(II) and Pt(IV) coordination compounds in rats]. / Nephrotoxizität und Myelotoxizität antineoplastisch wirksamer Pt(II)- und Pt(IV)-Koordinationsverbindungen bei Ratten.

In comparison with cis-DDP four new platinum (II) and platinum (IV) complexes were evaluated for their acute nephrotoxic and myelotoxic potency in male rats following i.v. administration of maximum tolerated doses on 5 consecutive days. Parameters for nephrotoxicity determined on day 6, 13 and 22 after the first administration of the drugs included blood, urea nitrogen, serum creatinine, urine volume, urinary glucose and tubule cell excretion. Parameters for myelotoxicity determined on the same days included leucocytes, platelets, hemoglobin and hematocrit. Cis-DDP was found to be the most nephrotoxic compound. The myelotoxicity of the new platinum complexes appeared to be similar to that of cis-DDP with exception of trans-ODDP.

[Biological effects of coordinated compounds of transitional metals. 7. Antiviral activity of 4-methyl-2-aminopyridine palladium chloride against herpes simplex virus type 1 and type 2 in vitro and in vivo]. / Uber biologische Wirkungen von Koordinationsverbindungen der Ubergangsmetalle. 7. Zur antiviralen Wirksamkeit von 4-Methyl-2-amino-pyridinpalladiumchlorid gegenüber Herpes simplex-Virus Typ 1 und Typ 2 in vitro und in vivo.

4-Methyl-2-amino-pyridine-palladium chloride (MAP) showed an antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in a serum-free medium under in vitro conditions. The replication of these viruses on primary rabbit testes cells was completely suppressed by 10(-5) M/l MAP. In animal tests using ABD2-mice the course of HSV-1 and HSV-2 encephalitis was not influenced by MAP indicated by mean survival time and lethality.

[The biological effects of coordination compounds of transitional metals. 6. Effect of 4-methyl-2-aminopyridine-palladium chloride and cis-dichlorodiammine-platinum(II) on retroviruses and the virus-associated RNA polymerase of the influenza virus]. / Uber biologische Wirkungen von Koordinationsverbindungen der Ubergangsmetalle. 6. Wirkung von 4-Methyl-2-aminopyridin-palladiumchlorid und cis-dichloro-diammin-Platin(II) auf Retroviren und die virus-assoziierte RNS-Polymerase von Influenzavirus.

The effect on retroviruses of two transition metal complexes of known antiviral activity, 4-methyl-2-amino-pyridine-palladium-chloride (MAP) and cis-dichloro-diammine-platinum(II) (cis-DDP) has been investigated. The experiments included the evaluation of the action of compounds on virus particle-associated reverse transcriptase in exogenous assays, on virus propagation in persistently infected cell cultures and on virus infectivity in mice. In disrupted viruses and in the absence of excess protein, the reverse transcriptase was inhibited by MAP but not by cis-DDP. The same results were obtained when examining the activity of the virus-associated RNA polymerase of influenza virus A/WSN. Both compounds did not inhibit the replication of retroviruses in cell cultures, except at high dose levels which exerted toxic action on both cells and virus formation. The leukemogenicity of Rauscher murine leukemia virus was strongly inhibited when the virus had been incubated with MAP before inoculation. A similar treatment with cis-DDP did not influence viral leukemogenicity. Despite somewhat different results with both compounds tested, we conclude from the present results that the above mentioned compounds cannot be considered as antiretroviral drugs.

[Biological activity of transition metal complexes. 5. Effect of dimethyl sulfoxide on the cytotoxic, antiviral and antitumoral properties of cis-dichlorodiammineplatinum (II): "cisplatin"]. / Uber biologische Wirkungen von Koordinationsverbindungen der Ubergangsmetalle. 5. Zum Einfluss von Dimethylsulfoxid auf die zytotoxischen, antiviralen und antitumoralen Eigenschaften von Cis-dichloro-diammin-platin (II): "Cis-Platin".

In water or dimethyl sulfoxide solutions cis-platinum is subject of time depending solvolytic reactions leading to compounds with different biological effectivity. Whereas the inactivation of vaccinia, vesicular stomatitis and adeno virus type 5 was not changed if dimethyl sulfoxide or dimethyl formamide instead of destilled water were used as solvents, long time stored solutions of cis-platinum in dimethyl sulfoxide were tolerated by cells cultivated in vitro in 8-25 times higher concentrations in comparison with a freshly solved preparation. Their antiviral effectivity was maintained. On the other hand experiments with mice showed that simultaneously with the decrease of toxicity of an aged cis-platinum solution in DMSO also its antileukemic activity disappeared. In a 5 weeks old cis-platinum solution in destilled water antitumor activity was preserved in spite of enhanced toxicity.

[Biological effects of coordination compounds of transitional metals. The beta-lactamase inhibitory effect of cis-platin, 2-aminopyridine palladium chloride, clavulanic acid and penicillanic acid sulfonate CP 45,899 in the nitrocefin test and Titertek/microtiter automatic system]. / Biologische Wirkungen von Koordinationsverbindungen der Ubergangsmetalle. beta-Lactamasen-inhibitorische Wirksamkeit von Cis-Platin, 2-Aminopyridin-palladium-chlorid, Clavulansäure und Penicillansäure-Sulfon CP 45 899 im Nitrocefin-Test und Titertek/Microtiter-Automatensystem.

The beta-lactamase-inhibiting activity of 6m-ethyl-pyrid-2-yl-ammine palladium-dichloride (Pd 25681) and cis-dichloro-diammine-platinum(II) was studied and compared with the enzyme inhibitory action of potassium clavulanate and the penicillanic acid sulfone CP 45899. Using the nitrocefin test method and the Titertek/Microtiter equipment CP 45899 and potassium clavulanate were the strongest inhibitors of the Bacillus cereus beta-lactamase. Cis-dichloro-diammine-platinum(II) was fourfold less active than the palladium complex PD 25681 in äquimolar concentration. The following ID50 values were found: CP 45899: 0.0281 microgram; K-clavulanate: 0.1274 microgram; Pd 25681: 3.8603 microgram; cis-dichlorodiammine-platinum(II): 12.5120 microgram/100 microliter.

[On the biological action of transition metal complexes. 3. About the antiviral activity of cis-dichloro diammine platinum (II) (author's transl)]. / Uber biologische Wirkungen von Koordinationsverbindungen der Ubergangsmetalle 3. Zur antiviralen Wirkung von Vis-dichloro-diammin-platin (II): "Cis-Platin".

The coordination compound cis-dichlorodiammineplatinum(II) (cis-DDP) was shown by Rosenberg et al. (17) to exhibit antitumour activity. Several authors have indicated limited virustatic properties of cis-DDP against bacterial, oncogenic, avipox and paramyxo viruses. In our investigations, cis-DDP significantly showed an antiviral action in vitro against enveloped DNA and RNA viruses, such as vaccinia, pseudorabies, herpes simplex type 1, Newcastle disease, influenza A/fowl plague, influenza A/Victoria 3/75, influenza A/Jena 48/78, influenza B/Johannesburg and vesicular stomatitis viruses. Out of the group of nonenveloped viruses, adenovirus type 4 and 5 were inhibited, whereas no inhibition against naked cardiovirus Mengo could be estimated. The antiviral action was proved against extracellular virus by dialysis experiments with vaccinia virus and also during the replication cycles of enveloped viruses. In trials with cell-free viruses the plaque reduction of all sensitive viruses mentioned above amounted to 100 per cent in comparison to the untreated controls caused by virus inactivation with loss of infectivity in contact with several concentrations of cis-DDP. On the other hand, the addition of the compound for one hour only immediately after infection or up to 8 hrs later produced a complete depression of further multiplication of vaccinia virus. Likewise, the replication of influenza virus A/FPV or VSV was inhibited whereas the multiplication of adenoviruses was not influenced in a comparable manner.

[On the biological action of transition metal complexes. 4. The antiviral activity of metallocene dichlorides of titanium and molybdenum (author's transl)]. / Uber biologische Wirkungen von Koordinationsverbindungen der Ubergangsmetalle 4. Zur antiviralen Wirkung der Metallocendihalogenide des Titans und Molybdäns.

In view of the fact that bis cyclopentadienyl metal dihalides are known to be anti-tumour drugs, we have investigated the antiviral activity of this type of coordination compounds. Bis cyclopentadienyl titanium dichloride (a) has shown significant antiviral efficiency in vitro against representatives of a nuber of enveloped DNA and RNA viruses. Inhibition of orthopoxvirus (vaccinia), herpes virus (pseudorabies), orthomyxoviruses (influenza A/fowl plague [FPV], influenza A/Victoria 3/75, influenza A/jena 48/78 and influenza B/Johannesburg), paramyxovirus (Newcastle disease [NDV]) and rhabdovirus (vesicular stomatitis [VSV]) was observed after direct contact with the compound under loss of infectivity up to 100%. Regarding the group of unenveloped viruses only adenovirus type 4 became influenced but not type 5. No antiviral activity could be found against the cardiovirus Mengo. The compound bis cyclopentadienyl molybdenum dichloride failed to show an antiviral action versus vaccinia, influenza A/FPV and influenza viruses B/Johannesburg. Application of the inhibitor (a) during the replication of vaccinia and influenza viruses A/FPV in cell cultures produced an additional effect of inhibition of virus multiplication. On the other hand, adenovirus type 4 and VSV replication was not affected by titanocene dichloride.

[On the biological action of transition metal complexes. 1. The antiviral activity of palladium aminopyridin-complexes (author's transl)]. / Uber biologische Wirkungen von Koordinationsverbindungen der Ubergangsmetalle. 1. Antivirale Wirkung von 2-Aminopyridinkomplexen des Palladiums.

Some aminopyridine complexes of palladium and PdCl2 showed an antiviral in vitro activity against enveloped DNA and RNA viruses such as vaccinia virus, pseudorabies virus, NDV and FPV. In contrast, naked RNA virus as mengovirus was not affected. The compounds were compatible for chicken embryo as well as FL cells in concentrations of 100-250 microM. The therapeutical index calculated from the maximally tolerated dose and the concentration causing a 50 per cent plaque reduction was determined with more than 45 for vaccinia virus, for example.

[On the biological action of transition metal complexes. 2. The antiviral activity of 4-methyl-2-amino-pyridine-palladium-chloride (IV)]. / Uber biologische Wirkungen von Koordinationsverbindungen der Ubergangsmetalle. 2. Zur antiviralen Wirkung von 4-methyl-2-amino-pyridin-palladiumchlorid (IV).

4-methyl-2-amino-pyridine-palladiumchlorid (IV) showed an inactivation of cell-free enveloped DNA and RNA viruses in serum-free saline such as vaccinia, pseudorabies, herpes type 1, Newcastle disease and influenza virus A/fowl plague, human influenza type A and B and vesicular stomatitis viruses, and adenovirus, a naked DNA virus, too. Picorna viruses were not inactivated, the inactivation of other viruses failed in medium with 10% serum. However the replication of enveloped viruses as checked with vaccinia and fowl plague viruses was inhibited, also when the compound was present only for 1 h after infection. Contrary to this the multiplication of adenovirus was depressed only with 90%. For the inactivation of viruses high concentrations were necessary than for the inhibition of replication. Therefore more than one kind of mode of action have to be taken into consideration.

Inhibition of mengovirus RNA-dependent RNA polymerase by an isatinisothiosemicarbazone and a piperidine-thiocarbonyl-hydrazone derivative in a cell-free system.

The inhibitory action of two antiviral compounds used at the maximum tolerated dosis in a cellular system led to a complete suppression of the infectious mengovirus yield and to a 100% plaque reduction. The products of the RNA polymerase reaction catalyzed by the microsomal-mitochondrial fraction of mengovirus-infected FL cells were analyzed by linear sucrose gradient centrifugation and polyacrylamid gel electrophoresis. The results showed that the inhibitors cause a general reduction of the synthesis of single-stranded viral RNA. The influence on double-stranded viral RNA was more obvious in the case of the isatinisothiosemicarbazone derivative.