Dissolution rate-limited absorption and complete bioavailability of roquinimex in man.

In order to investigate the bioavailability and the rate-limiting step of the absorption of roquinimex, an oral solution and a tablet formulation (Linomide(R)) were given to healthy volunteers. The study was conducted as a randomized three-period crossover study in seven male and seven female healthy volunteers. The subjects received an intravenous infusion, an oral solution and an oral tablet formulation, each of 5 mg (about 0.07 mg kg(-1)), as single doses after an overnight fast on three occasions, with a wash-out period of 3 weeks in between. Venous blood samples were taken over 7 days and the plasma concentrations of roquinimex were determined by high-performance liquid chromatography (HPLC) with ultraviolet (UV)-detection. The pharmacokinetics of roquinimex was characterized by a low plasma clearance, 4.9 mL h(-1) kg(-1) and a small volume of distribution, 0.22 L kg(-1). The oral bioavailability of the drug was complete for both the solution and the tablet formulation. The absorption rate was faster for the solution than for the tablet. The disposition of roquinimex was biphasic, with a terminal disposition half-life of 32 h. Between 4 and 8 hours after dosing, a secondary plasma peak was observed, indicating enterohepatic circulation of the drug. No major sex differences were shown in the pharmacokinetics of roquinimex. In conclusion, dissolution rate-limited absorption of roquinimex was shown, which demonstrates that disintegration and dissolution of the tablet play a major role in the absorption process of roquinimex. Despite the delayed absorption after administration of the tablet, the extent of absorption was complete.

Anti-angiogenic treatment with linomide as adjuvant to surgical castration in experimental prostate cancer.

PURPOSE: Escape from "castration inhibition," be it surgical or chemically induced, is still the major problem in prostate cancer treatment. New agents that can be given as adjuvant therapy are needed. Linomide has demonstrated both anti-tumor and anti-angiogenic activity with little toxicity in the Dunning R-3327 rat prostate tumor system. Therefore it was deemed essential to study the efficacy of this drug in the adjuvant situation. MATERIALS AND METHODS: Linomide, roquinimex, was administered 3 times a week i.p. alone or in conjunction with castration to rats bearing the Dunning R-3327 PAP rat prostate tumor and its effect on tumor growth analyzed. Similar experiments, in which Linomide 25 mg./kg./day was given in the drinking water were carried out in rats with the Dunning R-3327 G tumor. The effect of treatment on blood vessel density and blood flow in the tumor was also assessed using an image analysis system. RESULTS: Linomide, 2.5 & 40 mg./kg., administered from the day after castration inhibited the regrowth of the Dunning R-3327 PAP tumors In addition, Linomide 40 mg./kg. administered after tumor regrowth occurred following castration(week 10) inhibited further tumor growth. Inhibition of tumor regrowth after castration was also found in the Dunning G tumor. When Linomide treatment was stopped regrowth of the tumors occurred, either in the same animal or on transplantation to new intact hosts, demonstrating that the tumor cells were still viable. Tumor blood vessel density was decreased both after castration and Linomide treatment alone, 40 and 32% respectively. On combination of castration and Linomide a 60% decrease in blood vessel density was found. This was significantly different from either of the two treatments given alone. The enhancement on combining castration and Linomide was confirmed by a further decrease in blood flow, from 19 and 22 to 12 ml. per minute/gm. tissue respectively. CONCLUSIONS: Linomide, an anti-angiogenic drug, inhibits escape from "castration inhibition".

Chromosome aberrations and pharmacokinetics in patients receiving tauromustine as either a single or a repeated dose.

Tauromustine (TCNU) is an exploratory drug that has demonstrated activity in various solid tumors. We examined chromosome aberrations and plasma levels of the drug in two groups of patients receiving either a single dose of 130 mg/m2 or 40 mg/m2 on 3 consecutive days. Peak plasma concentrations (mean +/- SD) were obtained at a similar time after both treatments, i.e., at 38 +/- 25, 32 +/- 24, 28 +/- 14, and 40 +/- 26 min after administration of 130 mg/m2 on day 1 and after that of 40 mg/m2 on days 1, 2, and 3, respectively. In addition, the cumulative area under the curve (AUC value) determined after administration of 40 mg/m2 x 3 was similar to that noted after treatment with a single dose of 130 mg/m2, i.e., 180 and 179 micrograms min ml-1, respectively. Both treatments induced chromosome aberrations (CAs) in peripheral blood lymphocytes. A dose-dependent increase in the number of CAs was found, with 40 mg/m2 producing 5.5% CAs and 130 mg/m2 yielding 20.9% CAs at 24 h after treatment. In addition, although the drug concentration declined to a level under the detection limit between the daily treatments, drug-induced chromosome damage was cumulative, with the 90-min values increasing from 4.8% on day 1 to 14.3% CAs on day 3. In individual patients, no correlation was found between CAs and kinetic parameters; however, the total mean CA yield was in agreement with the total drug exposure (CAs, 14.3% and 14.6%, AUC 180 +/- 62.8 and 179 +/- 115 micrograms min ml-1, respectively.

The quinoline-3-carboxamide linomide inhibits angiogenesis in vivo.

Linomide (Roquinimex) has antitumor activity when given in vivo (but not when applied in vitro) that has been attributed to immune host mechanisms. Recent studies, however, suggest that Linomide may also possess antiangiogenic properties. The aim of the present study was to evaluate the antiangiogenic effect of Linomide using an intravital microscopic technique. Syngeneic pancreatic islets were isolated and implanted into the dorsal skinfold chamber of Syrian golden hamsters. This model allows detailed repeated in vivo observations and quantitative analysis of revascularization of pancreatic islet grafts. The neovascularization process of the islets is a highly reproducible phenomenon that is completed within about 2 weeks, resulting in a microvascular network very similar to that of islets in situ. The plasma concentration profile of Linomide following a single oral dose of the compound was determined. The elimination of Linomide was fast, the half-life being 2.6 +/- 0.2 h. Due to the short half-life, the hamsters were given Linomide twice a day. One group of animals (n = 9) was force-fed Linomide (100 mg/kg per day) from the day of implantation throughout the 2-week observation period, and the results were compared with those obtained in a nontreated control group (n = 7). At days 6, 10, and 14 after implantation, the neo-vasculature of the islets was examined. In the control group, 91% +/- 4% (mean +/- SEM) of the islets showed the first signs of angiogenesis at day 6, whereas in the Linomide-treated group the corresponding value was 48% +/- 12%. At days 10 and 14, the "take-rate" in the control group increased to 94% +/- 3% for day 0 and to 94% +/- 4% (n = 6) for day 14, whereas in the treated group the corresponding take-rate was 67% +/- 11% and 72% +/- 12%, respectively. The functional capillary density in the control group at days 6, 10, and 14 was 223 +/- 17,348 +/- 29, and 495 +/- 29 cm-1, respectively, and that in the Linomide treated group was 91 +/- 28, 181 +/- 43, and 229 +/- 47 cm-1, respectively. These results demonstrate that Linomide suppresses the neovascularization of the islet grafts by both delaying the onset of and reducing the percentage of islets displaying angiogenesis as well as by decreasing the rate of proliferation of capillary endothelium of the revascularized islets.

Determination of tauromustine and its demethylated metabolites in plasma and urine.

A sensitive, selective and precise high-performance liquid chromatographic method for simultaneous determination of tauromustine and its demethylated metabolites in plasma and urine has been developed. It is based on solid-phase extraction on C18 sorbent and separation on a semipolar column. The analytical procedure is described in detail. The method has been validated with respect to linearity, recovery, selectivity, precision and detection limit. The stability of the determined substances in various media has also been studied.

Pharmacokinetics of tauromustine in cancer patients. Phase I studies.

The pharmacokinetic properties of tauromustine (TCNU) were studied in 31 cancer patients who participated in phase I trials. The patients received single oral doses of tauromustine in the range of 20-170 mg/m2. Plasma samples were taken over 24 h after administration and analysed for tauromustine by reversed-phase liquid chromatography. Parent TCNU could be demonstrated in the plasma of all patients. Its absorption was rapid (tmax = 38 +/- 22 min), the half-life was 57 +/- 22 min (mean +/- SD), and maximal concentration (Cmax) and AUC values were linearly related to the dose level. Thus, our study does not indicate dose-dependent pharmacokinetics for the drug in the range of 20-170 mg/m2. Thrombocytopenia was the dose-limiting toxicity of TCNU; the reduction of platelet counts appeared to be linearly related to the log dose and Cmax and AUC values. TCNU appears to exhibit pharmacokinetic properties that are different from those of other nitrosoureas, which might be important for the clinical effect of the drug.

Anti-tumour, toxicological and pharmacokinetic properties of a novel taurine-based nitrosourea (TCNU).

A novel nitrosourea, 1-(2-chloroethyl)-3-[2-(dimethylaminosulfonyl) ethyl]-1-nitrosourea (TCNU) tauromustine, has been investigated in a broad anti-tumour screen and, in depth toxicology and initial pharmacokinetics carried out. TCNU and its two metabolites were found to exhibit equal or better oral efficacy than that of BCNU, CCNU, MeCCNU or chorozotocin against L1210 leukemia, Walker mammary carcinoma, Lewis Lung, Harding Passey melanoma and colon carcinoma C26. The toxicological profile of TCNU after acute and 3 months treatment was similar in mice and rats to that of CCNU, with the exception that, TCNU did not cause the chronic liver disturbances found for CCNU. In dogs treated for 6 weeks with TCNU leucopenia and thrombocytopenia were the major side effects. Parent TCNU was found in all dogs. The absorption was fast, the maximum level being reach after 25 mins and the mean absorption time was 22 mins. The mean half life was 16.1 mins after intravenous and 17.4 after oral administration. The combination of these factors make TCNU an interesting clinical candidate.

[Heritability in the incidence of rudimentary teats in milk cows of the Bohemian spotted breed]. / Dedivost výskytu nadpocetných struku u dojnic ceského strakatého Plemene.

The set of 2,230 dairy cows was studied for genotype influence on the occurrence of rudimentary teats in the dairy cows of Bohemian Spotted breed. In the studied population 57.62% cows had rudimentary teats. Out of this percentage, 45.23% of animals had only one small teat, 50.43% cows had two small teats and 4.34% had more than two rudimentary teats. The estimation of rudimentary teat heritability was carried out by the method of daughter regression to dams in 185 pairs. The calculated heritability coefficient was medium high (h2 = 0.56 +/- 0.15). As found out further, the dams having rudimentary teats had by 20% higher proportion of daughters with rudimentary teats than the dams without rudimentary teats. This relationship is statistically highly significant. The interrelationship between the dams and daughters as to the occurrence of one or two rudimentary teats was statistically insignificant. By means of the analysis of variance in the groups of half-sisters after 49 sires (the average number of animals per group amounted to 45), the intracorrelation coefficient was determined and used for the calculation of the heritability coefficient h2 = 0.26 +/- 0.07.

[Heredity of the position of rudimentary teats in cows of the Czech Spotted breed]. / Dedicnost lokalizace nadpocetných struku u krav plemene ceské strakaté.

A characteristic effect of bulls on the distribution of rudimentary teats in their daughters was demonstrated by the study of the influence of the genotype on the location of extra teats. The comparison of the mother--daughter pairs showed that the concordance of location of a single teat either on the right or on the left between the mother and daughter was found in 86.40% of all cases, whereas discordance was found just in 13.60% of the examined pairs. Concordance in the distance of rudimentary teats in a caudal direction from the rear teat was observed in 61.00% of the cases and discordance in 39.00% of the pairs. In 16 pairs of dizygotic twins, a congruence was also found in the majority of cases between the sibs as well as between the heifers and their mothers. In the whole set of cows under study, rudimentary teats located caudally represented 87.88% of all extra teats, small teats between the normal fore and rear teats represented 2.74%, rudimentary teats at the rear teats 9.03% and those at the fore teats 0.35%.