Synergistic Antivascular and Antitumor Efficacy with Combined Cediranib and SC6889 in Intracranial Mouse Glioma.

Prognosis remains extremely poor for malignant glioma. Targeted therapeutic approaches, including single agent anti-angiogenic and proteasome inhibition strategies, have not resulted in sustained anti-glioma clinical efficacy. We tested the anti-glioma efficacy of the anti-angiogenic receptor tyrosine kinase inhibitor cediranib and the novel proteasome inhibitor SC68896, in combination and as single agents. To assess anti-angiogenic effects and evaluate efficacy we employed 4C8 intracranial mouse glioma and a dual-bolus perfusion MRI approach to measure Ktrans, relative cerebral blood flow and volume (rCBF, rCBV), and relative mean transit time (rMTT) in combination with anatomical MRI measurements of tumor growth. While single agent cediranib or SC68896 treatment did not alter tumor growth or survival, combined cediranib/SC68896 significantly delayed tumor growth and increased median survival by 2-fold, compared to untreated. This was accompanied by substantially increased tumor necrosis in the cediranib/SC68896 group (p<0.01), not observed with single agent treatments. Mean vessel density was significantly lower, and mean vessel lumen area was significantly higher, for the combined cediranib/SC68896 group versus untreated. Consistent with our previous findings, cediranib alone did not significantly alter mean tumor rCBF, rCBV, rMTT, or Ktrans. In contrast, SC68896 reduced rCBF in comparison to untreated, but without concomitant reductions in rCBV, rMTT, or Ktrans. Importantly, combined cediranib/SC68896 substantially reduced rCBF, rCBV. rMTT, and Ktrans. A novel analysis of Ktrans/rCBV suggests that changes in Ktrans with time and/or treatment are related to altered total vascular surface area. The data suggest that combined cediranib/SC68896 induced potent anti-angiogenic effects, resulting in increased vascular efficiency and reduced extravasation, consistent with a process of vascular normalization. The study represents the first demonstration that the combination of cediranib with a proteasome inhibitor substantially increases the anti-angiogenic efficacy produced from either agent alone, and synergistically slows glioma tumor growth and extends survival, suggesting a promising treatment which warrants further investigation.

In vivo anticancer activity of vanillin semicarbazone.

OBJECTIVE: To evaluate the anticancer activity of vanillin semicarbazone (VSC) against Ehrlich ascites carcinoma (EAC) cells in Swiss albino mice. METHODS: The compound VSC at three doses (5, 7.5 and 10 mg/kg i.p.) was administered into the intraperitoneal cavity of the EAC inoculated mice to observe its efficiency by studying the cell growth inhibition, reduction of tumour weight, enhancement of survival time as well as the changes in depleted hematological parameters. All such parameters were also studied with a known standard drug bleomycin at the dose of 0.3 mg/kg (i.p.). RESULTS: Among the doses studied, 10 mg/kg (i.p.) was found to be quite comparable in potency to that of bleomycin at the dose of 0.3 mg/kg (i.p.). The host toxic effects of VSC was found to be negligible. CONCLUSIONS: It can be concluded that VSC can therefore be considered as potent anticancer agent.

Metaflumizone-amitraz (Promeris)-associated pustular acantholytic dermatitis in 22 dogs: evidence suggests contact drug-triggered pemphigus foliaceus.

Promeris Duo (PD) is a novel topical flea and tick preventative for dogs, which is also licensed for treatment of canine demodicosis. In this article, we present 22 dogs that all developed pemphigus foliaceus (PF)-like cutaneous drug reactions at the site of PD application. In eight dogs, the lesions were restricted to the application site (localized group). Signs of systemic illness were reported in three dogs, and four required immunosuppressive treatment. Direct immunofluorescence for IgG was positive in four dogs, although circulating antikeratinocyte IgG could not be detected in any tested sera. Complete remission was achieved in all dogs, with one patient still remaining on treatment. Fourteen dogs developed skin lesions at the application site as well as other noncontiguous areas (distant group). Systemic signs were reported in 11 dogs, and immunosuppression was required in 10 cases. Direct and indirect immunofluorescence tests were positive for antikeratinocyte autoantibodies in 10 of 13 and six of 10 patients with distant disease, respectively. Complete remission was achieved in 10 of 13 dogs with distant disease; one-third are still on treatment. Histological changes were similar to canine PF. Desmosomal architectural changes, assessed by desmoglein-1 immunostaining, were also similar to those of dogs with spontaneous autoimmune PF. Apoptosis did not appear to contribute to lesion formation, in either autoimmune or PD-associated PF. In conclusion, PD has the potential of triggering a variant of PF that resembles spontaneously occurring autoimmune PF at clinical, morphological, immunological and treatment outcome levels.

Field and laboratory trials of a novel metaflumizone house fly (Diptera: Muscidae) bait in California.

House fly responses to metaflumizone bait were studied in southern California. Field-strain, laboratory-reared flies in outdoor cages had access for 5 d to water and two containers of untreated sugar/dry milk (control), one container of untreated food and one container of metaflumizone bait, or one container of untreated food and one container of spinosad bait (positive control). Most fly mortality occurred between 0 and 48 h for spinosad and between 48 and 96 h for metaflumizone. On a commercial dairy, fly visitation and bait consumption were higher for metaflumizone bait than for sugar or imidacloprid bait. Flies seldom visited or consumed the imidacloprid bait. Approximately 32% of field flies collected directly from metaflumizone bait (single exposure) died when held in the laboratory with untreated food for 72 h versus < 5% mortality for flies from sugar or imidacloprid bait. Individual laboratory-reared females from a field strain and a susceptible laboratory strain were videotaped in the laboratory after exposure to untreated dry milk/sugar, metaflumizone bait, spinosad bait, and imidacloprid bait. Imidacloprid-induced mortality in field strain flies was low; when on the bait they spent proportionally less time feeding (38%) than did the laboratory strain flies (63%). Feeding by the field strain was more variable, and they fed less on all bait/food sources except metaflumizone. Metaflumizone has promise as a relatively slow-acting fly bait.

Pre-clinical pharmacokinetics evaluation of an anticonvulsant candidate benzaldehyde semicarbazone free and included in beta-cyclodextrin.

The study aimed to investigate the pharmacokinetics and tissue distribution of the benzaldehyde semicarbazone (BS) a potential antiepileptic drug, administered as a free drug or complexed beta-cyclodextrin (BS/beta-CD). Free BS and BS/beta-CD were administered to male Wistar rats as a 10mg/kg intravenous bolus dose. For the oral route, 50mg/kg and 100mg/kg doses of the free drug and 50mg/kg of the complex were administrated and plasma concentrations were determinated by a validated HPLC-UV method. Individual profiles were evaluated by non-compartmental and compartmental analysis using Excel and Scientist, respectively. Free BS plasma protein binding was 34+/-5%. A one-compartmental model adequately described all the plasma profiles for both formulations. After intravenous (10mg/kg) and oral (50mg/kg) administration, the V(d) (1.6+/-0.5 and 2.2+/-0.8L/kg, respectively) and the Cl(tot) (1.4+/-0.5 and 1.8+/-0.5L/hkg, respectively) determinated for the BS/beta-CD complex were higher than those obtained for the free drug, but the t(1/2) (0.8+/-0.1h) was similar (p<0.05). The oral bioavailability of the BS/beta-CD complex (approximately 37%) was approximately 2-fold of the free BS ( approximately 20%). The higher drug brain penetration (2.8) after BS/beta-CD dosing and the longer mean residence time in this organ, regardless of the administration route, reveals that the complex may be a potential drug carrier for the central nervous system delivery of BS.

Evaluation of the potential for interaction between a metaflumizone-amitraz combination and dexmedetomidine hydrochloride in dogs.

This study investigated the effects on cardiovascular parameters, if any, of a commercially available combination of metaflumizone and amitraz administered to healthy, telemetered beagles that were subsequently sedated with dexmedetomidine. Dogs were sedated first without any pretreatment and then after pretreatment with metaflumizone and amitraz. Baseline values of all parameters were within normal limits for all dogs before the first anesthetic event. At 10 and 20 minutes after onset of sedation, oxygen saturation as measured by pulse oximetry was significantly higher for dogs that were pretreated with metaflumizone and amitraz. At all times after induction of sedation, blood pressure, heart rate, and baseline body temperature for dogs pretreated with metaflumizone and amitraz were not statistically different from when they were not pretreated. In conclusion, prior treatment with metaflumizone and amitraz did not influence the hemodynamic response to dexmedetomidine in telemetered dogs.

Safety of a topically applied spot-on formulation of metaflumizone plus amitraz for flea and tick control in dogs.

Four laboratory studies were conducted in Beagle dogs to evaluate the safety of a novel ectoparasiticide combination of metaflumizone plus amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) when applied according to the recommended dosage of >/=20mgmetaflumizonekg(-1) plus >/=20mgamitrazkg(-1), at exaggerated and repeated dosages, and if accidentally orally ingested. Parameters evaluated included body weight, food consumption, clinical, physical and neurological examinations, clinical pathology and gross and microscopic pathology. Exaggerated and repeated topical treatment with metaflumizone plus amitraz administered at 1x, 3x and 5x the recommended dose had no effect on clinical findings, heart rates, body weight, food consumption, physical/neurological examinations, macroscopic and microscopic pathology. Very slight, transient, clinically insignificant increases in serum urea nitrogen were noted in some dogs treated at all dose rates tested. This effect was not persistent, was not dose-responsive, nor aggravated by repeated applications and was not associated with a corresponding increase in creatinine or renal pathology. Therefore, these increases in urea nitrogen were suspected to be of non-renal origin and were not considered toxicologically significant. Exaggerated doses (3x and 5x) caused very mild, transient hyperglycemia, most notably in some adult females. Transient and inconsistently noted mild increases in leukocytes, neutrophils and monocytes were observed in some 3x and 5x treated dogs at some intervals. None of the effects noted were aggravated by repeated administration. When 10% of the recommended topical dose was orally administered to mimic exposure due to licking the application, avoidance behaviors including spitting, head shaking, and salivation were noted immediately in all animals. Consequently, voluntary oral ingestion is considered unlikely. Transient decreased activity, slightly reduced body temperature and pale oral mucous membranes were noted in some animals beginning 1-2h posttreatment. Ataxia, resolving within 4h posttreatment, was noted in one female. Oral administration had no effect on clinical pathology. Results from these four studies indicate repeated use of metaflumizone plus amitraz causes no adverse health effects when used as recommended in dogs as young as 8 weeks of age.

Safety of a topically applied metaflumizone spot-on formulation for flea control in cats and kittens.

Four laboratory studies were conducted in cats of various ages to evaluate the safety of a novel low-volume topical spot-on containing 20% metaflumizone (ProMeris for Cats, Fort Dodge Animal Health, Overland Park, KS) when used in cats according to the recommended minimum dosage of 40mg metaflumizonekg(-1) delivered via fixed volume doses of 0.8ml for cats 4.0kg. Study parameters included body weight, food consumption, clinical, physical and neurological examinations, and clinical pathology including complete hematology, coagulation, clinical chemistry and urinalysis. Exaggerated and repeated topical applications of metaflumizone at 1x, 3x and 5x the proposed recommended dose in adult cats and kittens 8 weeks of age had no effect on mortality, body weight, food consumption, clinical, physical or neurological examinations, or clinical pathology parameters. Transient salivation was sporadically noted following some, but not all treatment applications. It occurred and resolved within minutes of treatment application in all groups, including cats treated with placebo. Consequently, it was not considered a direct result of treatment with the active ingredient, metaflumizone. Cats orally administered 10% of the recommended topical dose exhibited considerable avoidance behaviors including spitting, head shaking, and salivation. Therefore, voluntary oral exposure is unlikely. No other adverse signs were observed. Repeated use of metaflumizone caused no adverse health effects when administered at 5x the recommended dose and is safe when used as directed, even on kittens as young as 8 weeks of age.

Dose determination of a novel formulation of metaflumizone plus amitraz for control of cat fleas (Ctenocephalides felis felis) and brown dog ticks (Rhipicephalus sanguineus) on dogs.

A novel spot-on formulation containing metaflumizone and amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated in a laboratory study to determine the appropriate dose for efficacy against fleas and ticks on dogs for 1 month. Thirty-six Beagles were randomly allocated to six equal groups and individually housed. One group remained nontreated. Another was treated with a placebo formulation (solvents with no active ingredients). Three groups of dogs were treated topically with the metaflumizone plus amitraz formulation (150mg of each of metaflumizone and amitraz/ml), at volumes providing doses of 10, 20 and 40mgeachactive/kg. The final group was treated with a commercial spot-on providing 6.7mgfipronil/kg. All treatments were applied to the skin at a single spot between the scapulae on Day 0. Dogs were infested with 50 adult brown dog ticks (Rhipicephalus sanguineus) on each of Days -2, 5, 12, 19, 26, 33 and 40, and with 100 cat fleas (Ctenocephalides felis felis) on Days -1, 6, 13, 20, 27, 34 and 41. Dogs were examined and parasites "finger counted" on Day 1 to estimate knock down efficacy, and all animals were comb counted to determine the numbers of viable fleas and ticks on Days 7, 14, 21, 28, 35 and 42. There were no significant differences in parasite counts between the nontreated control and the placebo-treated control groups for either fleas or ticks (P>0.05) except for very slight reductions on Day 7 for fleas and Day 14 for ticks, demonstrating that the formulation excipients had no activity. The qualitative finger counts on Day 1 indicated that all of the insecticidal treatments resulted in a noticeable reduction in flea and tick numbers within 1 day of treatment. All of the metaflumizone and amitraz treatments and fipronil resulted in significantly lower flea and tick numbers relative to nontreated controls on all posttreatment count days (P<0.05). For the metaflumizone plus amitraz treatments, mean flea and tick counts for the 10mg/kg dose were significantly higher than those for the 20mg/kg dose (P<0.05) from Day 21 on. There was no significant advantage provided by the 40mg/kg dose over the 20mg dose throughout the entire study (P>0.05). The two higher metaflumizone plus amitraz doses provided >95% control of fleas and >90% control of ticks for at least 35 days after treatment, and this level of control was similar to that of the commercial fipronil product. The 20mg/kg dose was selected as the minimum commercial dose rate to provide effective flea and tick control for at least 1 month following a single treatment.

Topical formulations of metaflumizone plus amitraz to treat flea and tick infestations on dogs.

A topical spot-on solution was developed for treating pets that contained of active ingredients metaflumizone and amitraz and intended for use as an ectoparasiticide. The formulation vehicle system was designed by balancing the following three attributes of various solvents: evaporation/drying, surface spreading, and percutaneous absorption. The solvents were selected by evaluating the solubilization capacity of individual solvents with respect to the above active ingredients. The evaporation rates of various solvent systems were then determined. The visual observations of the treatment sites was also performed a day after treating the dogs to understand the cosmetic effect of various solvent systems. The lead formulations dried off within a day after application with no noticeable residue at the treatment site, while others produced appreciable powdery residue or a large wet and oily spot. The stability of the lead formulations was also evaluated over 2 years to demonstrate a 2-year shelf life of this product.

Synthesis and structure-activity relationship on anticonvulsant aryl semicarbazones.

Seven series of various substituted aryl semicarbazones were synthesized and evaluated for anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure threshold tests. A comprehensive structure-activity relationship was derived comparing the substituents on the aryl ring and in the carbimino terminal. Generally the order of activity was 4-F > 2-Br = 3-Br = 4-Cl > 4-CH(3) > 4-Br > 3-Cl > 3-CH(3) with respect to the primary aryl group. Most of the compounds exhibited activity both in the MES and scPTZ screens. The 4-fluorophenyl substituted semicarbazones (5a-5y) emerged as the most potent compounds exhibiting anticonvulsant activity in mouse intraperitoneal (i.p.) and rat per oral (p.o.) MES, scPTZ and psychomotor seizure (6 Hz) screens.

Synthesis and evaluation of 4-substituted semicarbazones of levulinic acid for anticonvulsant activity.

OBJECTIVE: A series of 4-aryl substituted semicarbazones of levulinic acid (4-oxo pentanoic acid) was designed and synthesized to meet the structural requirements essential for anticonvulsant activity. METHODS: All the compounds were evaluated for anticonvulsant activity. Anticonvulsant activity was determined after intraperitoneal (i.p.) administration to mice by maximal electroshock (MES) and subcutaneous metrazol (ScMet) induced seizure methods and minimal motor impairment was determined by rotorod test. RESULTS: A majority of the compounds exhibited significant anticonvulsant activity after intraperitoneal administration. In the present study 4-(4'-fluoro phenyl) levulinic acid semicarbazone emerged as the most active molecule, showing broad spectrum of activity with low neurotoxicity. Unsubstituted levulinic acid semicarbazone was found to be inactive in all the screens. CONCLUSION: The results obtained validate the hypothesis that presence of an aryl group near the semicarbazone moiety is essential for anticonvulsant activity. The results also indicate that the hydrophilic-hydrophobic site can accommodate hydrophilic groups.

4-sulphamoylphenyl semicarbazones with anticonvulsant activity.

A series of 4-sulphamoylphenyl semicarbazone derivatives were prepared starting from sulphanilamide and screened for anticonvulsant activity. The results indicated that greater protection was obtained in the maximal electroshock screen (MES) and subcutaneous strychnine (scSTY) than the subcutaneous pentylenetetrazole (scPTZ) tests. All the compounds showed low neurotoxicity when compared to the clinically used drugs. Compounds with substituted acetophenone (8-11) showed good activity in the rat oral MES screen. Seven compounds (6, 8-10, 12, 14 and 15) exhibited anticonvulsant activity greater than sodium valproate. Among the new derivatives evaluated, compound 10 emerged as the most active compound as indicated by its protection in the MES and scSTY screens and with low neurotoxicity. Seven compounds possessed sedative-hypnotic activity.

Design and synthesis of semicarbazones and their bio-isosteric analogues as potent anticonvulsants: the role of hydrogen bonding.

A series of p-nitrophenyl substituted semicarbazones (4a-c) and phenoxy/p-bromophenoxy acetyl hydrazones (8a-q) were synthesized and their anticonvulsant activity was screened against maximal electroshock seizure (MES), subcutaneous metrazole (ScMet) and subcutaneous strychnine (ScSty) tests. Compounds 4a-c with -NHCO- were found to be the most active in all these tests. These compounds were also active in the MES test after oral administration in rats. On the other hand, compounds 8a-q with -OCH2- were devoid of anticonvulsant activity. The studies revealed that the hydrogen bonding domain in semicarbazones, adjacent to the lipophilic aryl ring, is essential for the anticonvulsant activity.

Synthesis of isatin semicarbazones as novel anticonvulsants--role of hydrogen bonding.

PURPOSE: A series of substituted isatin semicarbazones and related bioisosteric hydrazones were designed and synthesised to meet the structural requirements essential for anticonvulsant properties. METHODS: The structures of all synthesised compounds were confirmed by means of infrared, proton magnetic resonance spectroscopy and by elemental analyses. All compounds were evaluated for their anticonvulsant activity by maximal electroshock (MES), subcutaneous metrazol (ScMet) and subcutaneous strychnine (ScSty) induced seizure methods and their neurotoxic effects were determined by rotorod test. RESULTS: A number of isatin semicarbazones exhibited significant protection after intraperitoneal administration at the dose of 100 and 300mg/kg. Some of them showed good anticonvulsant activity in MES test in rats after per oral administration at the dose of 30mg/kg. The bioisosteric hydrazone derivatives were inactive in all tests. Compound 6-chloroisatin-3- (4-bromophenyl)-semicarbazone has emerged as the most active analogue of the series showing good activity in all the three tests and was more active than phenytoin and valproic acid. CONCLUSIONS: The results evidenced the importance of hydrogen bonding and suggested a new pharmacophore model with four binding sites essential for anticonvulsant activity.

(Aryloxy)aryl semicarbazones and related compounds: a novel class of anticonvulsant agents possessing high activity in the maximal electroshock screen.

A number of (aryloxy)aryl semicarbazones and related compounds were synthesized and evaluated for anticonvulsant activities. After intraperitoneal injection to mice, the semicarbazones were examined in the maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ), and neurotoxicity (NT) screens. The results indicated that greater protection was obtained in the MES test than the scPTZ screen. Quantitation of approximately one-third of the compounds revealed an average protection index (PI, i.e. TD50/ED50) of approximately 9. After oral administration to rats, a number of compounds displayed significant potencies in the MES screen (ED50 of 1-5 mg/kg) accompanied by very high protection indices. In fact over half the compounds had PI figures of greater than 100, and two were in excess of 300. The compounds were essentially inactive in the scPTZ and NT screens after oral administration to rats. Various compounds displayed greater potencies and PI figures in the mouse intraperitoneal and rat oral screens than three reference clinically used drugs. The data generated supported a binding site hypothesis. Quantitative structure-activity relationships indicated a number of physicochemical parameters which contributed to activity in the MES screen. X-ray crystallography of five compounds suggested the importance of certain interatomic distances and bond angles for activity in the mouse and rat MES screens.

Anticonvulsant activities of some arylsemicarbazones displaying potent oral activity in the maximal electroshock screen in rats accompanied by high protection indices.

Various semicarbazones derived from aryl aldehydes, phenylalkyl aldehydes, and phenylalkyl ketones as well as some related compounds were evaluated for anticonvulsant activity. Most of the compounds displayed anticonvulsant activity in the maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) screens accompanied by neurotoxicity when given to mice by the intraperitoneal route. However quantitative data revealed protection indices (TD50/ED50) of less than 4 in general. Oral administration of the compounds to rats led to excellent potency in the MES screen accompanied by high protection indices while virtually no activity in the scPTZ test was displayed. These observations support the theory that one large hydrophobic group (in this case the aryl ring) and two electron donor atoms (present in the semicarbazono group) are requirements for protection in the MES screen. In general, the semicarbazones had rapid onsets of action, and one of the ways in which these compounds displayed their anticonvulsant activity is likely to be interaction with chloride channels. Empirical and semiempirical conformational calculations indicated that certain molecular fragments and hydrophobicity of these molecules affect bioactivity.

Influence of vehicle on topical efficacy of 2-acetylpyridine thiosemicarbazone and related derivatives on in vivo type 2 herpes simplex virus infections.

2-Acetylpyridine semicarbazone (APSC), 2-acetylpyridine thiosemicarbazone (APTSC) and 2-acetylpyridine-4-methyl-3-thiosemicarbazonoe (APMTSC) were evaluated against type-2 herpes simplex virus (HSV-2)-induced genitalis and encephalitis in mice and guinea pigs. The antiviral activity of these compounds was compared with that of acyclovir. With 1,3-butanediol as a topical treatment vehicle, 1% APSC and APTSC showed significant activity against the genital infection in mice, as evidenced by increased survivors and decreased severity of vaginal lesions. Reduced titers of virus recovered from the lesions were also observed with APTSC treatments. Eight different commercially available vehicles were compared to determine in which topically administered 1% APTSC would be most efficacious against the vaginal disease induced in mice. Significant results were observed with Squibb cream base, Eucerin base, and K-Y jelly; these effects were essentially equivalent to using 1,3-butanediol Unibase, Aquaphor, polyethylene glycol, polyvinyl alcohol and petrolatum were less effective as carrier vehicles. The herpesvirus genital infection in guinea pigs was treated with 1% APMTSC and APTSC comparing Squibb cream, Eucerin and K-Y jelly bases; while neither compound exerted striking effects against this infection in any vehicle, 1% APMTSC in Squibb cream was effective in increasing mean survival time and reducing lesion score and titers of recoverable virus. In this experiment, treatments with 1 and 5% acyclovir in polyethylene glycol base were effective in reducing titers of virus from the vaginal area. Orally administered APTSC (12.5, 25, 50 mg/kg/day given twice daily for 7 days) caused moderate prevention of death of mice infected intraperitoneally with HSV-2; subcutaneous injection of the compound was markedly effective with efficacy comparable to that of acyclovir at 120 mg/kg/day.