Showing papers in "Drug Research in 1996"

Free radical scavenging activity of curcuminoids.

Abstract: Three natural curcuminoids (curcumin (CAS 458-37-7), demethoxycurcumin, bisdemethoxycurcumin) and acetylcurcumin were compared for their ability to scavenge superoxide radicals and to interact with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) stable free radicals. The results showed that curcumin is the most potent scavenger of superoxide radicals followed by demethoxycurcumin and bisdemethoxycurcumin. Acetylcurcumin was inactive. Interaction with DPPH showed a similar activity profile. The study indicates that the phenolic group is essential for the free radical scavenging activity and presence of methoxy group further increases the activity.

Oxygen species scavenging activity of phenolic extracts from hawthorn fresh plant organs and pharmaceutical preparations.

Abstract: Different extracts of fresh vegetative and reproductive organs from Crataegus monogyna harvested during a whole season and from some pharmaceutical hawthorn preparations exhibit in vitro antioxidant activities using three different models of oxygen reactive species generation (superoxide anion, hydrogen peroxide and hypochlorous acid). All the tested samples show low IC50 values, the most efficient being fresh young leaves, fresh floral buds and pharmaceutical dried flowers. The activities seem to be especially bound to the total phenolic proanthocyanidin and flavonoid contents.

Influence of tramadol on neurotransmitter systems of the rat brain

Abstract: In in vitro receptor binding and synaptosomal uptake experiments the (+)-enantiomer of tramadol (CAS 148229-78-1) is specific for the mu-opioid receptor site and for the serotonin (5-HT) carrier, whereas the (-)-enantiomer (CAS 148229-79-2) has a higher affinity to the noradrenaline (NA) transporter. The antinociceptive active tramadol metabolite O-demethyltramadol (M1) shows a pronounced mu-selectivity. With respect to in vitro receptor binding experiments, the affinity of (+)-M1 to this opioid receptor subtype is more than two orders of magnitude higher than that of (+)-tramadol and approximately 1/10 that of morphine. Tramadol and M1 (and the enantiomers thereof) have no affinity to other receptor or uptake sites tested, e.g. 5-HT1A, 5-HT2, 5-HT3, NMDA (ligand: MK801), dopamine (DA)-D1, DA-D2, benzodiazepine, muscarine M1 and DA uptake (Ki > or = 2 x 10(-5) mol/l). Ex vivo neurotransmitter determinations show that tramadol (46.4 mg/kg i.p.) elevates the DA metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid and enhances DA release in definite brain areas. The active enantiomer of the racemic tramadol is the (+)-enantiomer. (+)-Tramadol significantly enhances the turnover rate of DA. The enantioselective elevation of DOPAC by (+)-tramadol is antagonized by naloxone (2 x 5 mg/kg i.p.). Morphine (21.5 mg/kg i.p.) enhances the turnover of NA in definite brain areas. Neither the NA-specific uptake inhibition nisoxetine (31.6 mg/kg i.p.) nor tramadol (or its (+)- and (-)-enantiomers) have any influence on the NA turnover. Tramadol reduces the levels of 5-HT and its metabolite 5-hydroxyindoleacetic acid. Morphine enhances, whereas tramadol reduces, 5-HT utilisation in the brain areas under assay. The 5-HT specific uptake inhibitor fluoxetine (20 mg/kg i.p.) shows the same influence on 5-HT turnover as tramadol. The results indicate that tramadol enhances DA turnover via an opioid mechanism. The interaction with the noradrenergic and serotonergic neurotransmission is clearly different from that of an opioid receptor agonist and closely resembles that of NA and 5-HT uptake inhibitors.

Detection of apoptosis in KG-1a leukemic cells treated with investigational drugs.

Abstract: Four investigational drugs, p-benzoquinone, primine, miconidine acetate, and artesunate (dihydroqinghaosusuccinate), with growth inhibitory activity against flagellatae (e.g. trypanosoma, leptomonas, plasmodium) were investigated for their capability to induce programmed cell death (apoptosis) in human KG-1a leukemic cells. The results were compared with those of three well established cytostatic agents (cisplatin, daunorubicin, cytosine-arabinoside) and ionizing radiation. The antitumor activity of the drugs was validated by a cellular growth inhibition assay. The depletion of glutathione by these four investigational drugs favours the hypothesis that formation of free radicals and subsequent DNA strand breaks may be critical mechanisms of action and that the glutathione redox cycle is involved in detoxification of these reactive molecules.

Pharmacokinetics of iron(III)-hydroxide sucrose complex after a single intravenous dose in healthy volunteers.

Abstract: The pharmacokinetics of iron were investigated after intravenous administration to 12 healthy volunteers of iron(III)-hydroxide sucrose complex (Venofer) as a single i.v. dose containing 100 mg Fe. The average predose concentration was 35.7 +/- 12.5 mumol/l. There was no statistically significant difference between the serum iron level before injection (0 h) and the level at 24 h after the injection. The compartment model used includes a Michaelis-Menten term and is in excellent agreement with the observed exchange of iron to transferrin and with the daily iron turnover by transferrin. The intravenously injected iron(III)-hydroxide sucrose complex led rapidly to high serum iron levels. Maximum measured levels averaged 538 mumol/l (30.0 mg/l) at 10 min after the injection. The terminal half-life of the injected iron was calculated to be 5.3 h. Mean total area under the curve (AUC) was 1491 mumol/l h, the mean residence time (MRT) was 5.5 h. The total body clearance was 20.5 ml/min. The volume of distribution of the central compartment (Vc) was 3.21, hence close to the volume of the serum; the volume of distribution at steady state (Vdss) was 7.31; and the volume of distribution during elimination (Vdarea) was 9.21. The calculated amount of iron transported by transferrin was 31.0 +/- 6.6 mg Fe/ 24h. In summary, the data show that the injected iron(III)-hydroxide sucrose complex is quickly cleared from the serum with a terminal half-life of approximately 5-6 h. Renal elimination of iron contributed very little to the overall elimination (in average < 5%). Renal elimination of sucrose averaged about 68 +/- 10% and 75 +/- 11% of the administered dose after 4 h and 24 h, respectively.

Therapy of bacterial vaginosis using exogenously-applied Lactobacilli acidophili and a low dose of estriol: a placebo-controlled multicentric clinical trial.

Abstract: The efficacy of vaginal tablets (Gynoflor) containing 50 mg of a lyophilisate of viable, H2O2-producing Lactobacillus acidophilus (at least 10(7) colony forming units/tablet) and 0.03 mg estriol (CAS 50-27-1) for the treatment of bacterial vaginosis (BV) was tested in a multicentric, randomised, placebo-controlled clinical trial with parallel-group design. 32 non-menopausal women with positive diagnoses for BV, including intermediate cases, participated in the trial. Patients were diagnosed using the classical clinical parameters of BV according to Amsel and using microscopic analysis of the Gram-stained vaginal smear. A positive clinical diagnosis of BV required at least 2 of the following 4 clinical criteria to be positive; greyish-white, homogeneous leukorrhea; vaginal pH > 4.5; KOH test for volatile amines; presence of clue cells. Microscopic diagnosis of BV, on the other hand, was obtained if examination of the Gram-stained vaginal smear showed less than 6 lactobacilli per field of view (1000 x magnification). This corresponds to another definition of BV as "lactobacilli deficiency syndrome". The efficacy of the 6-day therapy with 1-2 vaginal tablets daily was evaluated using both clinical and microscopic analysis. Using Amsel's classical clinical parameters of BV, the cure rate (defined as < or = 1 of the 4 clinical criteria positive) two weeks after the start of therapy was 77% in the verum group and 25% in the placebo group. Four weeks after the start of therapy, the cure rate was 88% in the verum group and 22% in the placebo group. At both control examinations, the cure rate for the test group was significantly higher than that for the placebo group (p < 0.05, Fisher's exact test, 2-sided, significance level 0.05). In addition, the trial showed that after 6 days of treatment with the test preparation, the lactobacilli were capable of recolonising the vagina. A significant increase in the number of lactobacilli was observed in the Gram-stained vaginal smear for the patient group treated with the test preparation compared to the placebo patient group (p < 0.05, Fisher's exact test, 2-sided, significance level 0.05), two and four weeks after the start of the 6-day treatment.

[Anti-inflammatory effect of Urtica dioica folia extract in comparison to caffeic malic acid].

Abstract: Urtica dioica extract is a traditionary used adjuvant therapeutic in rheumatoid arthritis The antiphlogistic effects of the urtica dioica folia extract IDS 23 (Extractum Urticae dioicae foliorum) and the main phenolic ingredient caffeic malic acid were tested concerning the inhibitory potential on biosynthesis of arachidonic acid metabolites in vitro The caffeic malic acid was isolated from Urtica folia extract using gel exclusion- and high performance liquid chromatography and identified by mass spectroscopy and nuclear magnetic resonance Concerning the 5-lipoxygenase products IDS 23 showed a partial inhibitory effect The isolated phenolic acid inhibited the synthesis of the leukotriene B4 in a concentration dependent manner The concentration for halfmaximal inhibition (IC50) was 83 microns/ml in the used assay IDS 23 showed a strong concentration dependent inhibition of the synthesis of cyclooxygenase derived reactions The IC50 were 92 micrograms/ml for IDS 23 and 38 micrograms/ml for the caffeic malic acid Calculating the content in IDS 23 the caffeic malic acid is a possible but not the only active ingredient of the plant extract in the tested assay systems It is demonstrated that the phenolic component showed a different enzymatic target compared with IDS 23 The antiphlogistic effects observed in vitro may give an explanation for the pharmacological and clinical effects of IDS 23 in therapie of rheumatoid diseases

1-Hydroxy-3-(methylpentylamino)-propylidene-1,1-bisphosphonic acid as a potent inhibitor of squalene synthase.

Abstract: Squalene synthase, the first committed enzyme for sterol synthesis, converts farnesyl pyrophosphate to squalene with presqualene pyrophosphate as an intermediate. It was discovered that BM 21.0955 (1-hydroxy-3-(methylpentylamino)-propylidene-1,1-bisphosphon ic acid), in development for the treatment of bone disorders, inhibited rat liver microsomal squalene synthase (K(i) = nmol/l). BM 21.0955 also inhibited sterol biosynthesis from mevalonate (IC50 = 42 nmol/l), and cholesterol biosynthesis in J774 cells (IC50 = mumol/l). Structural modifications on this molecule to make it more lipophilic may result in a new class of cholesterol-lowering agents.

Anticonvulsant activity of piperine on seizures induced by excitatory amino acid receptor agonists.

Abstract: In traditional Chinese medicine, a mixture of radish and pepper is used to treat epilepsy. The presumptive effectiveness of this prescription might be due to the anticonvulsant actions of the principal component of pepper, the alkaloid piperine (CAS 94-62-2). The effects of piperine on convulsions induced in mice by agonists at different excitatory amino acid receptor subtypes were studied. Piperine was shown to significantly block convulsions induced by intracerebroventricular injection of threshold doses of kainate, but to have no or only slight effects on convulsions induced by L-glutamate, N-methyl-D-aspartate or guanidinosuccinate. Piperine suspensions, injected intraperitoneally, 1 h before injection of the threshold intracerebroventricular dose of kainate for the induction of clonic convulsions (1 nmol), blocked these convulsions with an ED50 (and 95% confidence interval) of 46 (25-86) mg/kg. Although piperine did block convulsions, induced by kainate, the compound does not appear to act as a kainate receptor antagonist. Whole-cell currents induced by the application of kainate to spinal cord cells in primary dissociated cultures were not affected by co-application of piperine.

Comparative analysis of the cardiotoxicity proclivities of second generation antihistamines in an experimental model predictive of adverse clinical ECG effects.

Abstract: Terfenadine and astemizole belong to the second generation histamine H1 antagonists and are widely prescribed for allergic and upper respiratory diseases. The popularity of the newer H1 antihistamines is due to their ability to provide relief from allergic symptoms without the undesirable side effect of sedation commonly associated with first generation H1 receptor antagonists such as diphenhydramine and promethazine. Recent clinical evidence that the second generation histamine H1 antagonists terfenadine and astemizole have the potential for inducing life threatening ventricular arrhythmias has raised questions as to whether other drugs in this class have similar cardiotoxic potential. The objective of this study was to evaluate and compare the arrhythmogenic potential of a series of second generation antihistamines in a quantitative experimental model predictive of adverse ECG effects in man. Antihistamines were given intravenously and electrocardiographic (ECG) and cardiovascular parameters (blood pressure and heart rate) were measured. The ECG wave form was analyzed to determine QTc interval, PR interval, QRS interval and heart rate. To determine the relative cardiotoxic potential of the antihistamines, the lowest dose producing significant prolongation of the QTc interval was compared with the dose required to inhibit by 50% the peripheral bronchospasm elicited by histamine at 10 micrograms/kg i.v. (antihistamine ED50). The second generation antihistamines studied were astemizole (CAS 68844-77-9), carebastine (CAS 90729-42-3), cetirizine hydrochloride (CAS 83881-52-1), ebastine (CAS 90729-43-4), norastemizole (CAS 75970-99-9), terfenadine (CAS 50679-08-8) and terfenadine carboxylate (CAS 83799-24-0). The second generation antihistamines astemizole, ebastine and terfenadine produced pronounced dose-dependent QTc interval prolongation effects. These arrhythmogenic effects occurred at doses that were between 1 and 4 times their respective peripheral antihistamine doses. These drugs produced significant disruption of the ECG wave form including large amplitude, morphologically aberrant T-waves and, in some cases, torsades de pointes-type arrhythmias. In contrast, terfenadine carboxylate (100 mg/kg i.v.), norastemizole (20 mg/kg, i.v.) and carebastine (50 mg/kg, i.v.), the major metabolites of terfenadine, astemizole and ebastine, were largely devoid of adverse ECG effects. Similarly, cetirizine (20 mg/kg, i.v.) was also found to not alter ECG or cardiovascular function. These findings demonstrate that terfenadine, astemizole and ebastine exhibit significant arrhythmogenic effects including QTc interval prolongation, bradycardia and distortion of the ECG morphology in the guinea pig. The relative cardiotoxicity of these antihistamines based on the separation of antihistamine activity and adverse ECG effects was similar for terfenadine and astemizole, but slightly less for ebastine. In this model carebastine, cetirizine, loratadine, norastemizole and terfenadine carboxylate are devoid of QTc prolongation effects. Given the structural similarity of terfenadine and ebastine it is not surprising that these drugs produce significant cardiotoxicity in this animal model. Taken together, these results indicate that the ability to cause QTc interval prolongation and the proclivity for producing arrhythmias is not a class effect and is seen only with some second generation nonsedating antihistamines.

Efficacy of a fixed peppermint oil/caraway oil combination in non-ulcer dyspepsia.

Abstract: The efficacy and safety of the standardized herbal combination preparation of Enteroplant, consisting of peppermint oil (90 mg) and caraway (50 mg) in an enteric coated capsule, have been studied in a double-blind, placebo-controlled multicentre trial in patients with non-ulcer dyspepsia. A total of 45 patients were included in the trial after thorough physical and gastro-enterological examination. The primary outcome variables were the change in the intensity of pain and the global clinical impression (Clinical Global Impression [CGI], Item 2), which were evaluated for 39 patients (test preparation: 19, placebo: 20). After four weeks of treatment both target parameters were significantly improved for the group of patients treated with the peppermint oil/caraway oil combination compared to the placebo group (p = 0.015 and 0.008, respectively). Before the start of treatment all patients in the test preparation group reported moderate to severe pain, while by the end of the study 63.2% of these patients were free of pain. The pain symptoms had improved in a total of 89.5% of the patients in the active treatment group. After 4 weeks the Clinical Global Impressions were improved for 94.5% of the patients treated with the peppermint oil/caraway oil combination. The trial medication was also superior to placebo with respect to pain frequency, medical prognosis, the severity of the disorder and the efficacy index (CGI, Items 1 and 3), which were adopted as secondary end-points for evaluation of efficacy. There were similarly favourable findings for the herbal combination, compared with placebo, with respect to the reduction of other gastrointestinal symptoms. The combination preparation was found to be excellently tolerated. There was a total of 7 adverse events (test preparation: 4, placebo: 3), with a causal association with the treatment being ascribed in one case for the test preparation group and one case for the placebo group.

Comparison of tissue and plasma levels of ibuprofen after oral and topical administration.

Abstract: The penetration and absorption of ibuprofen (CAS 15687-27-1) from a topical gel and oral tablets were tested in an open study, performed in 17 patients with degenerative knee disorders requiring an operation Patients administered the topical test preparation (ibugel, 3 x 375 mg ibuprofen daily) or the standard oral preparation (2 x 600 mg ibuprofen daily) for 3 days prior to the operation Samples of blood, synovial fluid, muscle, fasciae and subcutis were obtained during the operation (15 h after the last administration) and analysed for ibuprofen content using a validated HPLC method Different absorption profiles were observed for topical and oral administration Oral administration led to higher concentrations in the plasma, synovial fluid and fasciae, while higher levels in the muscle and subcutis were found after topical administration After topical application, the concentrations in the fasciae, muscle and subcutis were significantly higher than those in the blood plasma and synovial fluid (p < 005) Very low levels of ibuprofen were observed in the subcutis after oral administration This can be explained by the different pathways This study demonstrated that concentrations of ibuprofen in the various biological samples were still within therapeutically effective levels 15 h after topical or oral administration By use of an oral comparison group, it has been possible to show that the concentrations in times directly under the site of topical application lie in the same order of magnitude as those found after preoral treatment Therapy of intra-articular inflammatory and degenerative joint diseases requires oral administration of non-steroidal anti-inflammatory drugs (NSAIDs) However, based on the results of this study, topical therapy with NSAIDs can be recommended for soft tissue rheumatism and periarticular insertion tendinopathia

Influence of the antibiotics erythromycin and azithromycin on the pharmacokinetics and pharmacodynamics of midazolam

Abstract: The pharmacokinetic and pharmacodynamic interaction between azithromycin (CAS 83905-01-5), an azalide antibiotic, and midazolam (CAS 59467-70-8), a short-acting hypnotic agent, was investigated in an open, three-way cross-over study, including erythromycin (CAS 114-07-8) as a positive control. Twelve healthy male and female subjects had standard doses of azithromycin (500 mg o.d. over 3 days), or erythromycin (500 mg t.i.d. over 5 days), or no pretreatment. On the day of the last dose, they ingested 15 mg midazolam. Blood samples were collected and psychometric tests performed. Erythromycin pretreatment (E) significantly changed the pharmacokinetics of midazolam compared to control (C), whereas azithromycin (A) had no such effect. The parameters are summarized as follows: area under the concentration-time curve, AUC (C) 173.8 h.ng.ml-1 vs. (E) 662.7 h.ng.ml-1*+ and (A) 220.0 h.ng.ml-1; concentration maxima (C) 67.2 ng.ml-1 vs. (E) 182.3 ng.ml-1*+ and (A) 86.7 ng.ml-1; elimination half-life (C) 2.21 h vs. (E) 4.85 h* and (A) 2.41 h (* p < 0.05 vs. (C), +p < 0.05 vs. (A)). Pharmacodynamic tests (digit symbol substitution test; critical flicker fusion test; subjective analog scale for rating of alertness; duration of sleep) consistently showed significant differences after erythromycin pretreatment compared to control, but not after azithromycin. Erythromycin, but not azithromycin, causes clinically significant changes in the pharmacokinetics and pharmacodynamics of midazolam.

Characterization of sulfation patterns of beef and pig mucosal heparins by nuclear magnetic resonance spectroscopy.

Abstract: Though differing only slightly in their degrees of sulfation, heparin preparations from pig mucosa and those from beef mucosa have consistently different 13C- and 1H-NMR spectra, which provide useful fingerprints for distinguishing the two types of heparin. Integrated areas of NMR signals associated with minor, undersulfated sequences (assigned by comparison with mono-dimensional spectra of selectively desulfated heparins and by analysis of two-dimensional spectra of heparins prepared from pig and beef mucosa) permit quantitation of differences in sulfation patterns. Undersulfation of pig mucosal heparins at position 6 of the hexosamine units, determined by 13C-NMR and expressed as percent glucosamines nonsulfated at C6 referred to total glucosamines, is substantially lower for pig mucosal heparins than for beef mucosal heparins (16.9-21.7% vs 36.7-40.7%; average values: 18.6% vs 40.3%). By contrast, undersulfation at position 2 of the iduronic acid units, determined by 1H-NMR and expressed as percent nonsulfated iduronic acid referred to total (sulfated + nonsulfated) iduronic acid is significantly higher for pig mucosal preparations (9.6-13.5% vs 2.1-2.7%; average values: 12.7% vs 2.3%). Pig mucosal heparins also have a significantly higher content of 3-O-sulfated glucosamine units, which are markers for the active site of heparin for antithrombin-III.

Effect of basic fibroblast growth factor on wound healing in healing-impaired animal models.

Abstract: The effect of basic fibroblast growth factor (bFGF) on wound healing was studied in healing-impaired animal models such as metabolic diseases (obesity and diabetes), infection, steroid treatment, malnutrition and chronic liver failure. bFGF treatment resulted in an acceleration of wound healing in an almost same dose range regardless of impairment causes or animal species used. The beneficial effects of bFGF on wound healing were suggested to be due to its potent angiogenesis and granulation tissue formation activities, leading to a rapid reepitherialization of the wound. In addition, the findings that bFGF promoted healing in infection wound and burn wound of diabetic mice, and burn wound of dietary-restricted rats indicated its ability to accelerate wound contraction, another important process of wound closure.

Ex-vivo in-vitro inhibition of lipopolysaccharide stimulated tumor necrosis factor-alpha and interleukin-1 beta secretion in human whole blood by extractum urticae dioicae foliorum.

Abstract: An extract of Urtica dioica folium (IDS 23, Rheuma-Hek), monographed positively for adjuvant therapy of rheumatic diseases and with known effects in partial inhibition of prostaglandin and leukotriene synthesis in vitro, was investigated with respect to effects of the extract on the lipopolysaccharide (LPS) stimulated secretion of proinflammatory cytokines in human whole blood of healthy volunteers. In the assay system used, LPS stimulated human whole blood showed a straight increase of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) secretion reaching maximum concentrations within 24 h following a plateau and slight decrease up to 65 h, respectively. The concentrations of these cytokines was strongly positively correlated with the number of monocytes/macrophages of each volunteer. TNF-alpha and IL-1 beta concentration after LPS stimulation was significantly reduced by simultaneously given IDS 23 in a strictly dose dependent manner. At time 24 h these cytokine concentrations were reduced by 50.8% and 99.7%, respectively, using the highest test IDS 23 assay concentration of 5 mg/ml (p < 0.001). After 65 h the corresponding inhibition was 38.9% and 99.9%, respectively (p < 0.001). On the other hand IDS 23 showed no inhibition but stimulated IL-6 secretion in absence of LPS alone. Simultaneously given LPS and IDS 23 resulted in no further increase. In contrast to described effects on arachidonic acid cascade in vitro, tested Urtica dioica phenol carbon acid derivates and flavonoides such as caffeic malic acid, caffeic acid, chlorogenic acid, quercetin and rutin did not influence LPS stimulated TNF-alpha, IL-1 beta and IL-6 secretion in tested concentrations up to 5 x 10(-5) mol/l. These further findings on the pharmacological mechanism of action of Urticae dioica folia may explain the positive effects of this extract in the treatment of rheumatic diseases.

Methylotrophic yeast hansenula polymorpha as production organism for recombinant pharmaceuticals.

Abstract: Since the onset of genetic engineering, yeasts belong to the preferred host cells for the production of heterologous proteins. They combine ease of genetic manipulation and cultivation with the ability to process and to modify the produced compounds according to a general eukaryotic scheme. Since yeasts do not contain pathogens, pyrogens or viral inclusions they constitute attractive production systems for proteins considered for therapeutic administration. At the beginning of gene technology the attention of biotechnologists focussed on the use of the best characterized species Saccharomyces cerevisiae. Insulin and hepatitis B vaccines are examples for S. cerevisiae-derived therapeutics. In recent years alternative yeast have become accessible for the techniques of modern molecular genetics and thus for potential applications in biotechnology. In this respect the methylotrophic yeast Hansenula polymorpha offers especially advantageous characteristics as host for the production of pharmaceutical proteins. As a consequence, production systems based on this yeast have been established for serum proteins, vaccines and other therapeutically important compounds. Some H. polymorpha-derived products are under preclinical or clinical trials at present and are expected to reach the market within the near future. In the following article the current status of this system is presented and discussed comparing it with other expression systems.

Cardiotoxic and drug interaction profile of the second generation antihistamines ebastine and terfenadine in an experimental animal model of torsade de pointes

Abstract: Second generation antihistamines are widely used because of their efficacy in treating allergic disorders without significant sedative side effects. Recent clinical evidence shows that some of the early prototypes in this class, namely terfenadine and astemizole, have the potential for producing torsade de pointes, a rare form of ventricular arrhythmia that is life-threatening. Important questions have been raised as to whether this is a property shared by newer, recently-introduced second generation antihistamines. The objective of this study was to characterize and compare the ECG and cardiovascular effects of terfenadine (CAS 50679-08-8) and ebastine (CAS 90729-43-4), a new second generation antihistamine, in an experimental animal model predictive of the cardiotoxic proclivity of these agents. Also, the drug interaction effect of the antifungal drug ketoconazole (CAS 65277-42-1) was evaluated, which blocks hepatic first-pass biotransformation of ebastine and terfenadine leading to increased cardiotoxity of terfenadine in man, on the ECG effects of terfenadine and ebastine in this animal model. Terfenadine (10 mg/kg) and ebastine (50 mg/kg) were administered intravenously to anesthetized guinea pigs. Electrocardiographic (ECG) and cardiovascular parameters (blood pressure and heart rate) were measured during the course of the experiment. The ECG wave form was analyzed to determine QTc interval, PR interval, QRS interval and heart rate. In separate studies in conscious guinea pigs, the effect of oral ketoconazole (200 mg) on the ECG effects of oral terfenadine (60 mg) and ebastine (10 mg) was studied. Terfenadine (10 mg/kg) and ebastine (50 mg/kg) produced significant prolongation of the QTc interval and disruption of the ECG signal when given intravenously to anesthetized guinea pigs. The ECG effects were characterized by large amplitude, morphologically aberrant T-waves, and instances of arrhythmogenic activity. Both drugs produced pronounced bradycardia and hypotension. In conscious animals, pretreatment with oral ketoconazole significantly enhanced the QTc interval prolongation effects of terfenadine and ebastine. Oral terfenadine and ebastine, when given alone at the doses tested, were devoid of adverse QTc interval prolongation effects in the conscious guinea pig. In separate studies in conscious guinea pigs, oral loratadine (10 mg; CAS 79794-75-5) given alone or in animals pretreated with ketoconazole did not affect ECG parameters. The present studies show that terfenadine and ebastine share similar cardiotoxic properties characterized by QTc interval prolongation, bradycardia, hypotension and proarrhythmogenic activity in the anesthetized guinea pig. In addition, pretreatment with ketoconazole enhances the QTc interval effect of both drugs, most likely due to the accumulation of parent compound that occurs after blockade of hepatic metabolism by CYP3A4. In conclusion, our findings indicate that ebastine and terfenadine display similarities in their inherent potential for cardiotoxic and adverse drug interaction effects. In contrast, loratadine is devoid of adverse ECG and drug interaction effects.

Cytokine secretion in whole blood of healthy subjects following oral administration of Urtica dioica L. plant extract

Abstract: Twenty healthy volunteers ingested for 21 days 2 capsules b.i.d. of an IDS 23/1 containing nettle leaf extract (Rheuma-Hek). Before and after 7 and 21 days the basal and the lipopolysaccharide (LPS) stimulated tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) concentrations were measured ex vivo. In vitro the effects of IDS 23/1 on the release of these cytokines were determined. Additionally basal interleukin-4 (IL-4) and interleukin-10 (IL-10) levels were recorded. Orally taken the test drug has ex vivo no effect on basal levels of TNF-alpha, IL-1 beta, IL-4, IL-6 or IL-10 which were always below detection limits. After 7 and 21 days ingestion ex vivo a decrease of LPS stimulated TNF-alpha release of 14.6 and 24.0%, respectively, was observed. IL-1 beta was reduced for 19.2 and 39.3%. In vitro IDS 23/1 added to whole blood resulted in an exceeded inhibition of LPS stimulated TNF-alpha and IL-1 beta secretion which correlated with the duration of the drug ingestion. Using the highest tested IDS 23/1 concentration the inhibition reached 50.5 (day 0) to 79.5% (day 21) for TNF-alpha and 90.0 (day 0) to 99.2% (day 21) for IL-1 beta, respectively. IDS 23/1 induced a pronounced release of IL-6 in absence of LPS only in vitro. The detected IL-6 concentrations were comparable to those after LPS stimulation, additive effects could not be observed. The absence of detectable IL-6 concentrations in whole blood ex vivo after oral ingestion of the tested drug as well as the differences in the inhibition patterns for TNF-alpha and IL-1 beta ex vivo and ex vivo in vitro suggest that the extract contains different pharmacological effective compounds with varying bioavailabilities.

Effect of d-limonene, alpha-pinene and cineole on in vitro transdermal human skin penetration of chlorpromazine and haloperidol

Abstract: The aim of this research is to carry out a comparative study of the ability to cross human skin of two neuroleptic drugs: chlorpromazine (CAS 50-53-3) and haloperidol (CAS 52-86-8), in the absence and in the presence of three terpenes (cineole, d-limonene and alpha-pinene) with the purpose of considering the possibility of improving their transdermal penetration profile. Franz diffusion cells were used, in conjunction with human skin as permeation membrane. The permeation parameters calculated were permeability constant (Kp), flux (J) and lag time (Tl) in the presence and in the absence of enhancers. None of the three enhancers assayed improved the penetration profile of chlorpromazine, and d-limonene even reduced the transdermal permeability (enhancement index, EI = 0.67) since its coefficient of relative activity was reduced, (Xr = 0.73). Cineole and d-limonene increased the permeation profile of haloperidol, giving EI values of 1.95 and 4.21, respectively, and leading to a fourfold increase in the flux value for both enhancers. alpha-Pinene did not modify the permeation profile of haloperidol. None of the three terpenes assayed had a significant effect on the lag time of chlorpromazine or haloperidol. In these experimental conditions the concentration values predicted at steady state of chlorpromazine formulated without enhancers are within the therapeutic range. In contrast, therapeutic levels of haloperidol cannot be predicted in the absence of enhancers such as d-limonene or cineole.

Synthesis, anticonvulsant and analgesic activities of some 6-substituted imidazo(2,1-b)-1,3,4-thiadiazole-2-sulfonamides and their 5-bromo derivatives

Abstract: A series of 6-substituted imidazo(2,1-b)-1,3,4-thiadiazole-2-sulfonamides (V) were prepared by condensation of 2-amino-1,3,4-thiadiazole-5-sulfonamide (II) with an appropriate 2-bromo-ketone (III). Bromination of V in glacial acetic acid gave the corresponding 5-bromo derivatives (VI). Five selected compounds (15-18 and 28) were evaluated for their anticonvulsant and analgesic activities. Compounds 15-17 showed maximum protection (83%) against pentylene tetrazole induced convulsions and maximum electroshock induced seizures while the standard phenobarbital sodium and phenytoin sodium showed 100% protection, respectively. Compounds 15, 16 and 18 showed superior analgesic activity to acetylsalicylic acid in rat caudal immersion test.

Comparative clinical efficacy and tolerability of oxerutins and horse chestnut extract in patients with chronic venous insufficiency.

Abstract: Oxerutins (O-(beta-hydroxyethyl)rutosides, HR, Venoruton) and horse chestnut extract (HCE) are active principles of first priority for the pharmacological treatment of chronic venous insufficiency (CVI). The efficacies of both compounds were shown in numerous, double-blind, randomized, placebo controlled clinical trials. Besides the direct comparison of the two compounds the aim of the study was to investigate the initial dose/maintenance dose concept for HR. 137 female, postmenopausal patients with CVI II finished the study according to protocol. Following one week placebo run-in the patients were treated either with 1000 mg/d HR, 600 mg/d HCE or 1000 mg/d for 4 weeks and than with 500 mg/d HR within the initial dose/maintainance dose concept for 12 weeks and observed for further 6 weeks. A main confirmative criterion was the volume reduction of the leg. Subjective criteria were descriptively evaluated. HR (1000 mg/d) was proven to be equivalent or better, reducing the leg volume (AUB0-18) by -5273 +/- 11418 ml.d compared to -3187 +/- 10842 ml.d under HR (1000 mg/d and 500 mg/d), and -3004 +/- 7429 ml.d under HCE-treatment. Both compounds exhibit a substantial carry-over effect. The maintenance posology of HR is able to stabilize the therapeutic obtained under initial dose conditions.

Investigation of the efficacy of oxerutins compared to placebo in patients with chronic venous insufficiency treated with compression stockings.

Abstract: The aim of this study was to investigate, if the the combined treatment of compression stockings and drug treatment with oxerutins (O-(beta-hydroxyethyl)-rutosides, Venoruton) provides additional benefit for patients with chronic venous insufficiency (CVI) compared to compression treatment alone. Oxerutins belong to the group of oedema protective agents and possess anti-exudative and membrane protective activity. A total of 133 female patients with CVI grade II participated in this double-blind, randomised, multi-centre, parallel-group study with two treatment groups. The whole study lasted for 19 weeks, and consisted of a one week placebo run-in phase, 12 weeks treatment phase, followed by a 6 weeks treatment-free follow-up period. All patients received a basis compression therapy that consisted of standard compression stockings. In order to standardise initial fitting of stockings in this multi-centre setting, stockings were fitted after one week of standard diuretics starting at baseline and then stockings were worn for the following 11 weeks. Patients were randomised to receive oxerutins (2 x 500 mg daily) or matching placebo. Leg volumes (water displacement) and associated subjective symptoms (visula analogue scale) were measured during a placebo run-in period at enrolment (week - 1) and half a week later (week - 1/2), at baseline week 0), at 4, 8, 12 weeks on treatment, and again after a 3- and 6-weeks treatment-free follow-up. The primary efficacy criterion, the area under the baseline from week 0 to week 18 (AUB0-18) of leg volume changes, as measurement of the global change of leg oedema during the study, resulted in a superior reduction of -5589 ml.d for the combined treatment with oxerutins compared to -2101 ml.d for placebo (p = 0.012). The mean change of leg volume compared to baseline after 12 weeks of treatment was -63.9 ml for stockings and oxerutins, and -32.9 ml for the patients who received stockings and placebo (p < 0.05). Oxerutins showed a prolonged effect in the follow-up phase compared to placebo, with mean AUB values for week 12 to week 18 of -1769 ml.d versus -133 ml.d (p < 0.01). The study demonstrated that the combined therapy of compression stockings and drug treatment with oxerutins is significantly superior in reducing leg oedema resulting from chronic venous insufficiency compared to compression treatment alone.

Pharmacological in vitro studies of the new 1,4-dihydropyridine calcium antagonist lercanidipine.

Abstract: The present studies were undertaken to examine the in vitro calcium antagonistic properties of lercanidipine (CAS 132866-11-6, Rec 15/2375) in vascular and non-vascular tissues, as well as its binding profile and in particular its affinity to the calcium channel binding sites. Lercanidipine proved to be endowed with high affinity for the dihydropyridine subunit of the L-type calcium channel, where it was much more potent than on the other receptors tested. The nature of the interaction of lercanidipine with the calcium channel appears competitive, as evidenced by a progressive increase in the apparent Kd of the ligand with no change in Bmax. The performed functional in vitro studies in isolated vascular and cardiac tissues demonstrated that lercanidipine has a slower onset and offset of calcium antagonistic activity compared with other calcium antagonists. The time-course of inhibition of vascular smooth muscle contraction showed substantial differences after addition of lercanidipine with regard to the other calcium antagonists tested (nitrendipine and amlodipine). On repeated washing of rat aorta to remove the drugs from the preparation, the effects of nitrendipine disappeared rapidly. After amlodipine incubation, contractility of the tissue was still impaired after 6 h washout with the highest concentrations tested, but completely recovered in 1-3 h after washout of the lowest concentration. On the contrary, the preparations incubated with lercanidipine showed a decrease in contractility that reached the maximum 1 to 3 h after the removal of the compound from the bath at all the active concentrations tested. The functional calcium antagonistic activity of lercanidipine was also evaluated as relaxing potency against the tonic contractions induced by preincubation of rat aorta, bladder and colon with 80 mmol/l K+. In rat aorta, lercanidipine proved more potent than nitrendipine. Comparing the IC50 values evaluated after 3 h of contact time, lercanidipine resulted more active on the vascular tissue with potency ratios of 177 and 8.5 for aorta vs bladder and aorta vs colon, respectively. In contrast, nitrendipine showed about the same activity in the three tested tissues, and potency ratios of 2.0 and 0.8 for aorta vs bladder and aorta vs colon were calculated. In rat aortic strips maintained during the incubation with lercanidipine at different degrees of depolarization, the functional calcium antagonistic activity markedly increased by raising the tissue depolarization and the potency ratio between the IC50 values evaluated at 5 and 100 mmol/l K+ resulted 138. Nitrendipine provided very similar results, whereas nifedipine activity did not seem to be affected by raising the tissue depolarization. The negative inotropic effects of lercanidipine on normally and partially depolarized rabbit ventricular strips, as well as in guinea-pig atria, were negligible in comparison to its effects on vasculature. On the whole these characteristics suggest a slow onset of action and long duration of effects also after in vivo administration. In addition, the unique vascular selectivity of lercanidipine implies that the therapeutically desirable vasodilator activity is not or scarcely associated with a decrease in cardiac contractile force.

Enhanced angiogenesis and granulation tissue formation by basic fibroblast growth factor in healing-impaired animals.

Abstract: The effect of basic fibroblast growth factor (bFGF) on angiogenesis and granulation tissue formation in normal and healing-impaired animals was studied. bFGF showed a dose-dependent enhancement of granulation tissue formation in the subcutaneous implantation of a paper disk in normal rats. Application of bFGF restored the formation in healing-impaired rat models treated with steroid, chemotherapy and X-ray irradiation. The angiogenic activity of bFGF was also demonstrated in the micro-pocket assay using the cornea of rabbits. Repeated applications of bFGF accelerated closure of full-thickness excisional wounds in diabetic mice, but the high doses showed rather diminished response. In contrast histological and gross evaluation of wound tissues revealed enhanced angiogenesis and granulation tissue formation in a dose-dependent manner. The findings suggested that the topical application of excess amounts of bFGF might reduce its ability to promote wound closure because of the prolonged responses in both neovascular and granulation tissue formation.

In vitro comparative assessment of the antioxidant activity of nacystelyn against three reactive oxygen species

Abstract: Thiol-containing molecules possess antioxidant properties that are of interest in the pharmacological inactivation of reactive oxygen species (ROS), particularly in the treatment of chronic inflammatory respiratory diseases. In the present study, the in vitro antioxidant activity of a new agent was examined and compared with other thiol containing molecules, N-acetylcysteine (NAC) and captopril. Nacystelyn (CAS 89344-48-9, NAL) is a L-lysine salt of NAC having demonstrated several advantages as compared to NAC. The deoxyribose assay used for assessing the scavenging effect of drugs against hydoxyl radicals (.OH) first showed a prooxidant effect for thiols at relatively low concentrations that was attributed to a reduction of Fe(III) ions added in the system. This interference could be corrected by increasing ascorbate concentration. Second order rate constants for reaction with OH were calculated by extrapolation of the linear part of competition plots. Both NAL and NAC appeared as potent .OH scavengers (Ks > 10(10) mol-1 s-1) and reacted faster than captopril. The horseradish peroxidase assay for assessing the activity of thiols against H202 could not be used because thiol derivatives were substrates for the enzyme. By using the dithio-bis-nitrobenzoic acid (DTNB) assay, first order rate constants for reaction with H2O2 were obtained showing that both NAL and NAC reacted quite slowly with this species (K approximately equal to 0.03 min-1) although faster than captopril. Finally, the elastase-alpha 1-antiproteinase assay for assessing the activity of thiols against HClO again demonstrated the superiority of NAC and NAL over captopril, but this time, NAL was more efficient in maintaining the protease/antiprotease balance than NAC. This last observation may be of importance and deserves further investigation as HClO has been implicated in lung tissue damages during inflammatory respiratory diseases.

Antimicrobial activity of carbene complexes of rhodium(I) and ruthenium(II).

Abstract: Twenty-four carbene-rhodium(I), carbene-ruthenium(II) complexes and related compounds were evaluated for their in vitro antimicrobial activity against the Gram-positive bacteria Enterococcus faecalis (ATCC 29212) and Staphylococcus aureus (ATCC 29213) and Gram-negative bacteria Escherichia coli (ATCC 25922), Pseudmonas aeruginosa (ATCC 27853). The compounds 1, 2, 3, 5, 7, 8, 9, 16, 18 and 19 were found very effective to inhibit the growth of Enterococcus faecalis and Staphylococcus aureus at the minimum inhibitory concentrations (MICs) of 5, 25, 5, 50, 25, 24, 24, 24, 6.25and 12.5 micrograms/ml, respectively. The compounds 6, 10, 12, 14, 15 and 17 were significantly effective against Enterococcus faecalis and Staphylococcus aureus with MIC values of 100-200 micrograms/ml. The compounds 2, 6 and 11 were also significantly effective against Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa with MIC values of 200-400 micrograms/ml.

Stimulation of cytokine production via a special standardized mistletoe preparation in an in vitro human skin bioassay.

Abstract: The mistletoe preparation Lektinol is standardized with respect to bioactive mistletoe lectin, the active component of mistletoe. This standardized mistletoe preparation and its active components (mistletoe lectins) were compared in the skin2 bioassay in vitro for their capacity to stimulate interleukin 1 alpha and interleukin 6 release from skin analogue tissue, composed of human cells in their naturally secreted matrix. The standardized mistletoe preparation, its basic ingredient, aqueous mistletoe extract, and pure mistletoe lectins all stimulated IL-1 alpha and IL-6 release from skin2 tissues during 24 h incubation. The amounts of cytokines released from various skin2 tissue lots by mistletoe lectin I (ML I) (0.75-8.0 ng/ml) and by the standardized mistletoe preparation remained relatively constant across a series of different batches. Concentration-response curves to the standardized mistletoe preparation and ML I were similar for IL-1 alpha and IL-6 release. The importance of the concentration of mistletoe lectins for the cytokine-releasing action of the standardized mistletoe preparation was confirmed using a neutralizing anti-mistletoe lectin antiserum. CONCLUSIONS. Using the skin2 method it was shown that reproducible stimulation of cytokine release by a standardized mistletoe preparation from batch to batch is one of the notable features of its pharmaceutical quality. This standardized mistletoe preparation therefore represents a preparation with constant immunobiological effects. Mistletoe lectins of the standardized mistletoe preparation are the active substances in the skin2 bioassay. The skin2 method is a reliable quantitative bioassay for determination of immunopharmacological effects.

Effects of extracts from Populus tremula L., solidago virgaurea L. and Fraxinus excelsior L. on various myeloperoxidase systems.

Abstract: Extracts from Populus tremula, Solidago virgaurea and Fraxinus excelsior are used as anti-inflammatory drugs. The effects of these extracts on myeloperoxidase (MPO), an enzyme liberated by activated granulocytes and known to produce the destructive agent hypochloric acid, were investigated. Populus and Fraxinus inhibited this enzyme, Solidago was without effect. These results were obtained concordantly with four different MPO-assays (H 2 O 2 /MPO ; X/XOD/MPO ; activated PMN ; and elastase/α 1 -PI-MPO). Fractionation of Populus and Fraxinus extracts showed that this inhibition is due to several different compounds. Well known or wide spread substances as e.g. rutin, salicylic acid, chlorogenic acid etc. had no or only little effect on the enzyme.

Studies on the effect of the new non-steroidal aromatase inhibitor fadrozole hydrochloride in an endometriosis model in rats.

Abstract: The therapeutic effect of the new nonsteroidal aromatase inhibitor fadrozole hydrochloride (4-(5,6,7,8-tetrahydro-imidazo[1,5a]pyridin-5-yl)benzonitrile monohydrochloride, fadrozole, CAS 102676-31-3, CGS16949A) was assessed using a surgically induced endometriosis model in rats. In nontreated rats, the endometrial transplants on the abdominal wall developed large cysts with fluid. In the fadrozole treated group, the cystic volume of the transplants decreased in a dose-dependent manner. The weights of the hemi-uteri were markedly reduced by fadrozole treatment. Fadrozole produced a dose-dependent increase in percentage of vaginal diestrous days. In ovariectomized group, the growth of the transplants was also suppressed, and the weights of the hemi-uteri decreased markedly. Histologically, the signs of growth suppression and/or atrophic changes such as minimization of luminal size, cuboidal piknotic epithelium and/or contraction of stroma were observed in ovariectomized or fadrozole treated groups. The right uterine horns also showed marked atrophic changes as with the transplants. The present study strongly indicates that the new selective aromatase inhibitor fadrozole should be useful for the treatment of endometriosis.