Pharmacokinetics of canrenone and metabolites after base hydrolysis following single and multiple dose oral administration of spironolactone

Summary The pharmacokinetics of canrenone and total metabolites after base hydrolysis was studied in eight young volunteers following single and multiple dose oral administration of spironolactone. The plasma levels of canrenone and total metabolites were fitted to a two-compartment open model with a first-order absorption process. From our eight normal subjects studied, the harmonic mean of the distributive half-life (t_1/2) of canrenone was found to be 1.66 h, and the harmonic mean of the terminal elimination half-life (t_1/2) to be 22.6 h. Harmonic means of the distributive and elimination half-lives of total metabolites after base hydrolysis were 2.48 h and 28.8 h respectively. The accumulation ratio of canrenone was 2.53, whereas that of total metabolites was 1.89. Despite the fact that spironolactone has been shown to induce hepatic metabolism of other drugs, no evidence of autoinduction was noted in the present study, as plasma levels of canrenone and total metabolites were found to obey a linear two-compartment model with reproducible absorption and disposition after single and multiple doses.     

Trennung und Bestimmung der Nucleotide des Gehirns

Ohne ZusammenfassungFolgende Abkürzungen werden in der Arbeit verwendet AMP Adenosin-5-monophosphat - ADP Adenosin-5-diphosphat - ATP Adenosin-5-triphosphat - GMP Guanosin-5-monophosphat - GDP Guanosin-5-diphosphat - GTP Guanosin-5-triphosphat - IMP Inosin-5-monophosphat - UMP Uridin-5-monophosphat - UDP Uridin-5-diphosphat - UTP Uridin-5-triphosphat - UDPAG Uridin-5-diphosphat-N-acetylglucosamin - UDPG Uridin-5-diphosphat-glucose - DPN Diphosphopyridinnucleotid - TPN Triphosphopyridinnucleotid Mit 10 TextabbildungenMit Unterstütznng der Deutschen Forschungsgemeinschaft.     

Difference in metabolic profile of potassium canrenoate and spironolactone in the rat: Mutagenic metabolites unique to potassium canrenoate

The metabolic fates of potassium canrenoate (PC) and spironolactone (SP) were compared for the rat in vivo and in vitro. Approximately 18% of an in vivo dose of SP was metabolized to canrenone (CAN) and related compounds in the rat. In vitro, 20–30% of SP was dethioacetylated to CAN and its metabolites by rat liver 9000 g supernatant (S9). Thus, the major route of SP metabolism is via pathways that retain the sulfur moiety in the molecule. PC was metabolized by rat hepatic S9 to 6, 7- and 6, 7-epoxy-CAN. The -epoxide was further metabolized to its 3- and 3-hydroxy derivatives as well as its glutathione (GSH) conjugate. Both 3- and 3-hydroxy-6, 7-epoxy-CAN were shown to be direct acting mutagens in the mouse lymphoma assay, whereas 6, 7- and 6, 7-epoxy-CAN were not. These mutagenic metabolites, their precursor epoxides and their GSH conjugates were not formed from SP under identical conditions. The above findings appear to be due to inhibition of metabolism of CAN formed from SP by SP and/or its S-containing metabolites, since the in vitro metabolism of PC by rat hepatic microsomes was appreciably reduced in the presence of SP. The hypothesized mechanism(s) for this inhibition is that SP and its S-containing metabolites specifically inhibit an isozyme of hepatic cytochrome P-450 or SP is a preferred substrate over PC/CAN for the metabolizing enzymes. Absence of the CAN epoxide pathway in the metabolism of SP provides a possible explanation for the observed differences in the toxicological profiles of the two compounds.     

The effect of selective α1- and α2-adrenoceptor stimulation on intraocular pressure in the conscious rabbit

Summary The influence of topically applied selective ₁- and ₂-adrenoceptor agonists on intraocular pressure and the diameter of the pupil was investigated in conscious rabbits. Selective stimulation of the ₁-subtype of receptors induced an elevation in intraocular pressure, accompanied by mydriasis, whereas stimulation of the ₂-subtype caused a marked and dose-dependent ocular hypotensive response, which was blocked by the selective ₂-adrenoceptor antagonist yohimbine. ₂-Agonists induced neither macroscopic ocular side effects, nor an effect on the pupil size. Possibly, the subclass of ₂-adrenoceptor stimulating drugs represent a group of new antiglaucomatous agents.     

Dose-dependent excretion of DDE(1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) in rats

Dose-dependent excretion of p,pDDE in rats was investigated. p,pDDE itself was the major excreta in rats. But some o,p'isomer of DDE was detected in feces by GC-MS analysis. The excretion of p,p'DDE after a single administration was modified by its dose level.The time pattern of p,pDDE excretion agrees well with the modified Hill equation. The value of the equilibrium constant (K) increases in proportion to time t after p,pDDE administration.Using the modified Hill equation and the linear K equation, the excretion rate of p,pDDE during the experimental time t can be estimated. The estimated p,pDDE excretion rate in feces agrees well with the measurements.     

The influence of 8-Br 3′,5′-cyclic nucleotide analogs and of inhibitors of 3′,5′-cyclic nucleotide phosphodiesterase,on noradrenaline secretion and neuromuscular transmission in guinea-pig vas deferens

Summary The effects of 3,5-cyclic nucleotide phosphodiesterase (PDE) inhibitors and of 8-Br 3,5-cyclic nucleotide analogs on nerve-muscle transmission were studied in the guinea-pig vas deferens preincubated with ³H-noradrenaline.8-Br cyclic AMP and the PDE inhibitors 3-isobutyl-1-methylxanthine (IBMX) and 3-propionyl-4-hydrazinopyrazolopyridine (SQ 20006) enhanced the secretion of ³H-NA evoked by transmural nerve stimulation. 8-Br cyclic GMP was without effect in this respect.The muscle contraction evoked by transmural nerve stimulation, high potassium or by application of exogenous noradrenaline was depressed by IBMX and SQ 20006. The contraction evoked by transmural nerve stimulation was enhanced by 8-Br cyclic AMP and depressed by 8-Br cyclic GMP.These findings suggest differential involvement of 3,5-adenosine- and guanosine-cyclic nucleotides in excitation-secretion-coupling in the noradrenergic sympathetic nerves, and in excitation-contraction-coupling in the smooth muscle, of guinea-pig vas deferens.     

Bedeutung der N- und α-Methylierung für die Affinität von Brenzcatechinaminen zu den adrenergischen Receptoren

Summary 1. N-methylation of dopamine yielding epinine means potentiation of the -adrenergic pressor action in the cat. It is only N-methylation which renders dopamine to a direct acting -sympathomimetic amine: the positive inotropic effect of epinine on the isolated electrically driven guinea pig auricle remained uninfluenced by pretreatment of the animals with reserpine, whereas the dose-response curve of dopamine was shifted to the right.The blood pressure lowering effect of epinine after phenoxybenzamine was—in contrast to that of dopamine—abolished by pronethalol.—N-methylation of noradrenaline doubled the affinity for the -receptors of the heart.2. Also by -methylation dopamine gains affinity to the adrenergic -receptors (heart and vessels): d--methyldopamine, an exclusively directly acting catecholamine, had a 40 times stronger inotropic action than dopamine on reserpinized auricles; the action of l--methyldopamine, a mainly indirectly acting amine, was only 4 times stronger than dopamine.-methylnoradrenaline, although having the same inotropic activity as noradrenaline, had a 10 times stronger depressor action than noradrenaline in the cat pretreated with phenoxybenzamine.By -methylation, the -adrenergic pressor effect of dopamine as well as that of noradrenaline was enhanced only in the range of lower doses since the dose-response curves of the -methylated compounds were generally less steep than those of the non-methylated catecholamines, indicating a lower intrinsic activity of the -methylated derivatives.3. The N- and -methylated catecholamines -methylepinine and -methyladrenaline resp. were blood pressure lowering agents per se, because both methylgroups additively enhanced the affinity to the vascular -receptors. -methylepinine was the most potent -sympathomimetic on the heart in the dopamine series (dopamine < d--methyldopamine epinine < dl--methylepinine). However, in the noradrenaline series the twofold methylated compound -methyladrenaline had the lowest positive inotropic action (d(–)-adrenaline > d(–)-noradrenaline (–)erythro--methylnoradrenaline > (–) erythro--methyladrenaline).4. From the results the following conclusions are drawn: The N- as well as the -methyl-group exerts and +I-effect on the ammonium group. Thereby, protonation will be increased which leads to an enhanced affinity of the resp. catecholamine to the adrenergic - and -receptor. Since the -CH₃ group—dependant upon its steric configuration—also causes a steric hindrance at the receptor site, the increase in affinity due to the +I-effect is partially neutralized. By that the lower intrinsic affinity of the -methylated compounds as indicated by the different slope of their pressor dose-response curves, is also readily explained. Furtheron it is intelligible why -methylation enhanced the -adrenergic activity in the less potent dopamine series (preponderance of the +I-effect), whereas it lowered the affinity to the cardiac -receptors in the noradrenaline series (preponderance of the steric hindrance).5. Although -methyladrenaline was the least potent -sympathomimetic of the noradrenaline series in the guinea pig heart, it was the most potent compound in lowering the cat's blood pressure. Therefore, it seems to be questionable whether the cardiac and the vascular -receptors and/or the mechanisms by which they induce the pharmacodynamic actions are identical.

Über einen Teil der Ergebnisse wurde auf der 7. Frühjahrstagung der Deutschen Pharmakologischen Gesellschaft in Mainz, 24.–27. April 1966, berichtet (Palm, Langeneckert u. Holtz, 1966).     

Hydroxysteroid-Dehydrogenasen, Δ5-3-Ketosteroid-Isomerase und Δ4-Steroid-Hydrogenase in roten Blutzellen

Zusammenfassung 18 ausgewählte Steroide werden auf ihre Umsetzung durch rote Blutzellen von Ratte, Rind und auch Mensch untersucht. Über die papierchromatographische und teilweise auch spektrophotometrische Identifikation der erhaltenen Metaboliten wird nachgewiesen, daß die Erythrocyten eine Vielzahl von Steroidfermenten enthalten. Gefunden werden vor allem 3-, 3-, 16-, 17- und 17-Hydroxysteroid-Dehydrogenasen. Dagegen lassen sich 11- und 16-Hydroxysteroid-Dehydrogenasen nicht nachweisen. Die relativen Aktivitäten der verschiedenen Fermente in der jeweiligen Blutart werden beschrieben. Die Erythrocyten zeigen artgebundene Unterschiede in Stereospezifität und Aktivität der Hydroxysteroid-Dehydrogenasen. Neben den genannten Enzymen sind in den roten Blutzellen der Ratte noch eine Isomerase (^{5 4}) und eine ⁴-Hydrogenase enthalten. Außer den Reaktionen, die durch die aufgezählten Fermentnamen bezeichnet sind, werden von den Zellen noch Umsetzungen bewirkt, die ihrer Art nach nicht aufgeklärt wurden. Die Ergebnisse werden im Hinblick auf den Stoffwechsel der 16,17-substituierten Oestrogene und auf die Natur der Hydroxysteroid-Dehydrogenasen diskutiert.Mit 3 TextabbildungenEin Teil der Ergebnisse wurde am 24. 9. 1959 auf der Tagung der Gesellschaft für physiologische Chemie e. V. in Berlin vorgetragen.Meinem verehrten Lehrer, Herrn Professor P. Wels, in Dankbarkeit zum 70. Geburtstag gewidmet.     

Relationship of metabolism of 2′-, 3′- and 5′-adenine nucleotides to presynaptic inhibition of transmitter release in rat vas deferens

Summary In the isolated rat vas deferens stimulated at 0.2 Hz, a series of 2, 3-, and 5-substituted adenine nucleotides all inhibited the twitch responses, their actions being potentiated by the nucleoside transport inhibitors, HNBTGR, NBMPR and dipyridamole.The metabolism of these nucleotides was examined utilising HPLC analysis of the bathing medium after exposure to 30 M nucleoside or nucleotide for 5 min. 5-AMP, 5-ADP, 5-ATP, and NAD⁺ were all partially hydrolysed to adenosine, the relative extent of this being 5-AMP>5-ADP=5-ATPNAD⁺. However, the other nucleotides examined were not detectably converted to adenosine or to adenosine deamination products.These results indicate that the 2-, 3- and 5-substituted nucleotides studied act at a P₁-purinoceptor in rat vas deferens to inhibit neurotransmission and, with the exception of 5-AMP, 5-ADP, 5-ATP and NAD⁺, all appear to act directly at this receptor. However, the 5-adenine nucleotides (AMP, ADP and ATP) and NAD⁺ all appear to act at least partially indirectly subsequent to their hydrolysis to adenosine.Abbreviations. The following abbreviations are used ADA adenosine deaminase (EC 3.5.4.4) - 5-ADP adenosine 5-diphosphate - 2,5-ADP adenosine 2,5-diphosphate - 3 5-ADP, adenosine 3,5-diphosphate - 2-, 3 or 5-AMP adenosine 2-, 3-, or 5-monophosphate - 5-ATP adenosine 5-triphosphate - cNADP⁺ -nicotinamide dinucleotide 2,3-cyclic monophosphate - CoA coenzyme A - HNBTGR 6-(2-hydroxy-5-nitrobenzyl)-thioguanosine - NAD⁺ -nicotinamide adenine dinucleotide - NADP⁺ -nicotinamide adenine dinucleotide phosphate - NBMPR 6-(4-nitrobenzylthio)-purine riboside     

Development and Use of Enzyme-Linked Immunosorbent Assays (ELISA) for the Detection of Protein Aggregates in Interferon-Alpha (IFN-α) Formulations

Purpose. Protein aggregates are thought to be involved in the immunogenicity of recombinant proteins in humans. To probe human IFN- formulations for the presence of soluble protein aggregates, enzyme-linked immunosorbent assays (ELISA) were developed. Methods. For the detection of IFN--IFN- and HSA-IFN- aggregates, sandwich ELISAs were developed using a monoclonal anti-IFN- antibody as a capture antibody and the same anti-IFN- antibody and an anti-human serum albumin (HSA) antibody (HRP-labeled), respectively. Results. Marketed freeze-dried, HSA-containing IFN- formulations tested in the ELISAs all contained IFN--IFN- and/or HSA-IFN- protein aggregates, although in varying amounts. These aggregates were predominantly IFN- dimers and 1:1 conjugates of HSA with IFN-. Test formulations revealed that aggregation of IFN- was strongly affected by the presence of pharmaceutical excipients, pH of the formulation, lyophilisation procedure, and storage temperature and time. Conclusions. The ELISAs are rapid, highly specific for aggregates in the presence of both IFN- and HSA monomers and allow the direct detection of both types of aggregates in formulations in the nanogram range. The new assays will assist the monitoring of the aggregate-inducing processes during IFN- formulation and storage in an early phase and the development of aggregate-free IFN- formulations.     

Facilitating interaction between rauwolscine and angiotensin in the mesenteric artery of the rabbit

Summary The interaction between rauwolscine and angiotensin II was investigated in the isolated mesenteric artery of the rabbit. Rauwolscine, known as an antagonist at ₂-adrenoceptors, did not induce contraction itself but interacted with angiotensin to produce a facilitated response of the vascular tissue. In the presence of rauwolscine, the contractile response of the tissue to angiotensin was markedly enhanced. The degree of facilitation appeared to be dependent on the rauwolscine concentration used rather than that of angiotensin. Moreover, rauwolscine induced a concentration-dependent increase in tension (pD₂=6.8) in the presence of even subcontractile concentrations of angiotensin (10^–10 mol/l). This effect was not attributable to an indirect action involving presynaptic catecholamines, as revealed by the use of tissue strips from animals pretreated with reserpine or after chemical sympathectomy. Furthermore, an interaction via the prostaglandin system was excluded by negative results obtained with indomethacin. The agonistic effect of rauwolscine was significantly attenuated by phentolamine (₁/₂) but not by prazosin (₁) or phenoxybenzamine when applied for only a short time. The ₂-antagonist BDF 6143 behaved like rauwolscine whereas the ₁-antagonist corynanthine, a stereoisomer of rauwolscine, did not. The results indicate that the rauwolscine effect is mediated by a receptor with ₂-characteristics. In general, angiotensin appears to interfere with some process which determines the expression of a drug's intrinsic effect.This study was supported by a grant of the Deutsche Forschungsgemeinschaft     

α1-adrenoceptor subtype affinities of drugs for the treatment of prostatic hypertrophy

Summary We have used radioligand binding and inositol phosphate accumulation studies to determine the affinity at mixed _1A- and _1B-adrenoceptors (rat cerebral cortex and kidney), _1A-adrenoceptors (rat cerebral cortex and kidney following inactivation of _1B-adrenoceptors by chloroethylclonidine treatment) and _1B-adrenoceptors (rat spleen) for drugs currently under investigation for the treatment of benign prostatic hypertrophy, alfuzosin, naftopidil and (–)- and (+)-tamsulosin. Alfuzosin and naftopidil had similar affinities in all model systems (approximately 10 nM and 130 nM, respectively) and lacked relevant selectivity for ₁-adrenoceptor subtypes. Their potency to inhibit noradrenaline-stimulated inositol phosphate formation in cerebral cortex matched their affinities as determined in the binding studies. Tamsulosin had higher affinity at _1A- than at _1B-adrenoceptors, and was slightly more potent than alfuzosin and naftopidil at _1B- and considerably more potent at _1A-adrenoceptors. However, the interaction of the tamsulosin isomers with chloroethylclonidine-insensitive (_1A-like) adrenoceptors was complex. A detailed analysis of the tamsulosin data and those obtained with other drugs, most notably noradrenaline and oxymetazoline, suggested that chloroethylclonidine-insensitive ₁-adrenoceptors may be heterogenous and that this heterogeneity may differ between cerebral cortex and kidney of the rat.     

Hemmung der Insulininkretion durch α-Receptoren stimulierende Substanzen

Summary Experiments are described in which the influence of an -adrenergic blocking agent, phentolamine, and of two hypotensive drugs, diazoxide and 2-(2,6-dichlorophenylamino)-2-imidazoline hydrochloride (DCAI) on blood glucose, plasma insulin and glucose-stimulated insulin secretion has been measured in male Wistar rats.Blood glucose concentration has been found to be decreased and plasma insulin concentration has been found to be increased after one or two injections of 50 mg phentolamine/kg b.w., intraperitoneally. These results are in accordance with the observation that -adrenergic stimulation inhibits and -adrenergic stimulation promotes insulin secretion (Porte, 1967 a, 1967 b). If the -adrenergic stimulatory effect of endogenous catecholamines is blocked by phentolamine, the remaining -adrenergic stimulatory effect of endogenous epinephrine leads to an increase in insulin secretion.Treating rats with diazoxide (200 mg/kg b.w., i.v.) or DCAI (200 g/kg b.w., s.c.), respectively, has been found to lead to a decrease in plasma insulin concentration as well as to an almost complete inhibition of the ability of the pancreas to secrete insulin in response to an elevation of blood glucose concentration. As these effects have been found to be abolished by pretreatment with phentolamine, the inhibition of insulin secretion caused by diazoxide and DCAI may be regarded as being mediated by -adrenergic stimulation.Recent studies of Turtle and Kipnis (1967) have shown that -adrenergic stimulation lowers islet 3,5-AMP concentration and prevents the increase in islet 3,5-AMP concentration which is caused by -adrenergic stimulation. In view of these results indicating an antagonistic influence of - and -adrenergic stimulation on 3,5-AMP formation in islet tissue, the inhibitory action of diazoxide and DCAI on insulin secretion may be explained by a decrease in adenyl cyclase activity in this tissue.

Wir danken der Deutschen Forschungsgemeinschaft für die Unterstützung unserer Untersuchungen.     

Relaxation of hormonally stimulated smooth muscular tissues by the 8-bromo derivative of cyclic GMP

Summary Substances that cause contraction or relaxation of smooth muscle have been shown to increase intracellular levels of cyclic GMP. Because of the unclear role of cyclic GMP in the control of smooth muscle tone, cyclic GMP derivatives were exogenously applied to various smooth muscle preparations and their effects on tissue tone were studied.Whereas the basal tone of the rat ductus deferens was not affected by exogenous cyclic GMP or its dibutyryl or 8-bromo derivatives, the contractile responses of this tissue to noradrenaline and acetylcholine were depressed by preincubation with 10 M 8-bromo cyclic GMP (Br-cGMP). The 8-bromo derivatives of 2:3-cyclic GMP, 5-GMP and guanosine were without effects. Cyclic AMP levels were not changed by Br-cGMP. The frequency of oxytocin-stimulated rat uteri was also depressed by Br-cGMP (10 M). In helical strips of rat and rabbit aortae, Br-cGMP (1–100 M) caused a concentration-dependent, rapid decrease in noradrenaline-stimulated tissue tension. Br-2:3-cyclic GMP was ineffective. Noradrenaline-stimulated strips from hog spleen arteries were less sensitive to Br-cGMP than aortic tissue. In ductus deferentes and aortic strips stimulated by K⁺ at a depolarizing concentration, Br-cGMP caused less relaxation than under hormonal stimulation.These findings support the concept that cyclic GMP is involved in the control of smooth muscle tone and that hormone- and drug-induced elevations of the cyclic GMP level can reduce contractile responses to neurotransmitters and hormones.Abbreviations cGMP Guanosine 3:5-monophosphate, cyclic GMP - dibutyryl cGMP N², 2-O-dibutyryl guanosine 3:5-monophosphate - Br-cGMP 8-bromo guanosine 3:5-monophosphate - Br-2:3-cGMP 8-bromo guanosine 2:3-monophosphate - Br-GMP 8-bromo guanosine 5-monophosphate - Br-Guo 8-bromo guanosine, Br-guanosine - cAMP adenosine 3:5-monophosphate, cyclic AMP - dibutyryl cAMP N⁶, 2-O-dibutyryl adenosine 3:5-monophosphate - Br-cAMP 8-bromo adenosine 3:5-monophosphate This work was supported by grants from the Deutsche Forschungsgemeinschaft. Preliminary reports were presented (Schultz, 1977b; Schultz et al., 1978).     

Toxicity and 7-ethoxyresorufin O-deethylase-inducing potency of coplanar polychlorinated biphenyls (PCBs) in chick embryos

The toxicities of the coplanar polychlorinated biphenyls 3,3,4,4-tetrachlorobiphenyl (TCB), 3,3,4,4,5-pentachlorobiphenyl (PeCB) and 3,3,4,4,5,5hexachlorobiphenyl (HCB) were compared in a 72-h study on chick embryos. The substances were injected into the air sacs of hens' eggs preincubated for 7 days. Mortality was measured 72 h later and corresponding LD₅₀ values were calculated. The rank order of toxicity was PeCB> TCB>HCB. Using the same injection procedure, the potencies of these chlorobiphenyls with regard to their induction of hepatic 7-ethoxyresorufin O-deethylase activity were compared. The ranking order of the substances as inducers was the same as their order when ranked according to toxicity. The three coplanar chlorobiphenyls were considerably more toxic and potent as inducers than the nonplanar 2,2,4,4,5,5-hexachlorobiphenyl. In a 2-week toxicity study, PeCB and HCB were injected into the yolks of hens' eggs preincubated for 4 days. PeCB was about 50-fold more potent than HCB in causing embryonic death. Both substances caused abnormalities, including edema, liver lesions, microphthalmia and beak deformities.     

Synthesis and Anti-inflammatory Effect of Chalcones and Related Compounds

Purpose. Mast cell and neutrophil degradations are the important players in inflammatory disorders. Combined with potent inhibition of chemical mediators released from mast cells and neutrophil degranulations, it could be a promising anti-inflammatory agent. 2,5-Dihydroxychalcone has been reported as a potent chemical mediator and cyclooxygenase inhibitor. In an effort to continually develop potent anti-inflammatory agents, a novel series of chalcone, 2- and 3-hydroxychalcones, 2,5-dihydroxychalcones and flavanones were continually synthesized to evaluate their inhibitory effects on the activation of mast cells and neutrophils and the inhibitory effect on phlogist-induced hind-paw edema in mice. Methods. A series of chalcones and related compounds were prepared by Claisen-Schmidt condensation of appropriate acetophenones with appropriate aromatic aldehyde and the anti-inflammatory activities of these synthetic compounds were studied on inhibitory effects on the activation of mast cells and neutrophils. Results. Some chalcones showed strong inhibitory effects on the release of -glucuronidase and histamine from rat peritoneal mast cells stimulated with compound 48/80. Almost all chalcones and 4-hydroxyflavanone exhibited potent inhibitory effects on the release of -glucuronidase and lysozyme from rat neutrophils stimulated with formyl-Met-Leu-Phe (fMLP). Some chalcones showed potent inhibitory effects on superoxide formation of rat neutrophils stimulated with fMLP/cytochalasin B (CB) or phorbol myristate acetate (PMA). 2,3-Dihydroxy-, 2,5-dihydroxy-4-chloro-, and 2,5-dihydroxychalcone showed remarkable inhibitory effects on hind-paw edema induced by polymyxin B in normal as well as in adrenalectomized mice. Conclusions. These results indicated that the anti-inflammatory effects of these compounds were mediated, at least partly, through the suppression of chemical mediators released from mast cells and neutrophils.     

Fenofibrate decreases asymmetric dimethylarginine level in cultured endothelial cells by inhibiting NF-κB activity

Previous investigations have demonstrated that endogenous inhibitors of nitric oxide synthase (NOS), such as asymmetric dimethylarginine (ADMA), contribute importantly to endothelial dysfunction, and that fenofibrate has a protective effect on the endothelium in rats treated with low-density lipoprotein (LDL) by reducing ADMA levels. In the present study, we explored further the possible mechanism underlying inhibition of ADMA generation by fenofibrate in cultured human umbilical vein endothelial cells (HUVECs). Endothelial injury was induced in cultured HUVECs by incubation with oxidative LDL (ox-LDL) and the levels of ADMA, lactate dehydrogenase (LDH), NO and tumour necrosis factor- (TNF-) in the conditioned medium were measured. Cell viability and the activity of dimethylarginine dimethylaminohydrolase (DDAH) and nuclear factor-B (NF-B) in the cultured HUVECs were also determined. Incubation of HUVECs with ox-LDL (100 g/ml) for 24 h markedly elevated ADMA, LDH and TNF- in the conditioned medium and significantly increased the activity of NF-B, concomitantly with a significant decrease in the activity of DDAH and the content of NO. Pretreatment with fenofibrate (3, 10 or 30 M) significantly inhibited the increases in ADMA, LDH and TNF-, attenuated the decreased levels of NO and the decreased activity of DDAH and prevented the activation of NF-B. Similar effects were observed in the presence of pyrrolidine dithiocarbamate (PDTC, 10 M), an antagonist of NF-B. The beneficial effects of fenofibrate on cultured endothelial cells were abolished by MK-886, a specific peroxisome proliferator-activated receptor- (PPAR) antagonist. The present results suggest that fenofibrate inhibits ox-LDL-induced endothelial cell damage by decreasing ADMA and increasing DDAH activity, and the protective effects of fenofibrate on endothelial cells may be related to reduction of NF-B activity by activation of the PPAR receptor.     

Sympathicomimetische Wirkungen von Papaverinderivaten

Zusammenfassung In früheren Untersuchungen hatte Tetrahydropapaverolin (THP), das sich chemisch von dem musculotropen Papaverin durch Demethylierung der Methoxygruppen und Hydrierung des N-haltigen Rings unterscheidet, sich als sehr wirksames -Sympathicomimeticum erwiesen. Untersuchungen über Beziehungen zwischen chemischer Konstitution und -sympathicomimetischer Wirksamkeit von Derivaten des THP und Papaverins am Blutdruck der Katze und am elektrisch gereizten linken Vorhof des Meerschweinchenherzens haben ergeben:1. Die blutdrucksenkende Wirkung sowohl des Papaverins als auch seines partiell demethylierten (3,4-Desmethylpapaverin) und hydrierten Derivates (Tetrahydropapaverin) war, im Gegensatz zu derjenigen des THP, resistent gegen Propranolol. Das vollständig demethylierte Derivat (Papaverolin) war wirkungslos.Demgegenüber erwies sich die positiv inotrope Herzwirkung des Papaverins als eine direkte, -sympathicomimetische. Sie blieb nach Reserpinvorbehandlung bestehen und wurde durch Pronethalol kompetitiv abgeschwächt. 3,4-Desmethylpapaverin und Papaverolin waren schwächer wirksam als Papaverin. Tetrahydropapaverin wirkte nur negativ inotrop. Diese allen Papaverinderivaten zukommende chinidinartige Wirkungskomponente könnte die Ursache für ihre niedrige -adrenergische intrinsic activity (0,6) sein.2. Alle chemischen Eingriffe in das Molekül des THP, z. B. Alkylierung an C₃ oder am Stickstoff sowie Dehydroxylierung an C₃ und C₄, führten zu einer Abschwächung der -sympathicomimetischen Wirksamkeit am Herz und am Blutdruck. Eine, auch dem THP wahrscheinlich zukommende, jedoch durch die ausgeprägte -sympathicomimetische Wirksamkeit überdeckte -sympathicomimetische, blutdrucksteigernde Wirkung trat jetzt in Erscheinung.3. THP, sozusagen ein dimeres Dopamin, besitzt von allen untersuchten Papaverinderivaten die für die Ausübung -sympathicomimetischer Wirkungen optimale chemische Konfiguration. Ein großmolekularer Phenyläthyl-Substituent am Stickstoff verursacht maximale Aktivierung der sekundären Aminogruppe (+ I-Effekt). Zusammen mit den vier freien phenolischen OH-Gruppen verleiht er dem Molekül die hohe Affinität zu den adrenergischen -Receptoren.Über einen Teil der Ergebnisse wurde auf der 8. Frühjahrstagung der Deutschen Pharmakologischen Gesellschaft in Mainz (1967) berichtet (Langeneckert, et al., 1967).     

Viscoelastic Properties of Bioadhesive,Chlorhexidine-Containing Semi-Solids for Topical Application to the Oropharynx

Purpose. This study examined the viscoelastic properties of bioadhesive, chlorhexidine-containing semi-solid formulations, designed for topical application to the oropharynx. Methods. Oscillatory rheometry was performed using a Carri-Med CSL²-100 rheometer at 20.0 ± 0.1° C in conjunction with parallel plate geometry (2 cm diameter, 0.5 mm sample thickness). Samples were subjected to a constant strain (6.5 × 10^–3 rad) and defined viscoelastic parameters, namely storage modulus (G), loss modulus (G), loss tangent (tan ) and dynamic viscosity (), measured over a defined frequency range (0.01-1.0 Hz). Results. As the oscillatory frequency was increased, G G of all formulations increased, whereas both and tan significantly decreased. The magnitude of increase of G and G as a function of frequency was relatively small, indicating that, in general, the formulations were non-cross-linked elastic systems. Increasing concentrations of HEC, PVP and PC significantly increased G, G, yet decreased tan observations that may be attributed to the physical state of each polymer in the formulations. Formulation elasticity increased (i.e. tan decreased) as a result of increased entanglement of polymeric chains of dissolved components (i.e. HEC and PVP) and the restrained extension of swollen, cross-linked chains of PC. Additionally, in formulations where the saturation solubility of PVP was exceeded and/or insufficient 'free-water' was available for maximal swelling of PC, formulation elasticity increased as a result of the increasing mass of dispersed solid particles of PVP and/or PC. Formulation increased due to the attendent effects of polymer chain entanglement and polymer state on overall formulation viscosity. Conclusions. Following application to the oropharynx, the formulations will behave as elastic systems. Thus, these formulations would be expected to offer advantageous clinical properties, e.g., prolonged drug release, increased bioadhesion. However, it is noteworthy that the final choice of formulation for clinical evaluation will involve a compromise between viscoelastic characteristics and acceptable textural properties, e.g. ease of product application. This study has shown the applicability of oscillatory rheometry for both the characterisation and selection of candidate, topical bioadhesive formulations for clinical evaluation.     

Antitumor Agents. 125. New 4β-Benzoylamino Derivatives of 4′-O-Demethyl-4-desoxypodophyllotoxin and 4β-Benzoyl Derivatives of 4′-O-Demethylpodophyllotoxin as Potent Inhibitors of Human DNA Topoisomerase II

A series of 4-benzoylamino (5-17) derivatives of 4-O-demethyl-4-desoxypodophyllotoxin and 4-benzoyl (18-20) derivatives of 4-O-demethyl podophyllotoxin have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. Compounds 5-13 and 15-17 are more potent than etoposide in causing DNA breakage, while compounds 9, 10, 13, 14, 16, and 20 are more active than etoposide in their inhibition of the human DNA topoisomerase II. The order for the enzyme inhibitory activity of the derivatives of 4-O-demethyl-4-desoxypodophyllotoxin is 4-arylamino > 4-benzylamino > 4-benzoylamino.