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Biomedical subjects

A Stütz

Publications and source records attributed to A Stütz.

At least 19 recordsLinked to original sources

A novel anti-inflammatory drug, SDZ ASM 981, for the topical and oral treatment of skin diseases: in vivo pharmacology.

There is a need for safe and effective therapies for inflammatory skin diseases. Current topical and systemic treatment of psoriasis is effective but suffers from side-effects or is inconvenient. The therapeutic armamentarium for atopic dermatitis is very limited and far from satisfactory. In vivo preclinical data are presented for SDZ ASM 981, a novel ascomycin macrolactam derivative with high anti-inflammatory activity. Anti-inflammatory activity was observed in mouse, rat and pig models of allergic contact dermatitis. In the pig model, topical SDZ ASM 981 was as effective as the ultrapotent corticosteroid clobetasol-17-propionate, and when compared with a series of commercial topical corticosteroid preparations, 0.1% SDZ ASM 981 had equivalent efficacy to clobetasol-17-propionate (0.05%), the most potent product on the market. Unlike the corticosteroid, however, SDZ ASM 981 did not cause skin atrophy in pigs. SDZ ASM 981 potently inhibited allergic contact dermatitis in mice and rats when given systemically, and oral treatment was more effective than cyclosporin A in rats. Furthermore, SDZ ASM 981 has a low potential for affecting systemic immune responses, as demonstrated in rat models of localized graft vs. host reaction and allogeneic kidney transplantation. Preclinical results suggest that SDZ ASM 981 has the potential to be a well-tolerated and effective drug for topical as well as oral treatment of inflammatory skin diseases.

Administration, Cutaneous

SDZ 281-977: a modified partial structure of lavendustin A that exerts potent and selective antiproliferative activities in vitro and in vivo.

The chemical derivatization of biologically active microbial metabolites continues to be a promising approach to the identification of new drugs. We recently synthesized the novel antiproliferative compound SDZ 281-977, 5-[2-(2,5-dimethoxy-phenyl)ethyl]-2-hydroxy-benzoic acid methylester, a derivative of the EGF receptor tyrosine kinase inhibitor lavendustin A. Here we report on our studies of the anticancer efficacy and the mode of action of SDZ 281-977. The growth of both the human pancreatic tumor cells MIA PaCa-2 and the human vulvar carcinoma cells A431 was inhibited in the low micromolar range. Tumors from these cells were induced in nude mice and were shown to respond to orally or intravenously administered SDZ 281-977. In contrast, no antitumor effect was detected in rats bearing dimethylbenzanthracene-induced mammary tumors. Studies in mice indicated that SDZ 281-977 was neither immunosuppressive nor hematosuppressive at doses effectively inhibiting tumor growth. Surprisingly, the mode of action of SDZ 281-977 apparently does not involve inhibition of EGF receptor tryosine kinase, because, in contrast to lavendustin A, SDZ 281-977 failed to inhibit this enzyme in a cell-free assay. The mechanism of the antiproliferative effect can be explained on a cellular level by the ability of the compound to arrest cells in mitosis. SDZ 281-977 is thus the first example of an antimitotic agent derived from the potent tyrosine kinase inhibitor lavendustin A. The therapeutic potential of SDZ 281-977 is enhanced by the fact that it is not subject to multidrug resistance, because tumor cells expressing the multidrug resistance phenotype were as sensitive to SDZ 281-977 as their nonresistant counterparts. In conclusion, SDZ 281-977 represents a novel lavendustin A derivative with potent antiproliferative properties in vitro and in vivo that may be explained on the basis of its antimitotic effects. SDZ 281-977 may be a candidate drug for the treatment of selected cancers, including those expressing the multidrug resistance phenotype.

Animals

Clearing of psoriasis by a novel immunosuppressive macrolide.

Accumulating evidence suggests that psoriasis may be a genetically determined immunogenic, inflammatory disorder based on an ongoing autoreactive Th-1 response. Systemic immunosuppressive therapy is highly effective but fraught with longterm side effects. Our research therefore focuses on therapeutic strategies that induce local immunosuppression in the skin by topical, transepidermal delivery of immunosuppressive drugs. SDZ 281-240 is a newly developed macrolide of the ascomycin type. It is immunosuppressive by mechanism of action similar to that of FK506 but has no antiproliferative activity against keratinocytes in vitro. To evaluate whether SDZ 281-240 exhibits antipsoriatic activity when applied topically, we tested 15 patients with severe, recalcitrant psoriasis, using a microplaque assay in randomized, double-blind, placebo-controlled study, comparing the therapeutic efficacy of the macrolide with a potent halogenated corticosteroid and vehicle. All patients showed a significant improvement of psoriatic lesions treated with two concentrations of the macrolide and, as expected, with the corticosteroid but not with placebo. Both concentrations of the macrolide led to clearing of psoriasis after 10 days of treatment and biopsies confirmed a reversal of the histopathological and immunopathological phenotype of psoriasis to that of normal skin. Thus, an immunosuppressive agent that interferes with early T cell activation can be designed to penetrate into psoriatic lesions when applied topically and to be functionally active within the skin to suppress the ongoing psoriatic process.

Administration, Topical

Synthesis and structure-activity relationships of side-chain-substituted analogs of the allylamine antimycotic terbinafine lacking the central amino function.

Terbinafine is a therapeutically used inhibitor of fungal squalene epoxidase that has prompted extensive derivatization programs for structure-activity relationship studies. In the present study, derivatives of terbinafine were synthesized that lack the central tertiary amino group but have polar substitutents at the tert-butyl residue of the side chain. Evaluation of the antifungal potential revealed that representatives of this novel structural type can also exhibit broad antifungal activity, indicating that the central amino function of allylamine antimycotics is not essential for inhibition of fungal growth. Potency appears to correlate with the polarity of the introduced functional groups, while broad antifungal activity seems to be restricted to compounds with basic substituents. The dimethylamino-substituted "carba-analog" of terbinafine (8k) showed the best antimycotic profile within the whole series.

Antifungal Agents

Nail incorporation kinetics of terbinafine in onychomycosis patients.

Patients with toe-nail onychomycosis were treated with terbinafine (250 mg daily, n = 20) for either 6 or 12 weeks in a randomized double-blind study. Plasma and distal nail clippings were taken before initiation of therapy and 1, 6, 12, 18, 24, 36 and 48 weeks thereafter. Analytical data of terbinafine extracted from nail clippings or plasma were obtained by high-performance liquid chromatography (HPLC). Nail extracts and isolated HPLC terbinafine peaks were analysed using a combined gas chromatography-mass spectroscopy system (GC-MS) for unequivocal identification of the drug. Terbinafine could be detected in the distal nail in the majority of the patients within 1 week of starting therapy. Maximum terbinafine levels of 0.52 and 1.01 micrograms/g were measured after 18 weeks in the 6- and 12-week treatment groups, respectively. While plasma levels decreased rapidly after termination of therapy terbinafine was detected in the nails as long as 30 weeks (6 weeks treatment) and 36 weeks (12 weeks treatment) after termination of therapy at a range of 0.28-0.19 microgram/g. The drug concentrations measured at all time points are well above the minimum inhibitory concentration (MIC) for dermatophytes and other fungi. These data suggest that the drug reaches the nail plate rapidly and persists there for several months after cessation of active treatment.

Antifungal Agents

Novel antiproliferative agents derived from lavendustin A.

The active partial structure of the potent tyrosine kinase inhibitor lavendustin A was derivatized in the search for novel agents against cellular proliferation. The antiproliferative potential of the new derivatives was determined using the human keratinocyte cell line HaCaT as the primary test system. Whereas the lavendustin A partial structure is ineffective in inhibiting cell proliferation, esterification of its carboxylic acid function leads to measurable antiproliferative activity. Additional O-methylation of the 2,5-dihydroxyphenyl moiety yields activity in the micromolar range. Further substantial increases in activity are achieved by replacing the nitrogen with oxygen and carbon within the 2,5-dimethoxyphenyl series (but not within the 2,5-dihydroxyphenyl analogs) leading to 5-[2-(2,5-dimethoxyphenyl) ethyl]-2-hydroxybenzoic acid methyl ester (13) as the most potent analog identified to date. These increases in antiproliferative activity are paralleled, however, by the disappearance of activity against the epidermal growth factor receptor-associated tyrosine kinase, suggesting another mechanism of action.

Antineoplastic Agents

Synthesis and structure-activity relationships of the novel homopropargylamine antimycotics.

Analogues of the antimycotic allylamine terbinafine were prepared in which the naphthalene and the tert-butyl-acetylene moieties were preserved, but the spacer between these two groups was varied, and the antifungal activity of the new compounds was evaluated. All modifications of the original spacer such as reduction of the double bond, switching the position of the nitrogen atom, shortening, and elongation resulted in decreased potencies with one exception: Compounds with the CH2NMeCH2CH2 group between the 1-naphthalene and the optionally substituted tert-butyl-acetylene function demonstrated high antifungal activity in vitro. The new homopropargylamine derivatives are more potent than terbinafine against Aspergillus fumigatus. The results support the hypothesis that two lipophilic domains linked by a spacer of appropriate length and a polar center at a defined position in the spacer are the general requirements for high activity of allylamine antimycotics.

Alkynes

Synthesis and structure-activity relationships of naphthalene-substituted derivatives of the allylamine antimycotic terbinafine.

Derivatives of the allylamine antimycotic terbinafine (1) with varied substitution at the naphthalene ring system have been prepared, and their antifungal activity has been evaluated. In general, the potency is strongly dependent on the bulkiness of the substituent. Only hydrogen or in some cases fluorine are tolerated as substituents at positions 2-4 and 6-8 of the naphthalene moiety, whereas 5-substituents may be larger in size (F, Cl, Br, Me). Derivatives with fluorine at positions 3, 5, and 7 or chlorine at position 5 showed enhanced activity against yeasts relative to 1. This increase in sensitivity could be intensified by simultaneous introduction of two fluoro substituents at positions 5 and 7. Compound 7q demonstrated 8- to 16-fold improved potency against Aspergillus fumigatus, Candida albicans, and Candida parapsilosis.

Allylamine

Synthesis and structure-activity relationships of phenyl-substituted benzylamine antimycotics: a novel benzylbenzylamine antifungal agent for systemic treatment.

Derivatives of the benzylamine antimycotics with an extra phenyl ring incorporated in the side chain have been prepared and their antifungal activity evaluated. The potency is strongly dependent on the distance between the two phenyl groups and the type of spacer. Linking the aryl rings with a quaternary carbon atom resulted in the identification of highly active compounds 7f and 12a, having a novel 4-benzylbenzylamine side chain. Compound 7f and its 7-benzo[b]thienyl analogue 12a show significantly enhanced efficacy, in particular against Candida albicans, and are among the most potent allyl/benzylamine antimycotics identified so far. Extended investigations with the benzylbenzylamine derivative 7f revealed that, in addition to the enhanced antimycotic profile, the compound is the first representative of the benzylamine antimycotics suitable for systemic treatment.

Alkylation

Penetration of Sandimmune (cyclosporin A) in rat skin in vitro. Effects of penetration enhancers and solvents.

The effect of various fatty acids or alcohols on the penetration rates and skin concentrations of cyclosporin A (Sandimmune; CyA) was evaluated in an in vitro model using skin of hairless rats. The influence of chain length, number and position of double bonds and branching of the carbon chain of the enhancer were investigated. In addition the penetration dependency of CyA on the concentration of both enhancer and CyA was studied. CyA was quantitated by high-performance liquid chromatography. The penetration rates of CyA through rat skin decreased with increasing number of double bonds of the enhancer and decreasing CyA concentrations in the donor solution, and increased with increasing chain length of the enhancer. Enhancers increase penetration rates by a factor of up to 20-90 in alcoholic vs. maximally 5-fold in oily compositions. Enhancers increase skin concentrations of CyA by a factor of up to 10-25 in alcoholic and about 4-20 in oily compositions.

Animals

Immunosuppressive macrolides of the type FK 506: a novel class of topical agents for treatment of skin diseases?

The immunosuppressive macrolide antibiotics FK 506 and rapamycin were tested for topical activity in experimental allergic contact dermatitis of farm pigs. This species was used because pig skin, in comparison to rodent skin, resembles human skin more closely. For comparison, cyclosporine A (CyA), which is orally but not topically active in patients with skin disease, dexamethasone, and clobetasol propionate were used. Treatment was performed twice, 30 min and 6 h after elicitation of challenge reaction. Topical application of 0.4 to 0.04% FK 506 caused a pronounced inhibition of inflammatory skin reactions of hypersensitivity to dinitrofluorobenzene. The treatment response was similar to the activity of 0.13% clobetasole. Dexamethasone (1.2%) was less active than clobetasol. In contrast, rapamycin and CyA were inactive at concentrations of 1.2 and 10%, respectively. Because the pig data on corticosteroids and cyclosporine A are in agreement with clinical findings, these studies indicate that immunosuppressive macrolides of the type FK 506 may be useful drugs for the topical treatment of human skin diseases that respond to local corticosteroids and oral treatment with cyclosporine A.

Animals

Synthesis and structure-activity relationships of benzo[b]thienylallylamine antimycotics.

Benzo[b]thiophene analogues of the allylamine antimycotic terbinafine (2) bearing the side chain at various positions and optionally substituted by halogen have been prepared and their antifungal activity studied. Derivatives bearing the side chain at positions 3, 4, or 7 are bioequivalents of 2. Compounds containing the allylamine side chain at position 7, with a further substituent at position 3, showed significantly enhanced activity against Candida albicans, an effect which appears to be specifically linked only to this particular substitution pattern. 3-Chloro-7-benzo[b]thienyl derivative 7m was found to be the most potent allylamine antimycotic identified so far. In general, substituted benzo[b]thiophenes can be used not only as potential equivalents of naphthalene in bioactive compounds but also as a tool to selectively modify biological activities.

Allylamine

Terbinafine inhibits the mitogenic response to platelet-derived growth factor in vitro and neointimal proliferation in vivo.

Terbinafine [(E)-N(6,6-dimethyl-2-hepten-4-ynyl)-N-methyl-1-naphthale nemethanamine], an antimycotic agent that inhibits fungal squalene epoxidase activity, was examined for its effects on platelet-derived growth factor (PDGF)-stimulated aortic smooth muscle cell DNA synthesis in vitro and neointimal proliferation in vivo. Exposure of bovine aortic smooth muscle cells to 0.25 to 25 microM terbinafine resulted in a concentration-dependent inhibition of PDGF-induced mitogenesis as determined by [3H]thymidine incorporation into DNA or cell number. The IC50 for inhibition of PDGF-stimulated smooth muscle cell DNA synthesis was approximately 5 microM. Micromolar concentrations of terbinafine also suppressed the mitogenic response to PDGF in fibroblasts. Neither the binding of [125I]PDGF to its plasma membrane receptors nor the uptake of [3H]thymidine or [3H]uridine was affected significantly by terbinafine. Oral administration of terbinafine (200 mg/kg/day) to rats for 2 days before and 14 days after balloon catheter injury to the carotid artery was associated with a 40% decrease in the area of the neointimal lesion. These observations indicate that terbinafine is both a potent in vitro antagonist of the smooth muscle cell mitogenic response to PDGF and an effective, well-tolerated p.o. active inhibitor of neointimal proliferation in vivo.

Animals

Synthesis and structure-activity relationships of naftifine-related allylamine antimycotics.

Naftifine (1) is the first representative of the new antifungal allylamine derivatives. Its biological activity is strictly bound to specific structural requirements that are unrelated to those of known antifungals. A tertiary allylamine function seems to be a prerequisite for activity against fungi. By systematic variation of the individual structural elements in 1, detailed structure-activity relationships are defined in which the phenyl ring is the structural feature permitting the widest variations. Versatile synthetic routes to allylamine derivatives and comparative biological data are presented.

Allylamine

Allylamine derivatives: new class of synthetic antifungal agents inhibiting fungal squalene epoxidase.

A new class of synthetic antifungal agents, the allylamines , has been developed by modification of naftifine , a topical antimycotic. SF 86-327, the most effective of these compounds so far, is highly active in vitro against a wide range of fungi and exceeds clinical standards in the oral and topical treatment of guinea pig dermatophytoses. SF 86-327 is a powerful specific inhibitor of fungal squalene epoxidase, a key enzyme in sterol biosynthesis.

Allylamine