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  • 1
    ISSN: 1573-904X
    Keywords: pilocarpine ; glaucoma ; nanoparticles ; betamethasone ; miosis ; intraocular pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The regional pharmacokinetics as well as the pharmacodynamics of pilocarpine-loaded nanoparticles for the treatment of glaucoma were investigated and compared to a solution of this drug. Poiybutylcy-anoacrylate nanoparticles were prepared by an emulsion polymerization process. Formulations with different drug concentrations (2–6%) as well as different particle concentrations were investigated and analyzed for size and drug loading. Drug binding to the particles was achieved at a level of 10–18% of the total drug content. The colloidal nanoparticles were sufficiently small (diameter: 100–300 nm) for a non-irritating application to the eye. All preparations were applied to the eyes of New Zealand white rabbits which were treated with betamethasone before to create an elevated intraocular pressure (IOP). Pilocarpine concentrations, assayed from aqueous humor using gaschromatography, increased by 23% (AUC) for nanoparticle suspensions compared to aqueous reference solutions. Additionally, t1/2 was prolonged and the elimination coefficient was significantly decreased. Pharmacodynamic effects such as miosis and IOP reduction were investigated. tmax values of aqueous humor concentration were observed to be in a similar time range as miosis tmax readings. It was found that at lower drug contents a more pronounced prolongation of miosis was achieved with nanoparticles versus a standard solution. The lOP-reduction was significantly prolonged with nanoparticles preparations; whereas maximum reduction was obtained with a reference solution after 1–2 hours, it was reached with nanoparticles at about 2–3 hours. Differences between nanoparticles and aqueous solutions were most pronounced at lower drug concentrations.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 1 (1989), S. 170-173 
    ISSN: 0899-0042
    Keywords: phenglutarimide enantiomers ; enantioselectivity ; antiparkinsonian drugs ; M1-selective antagonists ; rabbit vas deferens ; pirenzepine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The affinity of the enantiomers of phenglutarimide at three muscarinic receptor subtypes was examined in vitro using field-stimulated rabbit vas deferens (M1 receptors) and guinea pig atria (M2α receptors) and ileum (M2β receptors). Extremely high stereoselectivity was observed and higher affinities (up to 6000-fold) were found for the (+)-S-enantiomer. The stereoselectivity ratios were different at the three subtypes, and the stereochemical demands made by the muscarinic receptors were most stringent at M1 receptors. (+)-(S)-Phenglutarimide was found to be a potent M1-selective antagonist (pA2 at M1 = 8.53). Its receptor selectivity profile is qualitatively similar to that of pirenzepine. (-)-(R)-Phenglutarimide showed no comparable discriminatory properties.
    Additional Material: 1 Ill.
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  • 3
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sila-Pharmaca, 30. - (2-Aminoethyl)cycloalkylphenylsilanols: Bioisosteric C/Si Exchange in Parasympatholylics of the Trihexyphenidyl, Cycrimine, and Procyclidine TypeThe synthesis of the (2-aminoethyl)cycloakylphenylsilanols 5b (sila-trihexyphenidyl), 6b (Sila-cycrimine), 7b (sila-procyclidine), and 8b is described. Starting with CI2(C6H5)SiCh—CH2(9), 5b-8b were obtained by five reaction steps with a total yield of 32-40%. The C/Si pairs 5a,b-8a,b, were tested for antimuscarinic activity on the isolated guinea-pig ileum. The increase of affinity of the muscarinic receptor caused by sila-substitution of 5a-8a is less marked than in the case of the structurally related C/Si 1a,b-4a,b.
    Notes: Die Synthese der (2-Aminoethyl)cycloalkylphenylsilanole 5b (Sila-Trihexyphenidyl), 6b (Sila-Cycrimin), 7b (Sila-Procyclidin) und 8b wird beschrieben. 5b-8b wurden - ausgehend von Ci2(C?6H5)SiCCCCH—CH2 (9) - durch eine fünfstufige Reaktionsfolge mit einer Gesamtausbeute von 32-40% erhalten. Am isolierten Ileum des Meerschweinchens wurden die C/Si-Paare 5a,b-8a,b vergleichend auf ihre antimuskarinische Aktivität geprüft. Die durch die Sila-Substitution von 5a-8b erreichte Zunahme der Affinität zum Muskarinrezeptor ist deutlich weniger ausgeprägt als bei den strukturverwandten C/Si-Paaren 1a,b-4a,b.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0170-2041
    Keywords: Difenidol, (R)- and (S)-hexahydro- ; Antimuscarinic properties ; Muscarinic receptor subtypes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Properties of the Enantiomers of the Selective Antimuscarinic Agent 1-Cyclohexyl-1-phenyl-4-piperidino-1-butanol (Hexahydro-Difenidol)Using (S)- or (R)-mandelic acid as the resolving agent, the enantiomers of 1-cyclohexyl-1-phenyl-4-piperidino-2-butin-1-ol [(R)-2 and (S)-2] were prepared (enantiomeric purity: ee = 99.7%; calorimetric analysis). Catalytic hydrogenation (Pd/C contact) of (R)-2 and (S)-2 yielded the enantiomers of 1-cyclohexyl-1-phenyl-4-piperidino-1-butanol [(R)- and (S)-hexahydro-difenidol, (R)-1a and (S)-1a] which were isolated as hydrochlorides [(R)-1a ⋅ HCl and (S)-1a ⋅ HCl, ee = 99.7%]. The absolute configuration of the enantiomers of 1a and 2 was determined by an X-ray crystal structure analysis of the mandelate (S)-1a ⋅ (R)-C6H5CH(OH)COOH. (R)-Hexahydro-difenidol [(R)-1a] and (R)-2 exhibit a higher affinity for the atrial M2α and ileal M2β muscarinic receptors of the guinea pig than the respective antipodes (S)-1a and (S)-2 (atrial stereoselectivity index: 17 and 8.6, respectively; ileal stereoselectivity index: 193 and 44, respectively). In addition, (R)-1a and (R)-2 exhibit a significantly higher affinity for the M2β receptors of the ileum than for the M2α receptors of the atrium (atrium/ileum ratio: 21 and 10, respectively). Thus, (R)-1a and (R)-2 are valuable tools for the identification and characterization of muscarinic M2 subtypes. In contrast, the less potent (S)-enantiomers of 1a and 2 do not differentiate between M2α and M2β receptors.
    Notes: Durch Racematspaltung mit (S)- bzw. (R)-Mandelsäure wurden die Enantiomere von 1-Cyclohexyl-1-phenyl-4-piperidino-2-butin-1-ol [(R)-2 und (S)-2] dargestellt (Enantiomerenreinheit: ee = 99.7%, kalorimetrische Analyse). Katalytische Hydrierung (Pd/C-Kontakt) von (R)-2 und (S)-2 ergab die Enantiomere von 1-Cyclohexyl-1-phenyl-4-piperidino-1-butanol [(R)- und (S)-Hexahydro-Difenidol, (R)-1a und (S)-1a], die als Hydrochloride (R)-1a ⋅ HCl und (S)-1a ⋅ HCl isoliert wurden (ee = 99.7%). Die absolute Konfiguration der Enantiomere von 1a und 2 wurde durch Röntgenkristallstrukturanalyse des Mandelats (S)-1a ⋅ (R)-C6H5CH(OH)COOH bestimmt. (R)-Hexahydro-Difenidol [(R)-1a] und (R)-2 besitzen eine höhere Affinität zu den atrialen M2α-und ilealen M2β-Muscarinrezeptoren des Meerschweinchens als die entsprechenden Antipoden (S)-1a und (S)-2 (atrialer Stereoselektivitätsindex: 17 bzw. 8.6; ilealer Stereoselektivitätsindex: 193 bzw. 44). Darüber hinaus besitzen (R)-1a und (R)-2 eine signifikant höhere Affinität zu den M2β-Rezeptoren des Ileums als zu den M2α-Rezeptoren des Atriums und sind somit wertvolle Modellverbindungen zur Identifizierung und Charakterisierung von muscarinischen M2-Subtypen (Atrium/Ileum-Quotient: 21 bzw. 10). Im Gegensatz hierzu vermögen die schwächer wirksamen (S)-Enantiomere von 1a und 2 nicht zwischen den M2α- und M2β-Rezeptoren zu unterscheiden.
    Additional Material: 4 Ill.
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  • 5
    ISSN: 0170-2041
    Keywords: Difenidol, p-fluoro-hexahydro-, enantiomers of ; Muscarinic receptors, subtypes of ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantiomers of the antimuscarinic agent 1-cyclohexyl-1-(4-fluorophenyl)-4-piperidino-1-butanol [(R)- and (S)-p-fluorohexahydro-difenidol] [(R)- and (S)-2a] and their methiodides (R)-3 and (S)-3 were prepared with high enantiomeric purity. (R)-2a and (S)-2a (isolated as hydrochlorides) were obtained by catalytic hydrogenation (Pd/C contact) of the corresponding enantiomers of 1-cyclohexyl-1-(4-fluorophenyl)-4-piperidino-2-butyn-1-ol [(R)- and (S)-4]. Reaction of (R)-2a and (S)-2a with methyl iodide led to (R)-3 and (S)-3, respectively. The unsaturated precursors (R)- and (S)-4 (enantiomeric purity ≥99.80 and ≥99.94% e.e.; calorimetric analysis) were prepared by resolution of rac-4 [available from 4-FC6H4C(O)C6H11 by reaction with LiC≡CCH2NC5H10] using (R)- and (S)-mandelic acid as resolving agents. The absolute configurations of the (R) and (S) enantiomers of 2a, 3, and 4 were determined by an X-ray crystal-structure analysis of (S)-5, the methiodide of (S)-4. (R)-2a and (R)-3 exhibit a higher affinity for muscarinic M1, M2, M3, and M4 receptors (by up to two orders of magnitude) than their corresponding antipodes (S)-2a and (S)-3, the degree of stereoselectivity depending on the receptor subtype involved. (R)-2a represents a useful tool for muscarinic receptor research (affinity profile: M1 ≈ M3 ≈ M4 〉 M2).
    Additional Material: 2 Ill.
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  • 6
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sila-Pharmaca, 33.  -  Synthesis and Properties of the Selective Antimuscarinic Agent Cyclohexylphenyl(3-piperidinopropyl)silanolThe synthesis of the selective antimuscarinic agent cyclohexylphenyl(3-piperidinopropyl)silanol (1b) is described. Starting with (3-chloropropyl)trimethoxysilane, 1b was obtained by four reaction steps and isolated as hydrochloride 2b with a total yield of about 45%.  -  Because of its high pharmacological selectivity 1b has become a reference drug in experimental pharmacology for the differentiation of muscarinic receptors.
    Notes: Die Synthese des selektiven Antimuskarinikums Cyclohexylphenyl(3-piperidinopropyl)silanol (1b) wird beschrieben. 1b wurde - ausgehend von (3-Chlorpropyl)trimethoxysilan - durch eine vierstufige Reaktionsfolge erhalten und als Hydrochlorid 2b mit einer Gesamt-ausbeute von etwa 45% isoliert.  -  1b ist aufgrund seiner großen pharmakologischen Selektivität zu einer Standardsubstanz in der experimentellen Pharmakologie bei der Differenzierung von Muskarinrezeptoren geworden.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Absolute Configuration of the Enantiomers of the Antimuscarinic Agents Procyclidine and Tricyclamol Iodide: X-Ray Structural Analysis of (R)-1-[3-Cyclohexyl-3-hydroxy-3-phenyl-propyl]-1-methylpyrrolidinium IodideThe absolute configurations of the antimuscarinic agents procyclidine (1a) and tricyclamol iodide (2a) were established by X-ray structural analysis of (R)-1-[3-Cyclohexyl-3-hydroxy-3-phenyl-propyl]-1-methylpyrrolidinium iodide [(R)-tricyclamol iodide, (R)-2a]. The antimuscarinic potency of (R)-1a and (R)-2a is about 380 and 90 times, respectively, greater than that of the corresponding (S)-configurated enantiomers (guinea-pig ileum).
    Notes: Durch Röntgenstrukturanalyse von (R)-1-[3-Cyclohexyl-3-hydroxy-3-phenylpropyl]-1-methyl-pyrrolidiniumiodid [(R)-Tricyclamoliodid, (R)-2a] wurden die absoluten Konfigurationen der Enantiomere der Antimuskarinika Procyclidin (1a) und Tricyclamoliodid (2a) bestimmt. (R)-1a und (R)-2a sind etwa 380-bzw. 90mal stärker antimuskarinisch wirksam (isoliertes Meerschweinchen-Ileum) als die entsprechenden (S)-konfigurierten Enantiomere.
    Additional Material: 2 Ill.
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  • 8
    ISSN: 0268-2605
    Keywords: o-methoxy-sila-hexocyclium ; sila-hexocyclium ; sila-drugs ; antimuscarinics ; muscarinic receptor subtypes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the potent and highly selective silicon-containing antimuscarinic agent o-methoxysila-hexocyclium methyl sulfate and its corresponding tertiary amine (isolated as the dihydrochloride) is described. The quarternary compound is an o-methoxy derivative of sila-hexocyclium methyl sulfate, which represents one of the tools currently used in experimental pharmacology for the subclassification of muscarinic receptors. The o-methoxy derivative, the pharmacological profile of which differs substantially from that of the nonmethoxy compound, is also recommended as a tool for the investigation of muscarinic receptor heterogeneity.
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