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  • 1
    Electronic Resource
    Electronic Resource
    Pharmacokinetic and Pharmacodynamic Aspects of an Ophthalmic Pilocarpine Nanoparticle-Delivery-System (1994)
    Springer
    Pharmaceutical research 11 (1994), S. 1435-1442 
    Details
    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
    URL: http://dx.doi.org/10.1023/A:1018995923348
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  • 2
    Electronic Resource
    Electronic Resource
    Sila-Pharmaka, 30. (2-Aminoethyl)cycloalkylphenylsilanole: Bioisosterer C/Si-Austausch bei Parasympatholytika vom Typ des Trihexyphenidyls, Cycrimins und Procyclidins (1983)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 922-930 
    Details
    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
    URL: http://dx.doi.org/10.1002/jlac.198319830605
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  • 3
    Electronic Resource
    Electronic Resource
    Enantiomers of the muscarinic antagonist 1-cyclohexyl-1-(4-fluorophenyl)-4-piperidino-1-butanol (p-fluoro-hexahydro-difenidol): Synthesis, absolute configuration, and enantiomeric purity (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 523-527 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199119910196
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