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  • 1
    Electronic Resource
    Electronic Resource
    Coupling of Naltrexone to Biodegradable Poly(α-Amino Acids) (1987)
    Springer
    Pharmaceutical research 4 (1987), S. 305-310 
    Details
    ISSN: 1573-904X
    Keywords: naltrexone ; narcotic antagonist ; biodegradable ; poly(α-amino acid) ; poly-N 5-(3-hydroxypropyl)-L-glutamine (PHPG) ; copoly(hydroxypropyl-L-glutamine/L-leucine)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The narcotic antagonist naltrexone (I) was modified at the 3 and 14 hydroxyl positions and covalently coupled to a biodegradable poly(α-amino acid) backbone through a labile bond. Selective acetylation of I with acetic anhydride gave naltrexone-3-acetate (II), which was subsequently succinoylated to naltrexone-3-acetate-14-hemisuccinate (III) with succinic anhydride. The polymeric backbone chosen for initial coupling experiments was poly-N 5-(3-hydroxypropyl)-L-glutamine (PHPG). The side-chain hydroxyl functionality permitted covalent bonding of III through an ester linkage. Hydrolysis of covalently bound drug to give naltrexone or its derivatives (II and III) should be much slower than diffusion of drug through the polymer matrix. While hydrolysis of naltrexone from the polymer side chain is first order, release of drug from the matrix can be zero order due to the geometry of the device and the physical and chemical interactions between naltrexone and the polymer matrix. In vitro studies of PHPG–naltrexone conjugate in disk form did not show constant release because of the hydrophilic nature of the polymer backbone and the changing local chemical environment upon hydrolysis of drug–polymer linkages. The conjugated system was made more hydrophobic by coupling drug to copolymers of hydroxypropyl-L-glutamine (HPG) and L-leucine. Conjugates of III coupled with copoly(HPG-70/Leu-30) demonstrated a nearly constant, but slightly declining release rate of naltrexone and its derivatives for 28 days in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016493103302
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  • 2
    Electronic Resource
    Electronic Resource
    Photoregulated binding ability of a polymeric adsorbent containing a spiro[2H-chromen-2,2′-indoline] moiety (1981)
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 2 (1981), S. 617-620 
    Details
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1981.030020915
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  • 3
    Electronic Resource
    Electronic Resource
    Regulation of binding and releasing of cephalosporins by photoresponsive polymeric adsorbent (1981)
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 2 (1981), S. 95-98 
    Details
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1981.030020119
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  • 4
    Electronic Resource
    Electronic Resource
    Adsorption of photochromic azo dye onto styrene-divinylbenzene copolymer (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 19 (1981), S. 593-597 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.130191202
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  • 5
    Electronic Resource
    Electronic Resource
    Complex formation of amphiphilic polymers with azo dyes and their photoviscosity behavior (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 1907-1916 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hydrophobic interaction of amphiphilic copolymers, which contain 2-hydroxyethyl methacrylate(HEMA) and 1vinyl-2-pyrrolidone (VPy), with Methyl Orange (MO) was compared with that of HEMA-acrylamide (AAm) copolymers to deduce the correlation between their complexation ability in a photochromic azo dye and the photoviscosity effect in aqueous copolymer/dye complex solution. On the basis of the dialysis data and fluorometric analysis it appeared that the complexation dependence on HEMA content in the copolymers was due to the hydrophobic interaction between the polymer and the dye. For a comparable HEMA content AAm copolymers bound less MO than VPy copolymers. It was confiied by photoviscosity measurements that the conformation of the complex composed of photochromic azo dye and HEMA copolymer changed reversibly in response to the photo- and thermal isomerization of the dye. In HEMA-AAm copolymer systems the photoviscosity effect was small compared with that of HEMA-VPy copolymer systems. From these results it was concluded that the complexation ability of polymers due to the hydrophobic interaction was an important factor in producing a large photoinduced conformational change in water.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200722
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  • 6
    Electronic Resource
    Electronic Resource
    Photoinduced reversible pH change in aqueous solution of azoaromatic poly(carboxylic acid) (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 3687-3695 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To regulate the pH value of an aqueous solution containing polyelectrolyte by photoirradiation, an azoaromatic poly(carboxylic acid), acrylic acid(AA)-p-phenylazoacrylanilide (PAAn) copolymer was synthesized and the photoresponse of the polymer solution was investigated. AA-PAAn copolymer, which takes a compact form in the ordinary state owing to the presence of azoaromatic side chains, is transformed into an extended form when azoaromatic moieties are isomerized by photoirradiation. Thus, the pH value of the solution can be reversible regulated by irradiation and interruption of light through a change in polymer conformation. The range of the pH change was about 0.15. These phenomena can be explained on the basis of polarity change induced by the photoisomerization of azoaromatic side chains.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221206
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  • 7
    Electronic Resource
    Electronic Resource
    Photoregulated binding ability of azoaromatic polymer for surfactant (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 3039-3046 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Water-soluble polymeric azodyes containing an azobenzene moiety in their side chain, p-phenylazoacrylanilide (PAAn)-acrylamide (AAm) copolymers, were synthesized and the adsorption-desorption behavior of sodium dodecyl sulfate (SDS) onto these copolymers in water was investigated by means of conductivity measurements, with attention to the hydrophobicity of the copolymer. The conductivity of the PAAn-AAm copolymer/SDS complex aqueous solution decreased with increasing PAAn composition in the copolymer. This result indicates that the SDS molecules adsorbed onto the copolymer. The adsorption state of SDS molecules on the copolymer was considered to take a micellelike form. When the hydrophobicity of the PAAn-AAm copolymer was decreased by means of the photoisomerization of an azodye moiety, the conductivity of the PAAn-AAm copolymer/SDS aqueous solution increased. This phenomenon can be explained as a result of desorption of SDS molecules from the copolymer. When the light source was cut off, the conductivity took on its original value. This indicated that SDS was desorbed by the photochemical trans to cis and adsorbed by cis to trans isomerization of the PAAn moiety.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.170191201
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  • 8
    Electronic Resource
    Electronic Resource
    Photo-induced change in wettability and binding ability of azoaromatic polymers (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 239-245 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Photochromic polymers containing p-phenylazoacrylanilide were synthesized and the photo-induced hydrophobicity change on the surface of the polymer film was studied by measuring water wettability. The wettability increased with UV irradiation and returned to the original value with visible light irradiation. This photo-induced reversible change in wettability was considered to be caused by the large change of dipole moment across the azo bonds due to the isomerization of azo dye from trans to cis form. Furthermore, the photoresponsive polymeric adsorbent prepared from the azo polymer having adsorption behavior of a low molecular weight compound was studied. The binding ability of this polymeric adsorbent was decreased by UV irradiation. These results were attributed to the decreased hydrophobic interaction between the adsorbent and the adsorbate.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270125
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  • 9
    Electronic Resource
    Electronic Resource
    Photocontrolled adsorption chromatography for lysozyme using azoaromatic polymer (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 1897-1902 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Photoresponsive polymeric adsorbents containing an azobenzene moiety were prepared, and adsorption behavior of lysozyme onto the adsorbents was studied. In the dark the amount of lysozyme adsorbed increased with increasing hydrophobicity of the surface of the adsorbents. Therefore, it is suggested that hydrophobic interaction between lysozyme and the adsorbents plays an important role in their adsorption behavior. On irradiation with UV light, the amount of lysozyme adsorbed decreased. This result is due to increased polarity of the surface of the adsorbent induced by UV irradiation and the resultant reduction in hydrophobic interaction with lysozyme. When a column chromatography of lysozyme was carried out using the photoresponsive polymeric adsorbent as a packing material, lysozyme was eluted by photoirradiation in a system using water as the single solvent.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270604
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