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  • 1
    Electronic Resource
    Electronic Resource
    Absorbable biopolymers derived from dimer fatty acids (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 1275-1285 
    Details
    ISSN: 0887-624X
    Keywords: biodegradable polymers ; polyanhydride ; dimer fatty acid ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new class of aliphatic copolyanhydrides was synthesized from nonlinear hydrophobic dimers (FAD) of erucic acid and sebacic acid which possessed the desired physico-chemical and mechanical properties for use as a carrier for drugs. The polymers were synthesized by melt condensation to yield film-forming polymers with molecular weights of 250,000. The copolymer composition was determined by 1H-NMR and gravimetric methods. In vitro degradation studies showed that these polymers degrade following a first-order kinetics with a rapid degradation in the first 10 days leaving a residue which is mostly the FAD comonomer. The drug release from the polymer also followed a first-order kinetics which correlates with the degradation process of the polymer. Drugs like carboplatin, methotrexate, tetracycline, and gentamicin were released in vitro for over 2 weeks and in some cases over 6 weeks. In vivo biocompatibility tests in rats and rabbits in the brain, muscle, and subcutaneously, demonstrated their toxicological inertness and biodegradability. The 1 : 1 copolymer of FAD : SA was selected as a carrier for various applications including a gentamicin-releasing implant which is now undergoing human clinical trials for the treatment of osteomyelitis. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310523
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  • 2
    Electronic Resource
    Electronic Resource
    Biodegradable polymers derived from natural fatty acids (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 717-725 
    Details
    ISSN: 0887-624X
    Keywords: biodegradable polymers ; polyanhydride ; fatty acid ester ; ricinoleic acid ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new class of polyanhydrides synthesized from nonlinear hydrophobic fatty acid esters, based on ricinoleic, maleic acid, and sebacic acid, possessed desired physico-chemical and mechanical properties for use as drug carriers. The polymers were synthesized by melt condensation to yield film-forming polymers with molecular weights exceeding 100,000. Their rate of elimination from rats in the course of about 2 months was faster than that found for similar polyanhydrides previously tested. In vitro studies showed that these polymers underwent rapid degradation in the first 10 days. The drug release followed first-order kinetics, showing a rapid drug release rate in the first 10 days which correlated with the degradation of the polymers. The fatty acid ester monomers underwent in vitro enzymatic degradation to the natural starting acids. Tests in rats demonstrated their toxicological inertness and biodegradability. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330413
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  • 3
    Electronic Resource
    Electronic Resource
    Nystatin - dextran conjugates: Synthesis and characterization (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1229-1236 
    Details
    ISSN: 0887-624X
    Keywords: Nystatin ; dextran conjugates ; Candida ; polymer conjugates ; antifungal ; oxidized dextran ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coupling of nystatin (Nys), a water-insoluble antifungal agent, to dextran via an imine or amine bond was systematically investigated. Dextran was first oxidized to dialdehyde dextran using potassium periodate, purified from the oxidizing agent, and reacted with Nys to form the Schiff base. The Schiff base was reduced to the amine using borohydride. All reactions took place in water. The purification of the oxidized dextran from the oxidizing agent was essential to prevent oxidative degradation of Nys at the coupling step. The effects on the coupling yield of the following factors: dextran molecular weight, degree of oxidation (aldehyde content), Nys to dextran ratio, temperature, and reaction pH were studied. A 95% coupling yield was obtained at the optimized coupling conditions: pH 8.9 ± 0.1, 50% degree of oxidation, and initial ratio of Nys to dialdehyde dextran 1:2.5. In all experiments, dextran was decreased in molecular weight during the oxidation step. Both imine and amine forms of Nys-dextran conjugates were soluble in water and exhibited improved stability in aqueous solutions as compared to the unbound drug. The conjugates showed comparable minimum inhibitory concentration (MIC) values against Candida albicans and Cryptococcus neoformans. The conjugates were about 25 times less toxic than free Nys after a single injection in mice. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Polyanhydrides. IV. Unsaturated and crosslinked polyanhydrides (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 571-579 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Unsaturated polyanhydrides of the structure —[—(—CO—CH=CH—COO—)x—(—CO—R—COO—)y—]n—, were synthesized. The polymers were prepared by either melt or solution polycondensation. Weight average molecular weights of up to 30,000 were obtained. The double bonds remain intact throughout the polymerization process and were available for a secondary reaction to form a crosslinked matrix. Poly(fumaric acid) is crystalline and insoluble in common organic solvents. Copolymers of fumaric acid with aliphatic diacids are less crystalline and soluble in chlorinated hydrocarbons. These copolymers displayed nearly constant degradation rates and drug release rates under physiological conditions. The time for complete degradation of 14 × 1.5 mm discs of poly(fumaric anhydride) and poly(sebacic anhydride) occurred in 2 and 15 days, respectively, while their copolymers degraded within this range. Further crosslinking of the polyanhydrids is demonstrated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1991.080290413
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  • 5
    Electronic Resource
    Electronic Resource
    Degradable polymer blends. I. Screening of miscible polymers (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 1973-1981 
    Details
    ISSN: 0887-624X
    Keywords: polymer blends ; biodegradable polyesters ; polyanhydrides ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Blends of biodegradable polymers having properties distinct from the individual polymer components, and that are suitable for use as carriers of pharmaceutically active agents, were prepared from two or more polyanhydrides, polyesters, and mixtures of polyanhydrides and low molecular weight polyesters. The blends have different properties than the original polymers, providing a mean for altering the characteristics of the polymeric matrix without altering the chemical structure of the component polymers. Aliphatic, aromatic, and copolymers of polyanhydrides were miscible in each other and formed less crystalline compositions with a single melting point which was lower than the melting point of the starting polymers. The polyesters: poly(lactide-glycolide), poly(caprolactone), and poly(hydroxybutyric acid) presented some miscibility in each other. However, the polyanhydrides were immiscible with the polyesters resulting in a complete phase separation both in solution or in melt mixing. Only low molecular weight polyesters (in the range of 2000) of lactide and glycolide, mandelic acid, propylenefumarate, and caprolactone presented some miscibility with polyanhydrides. Similarly, poly(orthoester) and hydroxybutyric acid polymers formed a uniform mixture with the anhydride polymers which had the two melting points of the original polymers. Drug release from polymer blends composed of poly(hydroxybutyric acid) or low molecular weight poly(lactic acid) with poly(sebacic anhydride) (PSA) showed a constant release of drug for periods from 2 weeks to several months as a function of the PSA content in the blend. Increasing the content of PSA, a fast degrading polymer, increases the release rate from the blend. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310805
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  • 6
    Electronic Resource
    Electronic Resource
    The formation of propylene fumarate oligomers for use in bioerodible bone cement composites (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 973-985 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(propylene fumarate) (PPF) oligomers were synthesized by step polymerization using bis(2-hydroxypropyl fumarate) or propylene bis(hydrogen maleate) as starting materials. Oligomers possessing identical degrees of polymerization (DP), but varying in their end group character (either hydroxyl or carboxyl) were first prepared and characterized, then used as part of a bone cement preparation consisting of oligomer, tricalcium phosphate, calcium carbonate, and methyl methacrylate. Compressive strength of the resulting composite appeared to be dependent on both the degree of polymerization of the PPF, and the nature of the oligomers' end groups.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1990.080280503
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  • 7
    Electronic Resource
    Electronic Resource
    Polymeric drug and drug administration, Raphael M. Ottenbrite, ed., ACS, Washington, DC (1994), ACS symposium series 545 (1995)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 6 (1995), S. 215-215 
    Details
    ISSN: 1042-7147
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1995.220060319
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  • 8
    Electronic Resource
    Electronic Resource
    Stimulation of trigeminal motoneurons by in vivo implantation of glutamate-impregnated microspheres (1992)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 3 (1992), S. 337-344 
    Details
    ISSN: 1042-7147
    Keywords: Polyanhydride ; Microsphere ; Glutamate ; Trigeminal ; Motoneuron ; 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
    Notes: The objective of this study was to alter biomechanical forces generated by the muscles of mastication that affect the growth of the craniofacial skeleton through the implantation of neurotransmitter microspheres to stimulate trigeminal motoneurons (TMNe) in vivo. Polyanhydride microspheres containing L-glutamate were stereotaxically implanted 170-920 μm rostral to the left-side trigeminal motor nucleus (TMNu) in 17 Sprague-Dawley rats at 33-38 days old. Seven rats received blank-microsphere implants and two rats had empty delivery system penetration as controls. All rats were killed 10-14 days postsurgical for dissection, brain histology, osteometric data, and SEM analyses. Dimensions of the facial skeletons of glutamate-microsphere rats showed significant (P〈0.01, P〈0.05) differences when compared to control animals. Glutamate-microsphere animals also demonstrated significant (P〈0.01) differences between the dimensions of their implant-and nonimplant-side facial skeletons. SEM analyses indicated that glutamate-microsphere rats had greater implant-side wear of their mandibular incisors compared to blank-microsphere or delivery system controls. The skeletal alterations in the glutamate-microsphere rats are hypothesized to be due to increased implant-side TMNe and masticatory muscle activity patterns.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1992.220030609
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  • 9
    Electronic Resource
    Electronic Resource
    Polymeric biodegradable lipospheres™ as vaccine delivery systems (1992)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 3 (1992), S. 351-357 
    Details
    ISSN: 1042-7147
    Keywords: Lipospheres ; Vaccines ; Delivery systems ; Biodegradable polymers ; Adjuvants ; 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
    Notes: This study describes the preparation and use of polymeric lipospheresTM as a potential vehicle for the controlled-release of vaccines. Lipospheres are a new encapsulation technology for parenteral drug delivery that have been also used successfully as carriers of vaccines. A recombinant malaria antigen, R32NS1, derived from the circumsporozoite protein of Plasmodium falciparum, was incorporated in biodegradable polymeric lipospheres in the absence or presence of lipid A as an adjuvant. The immunogenicity of polymeric lipospheres composed of polylactide (PLD) or polycaprolactone (PCL) was tested in rabbits after intramuscular injection of the formulations. High levels of specific IgG antibodies were observed in the sera of the immunized rabbits up to 12 weeks after primary immunization, using a solid phase ELISA assay. PCL lipospheres containing the malaria antigen were able to induce sustained antibody activity after one single injection in the absence of immunomodulators. PCL lipospheres showed superior immunogenicity compared to PLD lipospheres, the difference being attributed to the different biodegradation rates of the polymers. Biodegradable polymeric lipospheres represent a pharmaceutically acceptable vaccine delivery system with immunopotentiating activity for humoral antibody responses. The high permeability to many therapeutic drugs, and a lack of toxicity, has made PCL and its derivatives well suited for controlled drug delivery. The results obtained in this study are very promising, with the expectation that the use of biodegradable polymeric lipospheres might be very useful in the conversion of multiple-dose vaccines to single-dose vaccination, avoiding the need for repeated immunizations.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1992.220030611
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  • 10
    Electronic Resource
    Electronic Resource
    Polymeric drug and drug administration, Raphael M. Otenbrite, ed. ACS, Washington, DC (1994), ACS symposium series 545 (1995)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 6 (1995), S. 216-216 
    Details
    ISSN: 1042-7147
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1995.220060320
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