Synthesis and Characterization of a Novel, Water‐Soluble Polymer with Pendant Groups Carrying cis‐Platinum Complex
31 Dec 2004-Journal of Macromolecular Science, Part A (Taylor & Francis Group)-Vol. 41, Iss: 7, pp 859-871
TL;DR: In this article, the synthesis and characterization of a polymer with pendant groups carrying a cisplatinum complex by the chemical modification route is discussed, and the polymer is further characterized using thermogravimetric analysis (TGA) as well as UV and fluorescence spectroscopic techniques.
Abstract: The synthesis and characterization of a polymer with pendant groups carrying a cis‐platinum complex by the chemical modification route is discussed. Diethyloxomalonate functionalized polystyrene (DPS) is synthesized by the Friedel–Crafts acylation of polystyrene with diethyloxomalonate in the presence of SnCl4, by a batch‐wise addition process. The reaction of DPS with cis‐diaquo(trans‐1,2‐diaminocyclohexane)platinum(II) results in the formation of a cis‐platinum chelated polymer (PtDPS). Proton NMR and IR spectroscopies are used to confirm the transformation. The polymer synthesized is further characterized using thermogravimetric analysis (TGA) as well as UV and fluorescence spectroscopic techniques. PtDPS thus synthesized is further modified into a water‐soluble polymer by another polymer modification reaction resulting in the introduction of thiobarbituric acid moieties.
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TL;DR: In this paper, a water-soluble polymer-cobalt-III-phenanthroline complex with calf thymus DNA has been explored using EBS, emission spectroscopy and gel electrophoresis techniques, and the presence of multiple small size molecular binding sites and free amino groups in a single big sized polymer molecule enhanced both the electrostatic and/or van der Waals interaction and partial intercalative bindings.
Abstract: The novel water-soluble polymer–cobalt(III) complex samples, cis -[Co(phen) 2 (BPEI)Cl]Cl 2 · 4H 2 O (phen = 1,10-phenanthroline, BPEI = branched polyethyleneimine), with different amounts of cobalt complex content in the polymer chain, were prepared by ligand substitution method in water–ethanol medium and characterized by Infra-red, UV–Vis, 1 H NMR spectral and elemental analysis methods. The interaction of these polymer–cobalt(III)-phenanthroline complex samples with calf thymus DNA has been explored using electronic absorption spectroscopy, emission spectroscopy and gel electrophoresis techniques. The presence of multiple small size molecular binding sites, namely, the cobalt(III)–phenanthroline complex moieties, and free amino groups in a single big sized polymer molecule enhanced both the electrostatic and/or van der Waals interaction and partial intercalative bindings with calf thymus DNA. The antitumor activity of a sample of polymer–cobalt(III) complex was determined using HEp-2 cell line and different cell death indicator stains and MTT assay. Many of the cultured HEp-2 cells treated with this complex suffered loss of viability and death mostly through apoptosis as evidenced by the nuclear and cytoplasmic morphology.
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10 Mar 2006
TL;DR: In this article, the authors provide an overview on the preparation and basic lithographically important characterization of new polymers based on poly(4-(1-hydroxyalkyl)styrene -co- styrene) [Poly(4-HAS -co)-S] for negative tone imaging at DUV lithography.
Abstract: Several synthetic approaches are available to make photoresist polymers for deep UV (DUV) lithography. Two approaches were widely used in semiconductor manufacturing: i) direct polymerization of corresponding monomers by (controlled) radical, (living) ionic polymerization ii) thermal or chemical catalyzed deprotection or protection of the macromolecules. The latter approach which is also called polymer modification chemistry (PMC) or polymer analogous chemistry offers several advantageous over the direct polymerization approach. In this presentation, we will provide an overview on the preparation and basic lithographically important characterization of new polymers based on poly(4-(1-hydroxyalkyl)styrene -co- styrene) [Poly(4-HAS -co- S)]. These polymers were synthesized for the first time by PMC and this methodology is an simple alternative for the synthesis of poly(4-HAS -co- S) than conventionally used synthetically challenging free radical or low temperature anionic polymerization of the protected monomer. We have synthesized high and low molecular weight (M n ) polymers with mole fraction of functional group ranging from partial to complete functionalization. Several formulations based on poly(4-HAS -co- S) were developed and tested for negative tone imaging at DUV lithography. Lithographic performance of these polymers at DUV lithography will be compared with their molecular weight and mole fraction of functional groups.
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References
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TL;DR: Methoxypolyethylene glycols and catalase modified by covalent attachment of PEG-1900 to 43% of the amino groups exhibited enhanced circulating lives in the blood of acatalasemic mice during repetitive intravenous injections and no evidence of tissue or organ damage was seen.
Abstract: Methoxypolyethylene glycols of 1900 daltons (PEG-1900) or 5000 daltons (PEG-5000) were covalently attached to bovine liver catalase using 2,4,6-trichloro-s-triazine as the coupling agent. Rabbits were immunized by the intravenous and intramuscular routes with catalase modified by covalent attachment of PEG-1900 to 43% of the amino groups (PEG-1900-catalase). The intravenous antiserum did not yield detectable antibodies against PEG-1900-catalase or native catalase, as determined by Ouchterlony and complement fixation methods, whereas the intramuscular antiserum contained antibodies to both PEG-1900-catalase and catalase. PEG-1900 did not react with either antiserum. Catalase was prepared in which PEG-5000 was attached to 40% of the amino groups (PEG-5000-catalase). This catalase preparation did not react with either antiserum. PEG-1900-catalase retained 93% of its enzymatic activity; PEG-5000-catalase retained 95%. PEG-5000-catalase resisted digestion by trypsin, chymotrypsin, and a protease from Streptomyces griseus. PEG-1900-catalase and PEG-5000-catalase exhibited enhanced circulating lives in the blood of acatalasemic mice during repetitive intravenous injections. No evidence was seen of an immune response to injections of the modified enzymes. Mice injected repetitively with PEG-5000-catalase remained immune competent for unmodieied catalase, and no evidence of tissue or organ damage was seen.
1,261 citations
TL;DR: In this article, a model for pharmacologically active polymers is presented for continuous variation in (a) solubility and toxicity, (b) fixation and removal of active material, and (c) body distribution.
Abstract: Although the concept of using pharmacologically active macromolecular compounds as drugs is still regarded with much skepticism for both theoretical and practical reasons, interest in this field has grown in recent years because of the opportunity to take advantage of the specific properties of polymeric materials. For low molecular weight drugs, changes in structure often lead to a loss of specific activity. On the other hand, the properties of macromolecular drugs depend on the structure of the polymer used and this can be varied over a wide range by the incorporation of comonomer units, by the application of polymer-analogous reactions, or by related structural changes. A new model is presented for pharmacologically active polymers which incorporates the possibility for continuous variation in (a) solubility and toxicity, (b) fixation and removal of active material, and (c) body distribution. Using the new model as a guide, examples of the synthesis and study of the biological activity of various macromolecular drugs are presented in order to emphasize the importance of this cooperative effort between polymer research and therapeutic problems.
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"Synthesis and Characterization of a..." refers background in this paper
...Targeted delivery of anticancer drugs to tumor cells/tissues can improve the therapeutic index of drugs by minimizing the toxic effects on healthy cells/tissues.([7]) For example, gel delivery systems allow the drug to be injected as a liquid, which solidifies at body temperature and slowly release the drug over an extended period....
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Journal Article•
01 Jan 2000-Journal of pharmacy & pharmaceutical sciences : a publication of the Canadian Society for Pharmaceutical Sciences
TL;DR: In most of the examples in the literature, a significant increase in the plasma half life of the protein more than compensates for any reduction in the pharmacologic effects of the polymer-protein conjugates.
Abstract: With the rapid advances in the field of biotechnology during the last decade, many peptides and proteins have been produced and evaluated for therapy of various diseases, including cancer. However, rapid clearance and the possibility of immunogenicity after the in vivo administration of these biotechnologydriven products have impeded their marketing. To circumvent these problems, synthetic and natural polymers such as polyethylene glycol (PEG) and dextrans, respectively, have been covalently attached to proteins, and some of these protein-polymer conjugates have shown promising therapeutic results. The conjugation of proteins with polymers usually causes a reduction in the recognition of the protein by the immune system, resulting in a decrease in protein clearance and immunogenicity. Most of the proteinpolymer conjugates retain the pharmacologic activity of the protein, although to a lesser extent than the native protein. Additionally, in most of the examples in the literature, a significant increase in the plasma half life of the protein more than compensates for any reduction in the pharmacologic effects of the polymer-protein conjugates. Therefore, polymer conjugation in most cases would result in a net increase in the pharmacologic activity of the protein.
189 citations
TL;DR: A simple carbohydrate polymer glycol chitosan (degree of polymerization 800 approx.) has been investigated for its ability to form polymeric vesicle drug carriers and the attachment of hydrophobic groups should yield an amphiphilic polymer capable of self‐assembly into vesicles.
Abstract: A simple carbohydrate polymer glycol chitosan (degree of polymerization 800 approx.) has been investigated for its ability to form polymeric vesicle drug carriers. The attachment of hydrophobic groups to glycol chitosan should yield an amphiphilic polymer capable of self-assembly into vesicles. Chitosan is used because the membrane-penetration enhancement of chitosan polymers offers the possibility of fabricating a drug delivery system suitable for the oral and intranasal administration of gut-labile molecules. Glycol chitosan modified by attachment of a strategic number of fatty acid pendant groups (11-16 mol%) assembles into unilamellar polymeric vesicles in the presence of cholesterol. These polymeric vesicles are found to be biocompatible and haemocompatible and capable of entrapping water-soluble drugs. By use of an ammonium sulphate gradient bleomycin (MW 1400), for example, can be efficiently loaded on to these polymeric vesicles to yield a bleomycin-to-polymer ratio of 0.5 units mg(-1). Previously polymers were thought to assemble into vesicles only if the polymer backbone was separated from the membrane-forming amphiphile by a hydrophilic side-arm spacer. The hydrophilic spacer was thought to be necessary to decouple the random motion of the polymer backbone from the ordered amphiphiles that make up the vesicle membrane. However, stable polymeric vesicles for use in drug delivery have been prepared from a modified carbohydrate polymer, palmitoyl glycol chitosan, without this specific architecture. These polymeric vesicles efficiently entrap water-soluble drugs.
134 citations