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Abraham J. Domb - One of the best experts on this subject based on the ideXlab platform.
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In Vivo Degradation and Elimination of Injectable Ricinoleic Acid- Based Poly(ester-anhydride)
Biomacromolecules, 2013Co-Authors: Boris Vaisman, Ariella Shikanov, Diana E. Ickowicz, Ester Abtew, Moran Haim-zada, Abraham J. DombAbstract:The in vivo degradation and elimination after subcutaneous implantation of injectable p(SA-RA) 3:7 copolymer in rats, followed by characterization of the polymer matrix composition during hydrolysis and erosion, is reported. Major chemical changes were observed during the first few days post implantation, the anhydride bonds hydrolyzed along with about 45% weight loss and a significant decrease in the molecular weight. 1H NMR spectral analysis was used to determine the structures and content of Ricinoleic Acid containing oligomeric chains present in the degraded polymer. The polymer degrades into ester oligomers of 2-4 Ricinoleic Acid units which further degrade to Ricinoleic Acid, a natural fatty Acid. The polymer hydrolytic degradation process fit the in vitro degradation process.
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poly sebacic Acid co Ricinoleic Acid biodegradable carrier for delivery of tamsulosin hydrochloride
Polymers for Advanced Technologies, 2011Co-Authors: Ehud Havivi, Shimon Farber, Abraham J. DombAbstract:Polyesteranhydrides synthesized by the transesterification of Ricinoleic Acid and sebacic Acid followed by anhydride polymerization were examined as potential controlled delivery carrier for tamsulosin. Polymers containing 70% Ricinoleic Acid are liquid at body temperature and semisolid at room temperature. It was found that upon addition of the liquid polymer to water it solidifies to form a stable semisolid polymer. Tamsulosin hydrochloride (TAM), a highly selective α1A-adrenoreceptor antagonist that has been used for the treatment of lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH), was incorporated in the polymers (2–20% w/w) and its release in buffer solution was monitored. TAM was released for over 24 days while the polymer carrier was being degraded. Hydrolysis of formulations was studied by monitoring the weight loss of the samples and the changes in the polymer molecular weight. TAM formulations stability in p(SA-RA) 30:70 under different temperatures was evaluated. The release rate of the drug from polymer was found to be affected by drug content: the higher the content, the faster was the release. Also, hydrolysis of formulation containing tamsulosin was faster due to the hydrophility of the drug. The drug formulation was found to be stable for a period of 6 months. Moreover, after subcutaneously injection into mice, the drug-loaded formulation becomes into gel and remains in the site of the injection. To conclude, Poly(sebacic Acid-co-Ricinoleic-Acid) containing ≥ 70% Ricinoleic Acid are injectable biodegradable polymers and are suitable candidates for the delivery of TAM for long acting therapy. Copyright © 2010 John Wiley & Sons, Ltd.
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Poly(sebacic Acid‐co‐Ricinoleic Acid) biodegradable carrier for delivery of tamsulosin hydrochloride
Polymers for Advanced Technologies, 2010Co-Authors: Ehud Havivi, Shimon Farber, Abraham J. DombAbstract:Polyesteranhydrides synthesized by the transesterification of Ricinoleic Acid and sebacic Acid followed by anhydride polymerization were examined as potential controlled delivery carrier for tamsulosin. Polymers containing 70% Ricinoleic Acid are liquid at body temperature and semisolid at room temperature. It was found that upon addition of the liquid polymer to water it solidifies to form a stable semisolid polymer. Tamsulosin hydrochloride (TAM), a highly selective α1A-adrenoreceptor antagonist that has been used for the treatment of lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH), was incorporated in the polymers (2–20% w/w) and its release in buffer solution was monitored. TAM was released for over 24 days while the polymer carrier was being degraded. Hydrolysis of formulations was studied by monitoring the weight loss of the samples and the changes in the polymer molecular weight. TAM formulations stability in p(SA-RA) 30:70 under different temperatures was evaluated. The release rate of the drug from polymer was found to be affected by drug content: the higher the content, the faster was the release. Also, hydrolysis of formulation containing tamsulosin was faster due to the hydrophility of the drug. The drug formulation was found to be stable for a period of 6 months. Moreover, after subcutaneously injection into mice, the drug-loaded formulation becomes into gel and remains in the site of the injection. To conclude, Poly(sebacic Acid-co-Ricinoleic-Acid) containing ≥ 70% Ricinoleic Acid are injectable biodegradable polymers and are suitable candidates for the delivery of TAM for long acting therapy. Copyright © 2010 John Wiley & Sons, Ltd.
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Hydrolytic degradation and drug release of Ricinoleic Acid-lactic Acid copolyesters.
Pharmaceutical research, 2006Co-Authors: Raia Slivniak, Aviva Ezra, Abraham J. DombAbstract:A systematic study on the degradation and drug release from l-lactic Acid and Ricinoleic-Acid-based copolyesters is reported. These copolyesters were synthesized by ring opening polymerization (ROP), melt condensation (COND) and transesterification (TRANS) of high molecular weight poly(lactic Acid) (PLA) with Ricinoleic Acid (PLA-RA), and repolymerization by condensation to yield random and block copolymers of weight average molecular weights (Mw) between 3000 and 13,000. All polymers showed an almost zero-order weight loss, with a 20–40% loss after 60 days of incubation. Lactic Acid release to the degradation solution is proportional to weight loss of the polymer samples. The main decrease in molecular weight was observed during the first 20 days, followed by a slow degradation phase, which kept the number average molecular weight (Mn) at 4000–2000 for another 40 days. Water-soluble 5FU was released from Ricinoleic-Acid-based polymers faster than slightly water-soluble triamcinolone. Drug release into phosphate-buffered saline (pH 7.4, 0.1 M) at 37°C from P(LA-RA) 60:40 prepared by condensation of the Acids was faster than from pasty P(PLA-RA) 60:40 synthesized by transesterification for both drugs.
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Poly(sebacic Acid-co-Ricinoleic Acid) biodegradable injectable in situ gelling polymer.
Biomacromolecules, 2006Co-Authors: Ariella Shikanov, Abraham J. DombAbstract:The investigated polymers, poly(sebacic Acid-co-Ricinoleic Acid) containing ≥70% Ricinoleic Acid, may be injected via a 22 gauge needle and become gel upon contact with aqueous medium, both in vitro and in vivo. Various properties of the polymers including viscosity, thermal analysis, and in vivo behavior, before and after exposure to aqueous medium, were determined. These polymers were observed using scanning electron microscopy (SEM) at dry and wet states. It was found that the viscosity and melting temperature of P(SA:RA) increased after exposure to buffer. The viscosity at 37 °C of P(SA:RA)3:7 had the highest increase: from 4200 cP before to 8940 cP after exposure to buffer; in the case of P(SA:RA)25:75 before exposure to buffer the viscosity was 1150 cP while after it raised to 3200 cP. The viscosity of P(SA:RA)2:8 also increased from 400 cP before exposure to buffer to 1000 cP after. On the other hand polymer without sebacic Acid, (poly(Ricinoleic Acid)), did not show gelation properties. Thermal a...
Raia Slivniak - One of the best experts on this subject based on the ideXlab platform.
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Hydrolytic degradation and drug release of Ricinoleic Acid-lactic Acid copolyesters.
Pharmaceutical research, 2006Co-Authors: Raia Slivniak, Aviva Ezra, Abraham J. DombAbstract:A systematic study on the degradation and drug release from l-lactic Acid and Ricinoleic-Acid-based copolyesters is reported. These copolyesters were synthesized by ring opening polymerization (ROP), melt condensation (COND) and transesterification (TRANS) of high molecular weight poly(lactic Acid) (PLA) with Ricinoleic Acid (PLA-RA), and repolymerization by condensation to yield random and block copolymers of weight average molecular weights (Mw) between 3000 and 13,000. All polymers showed an almost zero-order weight loss, with a 20–40% loss after 60 days of incubation. Lactic Acid release to the degradation solution is proportional to weight loss of the polymer samples. The main decrease in molecular weight was observed during the first 20 days, followed by a slow degradation phase, which kept the number average molecular weight (Mn) at 4000–2000 for another 40 days. Water-soluble 5FU was released from Ricinoleic-Acid-based polymers faster than slightly water-soluble triamcinolone. Drug release into phosphate-buffered saline (pH 7.4, 0.1 M) at 37°C from P(LA-RA) 60:40 prepared by condensation of the Acids was faster than from pasty P(PLA-RA) 60:40 synthesized by transesterification for both drugs.
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Macrolactones and Polyesters from Ricinoleic Acid
Biomacromolecules, 2005Co-Authors: Raia Slivniak, Abraham J. DombAbstract:A systematic study on the synthesis, characterization, and polymerization of Ricinoleic Acid (RA) lactone is reported. Ricinoleic Acid lactones were synthesized by refluxing pure Ricinoleic Acid in chloroform (10 mg/mL) with dicyclohexylcarbodimide and (dimethylamino)pyridine as catalyst. Purification of RA lactones was performed by silica gel chromatography. The reaction resulted in a 75% yield of Ricinoleic Acid lactones. IR and NMR analysis confirmed the formation of cyclic compounds. Polymerization of the Ricinoleic Acid lactones with catalysts commonly used for ring-opening polymerization of lactones, under specific reaction conditions, resulted in oligomers. Copolymerization with lactide (LA) by ring-opening polymerization, using Sn(Oct) as catalyst, yielded copolyesters with molecular weights (Mw) in the range of 5000−16000 and melting temperatures of 100−130 °C for copolymers containing 10−50% w/w Ricinoleic Acid residues. Degradation studies of the copolymers were performed in 0.1 M phosphate buf...
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Lactic and Ricinoleic Acid Based Copolyesters Stereocomplexation
Macromolecules, 2005Co-Authors: Raia Slivniak, Robert Langer, Abraham J. DombAbstract:A systematic study of the synthesis and stereocomplexation of l-lactic Acid and Ricinoleic Acid based copolyesters is reported. l-lactic Acid and Ricinoleic Acid based copolyesters were synthesized by melt condensation and transesterification of high-molecular-weight poly(lactic Acid) (PLA) with Ricinoleic Acid and repolymerization by condensation to yield random and block copolymers of molecular weights between 3000 and 5000. To correlate between the copolyesters synthesized by polycondensation and transesterification, P(LA-RA)s with different PLA blocks were synthesized. The relative degree of crystallinity of those copolyesters depends directly on PLA block size, which is the only difference between the corresponding polymers. 1H NMR spectroscopy analysis coupled with information from DSC allowed correlation between the degree of crystallinity and PLA block size. P(l-LA-RA)s and enantiomeric d-PLA were mixed together in acetonitrile solution to form stereocomplexes. Stereocomplex formation was dependen...
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Lactic Acid and Ricinoleic Acid Based Copolyesters
Macromolecules, 2005Co-Authors: Raia Slivniak, Abraham J. DombAbstract:Copolyesters based on purified Ricinoleic (RA) and lactic (LA) Acids with different RA:LA ratios were synthesized by thermal polycondensation and by transesterification of high molecular weight poly(lactic Acid) (PLA) with Ricinoleic Acid and repolyesterification. Thermal polycondensation resulted in random P(LA−RA) copolyesters of molecular weights between 2000 and 8000 with the polymers containing 20% or more RA were liquid at room temperature. Transesterification of high molecular weight PLA with pure Ricinoleic Acid and repolymerization of those oligomers by condensation resulted in multiblock P(PLA−RA) copolyesters of molecular weights between 6000 and 14000. Polymers containing 50% RA were liquid at room temperature. 1H NMR spectroscopy analysis coupled with information from DSC allowed determination of the polymer structure. Polymers prepared by thermal polycondensation are random copolymers (h > 1), while the copolymers prepared by transesterification have a multiblock character (h < 1). The LA nu...
Ariella Shikanov - One of the best experts on this subject based on the ideXlab platform.
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In Vivo Degradation and Elimination of Injectable Ricinoleic Acid- Based Poly(ester-anhydride)
Biomacromolecules, 2013Co-Authors: Boris Vaisman, Ariella Shikanov, Diana E. Ickowicz, Ester Abtew, Moran Haim-zada, Abraham J. DombAbstract:The in vivo degradation and elimination after subcutaneous implantation of injectable p(SA-RA) 3:7 copolymer in rats, followed by characterization of the polymer matrix composition during hydrolysis and erosion, is reported. Major chemical changes were observed during the first few days post implantation, the anhydride bonds hydrolyzed along with about 45% weight loss and a significant decrease in the molecular weight. 1H NMR spectral analysis was used to determine the structures and content of Ricinoleic Acid containing oligomeric chains present in the degraded polymer. The polymer degrades into ester oligomers of 2-4 Ricinoleic Acid units which further degrade to Ricinoleic Acid, a natural fatty Acid. The polymer hydrolytic degradation process fit the in vitro degradation process.
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Poly(sebacic Acid-co-Ricinoleic Acid) biodegradable injectable in situ gelling polymer.
Biomacromolecules, 2006Co-Authors: Ariella Shikanov, Abraham J. DombAbstract:The investigated polymers, poly(sebacic Acid-co-Ricinoleic Acid) containing ≥70% Ricinoleic Acid, may be injected via a 22 gauge needle and become gel upon contact with aqueous medium, both in vitro and in vivo. Various properties of the polymers including viscosity, thermal analysis, and in vivo behavior, before and after exposure to aqueous medium, were determined. These polymers were observed using scanning electron microscopy (SEM) at dry and wet states. It was found that the viscosity and melting temperature of P(SA:RA) increased after exposure to buffer. The viscosity at 37 °C of P(SA:RA)3:7 had the highest increase: from 4200 cP before to 8940 cP after exposure to buffer; in the case of P(SA:RA)25:75 before exposure to buffer the viscosity was 1150 cP while after it raised to 3200 cP. The viscosity of P(SA:RA)2:8 also increased from 400 cP before exposure to buffer to 1000 cP after. On the other hand polymer without sebacic Acid, (poly(Ricinoleic Acid)), did not show gelation properties. Thermal a...
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Poly(sebacic Acid-co-Ricinoleic Acid) biodegradable carrier for paclitaxel--effect of additives.
Journal of controlled release : official journal of the Controlled Release Society, 2005Co-Authors: Ariella Shikanov, Aviva Ezra, Abraham J. DombAbstract:Injectable polymeric formulation for paclitaxel was studied. Poly Ricinoleic Acid and sebacic Acid were synthesized. The effect of additives on the viscosity of polymer, paclitaxel release, and polymer degradation was investigated both in vitro and in vivo. Additives that were used in this study were Ricinoleic Acid, phospholipid, PEG 400, and PEG 2000. Addition of 20% Ricinoleic Acid to P(SA:RA)3:7 liquefied the formulation and allowed injection of the formulation containing paclitaxel via a 22-G needle at room temperature with no effect on paclitaxel release rate. Addition of PEG 400, PEG 2000, and phospholipid to the formulation did not affect the paclitaxel release from the formulation. The degradation of modified formulations with paclitaxel and additives was examined in vitro and by subcutaneous injection of liquid formulations to the backspace via a 22-G needle into seven groups of four C3H mice. In vivo formulations with additives (20% Ricinoleic Acid and PEG or phospholipid) and 5% paclitaxel content degraded faster than the formulation with only 20% Ricinoleic Acid and the same paclitaxel content: 51% and 54% versus 43%. The slowest degradation (26% in 1 week) was of the formulation containing 10% paclitaxel. The release rate in vivo was affected by the paclitaxel content; the higher the content, the slower was the release. By using additives, we could adjust the physical characteristics of the surgical paste while maintaining a desirable system for sustained paclitaxel release.
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Poly(sebacic Acid-co-Ricinoleic Acid) biodegradable carrier for paclitaxel—effect of additives☆
Journal of Controlled Release, 2005Co-Authors: Ariella Shikanov, Aviva Ezra, Abraham J. DombAbstract:Injectable polymeric formulation for paclitaxel was studied. Poly Ricinoleic Acid and sebacic Acid were synthesized. The effect of additives on the viscosity of polymer, paclitaxel release, and polymer degradation was investigated both in vitro and in vivo. Additives that were used in this study were Ricinoleic Acid, phospholipid, PEG 400, and PEG 2000. Addition of 20% Ricinoleic Acid to P(SA:RA)3:7 liquefied the formulation and allowed injection of the formulation containing paclitaxel via a 22-G needle at room temperature with no effect on paclitaxel release rate. Addition of PEG 400, PEG 2000, and phospholipid to the formulation did not affect the paclitaxel release from the formulation. The degradation of modified formulations with paclitaxel and additives was examined in vitro and by subcutaneous injection of liquid formulations to the backspace via a 22-G needle into seven groups of four C3H mice. In vivo formulations with additives (20% Ricinoleic Acid and PEG or phospholipid) and 5% paclitaxel content degraded faster than the formulation with only 20% Ricinoleic Acid and the same paclitaxel content: 51% and 54% versus 43%. The slowest degradation (26% in 1 week) was of the formulation containing 10% paclitaxel. The release rate in vivo was affected by the paclitaxel content; the higher the content, the slower was the release. By using additives, we could adjust the physical characteristics of the surgical paste while maintaining a desirable system for sustained paclitaxel release.
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Poly(sebacic Acid-co-Ricinoleic Acid) biodegradable carrier for paclitaxel: in vitro release and in vivo toxicity.
Journal of biomedical materials research. Part A, 2004Co-Authors: Ariella Shikanov, Michal Y. Krasko, Abraham Nyska, Boris Vaisman, Abraham J. DombAbstract:Polyesteranhydrides synthesized by the transesterification of Ricinoleic Acid and sebacic Acid followed by anhydride polymerization were examined as potential controlled delivery carrier for paclitaxel. Solid and liquid polymers were used. Polymers containing 30% Ricinoleic Acid are solid whereas polymers containing 70% Ricinoleic Acid are liquid at body temperature and semisolid at room temperature. It was found that upon addition of the liquid polymer to water it solidifies to form a stable semisolid. Paclitaxel, a potent antitumor agent, was incorporated in the polymers (5-20% w/w) and its release in buffer solution was monitored. Paclitaxel was released for over 100 days while the polymer carrier was being degraded. The release rate was affected by the paclitaxel content; the higher the content, the slower was the release. The toxicity of the polymers and formulations with paclitaxel was examined by subcutaneous injection of liquid polymer samples or implantation of solid polymer specimens to mice for different time periods. Histopathological examination of the tissue surrounding the implant showed minor inflammation 1 week after the injection and no inflammation 3 weeks after implantation. Injection of the polymer without paclitaxel showed no adverse effects.
Alexander Kamper - One of the best experts on this subject based on the ideXlab platform.
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ethenolysis of Ricinoleic Acid methyl ester an efficient way to the oleochemical key substance methyl dec 9 enoate
RSC Advances, 2012Co-Authors: Arno Behr, Stephanie Krema, Alexander KamperAbstract:In the ethenolysis of the renewable raw material Ricinoleic Acid methyl ester the valuable oleochemical key substance methyl dec-9-enoate is produced. Detailed optimizations lead to a high conversion and yield of the desired product. Another interesting product, the dec-1-ene-4-ol, is built by this reaction as coproduct. The products are accessible under mild reaction conditions and with the use of only small amounts of a commercial available homogeneous ruthenium catalyst. The results obtained are also achievable in the ethenolysis of Ricinoleic Acid and castor oil, under the same mild reaction conditions.
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Ethenolysis of Ricinoleic Acid methyl ester – an efficient way to the oleochemical key substance methyl dec-9-enoate
RSC Advances, 2012Co-Authors: Arno Behr, Stephanie Krema, Alexander KamperAbstract:In the ethenolysis of the renewable raw material Ricinoleic Acid methyl ester the valuable oleochemical key substance methyl dec-9-enoate is produced. Detailed optimizations lead to a high conversion and yield of the desired product. Another interesting product, the dec-1-ene-4-ol, is built by this reaction as coproduct. The products are accessible under mild reaction conditions and with the use of only small amounts of a commercial available homogeneous ruthenium catalyst. The results obtained are also achievable in the ethenolysis of Ricinoleic Acid and castor oil, under the same mild reaction conditions.
Arno Behr - One of the best experts on this subject based on the ideXlab platform.
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ethenolysis of Ricinoleic Acid methyl ester an efficient way to the oleochemical key substance methyl dec 9 enoate
RSC Advances, 2012Co-Authors: Arno Behr, Stephanie Krema, Alexander KamperAbstract:In the ethenolysis of the renewable raw material Ricinoleic Acid methyl ester the valuable oleochemical key substance methyl dec-9-enoate is produced. Detailed optimizations lead to a high conversion and yield of the desired product. Another interesting product, the dec-1-ene-4-ol, is built by this reaction as coproduct. The products are accessible under mild reaction conditions and with the use of only small amounts of a commercial available homogeneous ruthenium catalyst. The results obtained are also achievable in the ethenolysis of Ricinoleic Acid and castor oil, under the same mild reaction conditions.
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Ethenolysis of Ricinoleic Acid methyl ester – an efficient way to the oleochemical key substance methyl dec-9-enoate
RSC Advances, 2012Co-Authors: Arno Behr, Stephanie Krema, Alexander KamperAbstract:In the ethenolysis of the renewable raw material Ricinoleic Acid methyl ester the valuable oleochemical key substance methyl dec-9-enoate is produced. Detailed optimizations lead to a high conversion and yield of the desired product. Another interesting product, the dec-1-ene-4-ol, is built by this reaction as coproduct. The products are accessible under mild reaction conditions and with the use of only small amounts of a commercial available homogeneous ruthenium catalyst. The results obtained are also achievable in the ethenolysis of Ricinoleic Acid and castor oil, under the same mild reaction conditions.
