In this study,a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method,among which,progestin levonorgestrel(LNG)was used as a model drug.Photo-cross-linked aliphatic polyc...In this study,a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method,among which,progestin levonorgestrel(LNG)was used as a model drug.Photo-cross-linked aliphatic polycarbonates(APCs),namely,poly(trimethylene carbonate-co-2,2′-dimethyltrimethylene carbonate)[P(TMC-co-DTC)]elastomers,were used as the drug delivery matrix.The results obtained from the degradation experiments carried out in Sprague-Dawley(SD)rats showed that the cross-linked elastomer had the degradation characteristics of the surface erosion degradation mechanism,with no generation of acid degradation products,and excellent form-stability,which met the performance requirements of the matrix for a long-acting sustained-release delivery system.The in vitro cytotoxicity tests and histological and immunohistochemical evaluations showed good biocompatibility and biosafety of the elastomer matrix material and contraceptive implants.Subsequently,the implant formulations were screened by in vitro release experiments,and their release kinetics were explored.Finally,in the evaluation study of the in vivo anti-fertility effect,the implants exhibited excellent dimensional stability and were degraded by a surface erosion mechanism.LNG achieved a stable and sustained release in female SD rats,maintaining a long-acting contraceptive duration of up to 4 months.The contraceptive implants obtained in this study could be used to address the limitations of currently available formulations,which required secondary surgical removal and a single means of regulating drug release kinetics.Therefore,these implants could provide a new option for birth control needs and may be of significance in reducing the incidence of induced abortion and protecting female fertility.展开更多
High-molecular-weight aliphatic polycarbonates（APCs） were synthesized through a two-step transesterification process under solvent-free conditions. Oligomers with equal numbers of hydroxyl and phenyl carbonate termi...High-molecular-weight aliphatic polycarbonates（APCs） were synthesized through a two-step transesterification process under solvent-free conditions. Oligomers with equal numbers of hydroxyl and phenyl carbonate terminal groups could be easily controlled by using equimolar amounts of diphenyl carbonate（DPC） and aliphatic diols as feedstocks in the first step. In the second step, the high-molecular-weight APCs can be obtained by connecting -OH with -OC（O）OC6H5 end-group upon removing the generated phenol at reduced pressure. Mg（OAc）2 was found to be the best catalyst for this process among the screened catalysts, which gave the poly（l,4-butylene carbonate）（PBC） a weight-average molecular weight（Mw） of 148600 and a yield of 84.8% under its suitable reaction conditions. In addition, based on the results of X-ray diffraction（XRD）, scanning electron microscopy（SEM） and fourier transform infrared spectroscopy（FTIR）, a possible reaction mechanism over Mg（OAe）2 was proposed for APCs synthesis.展开更多
A new degradable aliphatic poly(butylene-co-e-caprolactone carbonate) (PBCL) was synthesized through the terpolymerization of carbon dioxide, 1,2-butylene oxide (BO) and e-caprolactone (CL), a polymer supported bimeta...A new degradable aliphatic poly(butylene-co-e-caprolactone carbonate) (PBCL) was synthesized through the terpolymerization of carbon dioxide, 1,2-butylene oxide (BO) and e-caprolactone (CL), a polymer supported bimetallic complex (PBM) was used as a catalyst. The terpolymers prepared were characterized by FT-IR,1H NMR, 13C NMR, WXRD and DSC. The hydrolysis tests were carried out to appraise the degradability of the copolymers.展开更多
In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction par...In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.展开更多
A new cyclic carbonate, 2,2-ethylenedioxypropane-1,3-diol carbonate (EOPDC), was synthesized through a two-step reaction from dihydroxyacetone dimer, and polymerized in bulk initiated by Sn(Oct)2 to give a high molecu...A new cyclic carbonate, 2,2-ethylenedioxypropane-1,3-diol carbonate (EOPDC), was synthesized through a two-step reaction from dihydroxyacetone dimer, and polymerized in bulk initiated by Sn(Oct)2 to give a high molecular weight polycarbonate. The structure of monomer and the polymer were characterized by FT-IR, 1H NMR, 13C NMR. The cytotoxicity of the obtained polycarbonate was investigated by MTT assay.展开更多
Zinc(Zn)alloys have demonstrated significant potential in healing critical-sized bone defects.However,the clinical application of Zn alloys implants is still hindered by challenges including excessive release of zinc ...Zinc(Zn)alloys have demonstrated significant potential in healing critical-sized bone defects.However,the clinical application of Zn alloys implants is still hindered by challenges including excessive release of zinc ions(Zn^(2+)),particularly in the early stage of implantation,and absence of bio-functions related to complex bone repair processes.Herein,a biodegradable aliphatic polycarbonate drug-eluting coating was fabricated on zinc-lithium(Zn-Li)alloys to inhibit Zn^(2+)release and enhance the osteogenesis,angiogenesis,and bacteriostasis of Zn alloys.Specifically,the photo-curable aliphatic polycarbonates were co-assembled with simvastatin and deposited onto Zn alloys to produce a drug-loaded coating,which was crosslinked by subsequent UV light irradiation.During the 60 days long-term immersion test,the coating showed distinguished stable drug release and Zn^(2+)release inhibition properties.Benefiting from the regulated release of Zn^(2+)and simvastatin,the coating facilitated the adhesion,proliferation,and differentiation of MC3T3-E1 cells,as well as the migration and tube formation of EA.hy926 cells.Astonishingly,the coating also showed remarkable antibacterial properties against both S.aureus and E.coli.The in vivo rabbit critical-size femur bone defects model demonstrated that the drug-eluting coating could efficiently promote new bone formation and the expression of platelet endothelial cell adhesion molecule-1(CD31)and osteocalcin(OCN).The enhancement of osteogenesis,angiogenesis,and bacteriostasis is achieved by precisely controlling of the released Zn^(2+)at an appropriate level,as well as the stable release profile of simvastatin.This tailored aliphatic polycarbonate drug-eluting coating provides significant potential for clinical applications of Zn alloys implants.展开更多
CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. ...CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. They may find wide applications in many fields.展开更多
The master curves of a series of aliphatic polycarbonates （APCs） with different lengths of methylene segments in the repeat unit were obtained by dynamic rheological measurements. The plateau modulus and entanglemen...The master curves of a series of aliphatic polycarbonates （APCs） with different lengths of methylene segments in the repeat unit were obtained by dynamic rheological measurements. The plateau modulus and entanglement molecular weight were determined and cross-checked by different methods. Though having distinct difference in chemical structure of repeat units, both APCs and bisphenol-A polycarbonates have the similar entanglement weight and entanglement spacing. On the other side, the plateau modulus decreases with increasing the length of the side group of aliphatic polycarbonates with different side-chain lengths in the literature. The packing length model can explain the relationship between chain structure and entanglements.展开更多
Developing green and well-controlled polymerization methods is of great significance for the preparation of biomedical polymer materials.In this contribution,an efficient organocatalytic ring-opening polymerization(RO...Developing green and well-controlled polymerization methods is of great significance for the preparation of biomedical polymer materials.In this contribution,an efficient organocatalytic ring-opening polymerization(ROP)of a class of seven-membered cyclic carbonates(T6DO,T6HDO,C6DO,C6HDO)containing cis-or trans-cyclohexane structure was established.Organic catalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)promoted living polymerization of these cyclic carbonates to deliver polycarbonate and block copolymer products with predictable molecular weights and narrow dispersity.The robust TBD-mediated ROP at 90°C showcased turnover frequency(TOF)up to 10^(3)h^(−1).The resulting amorphous polycarbonates displayed good thermal stability.展开更多
基金sponsored by the Natural Science Foundation of Liaoning Province(Nos.2022-YGJC-69,2021-BS-110)the support program for excellent young scholars of China Medical University.
文摘In this study,a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method,among which,progestin levonorgestrel(LNG)was used as a model drug.Photo-cross-linked aliphatic polycarbonates(APCs),namely,poly(trimethylene carbonate-co-2,2′-dimethyltrimethylene carbonate)[P(TMC-co-DTC)]elastomers,were used as the drug delivery matrix.The results obtained from the degradation experiments carried out in Sprague-Dawley(SD)rats showed that the cross-linked elastomer had the degradation characteristics of the surface erosion degradation mechanism,with no generation of acid degradation products,and excellent form-stability,which met the performance requirements of the matrix for a long-acting sustained-release delivery system.The in vitro cytotoxicity tests and histological and immunohistochemical evaluations showed good biocompatibility and biosafety of the elastomer matrix material and contraceptive implants.Subsequently,the implant formulations were screened by in vitro release experiments,and their release kinetics were explored.Finally,in the evaluation study of the in vivo anti-fertility effect,the implants exhibited excellent dimensional stability and were degraded by a surface erosion mechanism.LNG achieved a stable and sustained release in female SD rats,maintaining a long-acting contraceptive duration of up to 4 months.The contraceptive implants obtained in this study could be used to address the limitations of currently available formulations,which required secondary surgical removal and a single means of regulating drug release kinetics.Therefore,these implants could provide a new option for birth control needs and may be of significance in reducing the incidence of induced abortion and protecting female fertility.
文摘High-molecular-weight aliphatic polycarbonates（APCs） were synthesized through a two-step transesterification process under solvent-free conditions. Oligomers with equal numbers of hydroxyl and phenyl carbonate terminal groups could be easily controlled by using equimolar amounts of diphenyl carbonate（DPC） and aliphatic diols as feedstocks in the first step. In the second step, the high-molecular-weight APCs can be obtained by connecting -OH with -OC（O）OC6H5 end-group upon removing the generated phenol at reduced pressure. Mg（OAc）2 was found to be the best catalyst for this process among the screened catalysts, which gave the poly（l,4-butylene carbonate）（PBC） a weight-average molecular weight（Mw） of 148600 and a yield of 84.8% under its suitable reaction conditions. In addition, based on the results of X-ray diffraction（XRD）, scanning electron microscopy（SEM） and fourier transform infrared spectroscopy（FTIR）, a possible reaction mechanism over Mg（OAe）2 was proposed for APCs synthesis.
文摘A new degradable aliphatic poly(butylene-co-e-caprolactone carbonate) (PBCL) was synthesized through the terpolymerization of carbon dioxide, 1,2-butylene oxide (BO) and e-caprolactone (CL), a polymer supported bimetallic complex (PBM) was used as a catalyst. The terpolymers prepared were characterized by FT-IR,1H NMR, 13C NMR, WXRD and DSC. The hydrolysis tests were carried out to appraise the degradability of the copolymers.
基金The subject supported by National Natural Science Foundation of China
文摘In this paper the miscibility of poly (ε-caprolactone) (PCL) and aliphatic polycarbonate (APC) is studied by using DSC. The results show that PCL and APC are miscible in all ranges of composition. The interaction parameter between the polymers is calculated from the melting point depression data. Using optical microscope, the shapes of the PCL spherulites in the blends are observed.
基金This work was financially supported by The National Key Basic Research Program of China(G1999064703).
文摘A new cyclic carbonate, 2,2-ethylenedioxypropane-1,3-diol carbonate (EOPDC), was synthesized through a two-step reaction from dihydroxyacetone dimer, and polymerized in bulk initiated by Sn(Oct)2 to give a high molecular weight polycarbonate. The structure of monomer and the polymer were characterized by FT-IR, 1H NMR, 13C NMR. The cytotoxicity of the obtained polycarbonate was investigated by MTT assay.
基金support for this work from the National Natural Science Foundation of China,China (52173127).
文摘Zinc(Zn)alloys have demonstrated significant potential in healing critical-sized bone defects.However,the clinical application of Zn alloys implants is still hindered by challenges including excessive release of zinc ions(Zn^(2+)),particularly in the early stage of implantation,and absence of bio-functions related to complex bone repair processes.Herein,a biodegradable aliphatic polycarbonate drug-eluting coating was fabricated on zinc-lithium(Zn-Li)alloys to inhibit Zn^(2+)release and enhance the osteogenesis,angiogenesis,and bacteriostasis of Zn alloys.Specifically,the photo-curable aliphatic polycarbonates were co-assembled with simvastatin and deposited onto Zn alloys to produce a drug-loaded coating,which was crosslinked by subsequent UV light irradiation.During the 60 days long-term immersion test,the coating showed distinguished stable drug release and Zn^(2+)release inhibition properties.Benefiting from the regulated release of Zn^(2+)and simvastatin,the coating facilitated the adhesion,proliferation,and differentiation of MC3T3-E1 cells,as well as the migration and tube formation of EA.hy926 cells.Astonishingly,the coating also showed remarkable antibacterial properties against both S.aureus and E.coli.The in vivo rabbit critical-size femur bone defects model demonstrated that the drug-eluting coating could efficiently promote new bone formation and the expression of platelet endothelial cell adhesion molecule-1(CD31)and osteocalcin(OCN).The enhancement of osteogenesis,angiogenesis,and bacteriostasis is achieved by precisely controlling of the released Zn^(2+)at an appropriate level,as well as the stable release profile of simvastatin.This tailored aliphatic polycarbonate drug-eluting coating provides significant potential for clinical applications of Zn alloys implants.
基金This project was supported by the National Natural Science Foundation of China(No.20274053).
文摘CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. They may find wide applications in many fields.
基金financially supported by National Natural Science Foundation of China(No.20874109)National High Technology Research and Development Program of China(No.2009AA033601) and the Chinese Academy of Sciences
文摘The master curves of a series of aliphatic polycarbonates （APCs） with different lengths of methylene segments in the repeat unit were obtained by dynamic rheological measurements. The plateau modulus and entanglement molecular weight were determined and cross-checked by different methods. Though having distinct difference in chemical structure of repeat units, both APCs and bisphenol-A polycarbonates have the similar entanglement weight and entanglement spacing. On the other side, the plateau modulus decreases with increasing the length of the side group of aliphatic polycarbonates with different side-chain lengths in the literature. The packing length model can explain the relationship between chain structure and entanglements.
基金supported by the National Natural Science Foundation of China(Nos.22071163,22371194,and 22301197)the Fundamental Research Funds from Sichuan University,China(No.2023SCUNL103).
文摘Developing green and well-controlled polymerization methods is of great significance for the preparation of biomedical polymer materials.In this contribution,an efficient organocatalytic ring-opening polymerization(ROP)of a class of seven-membered cyclic carbonates(T6DO,T6HDO,C6DO,C6HDO)containing cis-or trans-cyclohexane structure was established.Organic catalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)promoted living polymerization of these cyclic carbonates to deliver polycarbonate and block copolymer products with predictable molecular weights and narrow dispersity.The robust TBD-mediated ROP at 90°C showcased turnover frequency(TOF)up to 10^(3)h^(−1).The resulting amorphous polycarbonates displayed good thermal stability.
