ABSTRACT
Objective To evaluate the effect of two polymer membranes, polyhydroxyalkanoates(PHA)and polylactic acid(PLA)during glaucoma filtration surgery(GFS),and to evaluate the morphology of membranous PHA after interlamellar implantation. Methods Twenty-eight New Zealand white rabbits were chosen and twenty-four of them were randomly divided into 6 groups(n=4):the PHA-low group,PHA-high group,PLA-low group,PLA-high group,positive control group(MMC group)and blank control group. The rabbits in each group received GFS. The corresponding polymer membranes were implanted under the scleral flap,while the MMC group was treated with 0.2 mg/mL mitomycin C(MMC) for 3 minutes,and the blank control group was treated without extra drugs. The intraocular pressure(IOP)was examined at 0 d,1 d, 3 d, 7 d, 14 d, 28 d and 84 d after GFS. The corneal layers of four rabbits were implanted with PHA membranes and the corneal morphological changes were observed after 84 d. Results The IOP of the PHA-low and PLA-high groups was lower than that of the blank control group at 84 d after GFS(P < 0.05),and was similar with that of the MMC group(P> 0.05). Morphological studies showed that there were no collagenous fibers filling in the duct, and the collagenous fibers around the membranes were generally arranged in parallel. There were no obvious changes in the peripheral collagen structure after implantation of PHA membranes between the corneal layers. Conclusions Application of PHA and PLA membranes during GFS in rabbits may maintain the level of IOP,and the effect is similar with MMC. The mechanism may be achieved through the mechanical blocking of fibrous tissue.
ABSTRACT
Polylactic acid is synthesized indirectly by the polymerization method, according to the standard GB/T 16886.18-2011, the evaluation parameters and methods about chemical characterization of polylactic acid have been established. By using rigorous and comprehensive comparative analysis, the chemical equivalency of domestic and imported polylactic acid materials has been proved, along with the "Medical Device Biology Evaluation and Review Guide", paving the way of using domestic polylactic acid in implantable medical devices.
Subject(s)
Equipment and Supplies , Lactic Acid , Polyesters , Chemistry , PolymersABSTRACT
Objective To investigate the effect of protamine(PS)coated polylactic acid(PLA)nanocapsule on the immune response of murine bone marrow-derived dendritic cells(BMDCs).Methods PLA nanocapsules were prepared by W1/O/W2 method.Protamine was used to modify the surface of PLA nanocapsule that encapsulated ovalbumin(OVA),a model anti-gen.The prepared OVA/PLA/PS nanocapsules were used to stimulate BMDCs.Flow cytometry was used to analyze the ex-pression of surface molecules CD80,CD83,CD86,MHCⅠ,and MHC Ⅱ,and the uptake of nanocapsule.The levels of IL-12 p70 secreted by BMDCs were detected by ELISA.Results OVA/PLA/PS nanocapsules could significantly up-regulate the expres-sion of CD80,CD83,MHCⅠ,and MHC Ⅱ in BMDCs,and increase the secretion of IL-12 p70 by BMDCs.Furthermore,OVA/PLA/PS nanocapsules could enhance the uptake efficiency of OVA by BMDCs.Conclusion OVA/PLA/PS nanocapsule can en-hance the immune response of BMDCs,and may become a good drug delivery carrier.
ABSTRACT
Objective:To construct double-layered controlled release system containing SDF-1 and rhBMP-2 molecules and to study the release profile of the system in vitro.Methods:The polylactic acid/chitosan(PLA/CS)nanoparticles were prepared with “emulsification-solution evaporation method”,the preparation parameters were determined by orthogonal test design.The particle size was observed by nanoparticle size analyzer,the morphology of the nanoparticles was observed with electron microscope.Then rhBMP-2 and SDF-1 were loaded into the nanoparticles in the process of emulsification,the loading efficiency and encapsulation efficiency were calculated and in vitro release was observed.Results:The double-layer nanoparticles showed spherical geometry,smooth surface and complete separation. The average particle size of the nanoparticles was (542.33 ±14.38)nm;The drug loading and incorporation efficiency of rhBMP-2 were (82.41 ±1.05)% and (24.67 ±0.43)ng/mg,those of rhBMP-2 were (75.58 ±0.84)% and (22.63 ±0.41)ng/mg,respectively. The release time of the drug from the system sustained over at least 30 days,the release profile of both drugs showed “biphasic release”. The cumulative release rate of SDF-1 and rhBMP-2 was 72.85% and 91.01% in 30 days respectively.Conclusion:The SDF-1 and rh-BMP-2 loaded PLA/CS nanoparticles have excellent morphology,high entrapment and good sustained-release in vitro.
ABSTRACT
OBJECTIVE: To prepare lappaconitine (LA)-loaded polylactic acid (PLA) nanoparticles (LA/PLA NPs) and investigate its release properties in vitro. METHODS: LA/PLA NPs were prepared by optimized emulsion-solvent evaporation method with biodegradable PLA as carrier material and polyvinyl alcohol (PVA) as emulsifier. The entrapment efficiency and drug loading rate of LA were used as the main evaluation indexes to optimize the preparation process by orthogonal design method. The mean particle size was measured by laser particle size analyzer; the morphology of LA/PLA NPs was observed by atomic force microscope; the in vitro release behavior was studied by dynamic dialysis. RESULTS: The optimized LA/PLA NPs were spherical. The mean particle size was (429±9.19) nm, the entrapment efficiency and drug loading rate were (86.34±2.15)% and (45.85±1.34)%, respectively. The in vitro release study showed that the LA/PLA NPs could provide a continuous release of LA for 15 d. CONCLUSION: LA/PLA NPs with high entrapment efficiency and drug loading rate are prepared successfully, and show sustained release effect for LA in vitro.