Experimental Study On LNG Release Mode In MAS-IUS

Objective: To develop a new IUS of prevention and treatment of certain gynecological diseases with both contraceptive and small side effects.That is,"nickel-titanium memory alloy nano-copper silicone levonorgestrel intrauterine system(Memory Alloy Silicone Intrauterine System [MAS-IUS])".Methods: This study intended to use titanium-nickel alloy wire,silica gel,nano-copper and levonorgestrel(LNG),polydimethylsiloxane as these materials,to develop these MAS-IUS models,In this study,the influence of the thickness of nano-copper-silica gel sheath and the existence form of LNG on the release pattern of LNG in MAS-IUS was observed and analyzed,and experimental data were provided for the development of MAS-IUS.Results: LNG release rate in these MAS-IUS models decreased with the thickness of controlling sheath.LNG release in each group tended to be stable after 5 days,showing the law of sustained release and fluctuating within a certain range.The release rate of LNG in the MAS-IUS model of PDMS supersaturated state was significantly lower than that of LNG monomeric in the MAS-IUS model with the same thickness of silica gel film.There was no burst release.Conclusion: The release of LNG in MAS-IUS could be controlled by adjusting the thickness sheath of nano-copper-silica gel.and the existence form of LNG.Part OneExperiment Study On LNG Release Manner In MAS-IUS With Different Thickness Sheath Of Sodium-copper-silica GelObjective: To investigate the effect of different thickness sheath of nano-copper-silica gel on the release of levonorgestrel(LNG)in Memory Alloy Silicone Intrauterine System(MAS-IUS),and explore its release pattern.Methods: The Ti-Ni alloy wire(diameter of 0.3 mm)was spirally formed at 280 ? as an alloy wire tube with 3 mm outer diameter.A mixture of nano-copper-silica gel with certain ratio(mass ratio)were used to close the outer wall of the alloy wire tube frame,therefore,different thickness sheath with 0.5 mm,1.0 mm,1.5 mm and 2.0 mm "titanium nickel memory alloy nano silicone tube" model were prepared,52 mg of LNG were placed in the tube and both ends of the tube were sealed with a silicone adhesive,so that these MAS-IUS models with different thickness sheath of sodium-copper-silica gel were prepared.The MAS-IUS with different thickness sheath were immerged in a centrifuge tubes containing with 10 ml of absolute ethanol,then the tubes were placed in a thermostatic water bath at 37°C.The amount of LNG in the centrifuge tube was measured periodically with a UV spectrophotometer.Results: LNG release rate in these MAS-IUS models decreased with the thickness of controlling sheath.LNG release in each group tended to be stable after 5 days,showing the law of sustained release and fluctuating within a certain range.Conclusion: LNG in MAS-IUS manifested as the manner of burst release firstly then slow release.The release of LNG in MAS-IUS could be controlled by adjusting the thickness sheath of nano-copper-silica gel.Part TwoExperimental Study On LNG Release Manner In MAS-IUS With LNG Of The PDMS SupersaturationObjective: To study the release manner of LNG in the PDMS supersaturated state in MAS-IUS.Methods: 52 mg LNG of PDMS supersaturated state was placed in the tube,and both ends of the tube were sealed with a silicone adhesive,so that the MAS-IUS model was prepared.The MAS-IUS models were placed in a 10 ml centrifuge tube and placed in a constant temperature water bath at 37 °C.The amount of LNG in the centrifuge tube was measured periodically with a UV spectrophotometer.Results: The release rate of LNG in the MAS-IUS model of PDMS supersaturated state was significantly lower than that of LNG monomeric in the MAS-IUS model with the same thickness of silica gel film.There was no burst release.Conclusion: The release of LNG in the MAS-IUS model of PDMS supersaturated state shows zero-order release.The LNG release amount and release pattern in MAS-IUS model could be controlled by changing the existence form of LNG.