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Insulin is the most effective hypoglycemic drugs, the treatment of type Ⅰ diabetes necessities, but also for the adjuvant treatment of type Ⅱ diabetes, currently mainly in the form of injections administered. Because frequently requires long-term administration to patients caused great physical, psychological and economic burden, thus an urgent need to seek non-injectable route of administration, the development of oral insulin formulations become a research hotspot. The polymer nanoparticles as carriers for oral administration of insulin, insulin release rate can be controlled, to reduce degradation of pepsin, to improve bioavailability. This paper presents the structure of oral insulin nanoparticles, explore the particle preparation technology and related performance measurement. To be biocompatible and biodegradable lactic acid / glycolic acid copolymer (PLGA) as the carrier material, the use of W / O / W double emulsion solvent evaporation ultrasound insulin PLGA nanoparticles were prepared (PLGA-INS-NPs) . The effects of carrier type, concentration of oil phase, the external phase / oil phase volume ratio and colostrum emulsification time on the nanoparticle size and drug encapsulation efficiency, optimize nanoparticle formulation is: PLGA oil phase concentration 30 mg / mL , insulin concentration in the water phase 10 mg / mL, the oil phase / aqueous phase volume ratio of 5:1 inner, outer aqueous phase / oil phase volume ratio of 3:1. PLGA-INS-NPs average particle size (323.5 ± 3.9) nm, polydispersity index (0.298 ± 0.020), encapsulation efficiency (89.7 ± 1.8)%. Add a pH-sensitive material L, still using W / O / W double emulsion solvent evaporation ultrasound prepared insulin PLGA / L nanoparticles (PLGA / L-INS-NPs), explores the pH-sensitive material L way of adding and L / PLGA appearance of the mass ratio of the particle morphology, average particle size, encapsulation efficiency and in vitro release properties. PLGA / L-INS-NPs average particle size (181.9 ± 19.0) nm, polydispersity index (0.093 ± 0.031), encapsulation efficiency (94.25 ± 1.24)%. Studied the PLGA-INS-NPs and PLGA / L-INS-NPs in vitro release properties, PLGA / L-INS-NPs at pH = 1.2 HCl buffer, only about 20% of the release of insulin, significantly lower than the PLGA-INS-NPs Approximately 60% of the release; at pH = 7.4 phosphate buffer, PLGA / L-INS-NPs insulin release is about 90%, with a significant pH sensitivity performance. The effects of PLGA-INS-NPs (100 IU / kg) and PLGA / L-INS-NPs (50 IU / kg) administered orally hypoglycemic effect in diabetic rats. PLGA-INS-NPs does not have a hypoglycemic effect; rat oral PLGA / L-INS-NPs after 1 h 70% reduction in blood sugar, lowering blood sugar sustainable over 8 h, the relative bioavailability of 11.25%. The results of the development of oral insulin formulation provides an effective theory.
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