单甲氧基聚乙二醇-聚乳酸羟基乙酸共聚物纳米粒在大鼠鼻黏膜的转运研究

Transport of mPEG-PLGA nanoparticles across the rat nasal mucosa

研究单甲氧基聚乙二醇聚乳酸羟基乙酸共聚物纳米粒(mPEG-PLGA-NPs)的粒径大小、mPEG相对分子质量及覆盖密度,zeta电位对其在大鼠鼻黏膜转运的影响。以mPEG-PLGA共聚物为载体材料,香豆素-6为荧光标记物,采用纳米沉淀法和乳化溶剂挥发法制备不同理化性质的mPEG-PLGA-NPs及壳聚糖包裹的PLGA-NPs,并测定其粒径大小、zeta电位、香豆素的荧光标记效率、体外泄漏率及在溶菌酶中的稳定性等。采用激光共聚焦显微镜技术研究纳米粒的理化性质对其在大鼠鼻黏膜转运的影响。纳米粒分散均匀,PLGA-NPs表面带负电荷,经mPEG修饰后zeta电位接近电中性,壳聚糖包裹后表面荷正电。香豆素的荧光标记效率均>80%。4 h内香豆素-6纳米粒的泄漏百分率<5%。纳米粒在溶菌酶中基本稳定。结果显示,zeta电位近中性的mPEG-PLGA-NPs在鼻黏膜的转运能力显著高于带正电荷的CS-PLGA-NPs及带负电荷的PLGA-NPs(P<0.05),并且随着mPEG相对分子质量和覆盖密度的增加及粒径的增大,其在鼻黏膜的转运能力增强。mPEG-PLGA-NPs在大鼠鼻黏膜的转运能力与其表面亲水性、zeta电位及粒径大小密切相关。

To investigate the effects of particle size, mPEG molecular weight, coating density and zeta potential of monomethoxyl poly（ethylene glycol）-poly（lactic-co-glycolic acid） （mPEG-PLGA） nanoparticles on their transportation across the rat nasal mucosa, mPEG-PLGA-NPs with different mPEG molecular weights （Mr 1 000, 2 000） and coating density （0, 5%, 10%, 15%） and chitosan coated PLGA-NP, which loaded coumarin-6 as fluorescent marker, were prepared with the nanoprecipitation method and emulsion-solvent evaporation method, and determine their particle size, zeta potential, the efficiency of fluorescent labeling, in vitro leakage rate and the stability with the lysozyme were determined. The effects of physical and chemical properties on the transmucosal transport of the fluorescent nanoparticles were investigated by confocal laser scanning microscopy （CLSM）. The result showed that the size of nanoparticles prepared with nanoprecipitation method varied between 120 and 200 nm; the size of nanoparticles prepared with emulsion-solvent evaporation method varied between 420 and 450 nm. Nanoparticles dispersed uniformly; the zeta potential of PLGA-NPs was negative; mPEG-PLGA-NPs was close to neutral; chitosan coated PLGA-NPs was positive; and the efficiency of fluorescent labeling were higher than 80%. In vitro leak was less than 5% within 4 h and nanoparticles were basically stable with lysozyme. The CLSM results show that the transportation efficiency of mPEG-PLGA-NPs with a high PEG coating density and high mPEG molecular weight was significantly higher than that of uncoated PLGA nanoparticles and also that of chitosan coated PLGA-NPs （P〈0.05）. The hydrophilcity, zeta potential and particle size of nanoparticles play important roles on the efficiency of mPEG-PLGA nanoparticles to transport across the rat nasal mucosa.