Singh K H, Shinde U A
Department of Pharmaceutics, Bombay College of Pharmacy, Mumbai, India.
Pharmazie. 2011 Aug;66(8):594-9.
Various efforts have been made to improve the bioavailability and to prolong the residence time of eye drops. Drug loaded polymeric nanoparticles offer several favorable biological properties. Thus, brimonidine tartrate (BT) loaded chitosan (CS) nanoparticles were prepared by inducing the ionic gelation upon addition of sodium tripolyphosphate (TPP). Nanoparticles were characterized by TEM, SEM, particle size, polydispersity index (PI), DSC, IR, entrapment efficiency which gave an insight of physicochemical interaction that influenced the CS nanoparticle formation and entrapment of BT. In vitro release of BT nanoparticle showed sustained release over the period of 4 h in saline phosphate buffer pH 7.4. Both placebo and BT loaded nanoparticles had a mean particle size range of about 270-370 nm with PI less than 0.5. DSC studies demonstrated structural interactions between BT, TPP and CS matrix. Entrapment efficiency of the CS nanoparticles ranged from 36-49% depending on the CS:TPP weight ratio. In vivo studies confirmed a significant sustained effect of BT nanoparticles compared to conventional eye drops. These results suggest that BT loaded CS nanoparticles could help to reduce dosage frequency by sustained drug release in the treatment of glaucoma.
人们已经做出了各种努力来提高眼药水的生物利用度并延长其停留时间。载药聚合物纳米颗粒具有多种有利的生物学特性。因此，通过加入三聚磷酸钠（TPP）诱导离子凝胶化制备了载有酒石酸溴莫尼定（BT）的壳聚糖（CS）纳米颗粒。通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）、粒径、多分散指数（PI）、差示扫描量热法（DSC）、红外光谱（IR）、包封率对纳米颗粒进行了表征，这些表征深入了解了影响CS纳米颗粒形成和BT包封的物理化学相互作用。BT纳米颗粒在pH 7.4的磷酸盐缓冲盐水中的体外释放显示在4小时内呈持续释放。安慰剂和载有BT的纳米颗粒的平均粒径范围约为270-370 nm，PI小于0.5。DSC研究表明BT、TPP和CS基质之间存在结构相互作用。CS纳米颗粒的包封率根据CS:TPP重量比在36%-49%之间。体内研究证实，与传统眼药水相比，BT纳米颗粒具有显著的持续效果。这些结果表明，载有BT的CS纳米颗粒在青光眼治疗中通过持续药物释放有助于减少给药频率。
