Karataş Ayşegül, Sonakin Ozlem, Kiliçarslan Müge, Baykara Tamer
Faculty of Pharmacy, Department of Pharmaceutical Technology, Ankara University, Tandoğan, Ankara, Turkey.
J Microencapsul. 2009 Feb;26(1):63-74. doi: 10.1080/02652040802141039.
The aim of this study was to prepare poly (epsilon-caprolactone) (PCL) microparticles of Levobunolol HC1 (L-HC1) for use as an anti-glaucomatous drug to the eye. The double emulsion (W/O/W) solvent evaporation technique was used for encapsulating L-HC1 as a hydrophilic drug. The study examined the impact of different factors including the pH and volume of the external aqueous phase, the concentration of polyvinylalcohol (PVA) and Pluronic F68 (PF68) used as stabilizers and drug/polymer ratios on the characteristics of the microparticles. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were used to identify the physical state of the drug and polymer. The zeta potential of the particles was also identified. Entrapment efficiency was found to be highest with a 0.5% PVA concentration and 100 mL volume of external aqueous phase at pH 12. The high efficiency was due to a reduction in the degree of drug ionization. The microparticles were spherical and appropriately sized for ophthalmic application. Drug release from the microparticles appears to consist of two components, with an initial rapid release followed by a slower stage. Drug release was slower when the microparticle was incorporated into the thermally reversible gel (Pluronic F127) in comparison to drug release from the free drug incorporated into the gel and drug release from the free microparticle.
本研究的目的是制备盐酸左布诺洛尔（L-HC1）的聚（ε-己内酯）（PCL）微粒，用作眼部抗青光眼药物。采用双乳液（W/O/W）溶剂蒸发技术包封亲水性药物L-HC1。该研究考察了不同因素的影响，包括外部水相的pH值和体积、用作稳定剂的聚乙烯醇（PVA）和普朗尼克F68（PF68）的浓度以及药物/聚合物比例对微粒特性的影响。使用扫描电子显微镜（SEM）和差示扫描量热法（DSC）来确定药物和聚合物的物理状态。还测定了微粒的ζ电位。发现在pH值为12时，PVA浓度为0.5%且外部水相体积为100 mL时包封效率最高。高效率是由于药物电离程度降低。微粒呈球形，大小适合眼科应用。微粒的药物释放似乎由两个部分组成，先是快速初始释放，随后是较慢阶段。与掺入热可逆凝胶（普朗尼克F127）中的游离药物的药物释放以及游离微粒的药物释放相比，当微粒掺入热可逆凝胶中时药物释放较慢。
