Alkhamis Khouloud A, Salem Mutaz S, Khanfar Mai S
Jordan University of Science and Technology, Irbid, 22110, Jordan.
AAPS PharmSciTech. 2008;9(3):866-9. doi: 10.1208/s12249-008-9123-z. Epub 2008 Jul 24.
The purpose of this investigation was to determine the mechanism of interaction between ketotifen fumarate and chitosan at different pH values. The specific surface area of chitosan was determined using gas sorption analyzer. The sorption experiments were conducted at pH 7 and 10 using two different particle size ranges of chitosan. The solutions were prepared at constant ionic strength and buffer concentration, with only varying the pH. The rotating bottle method was used for measuring the sorption. The average specific surface areas for the two different particle size ranges of chitosan were found to be 4.56 and 0.74 m(2)/g. The Langmuir-like equation and a model independent equation were both applied to the sorption experimental data. The extent of ketotifen uptake at pH 7 for small and large particles of chitosan was found to be 1,073 and 2,204 mg/g respectively. While the extent of ketotifen uptake at pH 10 for small and large particles of chitosan was found to be 4 and 11 mg/g respectively. The aforementioned results indicated that sorption of ketotifen fumarate at pH 7 is extremely high compared to pH 10 and that the sorption increases by decreasing the specific surface area of chitosan. Based on the results obtained, the following conclusions were reached. Ketotifen might be absorbed into the bulk structure of chitosan in addition to being adsorbed on the surface and the ability of chitosan to swell at pH 7 has a significant role in increasing its uptake.
本研究的目的是确定富马酸酮替芬与壳聚糖在不同pH值下的相互作用机制。使用气体吸附分析仪测定壳聚糖的比表面积。在pH值为7和10的条件下，使用两种不同粒径范围的壳聚糖进行吸附实验。溶液在恒定离子强度和缓冲液浓度下制备，仅改变pH值。采用旋转瓶法测量吸附量。发现壳聚糖两种不同粒径范围的平均比表面积分别为4.56和0.74 m²/g。将类朗缪尔方程和一个与模型无关的方程应用于吸附实验数据。发现壳聚糖小颗粒和大颗粒在pH值为7时的酮替芬摄取量分别为1073和2204 mg/g。而壳聚糖小颗粒和大颗粒在pH值为10时的酮替芬摄取量分别为4和11 mg/g。上述结果表明，与pH值为10时相比，富马酸酮替芬在pH值为7时的吸附极高，并且吸附量随着壳聚糖比表面积的减小而增加。基于所得结果，得出以下结论。酮替芬除了吸附在壳聚糖表面外，还可能被吸收到壳聚糖的主体结构中，并且壳聚糖在pH值为7时的溶胀能力对增加其摄取量具有重要作用。
