Matthews K H, Stevens H N E, Auffret A D, Humphrey M J, Eccleston G M
Department of Pharmaceutical Sciences, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 ONR, UK.
Int J Pharm. 2006 Apr 26;313(1-2):78-86. doi: 10.1016/j.ijpharm.2006.01.023. Epub 2006 Feb 28.
Lyophilised wafers are being developed as drug delivery systems that can be applied directly to the surface of suppurating wounds. They are produced by the freeze-drying of polymer solutions and gels. This study investigates the possibility of sterilising these glassy, solid dosage forms with gamma-irradiation and determining the rheological properties of rehydrated wafers post-irradiation. One series of wafers was formulated using sodium alginate (SA) modified with increasing amounts of methylcellulose (MC), the other being composed of xanthan gum (XG) and MC. Batches were divided into three lots, two of which were exposed to 25 and 40 kGrays (kGy) of Cobalt-60 gamma-irradiation, respectively, the third being retained as a non-irradiated control. Apparent viscosities of solutions/gels resulting from the volumetric addition of distilled water to individual wafers were determined using continuous shear, flow-rheometry. Flow behaviour on proprietary suppurating surfaces was also determined. Large reductions in viscosity were apparent for irradiated SA samples while those of XG appeared to be largely unaffected. In addition, an increase in the yield stress of xanthan formulations was observed. Xanthan wafers appeared to withstand large doses of irradiation with no detrimental effect on the rheology of reconstituted gels. This offers the possibility of manufacturing sterilisable delivery systems for wounds.
冻干薄片正在被开发为可直接应用于化脓伤口表面的药物递送系统。它们是通过聚合物溶液和凝胶的冷冻干燥生产的。本研究调查了用γ射线辐照对这些玻璃状固体剂型进行灭菌的可能性，并测定辐照后复水薄片的流变学性质。一系列薄片使用添加了不同量甲基纤维素（MC）的海藻酸钠（SA）配制，另一系列由黄原胶（XG）和MC组成。批次被分成三批，其中两批分别接受25和40千戈瑞（kGy）的钴-60γ射线辐照，第三批作为未辐照对照保留。通过连续剪切流动流变学测定向单个薄片中逐体积添加蒸馏水后所得溶液/凝胶的表观粘度。还测定了在专用化脓表面上的流动行为。辐照后的SA样品粘度大幅降低，而XG样品的粘度似乎基本未受影响。此外，观察到黄原胶制剂的屈服应力增加。黄原胶薄片似乎能承受大剂量辐照，对重构凝胶的流变学没有不利影响。这为制造用于伤口的可灭菌递送系统提供了可能性。
