CelgenTek Limited (part of the Zimmer Biomet group), Unit 4D, Western Business Park, Shannon, Co. Clare, Ireland.
Stokes Laboratories, Bernal Institute, University of Limerick, Ireland.
J Mech Behav Biomed Mater. 2018 Jan;77:116-124. doi: 10.1016/j.jmbbm.2017.09.002. Epub 2017 Sep 5.
Premixed calcium phosphate cements (CPC's) are becoming the material of choice for injectable cements as a result of their effective delivery to the target implantation site. For orthopaedic use, it is of vital importance that the attributes of these CPC's are not compromised by irradiation sterilization. Therefore, the aim of this study is to determine the influence of irradiation sterilization on a range of premixed CPC's, with an emphasis on improving product shelf life through the use of optimal packaging configurations and annealing steps. Electron spin resonance (ESR) confirmed the presence of free radicals in the inorganic phase of the CPC paste following irradiation. The inclusion of a 24-h annealing step was the only successful method in reducing the degree of free radical formation. Based on the results of injectability force testing, it was revealed that an annealing step greater than 24-h significantly altered the viscosity, however; at 24-h the key attributes of the CPC paste were minimally effected. Overall, it was established that vacuum packing the CPC paste, placing the contents into a foil pouch, gamma irradiating at the minimal dose required and using an annealing step of ≤ 24-h, has the potential to extend the shelf life of the cement.
预混磷酸钙骨水泥（CPC）因其可有效输送至目标植入部位而成为注射用骨水泥的首选材料。对于骨科应用而言，至关重要的是，辐照灭菌不会影响这些 CPC 的特性。因此，本研究的目的是确定辐照灭菌对一系列预混 CPC 的影响，重点是通过使用最佳包装配置和退火步骤来提高产品的保质期。电子自旋共振（ESR）证实辐照后 CPC 糊剂的无机相中存在自由基。仅通过包含 24 小时退火步骤，才能成功降低自由基形成的程度。基于可注射力测试的结果，揭示出退火步骤大于 24 小时会显著改变粘度，然而，在 24 小时时，CPC 糊剂的关键特性受影响最小。总体而言，研究结果表明，对 CPC 糊剂进行真空包装，将其内容物装入箔袋中，在所需的最小剂量下进行伽马辐照，并采用≤24 小时的退火步骤，有可能延长水泥的保质期。
