McLaren R L, McLaren A C, Vernon B L
Banner Good Samaritan Medical Center, 1300 N 12th Street, Suite 620, Phoenix, AZ 85006, USA.
Clin Orthop Relat Res. 2008 Jun;466(6):1372-6. doi: 10.1007/s11999-008-0199-2. Epub 2008 Mar 14.
Elution of antibiotics from antibiotic-loaded polymethylmethacrylate (AL-PMMA) increases when soluble particulate filler is added to increase the permeability of the PMMA. Antibiotic powder is in itself soluble particulate filler. For greater volume fractions of filler, greater elution occurs. The volume of generic tobramycin powder is more than 3.5 times the volume of proprietary tobramycin powder for a 1.2 g dose leading to the question: Does generic tobramycin elute from AL-PMMA faster than proprietary tobramycin? We performed elution studies on AL-PMMA beads made with 1.2 g of either generic tobramycin or proprietary tobramycin per batch of PMMA. Generic tobramycin eluted more than two times faster than proprietary tobramycin. The release mechanism started as dissolution-driven zero-order release for the generic bead set but for the proprietary bead set the released mechanism started as anomalous diffusion. The release mechanism progressed to diffusion-driven first-order release in both. The increased volume of the generic tobramycin caused more tobramycin to be available for release. The increased elution of tobramycin associated with the greater volume of generic tobramycin powder could lead to clinically higher levels of tobramycin in wound fluid and local tissues; however, the higher volume of powder could potentially cause greater mechanical compromise of the PMMA.
当添加可溶性颗粒填料以增加聚甲基丙烯酸甲酯（PMMA）的渗透性时，载抗生素聚甲基丙烯酸甲酯（AL-PMMA）中抗生素的洗脱量会增加。抗生素粉末本身就是可溶性颗粒填料。对于更大的填料体积分数，会发生更大程度的洗脱。对于1.2 g剂量，普通妥布霉素粉末的体积是专利妥布霉素粉末体积的3.5倍以上，这就引发了一个问题：普通妥布霉素从AL-PMMA中的洗脱速度是否比专利妥布霉素更快？我们对每批PMMA中含有1.2 g普通妥布霉素或专利妥布霉素制成的AL-PMMA珠进行了洗脱研究。普通妥布霉素的洗脱速度比专利妥布霉素快两倍以上。对于普通珠组，释放机制开始时是溶解驱动的零级释放，但对于专利珠组，释放机制开始时是异常扩散。两种珠组的释放机制都进展为扩散驱动的一级释放。普通妥布霉素体积的增加导致更多的妥布霉素可供释放。与普通妥布霉素粉末更大体积相关的妥布霉素洗脱增加可能导致伤口液和局部组织中妥布霉素的临床水平更高；然而，更高体积的粉末可能会对PMMA造成更大的机械损伤。
