Method for the Physical Analysis of Drug-bone Cement Composite

Abstract

Skeletal metastases are often complicated by progression to impending or pathologic fracture and fixation with polymethylmethacrylate (PMMA) bone cement is used for stabilization and pain relief. Adjuvant therapy involving the delivery of PMMA composites mixed with antibiotic or chemotherapeutic agents requires an understanding of the rate of drug diffusion from the cement in addition to measurement of its mechanical properties pre- and postelution of drug. We have developed a method for the analysis of drug diffusion rate and mechanical properties of drug-cement composites using PMMA/methotrexate as a model system. The analysis method revealed the addition of methotrexate to PMMA in concentrations of 1.8 g methotrexate per 40 g PMMA did not change the compression modulus of the cement pre- or postelution of drug. The PMMA/methotrexate composites displayed an average diffusion rate of 50 ng/(mm2)(hour) during the first 6 hours, which decreased to 10 ng/(mm2)(hour) by 36 hours. Diffusion modeling predicts the 20 x 13-mm cylindrical PMMA/methotrexate samples used by the method deliver 10% of the total methotrexate content within 80 hours and 25% of the total within 133 days.

In situ forming implants for local chemotherapy and hyperthermia of bone tumors

“…Similar findings were demonstrated by loading custom-made PMMA cement with MTX (4.5 % w/w) since the authors did not detect any changes in the compression modulus of the cement before or after drug elution [209]. Using two commercially available acrylic bone cements (Vertebroplastic TM and Confidence Ultra TM ) loaded with methotrexate at varying amounts, the same authors found a correlation between MTX elution and a decrease in flexural modulus as well as cement strength.…”

Effects of Incorporating Carboxymethyl Chitosan into PMMA Bone Cement Containing Methotrexate

“…The effects of CMCS incorporation on the mechanical properties of cement were determined by four-point bending and compression tests [ 24 ] ( Table 2 ; Fig 5 ). The bending modulus values ( Fig 6A ) of experimental groups 2, 3, and 5 (0.8% CMCS + 0.3% MTX, 1.6% CMCS + 0.6% MTX, and 3.2% CMCS + 1.2% MTX, respectively) were significantly higher than that of the corresponding control groups (containing MTX at the same concentrations).…”

In Vitro and In Vivo Effects of Antiblastic Loaded Polymethyl Methacrylate (Pmma) for the Management of Bone Metastasis: a Literature Review

“…According to Maccauro [7] "elution of MTX does not alter the compressive properties of the cement" and its use can be "an effective aid for the management of bone metastases requiring surgical curettage and acrylic cement implantation for structural support". Also Handal et al [14] confirmed with their analysis method that "the addition of methotrexate to PMMA in concentrations of 1.8 g methotrexate per 40 g PMMA did not change the compression modulus of the cement pre-or post-elution of drug". Kiri et al affirmed [10].…”