title: Analysis of the shelf life of a two-solution bone cement.
abstract: Two-solution bone cement consists of methyl methacrylate monomer and poly(methyl methacrylate) polymer dissolved together to yield a viscous solution. Two solutions are used such that the initiator, benzoyl peroxide (BPO), is placed in one solution and the activator, N,N, dimethyl-para-toluidine, is placed in the other. This approach to bone cement provides for a simplified use during surgery and eliminates some of the sources of porosity formation. However, the BPO-containing solution cement will spontaneously polymerize over time and will limit the useful shelf life of this component of the system. The activator-containing component is much more stable and is not as susceptible to spontaneous polymerization. In making two-solution cements, it is envisioned that antibiotics may be incorporated and that the polymer may be sterilized using gamma(gamma)-irradiation. Therefore, this study investigated the shelf life of the initiator-containing solution bone cement and studied the effects of initiator concentration, gamma-irradiation, gentamicin addition, and the role of storage temperature. Isothermal differential scanning calorimetry (Iso-DSC) techniques were used to monitor the polymerization of BPO-containing solutions. It was found that the shelf life was highly temperature dependent and followed an Arrhenius expression where refrigeration storage (4 degrees C) yielded approximately a 12-month storage time, while 70 degrees C storage results in setting in about 5-7 min. gamma-irradiation and gentamicin addition did not significantly affect the shelf life. Initiator concentration affected storage time with higher levels resulting in shorter shelf life.
authors.affiliation: Department of Bioengineering and Neuroscience, Syracuse University, Syracuse, NY 13244-5290, USA. jashim@syr.edu
authors.forename: J B
authors.initials: JB
authors.lastname: Shim
authors.forename: S J
authors.initials: SJ
authors.lastname: Warner
authors.forename: J M
authors.initials: JM
authors.lastname: Hasenwinkel
authors.forename: J L
authors.initials: JL
authors.lastname: Gilbert
mesh_terms: D001585:Benzoyl Peroxide / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D001843:Bone Cements / Q000032:analysis* / Q000737:chemistry* / Q000528:radiation effects; D004355:Drug Stability; D004356:Drug Storage / Q000379:methods*; D005720:Gamma Rays; D005839:Gentamicins / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods; D011109:Polymethacrylic Acids / Q000032:analysis* / Q000737:chemistry* / Q000528:radiation effects; D013696:Temperature
chemical_list: D001843:Bone Cements; D005839:Gentamicins; D011109:Polymethacrylic Acids; C038300:methylmethacrylate-methacrylic acid copolymer; D001585:Benzoyl Peroxide