Surfactant-stabilized Emulsion Increases Gentamicin Elution From Bone Cement

Abstract

Background Liquid antimicrobial use for antimicrobialloaded bone cement is limited because of decreased strength and small volume that can be loaded. Emulsifying the liquid antimicrobial into the monomer may address both issues. Questions/purposes We determined the effect of using a surfactant-stabilized emulsion on antimicrobial release, compressive strength, and porosity. Methods We made 144 standardized test cylinders from emulsified antimicrobial-loaded bone cement (three batches, 72 cylinders) and control antimicrobial-loaded bone cement made with antimicrobial powder (three batches, 72 cylinders). For each formulation, five specimens per batch (n = 15) were eluted in infinite sink conditions over 30 days for gentamicin delivery; five specimens per batch were axially compressed to failure after elution of 0, 1, and 30 days (n = 45); and two noneluted specimens and two gentamicin delivery specimens from each batch (n = 12) were examined under scanning electron microscopy for porosity. Antimicrobial release and compressive strength were compared across cement type and time using repeated-measures ANOVA. Results Emulsified antimicrobial-loaded bone cement released four times more antimicrobial than control. Compressive strength of emulsified antimicrobial-loaded bone cement was less than control before elution (58.1 versus 81.3 MPa) but did not decrease over time in elution. Compressive strength of control antimicrobial-loaded bone cement decreased over 30 days in elution (81.3 versus 73.9 MPa) but remained stronger than emulsified antimicrobial-loaded bone cement. Porosity was homogeneous, with pores ranging around 50 lm. Conclusions Emulsified antimicrobial-loaded bone cement has homogeneous porosity with increased drug release but a large loss of strength. Clinical Relevance Liquid antimicrobials are released from emulsified antimicrobial-loaded bone cement, but increased strength is needed before this method can be used for implant fixation.

Local Gentamicin Delivery From Resorbable Viscous Hydrogels Is Therapeutically Effective

“…The antimicrobial load must be low enough that the structural integrity of the cement fixation is not compromised [17,44]. Low-dose antimicrobial-loaded bone cement releases only a very small fraction of the drug load during the first week when it is needed [42,52,62]. Other investigational delivery vehicles, including calcium phosphate cements [30], hydroxyapatite composites [9,61], antibiotic implant coatings [2,3], and polymer beads/microparticles [4,46,47], also have drawbacks.…”

A novel liposomal drug delivery system for PMMA bone cements

“…To overcome the issue of phase separation, surfactants may be used. Miller et al attempted to use surfactants with gentamicin solution but found reductions in mechanical properties nevertheless due to the presence of water . Pelleted liposomes, obtained through ultra‐centrifugation in conjunction with amphiphilic polymers (containing a hydrophobic and a hydrophilic portion) may overcome this issue.…”

“…Miller et al attempted to use surfactants with gentamicin solution but found reductions in mechanical properties nevertheless due to the presence of water. 24 Pelleted liposomes, obtained through ultra-centrifugation in conjunction with amphiphilic polymers (containing a hydrophobic and a hydrophilic portion) may overcome this issue. Non-toxic, neutral surfactants, such as Pluronic block copolymers, which improve the miscibility of solutions, may be employed to overcome phase separation of the liposomes in methyl methacrylate.…”

Polymicrobial Biofilm Inhibition Effects of Acetate‐Buffered Chitosan Sponge Delivery Device

“…PMMA is widely used clinically, although applications are limited due to the nondegradability and slow release of antibiotic. Optimal loading concentrations for PMMA may be determined through modeling and rational selection, although slow release is still a concern requiring porosity inducing additives to improve elution of certain antibiotics . The duration of antibiotic release observed in vitro from sponges was relatively short compared with duration of up to 36 weeks of release from PMMA .…”