In vitro elution characteristics of gentamicin-impregnated Polymethylmethacrylate: premixed with a second powder vs. liquid Lyophilization

Abstract

Background Antibiotic-loaded bone cement, or antibiotic-impregnated polymethylmethacrylate (PMMA), were developed to prevent and treat bone and joint infections. Gentamicin is an antibiotic that is commonly used in combination with PMMA; however, gentamicin powder is hard to obtain in many countries. This study aimed to evaluate the elution characteristics of gentamicin-impregnated PMMA made with lyophilized liquid gentamicin, compared with PMMA; which is made from commercial gentamicin powder. Methods The experimental sample was divided into 2 groups: the gentamicin power group (PG-PMMA) and the lyophilized liquid gentamicin group (LG-PMMA). Ten cement spacers were prepared in each group. These were produced by mixing gentamicin powder, or lyophilized liquid gentamicin, with a powder polymer before adding the liquid monomer (2 g of gentamicin and 40 g of PMMA). The volume and surface area of the antibiotic-impregnated cement spacers were 50 cm3 and 110 cm2, respectively. Each spacer was immersed in phosphate-buffered saline, which was changed daily under sterile conditions. The solutions were collected to measure the level of gentamicin using the enzyme multiplied immunoassay technique (EMIT), at days 1, 2, 3, 4, 5, 6, 7, 14, 21, 28, 35 and 42. Results The collections from both groups had high concentrations of gentamicin on day 1 (113.63 ± 23.42 mg/dL in LG-PMMA and 61.7 ±8.37 mg/dL in PG-PMMA), but experienced a continuous decrease over time. The PMMA spacers from both groups could release gentamicin for up to 6 weeks (3.28 ± 1.17 mg/dL in LG-PMMA and 1.21 ± 0.28 mg/dL in PG-PMMA). However, there were significantly higher levels of gentamicin concentrations in the LG-PMMA group compared to the PG-PMMA group at all time points (P< 0.05). Conclusion Gentamicin-impregnated PMMA made with lyophilized liquid gentamicin had approximately a two times higher rate of antibiotic elution in preliminary in vitro studies, as compared with PMMA made with premixed gentamicin powder.

Is Gentamicin Elution Influenced by the Timing of Antibiotic Addition to the Bone Cement? An In Vitro Study on Articulating Hip Spacers

“…Regardless of this study's findings, it is essential to acknowledge delivery vehicles, types of antibiotics, dosage recommendations, indications, and tribological and mechanical properties when preparing antibiotic-loaded spacers or bone cement [20,21]. There is a difference in elution between powdered antibiotics and liquid antibiotics [22,23].…”

Untitled

“…Liawrungrueang, W. et al; aimed to evaluate the elution characteristics of gentamicin-impregnated PMMA made with lyophilized liquid gentamicin, which was compared with PMMA; which was made from commercial gentamicin powder. This study concluded that the Gentamicin-impregnated PMMA made with lyophilized liquid gentamicin showed a higher rate of antibiotic elution in preliminary in vitro studies when compared with PMMA made with premixed gentamicin powder 86 .…”

Antibiotic release from PMMA spacers and PMMA beads measured with ELISA: Assessment of in vitro samples and drain fluid samples of patients

“…Recent third generation antibiotic-impregnated PMMA spacer are able to provide a high concentration of antibiotics at the site of infections. 35 In recent years, material technology developments have offered several options for an improved and prolonged antibiotic pharmacokinetic released profile. It was the aim of this study to assess whether third generation antibiotic-impregnated PMMA spacer Stage-One select would exhibit superior antibiotic release profiles as compared of a gentamicin burst release, there is plateau phase with a significant lower prolonged release of gentamicin.…”

“…However, since there is a limited number of studies of prolonged antibiotic release concentrations, the current evidence regarding these concentrations should be interpreted with care. Recent third generation antibiotic‐impregnated PMMA spacer are able to provide a high concentration of antibiotics at the site of infections 35 . In recent years, material technology developments have offered several options for an improved and prolonged antibiotic pharmacokinetic released profile.…”