A validated quantitative colorimetric assay for gentamicin

Frutos, P.; Torrado, Susana; Perez-Lorenzo, M.E.; Frutos, G.

doi:10.1016/s0731-7085(99)00192-2

Cited by 74 publications

(59 citation statements)

References 8 publications

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“…Total eluant exchange was performed at 1, 3, 6, 12, 24, 48, 72, 120, and 168 hours. Gentamicin concentration in each eluant aliquot was determined using a ninhydrin-based colorometric assay [24]. Cumulative recovered gentamicin was then calculated.…”

Section: Gel Synthesis and Characterizationmentioning

confidence: 99%

Local Gentamicin Delivery From Resorbable Viscous Hydrogels Is Therapeutically Effective

Overstreet

McLaren

Calara

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background Local delivery can achieve the high antimicrobial concentrations necessary to kill biofilm-related microbes. Degradation times for resorbable carriers are too long. Hydrogels (gels of hydrophilic polymer in water) can degrade faster but release antimicrobials too quickly. We previously developed hydrogels based on the copolymer poly(N-isopropylacrylamide-co-dimethyl-c-butyrolactone acrylate-co-Jeffamine 1 M-1000 acrylamide) (PNDJ) with delivery times of several days with complete degradation in less than 6 weeks. Questions/purposes We asked: (1) What is the elution profile of gentamicin from PNDJ hydrogels? (2) Is gentamicin released from gentamicin-loaded PNDJ (G-PNDJ) hydrogel effective for treatment of orthopaedic infection? (3) Does local gentamicin delivery from G-PNDJ hydrogel cause renal dysfunction? Methods (1) Two formulations of G-PNDJ, lower dose (1.61 wt%) and higher dose (3.14 wt%), five samples each, were eluted in buffered saline under infinite sink conditions. (2) Infections were induced in 16 New Zealand White rabbits by inserting a Kirschner wire in a devascularized radius segment and inoculating with 7.5 9 10 6 colony-forming units Staphylococcus aureus. At 3 weeks, débridement was performed and a new Kirschner wire was placed in the dead space. Treatment was randomized to higher-dose G-PNDJ or no hydrogel. No systemic antimicrobials were used. Positive culture and acute inflammation on histology were used to determine the presence of infection 4 weeks postdébridement. (3) 3.14 wt% G-PNDJ, 0.75, 1.5, or 3.0 mL, was injected subcutaneously in nine Sprague-Dawley rats, three of each dose. Serum gentamicin, blood urea nitrogen, and creatinine were measured on Days 1, 3, 7, 14, and 28. Results (1) Gentamicin release was sustained over 7 days with the higher-dose formulation release profile similar to release from high-dose antimicrobial-loaded bone cement.(2) Four weeks postdébridement, infection was present in eight of eight no-hydrogel rabbits but zero of eight rabbits treated with G-PNDJ hydrogel (p \ 0.001). (3) Blood urea nitrogen and creatinine were transiently elevated

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Section: Gel Synthesis and Characterizationmentioning

confidence: 99%

Local Gentamicin Delivery From Resorbable Viscous Hydrogels Is Therapeutically Effective

Overstreet

McLaren

Calara

et al. 2015

Clinical Orthopaedics &Amp; Related Research

View full text Add to dashboard Cite

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“…This part of the molecule is more specific when compared to the amino group, but according to a previous study, the reaction is not sensitive enough, meaning that the detectable limit is below 200 µg/ml [25]. Therefore, the ninhydrin reagent could be safely chosen for our measurement, which was optimized based on Frutos's data [24]. With ninhydrin, the linear absorbance interval fell in the 10 -100 µg/ml range, so any sample containing over 100 µg/ml gentamicin had to be diluted.…”

Section: Functional Group Evaluationmentioning

confidence: 99%

“…The ideal bone substitute is osteoconductive, osteoinductive and osteogenic, and the search for the ideal material is ongoing [1,2]. Because biocompatibility and cost-effectiveness are also highly important, human allograft is frequently used, even though its accurate colorimetric determination method based on the amino group present in the gentamicin molecule [24,25].This may prove to be an inexpensive alternative for quantitative gentamicin detection compared to the existing analytical methods, like HPLC, ELISA or fluorometry [26].…”

Section: Introductionmentioning

confidence: 99%

Sustained Release of a Biodegradable Alginate Coating Covering Chemically Unbound Gentamicin on Human Bone Allograft; And a Method for Colorimetric Drug Release Measurement

HornyákM¹,

Csı́k²,

Lukacs³

et al. 2017

SOJPPS

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“…We used a ninhydrin assay (Alfa Aesar, Heysham, Lancashire, UK) to determine the gentamicin concentration in the eluate [7]. Gentamicin concentration from each site at each time point was determined by comparing the sample color change with a standard curve.…”

Section: Gentamicin Quantificationmentioning

confidence: 99%

Antimicrobial Release From Prefabricated Spacers Is Variable and the Dose Is Low

Goltzer

McLaren

Overstreet

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background High-dose antimicrobial-loaded bone cement (ALBC) is recommended to treat orthopaedic infections. Elution characteristics from prefabricated ALBC spacers and how they compare with hand-mixed ALBC are not well described. Questions/purposes (1) How does antimicrobial release from prefabricated spacers compare with release from hand-mixed ALBC over time? (2) Is antimicrobial release uniform across the surface of prefabricated ALBC spacers? (3) Do variations exist between different prefabricated spacer components? (4) Do textured surfaces release more antimicrobial than smooth surfaces? Methods Six prefabricated ALBC spacer components, two hip and four knee, and three hand-mixed ALBC formulations were studied in this comparative laboratory study. Gentamicin was eluted from 41 discrete sites over the surfaces of six spacer components and compared with elution from 15 ALBC specimens, five from each of three hand-mixed formulations. Elution was compared between spacer sites, components, and surface texture. Statistical analysis was performed by analysis of variance and Tukey's multiple-comparison test or t-test. Results Gentamicin release was highest in the first 24 hours for both prefabricated ALBC spacers and hand-mixed ALBC. Elution decreased over 7 days similarly for both. At Day 7, prefabricated ALBC spacers eluted more than hand-mixed 1 g ALBC (1 g ALBC: 1.49 ± 0.34, prefabricated: 3.59 ± 1.48, mean difference = 2.1 [0.2-4.0], p = 0.04) but eluted less than 5 g ALBC (9.21 ± 1.31, mean difference = À5.6 [À3.5 to À7.7], p \ 0.001) and less than 10 g ALBC (35.8 ± 1.69, mean difference = À32.2 [À29.8 to À34.6], p \ 0.001). Release varied from 2.7 to 9.9 lg/mm 2 over the surface of the spacers and from 3.5 to 5.5 lg/mm 2 between components with no component different than the others (Tukey). Release from textured surfaces was inconsistent. Conclusions Antimicrobial release from prefabricated ALBC spacers is consistent with low-dose ALBC. Variation across the surface and between components is small compared with changes in antimicrobial load. Clinical Relevance Antimicrobial release from prefabricated ALBC spacers is consistent with local antimicrobial delivered from other low-dose ALBC formulations.

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A validated quantitative colorimetric assay for gentamicin

Cited by 74 publications

References 8 publications

Local Gentamicin Delivery From Resorbable Viscous Hydrogels Is Therapeutically Effective

Local Gentamicin Delivery From Resorbable Viscous Hydrogels Is Therapeutically Effective

Sustained Release of a Biodegradable Alginate Coating Covering Chemically Unbound Gentamicin on Human Bone Allograft; And a Method for Colorimetric Drug Release Measurement

Antimicrobial Release From Prefabricated Spacers Is Variable and the Dose Is Low

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