In vitro and in vivo evaluation of ferric-hyaluronate implants for delivery of amikacin sulfate to the tarsocrural joint of horses.
OBJECTIVE
To assess the antimicrobial elution characteristics, toxicity, and antimicrobial activity of amikacin-impregnated ferric-hyaluronate implants (AI-FeHAI) for amikacin delivery to the tarsocrural joint of horses.


METHODS
Experimental study.


METHODS
AI-FeHAI implants, equine cartilage, and synovium, and horses (n=6).


METHODS
In vitro study: Five AI-FeHAI were placed in saline solution with daily replacement until implant degradation. Eluent was tested for amikacin concentration and bioactivity. Synovial and cartilage explants were incubated in the presence or absence of AI-FeHAI for 72 hours and subsequently assessed for morphology, viability, and composition. Synovial explants were incubated with Staphylococcus aureus in the presence or absence of AI-FeHAI. Spent medium was cultured daily and explants were assessed for morphology and viability after 96 hours. In vivo study: AI-FeHAI were placed in 6 tarsocrural joints. Standard cytologic analysis and amikacin concentration (SFAC) were determined in synovia obtained regularly for 28 days thereafter. Similar analyses were conducted after a single intra-articular injection of amikacin 6 months later.


RESULTS
In vitro study: Amikacin concentrations exceeded 16 microg/mL and inhibited S. aureus growth for 8 days. AI-FeHAI had no effect on cartilage explants. AI-FeHAI eliminated bacteria from synovial explants. In vitro study: After AI-FeHAI placement, SFAC was highest (140.78+63.81 microg/mL) at first sampling time. By 24 hours SFAC was <16 microg/mL. After intra-articular injection, SFAC was the highest (377.91 +/- 40.15 microg/mL) at first sampling time. By 48 hours SFAC was <16 microg/mL.


CONCLUSIONS
A single intra-articular amikacin injection demonstrated superior pharmacokinetics than AI-FeHAI prepared as described.


CONCLUSIONS
AI-FeHAI cannot be recommended for clinical use.
Cribb
Nicola C
NC
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada. ncribb@uoguelph.ca
Bouré
Ludovic P
LP
Hanna
W J Brad
WJ
Akens
Margarete K
MK
Mattson
Shawn E
SE
Monteith
Gabrielle J
GJ
Weese
J Scott
JS
D020341:Absorbable Implants / Q000662:veterinary; D000583:Amikacin / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D000818:Animals; D016503:Drug Delivery Systems; D006736:Horses; D006820:Hyaluronic Acid / Q000737:chemistry*; D007270:Injections, Intra-Articular / Q000662:veterinary; D007501:Iron / Q000737:chemistry*; D013643:Tarsus, Animal
D000583:Amikacin; D006820:Hyaluronic Acid; D007501:Iron