title: Development of a biodegradable antibiotic delivery system.
abstract: Antibiotic beads have been used as a drug delivery system for the treatment of various surgical infections. In this study, the copolymer 50:50 poly(DL-lactide):co-glycolide was mixed with vancomycin powder and hot compressing molded at 55 degrees C to form five types of biodegradable antibiotic beads. The beads were placed in 1 mL of phosphate buffered saline and incubated at 37 degrees C. The phosphate buffered saline was changed daily, and the removed buffer solutions were stored at -70 degrees C until the antibiotic concentration in each sample was determined by high performance liquid chromatography system assay. The concentration of vancomycin in each sample was well above the breakpoint sensitivity concentration (the antibiotic concentration at the transition point between bacterial killing and resistance to the antibiotic) for more than 32 days. The release was most marked during the first 48 hours. All copolymer 50:50 poly(DI lactide):co-glycolide biodegradable beads released high concentrations of the antibiotics in vitro for the time needed to treat bone infections (4 to 6 weeks). The diameter of the sample inhibition zone ranged from 6.5 mm to 10 mm, and the relative activity of vancomycin ranged from 12.5% to 100%. Copolymers with low heat of formation temperatures are required for making a controlled release system to prevent antibiotic decomposition, which occurs when using the hot compressing molded method. The rate and duration of release from the antibiotic beads can be adjusted by varying the diameter of the beads. This offers a convenient method to adjust the release rate to meet the specific antibiotic requirements for different patients.
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Keelung, Taiwan.
authors.forename: S S
authors.initials: SS
authors.lastname: Lin
authors.forename: S W
authors.initials: SW
authors.lastname: Ueng
authors.forename: S J
authors.initials: SJ
authors.lastname: Liu
authors.forename: E C
authors.initials: EC
authors.lastname: Chan
authors.forename: E K
authors.initials: EK
authors.lastname: Chao
authors.forename: C H
authors.initials: CH
authors.lastname: Tsai
authors.forename: K T
authors.initials: KT
authors.lastname: Chen
authors.forename: F C
authors.initials: FC
authors.lastname: Wei
authors.forename: C H
authors.initials: CH
authors.lastname: Shih
mesh_terms: D020341:Absorbable Implants; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000032:analysis / Q000494:pharmacology; D001672:Biocompatible Materials / Q000737:chemistry; D001673:Biodegradation, Environmental; D002021:Buffers; D002851:Chromatography, High Pressure Liquid; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems / Q000379:methods; D004352:Drug Resistance, Microbial; D006801:Humans; D006868:Hydrolysis; D019344:Lactic Acid / Q000737:chemistry; D008863:Microspheres; D010710:Phosphates / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D012044:Regression Analysis; D012965:Sodium Chloride / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects; D013499:Surface Properties; D013530:Surgical Wound Infection / Q000188:drug therapy; D013997:Time Factors; D014640:Vancomycin / Q000008:administration & dosage* / Q000032:analysis / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D002021:Buffers; D003692:Delayed-Action Preparations; D010710:Phosphates; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D012965:Sodium Chloride; D014640:Vancomycin