title: Pharmacokinetic model for cefazolin distribution during total hip arthroplasty in dogs.
abstract: OBJECTIVE
  To compare cefazolin pharmacokinetics in serum and concentrations in tissues during total hip arthroplasty in dogs with and without hip dysplasia, and to calculate the optimal dosage of cefazolin for prophylactic use during total hip arthroplasty.
  
  
  METHODS
  10 dogs with hip dysplasia and 3 clinically normal dogs.
  
  
  METHODS
  Blood samples and tissue specimens from the coxofemoral joint capsule, acetabulum, and femur were obtained during unilateral total hip arthroplasty. Cefazolin concentrations in serum and tissue specimen supernatant were determined, using high-performance liquid chromatography, for use in pharmacokinetic analysis. Mathematical simulation of serum cefazolin concentration was used to to predict the optimal dose.
  
  
  RESULTS
  Mean pharmacokinetic constants (SEM) were 0.146 (0.013) min-1 for alpha, 4.47 min for t1/2 alpha 0.015 (0.004) min-1 for beta, 46.83 min for t1/2 beta. Significant different was not detected for cefazolin distribution and elimination between dogs with and without hip dysplasia. Additional, significant difference was not observed in pharmacokinetic parameters describing distribution and elimination between the first and second doses of cefazolin. The predicted optimal dosage regimen was 8 mg/kg of body weight, i.v. every hour or mg/kg, i.v. every 2 hours.
  
  
  CONCLUSIONS
  For prophylactic i.v. treatment during total hip arthroplasty, use of cefazolin at a dosage of 8 mg/kg every hour or 22 mg/kg every 2 hours should maintain serum cefazolin concentrations at least 10x the minimum inhibitory concentration for 3 to 4 hours.
authors.affiliation: Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Marcellin-Little
authors.forename: M G
authors.initials: MG
authors.lastname: Papich
authors.forename: D C
authors.initials: DC
authors.lastname: Richardson
authors.forename: D J
authors.initials: DJ
authors.lastname: DeYoung
mesh_terms: D000077:Acetabulum / Q000737:chemistry; D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002358:Cartilage, Articular / Q000737:chemistry; D002437:Cefazolin / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004283:Dog Diseases / Q000382:microbiology / Q000517:prevention & control; D004285:Dogs / Q000378:metabolism* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005269:Femur / Q000737:chemistry; D006619:Hip Dysplasia, Canine / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects / Q000379:methods / Q000662:veterinary*; D008954:Models, Biological; D011183:Postoperative Complications / Q000517:prevention & control / Q000662:veterinary; D016459:Prosthesis-Related Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D002437:Cefazolin