Concentrations of cephalexin in mandibular alveolar bone, blood, and oral fluids

Fabrication and In Vitro Drug Delivery Evaluation of Cephalexin Monohydrate-Loaded PLA:PVA/HAP:TiO2 Fibrous Scaffolds for Bone Regeneration

Owing to the excellent osteoconductive property of hydroxyapatite, we aimed to design a cephalexin monohydrate-loaded PLA:PVA/HAP:TiO₂ nanofibrous scaffold to improve the drug delivery efficiency toward bone regenerative applications. In this study, HAP:TiO₂ (anatase and rutile phases) samples were prepared by a coprecipitation method, which were later blended with PLA:PVA polymeric solution (with and without the drug) to fabricate a nanofibrous matrix via the electrospinning technique. All the prepared samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, contact angle, porosity, and tensile strength tests. Further, in vitro biodegradation and the drug-releasing ability were examined by varying the concentration of cephalexin monohydrate in the composite matrix. Deposition of the apatite layer on the scaffolds was examined after incubation in simulated body fluid solution to confirm the bioactivity of the prepared nanofibers. Biocompatibility by the MTT assay and osteogenic differentiation by ARS staining were evaluated by culturing MG63 cells on PLA:PVA/HAP:TiO₂ nanofibers, which could ensue better support for cell proliferation. Consequently, the sustained release profile and better biocompatibility of the scaffolds revealed a strong potential use in bone regenerative applications.

Cefadroxil concentrations in human serum, gingiva, and mandibular bone following a single oral administration

Cefadroxil concentrations in human serum, gingiva, and mandibular bone were measured by a paper disk method following a single 500-mg oral dose. The mean peak concentrations in serum, gingiva, and mandibular bone occurred at the identical time, 3 hours, and were 12.92 micrograms/mL, 6.50 micrograms/g, and 2.67 micrograms/g, respectively. Mean cefadroxil concentration ratios of gingiva/serum and mandibular bone/serum at the peak time were 0.54 and 0.21, respectively. Mean concentrations in gingiva and mandibular bone at the peak time exceeded the minimum inhibitory concentrations for 90% of clinically isolated strains of a alpha-hemolytic streptococci.

Bacteria isolated from late prosthetic joint infections: dental treatment and chemoprophylaxis

The recommended administration of prophylactic antibiotics, before and during dental procedures, to persons with total joint prostheses is not without controversy. Hospital and dental charts of 2,693 patients in whom total prosthetic joints were placed at the Veterans Administration Hospitals of Ann Arbor and Allen Park, Michigan, as well as the University of Michigan Hospital, were analyzed. The identity of the micro-organism associated with the late (6 months after placement) infected prosthetic joint and the sensitivity of the organisms to specific antibiotics were recorded. Of the 30 (1.1%) late prosthetic joint infections, only one (0.04%) could be temporally associated with dental treatment. Fifty-three percent of the isolates were gram-positive staphylococci, the most common isolate being Staphylococcus epidermidis (36%). Pseudomonas aeruginosa was the most frequent gram-negative isolate cultured. Twenty-five of 34 isolates tested were resistant to penicillin, while only 3 of 36 isolates tested were resistant to a cephalosporin and 5 of 21 isolates tested were resistant to methicillin.

Bone penetration of antibiotics

Osteomyelitis is caused by bacterial pathogens and, less frequently, by other infectious agents. Treatment of osteomyelitis should include a course of antimicrobial therapy with a batericidal agent. This therapy should be directed at the causative bacteria isolated by bone biopsy and culture, not by wound swab cultures above the infected bone. The bactericidal agent should be demonstrated effective against the organism isolated from bone and should penetrate the bone in sufficient concentrations. Many studies have assessed bone penetration of antimicrobials, but methodological problems must be addressed. Penicillins, cephalosporins, aminoglycosides, erythromycin, lincomycin and clindamycin, and metronidazole have all been evaluated.

Amoxicillin concentrations in serum, jaw cyst, and jawbone following a single oral administration

Forty-four patient who underwent enucleation of jaw cysts were administered amoxicillin preoperatively. Specimens of venous blood (44), walls and fluids from periodontal (31) and dentigerous (13) cysts, and jawbone (26) were obtained during the operation and assayed for amoxicillin content. Measurable concentrations were found in all specimens. The levels were higher in periodontal cysts than in dentigerous cysts, and higher in maxillary bone than in mandibular bone. Since amoxicillin can easily and rapidly pass through the epithelial lining according to the change in concentration, the penetration by amoxicillin of blood/cyst wall/cyst fluid probably depends on simple diffusion.