title: Validation of a method for non-invasive in vivo measurement of growth factor release from a local delivery system in bone.
abstract: The therapeutic benefit of local administration of growth factors using controlled release systems for bone regeneration is under study. In the present work, a PDGF release profile from chitosan granules administered into bone defect produced in the femur of Wistar rats was obtained using 125I-PDGF as tracer and a probe-type gamma counter with a suitable collimator for detection. The measurement method was validated by the radioactivity values obtained from the isolated bones using a well-type gamma counter. Both the invasive and the non-invasive measurement methods were linear in the analyzed range, with coefficients of variation around 3% and 15%, respectively. A good correlation between the two methods was found for the 125I-PDGF release profile from the chitosan granules. These results confirm that a reliable release profile can be obtained for a drug incorporated into delivery systems for local bone therapy using this non-invasive measurement method.
authors.affiliation: Departamento de Ingeniería Química y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de La Laguna, 38200, La Laguna, Tenerife, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Delgado
authors.forename: Carmen
authors.initials: C
authors.lastname: Evora
authors.forename: Esther
authors.initials: E
authors.lastname: Sánchez
authors.forename: Manuel
authors.initials: M
authors.lastname: Baro
authors.forename: Araceli
authors.initials: A
authors.lastname: Delgado
mesh_terms: D000818:Animals; D001847:Bone Diseases / Q000188:drug therapy / Q000473:pathology; D001842:Bone and Bones / Q000737:chemistry / Q000378:metabolism*; D048271:Chitosan; D016503:Drug Delivery Systems; D005079:Excipients; D005269:Femur / Q000473:pathology; D007457:Iodine Radioisotopes; D008297:Male; D010316:Particle Size; D010982:Platelet-Derived Growth Factor / Q000008:administration & dosage* / Q000032:analysis* / Q000493:pharmacokinetics; D011208:Powders; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results
chemical_list: D005079:Excipients; D007457:Iodine Radioisotopes; D010982:Platelet-Derived Growth Factor; D011208:Powders; D048271:Chitosan