Calcitonin release system in the treatment of experimental osteoporosis. Histomorphometric evaluation

Bioabsorbable polyphosphazene matrices charged with 2-50 mug calcitonin wer e evaluated as calcitonin delivery systems for the controlled release of th is drug in an in vivo experimental model. Matrices were implanted under general anesthesia in osteopenic female rats. while a group of osteopenic animals (control group) received unloaded matr ices. After 30 days a second series of matrices. loaded and unloaded was, r espectively, implanted in both groups. In a third group of osteopenic femal e rats (positive control), 10 IU calcitonin were injected daily for two mon ths. A baseline group and a Awn operated group of animals were also include d in the study. The explanted matrices were histologically evaluated togeth er with the surrounding tissues, and bone histomorphometry was performed on Undecalcified sections from femurs. The results showed the good biocompati bility of the matrices. Bone histomorphometry revealed that bone architectu re in the treatment group was improved and results were not different from those observed after calcitonin injection. These data confirm a good in viv o behavior of the system, as well as a therapeutic effect of the released c alcitonin in the osteopenic condition. (C) 2001 Orthopaedic Research Societ y. Published by Elsevier Science Ltd. All rights reserved.