Preparation and evaluation of parathyroid hormone incorporated CaP coating via a biomimetic method

Parathyroid hormone (PTH) is a potent bone growth stimulator used for osteoporosis treatment. However, the inconvenience of daily administration and side effect of systemic exposure severely limit its use in clinical applications. Local, controlled delivery is a promising approach which can maintain therapeutic concentration locally for a long period. In this study, PTH was incorporated into a biomimetic calcium phosphate (CaP) coating via a coprecipitation process in a modified simulated body fluid (m-SBF). It was found that PTH was successfully incorporated into biomimetic CaP coating on titanium surface with a high incorporation efficiency. The incorporation of PTH into coatings had significantly changed the coating morphology, but the composition of the coating remained unchanged. Localized release of PTH had occurred in vitro, and was accompanied with partial dissolution of CaP coatings. Cell culture study demonstrated that the PTH released from CaP coatings fully retained its bioactivity. It had improved substantially MC3T3-E1 cell proliferation but slightly delayed the expression of alkaline phosphatase (ALP) of the cells. In summary, our results have shown that CaP coatings incorporated with PTH may be a promising approach for osteoporosis and other bone-related disease treatment in the future.