Background: Bone is a dynamic tissue that continuously undergoes the modeling and remodeling process to
maintain its strength and firmness. Bone remodeling is determined by functioning of osteoblast and osteoclast cells activity. The imbalance between functioning of osteoclast and osteoblast cells leads to osteoporosis. Osteoporosis is divided into primary and secondary osteoporosis. Generally, osteoporosis is diagnosed by measuring bone mineral density (BMD)
and various osteoblast and osteoclast cell markers.
Methods: Relevant literature reports have been studied and data collected using various search engines like google scholar, scihub, sciencedirect, pubmed etc. A thorough understanding of mechanism of bone targeting strategies has been discussed and related literature has been studied and compiled.
Results: Bone remodeling process has been described in detail including various approaches for targeting bone. Several
bone targeting moieties has been stated in detail alongwith their mechanism. Targeting of osteoclasts and osteoblasts using
various nanocarriers has been discussed in separate sections. The toxicity issues or Biosafety related to use of nanomaterials has been covered.
Conclusion: The treatment of osteoporosis targets the inhibition of bone resorption and use of agents that promote bone
mineralization to slow disease progression. Current osteoporosis therapy involves use of targeting moieties such as
bisphosphonates and tetracyclines for targeting of various drugs. Nanotechnology has been used for targeting of various
drug molecules such as RANKL-inhibitors, parathyroid hormone analogues, estrogen agonists and antagonists, Wnt signaling enhancer and calcitonin specifically to bone tissue (osteoclast and osteoblasts). So, a multicomponent treatment
strategy targeting both the bone cells will be more effective rather than targeting only osteoclasts and it will be potential
area of research in bone targeting used to treat osteoporosis.
The first section of review article covers various aspects of bone targeting. Another section comprises of details of various
targeting moieties such as bisphosphonates, tetracyclines; and various nanocarriers developed to target osteoclast and osteoblast cells and summarized data on in vivo models used for assessment of bone targeting, drawbacks of current strategies and future perspectives.