Formulation, development and optimization of raloxifene-loaded chitosan nanoparticles for treatment of osteoporosis.

Background: Osteoporosis (OP) is a disease of skeletal system and is associated with fragility fracture at the hip, spine and wrist. Various drugs have been used to treat OP. One of them is raloxifene hydrochloride (RLX), a second-generation selective estrogen receptor modulator (SERM) approved by the USFDA. RLX possesses only 2% absolute bioavailability (BA) by oral route due to its extensive first-pass metabolism.

Objective: The purpose of the current research work was to develop and evaluate RLX-loaded chitosan nanoparticles (CS-NPs) for treatment of OP with enhanced BA.

Methods: The RLX-loaded CS-NPs were prepared by gelation of CS with tripolyphosphate (TPP) by ionic cross-linking. Formulation was optimized and in vitro drug release and in vivo study were performed.

Conclusions: CS-NPs were formed by the ionic gelation method. The particle size, entrapment efficiency and loading efficiency varied from 216.65 to 1890 nm, 32.84 to 97.78% and 23.89 to 62.46%, respectively. Release kinetics showed diffusion-controlled and Fickian release pattern. In vivo study indicated higher plasma drug concentration with NPs administered intranasally as compared to drug suspension administered through oral route (p < 0.05). A significantly higher drug concentration in plasma was achieved in 10 min after nasal administration with respect to oral administration. Conclusions: The results suggest that RLX-loaded CS-NPs have better BA and would be a promising approach for intranasal (i.n.) delivery of RLX for the treatment of OP.