This study investigates the development of risedronate (RSD)-incorporated polycaprolactone (PCL)/chitosan composite films for potential use in drug delivery systems aimed at bone repair. PCL and chitosan were blended in varying ratios (25 %, 50 %, 75 % PCL), and their miscibility, morphology, and hydrophilicity were analyzed. The effects of incorporating RSD at different concentrations (10-7 to 10-4 M) on MG63 preosteoblast cell proliferation and differentiation were also evaluated. The results demonstrated that blending of the hydrophobic PCL with hydrophilic chitosan was challenging, due to poor miscibility and phase separation. Optimal blending conditions and drying temperatures were essential for homogeneous film formation. The incorporation of RSD influenced cellular behavior, with 50 % PCL showing the most effective cell proliferation and moderate hydrophilicity. However, higher RSD concentrations (10-4 M) inhibited proliferation, while lower concentrations (10-7 M) promoted it. RSD also enhanced osteoblast differentiation, as evidenced by increased alkaline phosphatase (ALP) activity, particularly in 75 % PCL films. These findings suggest that adjusting the PCL/chitosan ratio and RSD concentration can optimize drug release and cellular responses, making this composite system a promising candidate for bone tissue engineering applications.

Abstract
1. Introduction
2. Experimental Procedure
    2.1. Materials
    2.2. Fabrication of RSD-incorporated PCL/chitosanfilms
    2.3. FT-IR spectroscopy
    2.4. FE-SEM observation
    2.5. Measurement of contact angle
    2.6. Assessment of cell responses
    2.7. Statistical analysis
3. Results and Discussion
    3.1. Fabrication of PCL/chitosan composite films
    3.2. Observation of morphological changes
    3.3. Molecular and hydrophilicity changes
    3.4. Cellular responses
4. Conclusion
Acknowledgement
References

• Seunghwan Choy(Digital Health Research Division, Korea Institute of Oriental Medicine, Daejeon 34054, Republic of Korea) Corresponding author