FTIR Analysis and Injection Force Characteristics of a Novel Injectable Hydroxyapatite/Carboxymethyl Cellulose (Ca-HAp/CMC) Matrix for Soft Tissue Augmentation

This conference paper presents a new injectable hydroxyapatite/carboxymethyl cellulose (Ca‑HAp/CMC) hydrogel matrix for soft tissue augmentation. The formulation consists of spherical calcium hydroxyapatite (HAp) microspheres suspended in a CMC carrier gel, sterilized at 121 °C for 21 hours. FTIR spectroscopy confirmed characteristic absorption bands for both HA and CMC, indicating strong polymer–ceramic interaction and composite stability. The Ca‑HAp/CMC gel exhibited favorable rheological and extrusion properties, ensuring smooth injectability while maintaining sufficient viscosity and cohesion for subcutaneous delivery. In vivo testing in Sprague Dawley rats demonstrated biocompatibility, minimal inflammation, and stable dermal integration after seven days.