Improved Anti-Washout Property of Calcium Sulfate/Tri-Calcium Phosphate Premixed Bone Substitute with Glycerin and Hydroxypropyl Methylcellulose

Calcium sulfate/calcium phosphate (CS-CP)-based bone substitutes have been developed in premixed putty for usage in clinical applications. However, it is difficult to completely stop the bleeding during an operation because premixed putty can come into contact with blood or body fluids leading to disintegration. Under certain conditions depending on particle size and morphology, collapsed (washed) particles can cause inflammation and delay bone healing. In this context, anti-washout premixed putty CS-CP was prepared by mixing glycerin with 1, 2, and 4 wt% of hydroxypropyl methylcellulose (HPMC), and the resultant anti-washout properties were evaluated. The results showed that more than 70% of the premixed putty without HPMC was disintegrated after being immersed into simulated body fluid (SBF) for 15 min. The results demonstrated that the more HPMC was contained in the premixed putty, the less disintegration occurred. We conclude that CS-CP pre-mixed putty with glycerin and HPMC is a potential bone substitute that has good anti-washout properties for clinical applications.