Preliminary Genotoxicity Assessment of Calcium Phosphate Cement Incorporated with Palm Tocotrienol Using Bacterial Reverse Mutation Assay.

Background/Objectives: Calcium phosphate cement (CPC) is extensively utilised in bone repair owing to its biocompatibility, osteoconductivity, and compositional similarity to native bone. Functionalisation of CPC with palm tocotrienol may enhance its regenerative potential. However, the incorporation of phytochemicals requires safety evaluation to exclude potential genotoxic risks. This study investigated the mutagenic potential of CPC and tocotrienol-enriched CPC (CPC-T3) using the bacterial reverse mutation assay. Methods: Mutagenicity was evaluated in five bacterial strains, including Salmonella typhimurium TA100, TA98, TA1535, TA1537, and Escherichia coli WP2 trp uvrA, under both non-metabolic and metabolic activation conditions. Revertant colonies were quantified at multiple concentrations and mutagenicity ratios were calculated relative to the negative control. Results: Across all strains and metabolic conditions, neither CPC nor CPC-T3 induced reproducible or concentration-dependent increases in revertant colony numbers. Although isolated elevations were detected at certain concentrations, these findings lacked dose-response relationships and did not meet the criteria for a positive mutagenic response according to Organisation for Economic Co-operation and Development (OECD) Test Guideline No. 471. The performance of negative and positive controls confirmed the validity and sensitivity of the assay. Notably, the inclusion of palm tocotrienol did not alter the overall mutagenicity profile of CPC. Conclusions: CPC and CPC-T3 demonstrated no evidence of mutagenic activity under the conditions of the bacterial reverse mutation assay. These findings represent preliminary genotoxicity screening. Further mammalian genotoxicity and in vivo studies are warranted to support future translational development as implantable medical devices.