The irritative property of α-tricalcium phosphate to the rabbit skin

The aim of this study was to assess the irritant properties of a new developed calcium phosphate ceramic, α-tricalcium phosphate (α-TCP) after single application to intact skin of the rabbit. The test substance, α-TCP was produced by modified hydrothermal method and prepared in two different forms, as a solid material (disc 5 × 2 mm) and paste. Both, solid material and paste of α-TCP were evaluated for primary skin irritation to the ISO 10993-10:2002/Amd 1:2006 Biological Evaluation of Medical Devices − Part 10. At the end of the study macroscopic examination of the skin was performed. In this model, general and local tolerances were good. Score of primary irritation (SPI) and primary irritation index (PII) of α-TCP for both, solid material and paste, revealed that there was no significant toxicity/irritability (PII = 0.0) as compared to the negative control (PII = 0.0). Positive control did cause significant skin irritation in acute irritation test using Draize technique in rabbit model (PII = 2.11). Based on present results, it can be concluded that the the irritation potential of the tested material is negligible. However, other procedures for preclinical safety assessments of the α-TCP material are needed in order to completely elucidate its toxic potential.