Dynamic release of tinidazole from the degradable PLLA-tinidazole blend gel / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To determine the dynamic release of tinidazole from the degradable poly-lactic acid (PLLA)-tinidazole blend gel (a periodontal local drug delivery) by high-performance liquid chromatography (HPLC) in vitro and to observe the polylactic acid (as a vector of tinidazole) how to affect the release of tinidazole.</p><p><b>METHODS</b>HPLC analysis was conducted. The operating conditions were C18-ODS-A column, water-methanol-acetic acid as mobile phase at a flow rate of 1.5 ml/min and a detection wavelength at 310 nm and a column temperature at 30 degrees C.</p><p><b>RESULTS</b>The retention time of tinidazole was about 12 min. There was good linear relationship between the concentrations of tinidazole in blend gel and their peak areas in the ranges of 5 - 500 mg/L. The regression reaction was y = 0.836 + 8.452 2 x 10(-5) x (r = 0.998 6). RSD was 0.2%. Polylactic acid had no influence on the determination of tinidazole. The daily average release of tinidazole was 5.60%. The cumulative release of tinidazole was about 78.40% in 14 days.</p><p><b>CONCLUSION</b>The in vitro drug release analysis is an useful method in evaluating the performance of local drug delivery system. HPLC analysis is a simple and accurate method with good reproducibility.</p>

Evaluation on cytotoxicity of a new nano-hydroxyapatite as root canal filling sealer / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluated the cytotoxicity of a new nano-hydroxyapatite (n-HA) root canal sealer.</p><p><b>METHODS</b>In this study, the cytotoxicity was evaluated by the method of MTT assay in vitro, and culture medium F12 as control, three concentrations of the soaking material cultured with mouse osteoblast separately, to test the cell relative growth rate (RGR) of every group.</p><p><b>RESULTS</b>The toxicity graduation of the n-HA root canal sealer tends to 0 with the culture time increasing. The cell survival rate of n-HA root canal sealer showed high relatively. The OD value of cell was similar for the negative control and the extracts (P > 0.05).</p><p><b>CONCLUSION</b>The result indicated that n-HA root canal sealer was compatible with the testcells.</p>