Abstract: Objective： To establish microbial limit test methods for three iodine-containing preparations (iodine glycerol， iodine tincture， and compound iodine oral solution) to provide feasible technical pathways for their quality control and routine supervision. Methods： During the preparation of the test solution， a combination of sodium thiosulfate pentahydrate and polysorbate 80 was selected as the neutralizing agents. A methodological validation for the microbial limit test was conducted on 8 batches of iodine-containing preparations from 4 medical institutions， in accordance with the requirements of General Chapters 1105 and 1106 of the Chinese Pharmacopoeia (2025 Edition， Part Ⅳ). Results： A microbial counting method utilizing the plate count technique was adopted for three iodine-containing preparations after dilution with pH 7.0 sodium chloride-peptone buffer containing 1% sodium thiosulfate pentahydrate (g·mL-1) and 10% polysorbate 80 (g·mL-1)， while the test for specified microorganisms was conducted using the direct inoculation method. Specifically， for iodine glycerol (containing 2% iodine)， the dilution ratio was 1∶10， and the volume of trypticase soy broth (TSB) used for enriching specified microorganisms was 100 mL. For iodine tincture (containing 3% iodine)， the total aerobic microbial count was tested using a 1∶50 test solution， and the total combined yeast and mold count was tested using a 1∶10 test solution， with a TSB volume of 100 mL for the test of specified microorganisms. For compound iodine oral solution (containing 5% iodine)， the total aerobic microbial count was determined using a 1∶50 test solution in a split-plate method (0.5 mL per plate)， and the total combined yeast and mold count was determined using a 1∶10 test solution in a split-plate method (0.3-0.4 mL per plate)， with a TSB volume of 500 mL for the test of specified microorganisms. Conclusion： The combination of 1% sodium thiosulfate pentahydrate and 10% polysorbate 80 effectively neutralizes the antimicrobial activity of iodine glycerol， iodine tincture， and compound iodine oral solution.

Key words: font-size:medium, "> , Iodine glycerol； Iodine tincture； Compound iodine oral solution； Microbial limit test； Neutralizing agents