Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 0 0 2026 05 11 1459 1459 Motahhareh Mojarradi Department of Clinical Pharmacy, Faculty of Pharmacy, Islamic Azad University, Pharmaceutical Science Branch, Tehran, Iran. Kaveh Kazemian Toxicology Research Center, Aja University of Medical Sciences, Tehran, Iran. Amirhossein Ghanbarzamani Department of Clinical Pharmacy, Faculty of Pharmacy, Islamic Azad University, Pharmaceutical Science Branch, Tehran, Iran. Solmaz Ghaffari Department of Pharmaceutics, Faculty of Pharmacy, TeMS.C., Islamic Azad University, Tehran, Iran. Maryam Shiehmorteza Department of Clinical Pharmacy, Faculty of Pharmacy, Islamic Azad University, Pharmaceutical Science Branch, Tehran, Iran. 2025 10 23 2025 11 08 Background: Administering injectable medicines is an invasive procedure with potential risks, including unintentional contamination of the content by glass particles during ampoule preparation by the healthcare team. Injection of medication contaminated with microscopic particles into patients can cause serious adverse effects depending on the route of administration and particle size. This study aimed to evaluate the relationship between nurse gender, work experience, ampoule breaking method, and ampoule volume with the number and size of probable glass particles after breaking ampoules. Methods: A total of 183 ampoules (2 ml, 5 ml, and 10 ml) were studied. Thirty male and female nurses participated, who were categorized into three groups based on work experience: 1–5 years, 5–10 years, and over 10 years. The size and number of glass particles were examined using a dynamic light scattering (DLS) system. The morphological characteristics of the particles were further studied using inverted microscopy. Results: On average, 53.49% of the particles in the solution of the broken ampoules were greater than 10 μm in size. Additionally, 17.65% showed a size greater than 25 μm. The particle size ranged from 14.39 μm to 184 μm. The average size of glass particles was 42.65 μm in the 2 ml ampoules, 32.13 μm in the 5 ml ampoules, and 42.72 μm in the 10 ml ampoules. Conclusion: Based on the findings, the percentage of glass particles entering the ampoule's solution upon breaking is not influenced by individual nurse characteristics. Instead, it depends on the ampoule volume, with smaller volumes associated with a higher proportion of particles larger than 10 μm and 25 μm. While the average particle size tends to decrease as nurses’ work experience increases, smaller ampoules generally contain larger particles. However, the methods used by nurses to break the ampoule do not significantly affect particle size. https://aacc.tums.ac.ir/index.php/aacc/article/view/1459