목적: Glucocorticoids are the first-line therapy for idiopathic sudden sensorineural hearing loss (I-SSNHL), with intratympanic (IT) steroid injection used as immediate or salvage after initial treatment fails or after 2 weeks of symptom onset. However, effective drug delivery to the inner ear remains a significant challenge, leading to recent efforts to explore new drug delivery technologies. Dexamethasone palmitate (DP), a dexamethasone prodrug, is encapsulated in solid lipid nanoparticles composed of palmitic acid. Due to its hydrophobic properties, which differ from the hydrophilic nature of conventionally used dexamethasone sodium phosphate (DSP), DP’s lipid nanoparticles are expected to enhance drug delivery efficacy when administered intratympanically. To evaluate whether the chemical properties of these drugs are reflected in clinical practice, DSP and DP were injected into patients with I-SSNHL to compare the degree of hearing recovery. 방법: Patients aged 19 years or older who consented to participate in the study were included. Patients diagnosed with I-SSNHL and admitted to the hospital, who received oral methylprednisolone, also underwent simultaneous IT steroid injection. Patients were divided into two groups: those who received IT DSP and those who received IT DP. Pure- tone audiometry was evaluated serially, and the results were classified using the modified Siegel’s criteria. The hearing recovery group was defined as patients who achieved the complete recovery or partial recovery, while the non-recovery group included patients who had slight improvement or no improvement. Patients classified as non- serviceable ear according to the modified Siegel’s criteria were excluded from the analysis. 결과: 30 patients received IT DSP, and 15 patients received IT DP. There were no differences in age, gender, past medical history, BMI or impaired site between the two groups. In the laboratory findings, the percentage of neutrophils was higher in the IT DP group, and the percentage of lymphocytes was higher in the IT DSP group. The initial grade of the hearing impairment according to the modified Siegel’s criteria was more severe in the IT DP group, although the difference was not statistically significant. During the follow-up period, hearing recovery was higher in the IT DP group compared to the IT DSP group, with a p-value of 0.004 at 2 months of follow-up. 결론: In I-SSNHL, IT steroid injection is a relatively commonly used treatment method, and various reports have been published regarding its efficacy. According to this study, patients treated with DP, a dexamethasone binding with lipid nanoparticles, showed better hearing recovery outcomes, which may be attributed to differences in pharmacokinetic properties. Further large-scale clinical studies, as well as cellular and organ- level research, are needed to investigate the drug’s mode of action, evaluate its delivery process, and optimize the drug delivery into the inner ear.