Stability Assessment of Furosemide Oral Suspension in Hospital Extemporaneous Preparations

Background: Furosemide is a loop diuretic used extensively to treat adult and pediatric patients. In some hospitals, furosemide oral liquids are not available in stock, thus necessitating the extemporaneous preparation of the drug. This study evaluates the stability of on-the-spot formulations of furosemide oral suspensions from crushed tablets evaluated in various vehicles: Dextrose 50%, Dextrose 70%, Ora-Sweet, and Ora-Plus over 60 days. This examination was prompted by the frequent shortage of certain excipients in the hospital, leading to the need to switch to Dextrose 50% or Dextrose 70% when Ora-Sweet and Ora-Plus are out of stock. Methods: The extemporaneous furosemide oral suspensions were prepared following the same compounding method used in the pharmacy. The suspensions were maintained at 4 °C in the refrigerator and assessed immediately and later, on days 7, 14, 30, and 60. The assessed parameters included visual appearance, redispersion time, sedimentation volume, and pH levels for stability analysis. We also examined the drug content, dissolution of the suspension, and microbiological stability. Results: Initial examinations indicated that Dextrose 50% and Ora-Plus maintained pH levels and stable appearances, while significant changes, mainly in appearance and redispersion time, indicated the instability of Dextrose 70%. Ora-Sweet showed fluctuations but stabilized by day 30. Dissolution studies demonstrated that Ora-Plus had dissolution characteristics superior to the other formulations, while Dextrose 50% showed declining dissolution percentages over time. Overall, the Ora-Plus vehicle showed superior stability (60 days), followed by Ora-Sweet (30 days), while Dextrose 70% and Dextrose 50% showed shorter stability durations of 14 and 7 days, respectively. The microbiological test results showed no microbial growth. Conclusion: This study demonstrates that the vehicle used in extemporaneous furosemide suspensions critically affects their stability and performance. Ora-Plus emerged as the most suitable vehicle, maintaining physical, chemical, and microbiological stability over 60 days, with consistent pH, redispersion, and dissolution behavior. Ora-Sweet showed intermediate stability (30 days), while Dextrose 50% and 70% exhibited early instability—7 and 14 days, respectively—marked by sedimentation, poor redispersibility, and declining drug release. These findings underscore the importance of vehicle selection and regular stability monitoring in compounded formulations to ensure therapeutic reliability and patient safety.