3PC-038 Compounding and physicochemical stability study of dexamethasone mouthwash 0.1 mg/ml to prevent stomatitis associated with everolimus

<h3>Background and Importance</h3> Stomatitis is the inflammation of the oral mucosa, which usually manifests itself with swelling and ulcerous and painful lesions. It is a common adverse effect secondary to antineoplastic treatments, including everolimus. Due to its anti-inflammatory properties, Dexamethasone mouthwash is often used to alleviate these symptoms. However, there is no commercially available dexamethasone mouthwash in Spain. <h3>Aim and Objectives</h3> To determine the physicochemical stability of a compounded dexamethasone 0.1mg/ml mouthwash formula. <h3>Material and Methods</h3> A bibliographic search of different formulations was conducted to identify suitable formulations, and pharmacotechnical forms were consulted. Technical data sheets of raw materials were reviewed to ensure compatibility. The composition of the developed formulation is shown in table 1. Seven batches of two amber glass containers were prepared and stored refrigerated at 5°C. Appearance, organoleptic properties and precipitation were evaluated by visual inspection. Mass uniformity test was assessed in accordance with Ph. Eur. 2.9.27 test for multidose liquid preparations. Chemical stability of the formulations stored at 5 <b>± </b><b>0.1</b> °C was determined by UHPLC (Ultra-High Performance Liquid Chromatography) in an Acquity UPLC H-Class System chromatograph (Waters, Corporation Milford, MA). Dexamethasone content was assessed in duplicate at times 0, 7, 14, 28, and 60 days for closed containers and under normal use conditions. Results were expressed as a percentage of the remaining declared value (%DV). In addition, the pH of the formulations was determined throughout the stability study using a Crison GLP 21 pH Metre. <h3>Results</h3> No significant changes in organoleptic characteristics (colourless, odourless, sweet taste, light viscous consistency, and particles in suspension) were observed. The developed formulation met with the mass uniformity test (Ph. Eur. 2.9.27). The stability period established at 5°C for formulations under normal conditions was 28 days (103.09 <b>±</b> 1.2 %DV) and 60 days for closed containers (96,4 ± 0,7% DV). <h3>Conclusion and Relevance</h3> This study demonstrates the physicochemical stability of the compounded dexamethasone 0.1 mg/ml mouthwash for 28 days under normal use conditions and 60 days in closed containers at 5°C. Further studies, including microbiological stability testing, are underway to ensure long-term safety and efficacy. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest