Development, Optimization, and Stability Study of a Yataprasen Film-Forming Spray for Musculoskeletal Pain Management

Yataprasen (YTPS) remedy ethanolic spray, one of the National Thai Traditional Medicine Formulary, is extensively employed in Thai traditional healthcare to manage musculoskeletal pain and inflammation. Despite its widespread use, the quality and stability of the YTPS formulation, critical to its efficacy, safety, and patient adherence, have not been comprehensively studied. This research developed and optimized a film-forming spray (FFS) formulation of YTPS ethanolic extract and conducted a 6-month stability evaluation. The FFS shares similarities with gel formulations, particularly in its ability to form a cohesive, semi-solid film upon application, enhancing localized drug delivery and prolonged contact time. Key physicochemical properties, including density (0.8450-0.9086 g/cm³), pH (4.72-4.95), spray angle (55.58-60.10°), evaporation time (1.04-1.27 min), and theoretical film thickness (7.72-13.97 µm), were analyzed across varying storage conditions. Active components β-amyrin and stigmasterol demonstrated retention rates of 96.78% and 68.22%, respectively, under refrigerated conditions, with degradation rates accelerating at higher temperatures. Significant variations in density, spray angle, film thickness, and stigmasterol concentration were observed. Additionally, the RP-HPLC method was validated for the accurate and precise quantification of the bioactive compounds such as β-amyrin and stigmasterol, demonstrating excellent linearity within a 10-100 µg/mL range for both compounds with excellent linearity R² > 0.999. The results confirmed that YTPS-FFS exhibits good stability and that the validated HPLC method is reliable for routine quality control. These findings supported the potential of YTPS-FFS formulation as a standardized and effective dosage form for managing musculoskeletal conditions, advancing its role in modernized traditional medicine.