Microbiological and Physical Stability of Extemporaneous Oral Suspensions Compounded with SyrSpend® SF PH4

Extemporaneous oral suspensions are essential for patients who require flexible dosing or cannot swallow solid dosage forms, such as pediatric, geriatric, or immunocompromised patients. SyrSpend® SF PH4 is a preservative-free, sugar-free, and dye-free suspending vehicle designed to ensure both physical, chemical and microbiological stability in compounded formulations. This study evaluates the microbiological and physical stability of oral suspensions compounded with SyrSpend® SF PH4, containing a range of active pharmaceutical ingredients (APIs) including propranolol, domperidone, ondansetron, dexamethasone, tacrolimus, allopurinol, clopidogrel, and folic acid. The chemical stability had been assessed in a previous study, in the same laboratory. Formulations were assessed over 90 days under room temperature and refrigerated conditions. Physical parameters such as appearance and pH remained stable throughout the study period. Antimicrobial effectiveness testing (AET), conducted according to United States Pharmacopoeia guidelines, demonstrated rapid and sustained microbial reduction across all tested organisms (C. albicans, A. brasiliensis, E. coli, P. aeruginosa, and S. aureus), with counts reduced to below detectable limits by day 14 and maintained through day 28. These findings confirm the intrinsic preservative properties of SyrSpend® SF PH4 and support its use as a safe and effective vehicle for extemporaneous compounding, particularly when intended for vulnerable populations.