Physicochemical and microbiological stability studies of extemporaneous antihypertensive pediatric suspensions for hospital use.

Extemporaneous suspensions of the antihypertensive agents furosemide, spironolactone and hydrochlorothiazide for pediatric use have been prepared at University Hospital (Federal University of Santa Catarina - Brazil). The aim of this work was to investigate the physicochemical and microbiological stability of these suspensions over the estimated shelf-life period of seven days and, if necessary, to optimize the formulations by improving the chemical stability. The pediatric suspensions were prepared using drug raw material and were stored at 25 ± 2°C and 5 ± 3°C. Chemical stability was evaluated by HPLC assay of the suspensions for drug content. Physical stability was evaluated by sedimentation volume, redispersibility, particle size, and zeta potential. Viable bacterial and fungal contaminations were assessed according to the official compendium. Furosemide and spironolactone suspensions as prepared herein can be stored for 7 days. However, the hydrochlorothiazide suspension formulation at pH 6.5 demonstrated poor chemical stability and was optimized by adjusting the pH to 3.3 where the drug exhibited acceptable stability. The optimized formulation demonstrated to be stable over the required period of 7 days.