Stability of Spironolactone in an Extemporaneously Prepared Suspension at Two Temperatures

Abstract

OBJECTIVE:

To determine the stability of spironolactone in an extemporaneously prepared suspension at 22 and 4°C over a three-month storage period.

DESIGN:

Spironolactone suspension (1 mg/mL) was prepared in syrup NF, carboxymethylcellulose, and purified water USP. The suspension was stored in ten amber glass prescription bottles; five were stored at 22°C and five at 4°C. Samples were drawn from each bottle and analyzed in duplicate (n=10) on days 0, 7, 14, 28, 42, 56, 70, and 91. Spironolactone concentrations were measured by a reproducible and stability-indicating HPLC method. Inspection of visual and pH changes also was performed on each study day.

RESULTS:

The mean concentration of spironolactone was always higher than 98 percent of its initial concentration. The pH and appearance of the suspension did not change substantially.

CONCLUSIONS:

Spironolactone was stable in a suspension containing syrup, carboxymethylcellulose, and purified water for three months during storage in amber glass bottles at both 22 and 4°C.