DEGRADATION RATE OF FLUTICASONE PROPIONATE IN AN ALKALINE SOLUTION OF 0.1N NaOH : METHANOL = 1 : 1

Abstract

Fluticasone propionate (FLT)contains an ester group in its chemical structure. We herein investigated its stability in acidic and alkaline solutions with methanol. Each aqueous solution, which contained0.1N HCl, buffer solutions at pH 2, 4, 6 and 8, and 0.1N NaOH, with an equivalent volume of methanol, was mixed and used in stability studies at 37°C. The residual percentage of 0.1N NaOH : methanol = 1:1 at 37°Cfor 24 h was 1.73%. The degradation of FLT was observed. However, FLT was not degraded in solutions containing0.1N HCl, and buffer solutions at pH 2, 4, 6, and 8 at 37°C for 24 h. The degradation of FLT in 0.1N NaOH: methanol=1:1at 37°C was an apparent first order reaction with a rate constant of0.169± 0.003 (mean ± SD, n=3) h-1. Four degradation products were detected on a HPLC chart. The chart pattern obtained indicated that two peaks with shorter retention times of 3.7 and 4.4 min were the end products, while other peaks with later retention times of 4.6 and 5.8 min when that of FLT was 6.8 min were intermediate degradation products.