Sequential determination of hydrocortisone and epinephrine in pharmaceutical formulations via photochemically enhanced fluorescence

The study describes a simple and sensitive method for the sequential determination of hydrocortisone (HDC) and epinephrine (EP) in pharmaceutical formulations. The intrinsic fluorescence of epinephrine was measured before submitting the sample to a photochemical reaction to form a fluorescent product from HDC or HDC esters (succinate and acetate). The sample treatment eliminated the fluorescence from EP, thus minimizing spectral interference on the HDC fluorescence. Limits of detection (3S(b)/m) were estimated to be 40 ng mL(-1) for HDC or HDC salts and 0.2 ng mL(-1) for EP. Recovery experiments, made with commercial and laboratory simulated formulations, gave values between 96 and 103% for both HDC and EP. This method can be easily automated, e.g. via flow-injection techniques.