Use of 7-fluoro-4-nitrobenzo-2-oxo-1,3-diazole (NBD-F) for the determination of ramipril in tablets and spiked human plasma.

Ramipril, as a secondary amine compound, reacts with 7-fluoro-4-nitrobenzo-2-oxo-1,3-diazole (NBD-F) producing the corresponding fluorescent NBD-ramipril. According to this fact, spectrophotometric and fluorimetric methods for the determination of ramipril were developed. The effect of these parameters on the reaction product were carefully studied to optimize reaction conditions. The relationship between the absorbance at 465 nm and the concentration was found to be linear over the range 1-10 microg/ml. Moreover, the fluorescence intensity was also found to be directly proportional at the concentration over the range of 20-100 ng/ml at 530 nm after excitation at 465 nm. The proposed procedure was successfully applied to the determination of ramipril in both tablet dosage form and in plasma. Spectrophotometric determination of ramipril tablets yielded a percentage recovery of 98.66+/-0.38, while the percentage recovery of spectrofluorimetric determination of ramipril in spiked human plasma was 99.08+/-1.11%. The results obtained are in good agreement with those obtained by the reference method. No interference could be observed from the co-administered drug (hydrochlorothiazines).