Determination of Propranolol Hydrochloride in Propranolol Tablets and Human Urine by Fluorescence Spectrometry Based on Surfactant Fluorescence Enhancement

Based on the intrinsic fluorescence characteristics of propranolol hydrochloride (PRH) and the fluorescence enhancement effect of cetyltrimethylammonium bromide (CTAB) on PRH, test conditions such as the acidity of phosphate buffer solution (PBS), CTAB concentration, reaction time, excitation wavelength, and emission wavelength were optimized, and the research mentioned by the title was conducted. After grinding, water ultrasonic dispersion, centrifugation, and dilution of propranolol tablets, an appropriate amount was taken, and 0.1 mol·L⁻¹ PBS (pH 5.8) and 10 μmol·L⁻¹ CTAB solution were added. The mixture was vortexed, and stored at room temperature for 2 min. The fluorescence intensity of the system was measured at an excitation wavelength of 290 nm and emission wavelength of 365 nm. Urine samples before and after taking propranolol tablets were incubated at 100 ℃, and an appropriate amount was taken for detection according to the steps of propranolol tablet solution. It was shown that linear relationship between values of the PRH concentration and system fluorescence intensity was kept in the range of 0.40-100 μmol·L⁻¹, with detection limit (3s/k) of 120 nmol·L⁻¹. Commonly coexisting substances in urine samples including Cl⁻, Na⁺, Mg²⁺, testosterone, Br⁻, K⁺, Cu²⁺, spironolactone, Zn²⁺, Ca²⁺, benzthiazide, and hydrochlorothiazide did not interfere with PRH. Test for the spiked recovery was made on propranolol tablets and actual urine samples at the 3 concentration levels, giving recoveries of PRH in the range of 95.0%-105%, and RSDs (n=5) of the determined values ranged from 0.48% to 2.8%. The proposed method was used for the analysis of urine samples taking propranolol tablets for different time. The concentration of PRH in the urine sample was high at 2 h, and PRH was almost undetectable not less than 12 h.