Derivatization-free CTAB-induced fluorescence sensing strategy for determination of daptomycin in environmental, pharmaceutical, and biological samples

Abstract

A simple, economical, green, and sensitive spectrofluorimetric method was developed for the determination of the cyclic lipopeptide antibiotic daptomycin (DPT). The method is based on the sensitizing effect of the cationic surfactant cetyltrimethylammonium bromide (CTAB) on the weak fluorescent signal of DPT. After excitation at 373 nm, DPT-CTAB fluoresces at a maximum intensity of 458 nm. Under the optimized conditions, the method exhibits linearity over the concentration range of 0.50–10.0 μg/mL with a detection limit down to 0.11 μg/mL. The study revealed excellent selectivity towards DPT in the presence of the co-administered drugs. The proposed method was able to determine DPT in its commercial vials, and the results were comparable to those obtained by the reported method. The high sensitivity of the developed method allowed its estimation in water and biological fluids (spiked plasma and urine samples) with high % recoveries (95.89–105.99%). DPT was successfully determined in rat plasma after intra-peritoneal administration, and the method was applied for the calculation of its pharmacokinetic parameters (Cmax, t1/2, tmax, and AUC) in rat plasma. Comparison with the reported methods reveals many benefits of the proposed spectrofluorimetric method, such as greenness, simplicity, sensitivity, and reliability. Finally, different recent assessment tools confirmed the greenness and whiteness of the proposed method.