Determination of tigecycline from spiked human plasma and marketed formulation using scattering and fluorescence quenching methods with sustainability assessment

Tigecycline (TIG) is a minocycline derivative used as an antimicrobial and anticancer agent in the parenteral dosage form. The available analytical methods lack cost effectiveness or involve complex/lengthy sample preparation for the estimation of TIG. The current method requires the use of pH-4.5 acetate buffer; TIG forms an ion-associate complex with Eosin Y (EY) that results in the quenching of fluorescence with significant enhancement of Resonance Rayleigh Scattering (RRS), Frequency Doubling Scattering (FDS), and Second Order Scattering (SOS) fluorescence intensities. The maximum scattering wavelength, λex/λem, appears at 545/545 nm for RRS, 700/350 nm for SOS, and 251/502 nm for FDS, respectively. The optimum reaction conditions, the influencing factor, and the relation between the three scattering intensities and the concentration of TIG have been investigated. The methods exhibit high sensitivities; the detection limit for TIG was found to be 1.57 ng/mL (FQ), 0.347 ng/mL (RRS),0.162 ng/mL (FDS), and 0.322 ng/mL(SOS) method. The FDS method was the most sensitive amongst all newly developed methods. All the developed methods were validated as per the ICH Q2 (R1) guidelines and used to determine TIG in lyophilized powder and spiked human plasma.