Validated spectrofluorimetric assay of two co-administered drug mixtures containing hydroxychloroquine with either moxifloxacin or ofloxacin as a drug regimen for hospital-acquired pneumonia in covid-19 patients.

Moxifloxacin and ofloxacin are two broad-spectrum quinolone antibiotics. They are among the most widely used antibiotics nowadays in controlling the covid-19 pandemic. Hydroxychloroquine is an FDA-approved drug for the treatment of covid-19. This work describes a simple, green, selective, and sensitive spectrofluorimetric method for the assay of moxifloxacin and ofloxacin in presence of hydroxychloroquine as two co-administered mixtures used in the treatment of hospital-acquired pneumonia in the covid-19 patients. Simultaneous assay of hydroxychloroquine and moxifloxacin was carried out in methanol by direct spectrofluorimetric method (method I) at 375 nm and 550 nm respectively after excitation at 300 nm. The direct spectrofluorimetric assay was rectilinear over concentration range of (50.0-400.0) and (300.0-2500.0) ng/ml for hydroxychloroquine and moxifloxacin with LOD of 6.4 and 33.64 ng/ml and LOQ of 19.4 and 102.6 ng/ml for the two drugs respectively. While the assay of hydroxychloroquine and ofloxacin was carried out by measuring the first derivative synchronous amplitude for hydroxychloroquine at the zero crossing point of ofloxacin and vice versa at Δ λ = 140 nm (method II). Hydroxychloroquine was measured at 266 nm while ofloxacin at 340 nm over concentration range of (4.0-40.0 ng/ml) for hydroxychloroquine and (200.0-2000.0 ng/ml) for ofloxacin with LOD of 0.467 ng/ml and 25.3 ng/ml and LOQ of 1.42 ng/ml and 76.6 ng/ml for the two drugs respectively. the two methods were validated following ICH guidelines and were applied to the analysis of the two drugs in plasma with good percent recoveries (109.73-93.17 %).