HPTLC method for direct determination of gemifloxacin mesylate in human plasma

•We design innovative HPTLC method for determination of gemifloxacin mesylate in plasma without prior pretreatment for the first time.•This method provides high recovery with no any interference from the matrix and without pre-manipulation.•It has a great value when it is applied in the pharmacokinetic and bioavailability studies of gemifloxacin mesylate.•The method is suggested as approach for determination of other moderately polar and non-polar drugs in plasma.

Novel, simple and sensitive high performance thin-layer chromatography (HPTLC) with fluorescence detection has been successfully developed and validated for determination of gemifloxacin mesylate (GFX) in plasma samples without prior pretreatment. Montelukast (MK) was used as internal standard. GFX and MK in plasma samples were separated using a mobile phase consisting of a mixture of ethyl acetate:methanol:25% ammonia, (8:4.5:3, v/v/v). The emission intensity was measured using optical filter K400 after excitation at 342 nm. The Rf values for GFX and MK were 0.45 ± 0.03 and 0.79 ± 0.02, respectively. Under the optimum conditions, a linear relationship with good correlation coefficient (r = 0.9965, n = 6) was obtained in concentration range of 3–180 ng/band. The LOD and LOQ of the proposed method were 0.45 and 1.5 ng/band, respectively. The accuracy of the method was proved as the recovery % of GFX from spiked human plasma was 94.21–101.85%. The efficiency of the proposed method was confirmed by in-vivo application on human plasma in real patient samples. Moreover, the stability of GFX in plasma was carefully tested at different conditions and compared to others in aqueous solution.